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  • 301. Russo, Jorge G.
    et al.
    Widén, Erik
    Stockholm University, Nordic Institute for Theoretical Physics (Nordita). Uppsala University, Sweden.
    Zarembo, Konstantin
    Stockholm University, Nordic Institute for Theoretical Physics (Nordita). Uppsala University, Sweden.
    N=2 phase transitions and holography2019In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, no 2, article id 196Article in journal (Refereed)
    Abstract [en]

    We clarify the relationship between probe analysis of the supergravity dual and the large-N solution of the localization matrix model for the planar N=2 super-Yang-Mills theory. A formalism inspired by supergravity allows us to systematically solve the matrix model at strong coupling. Quite surprisingly, we find that quantum phase transitions, known to occur in the N=2 theory, start to be visible at the third order of the strong-coupling expansion and thus constitute a perturbative phenomenon on the string worldsheet.

  • 302. Russo, Jorge G.
    et al.
    Zarembo, Konstantin
    Stockholm University, Nordic Institute for Theoretical Physics (Nordita). Uppsala University.
    Evidence for large-N phase transitions in N=2*theory2013In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, no 4, p. 065-Article in journal (Refereed)
    Abstract [en]

    We solve, using localization, for the large-N master field of N = 2* super-Yang-Mills theory. From that we calculate expectation values of large Wilson loops and the free energy on the four-sphere. At weak coupling, these observables only receive non-perturbative contributions. The analytic solution holds for a finite range of the 't Hooft coupling and terminates at the point of a large-N phase transition. We find evidence that as the coupling is further increased the theory undergoes an infinite sequence of similar transitions that accumulate at infinity.

  • 303. Schomerus, Volker
    et al.
    Sobko, Evgeny
    Stockholm University, Nordic Institute for Theoretical Physics (Nordita).
    From spinning conformal blocks to matrix Calogero-Sutherland models2018In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, no 4, article id 052Article in journal (Refereed)
    Abstract [en]

    In this paper we develop further the relation between conformal four-point blocks involving external spinning fields and Calogero-Sutherland quantum mechanics with matrix-valued potentials. To this end, the analysis of [1] is extended to arbitrary dimensions and to the case of boundary two-point functions. In particular, we construct the potential for any set of external tensor fields. Some of the resulting Schrodinger equations are mapped explicitly to the known Casimir equations for 4-dimensional seed conformal blocks. Our approach furnishes solutions of Casimir equations for external fields of arbitrary spin and dimension in terms of functions on the conformal group. This allows us to reinterpret standard operations on conformal blocks in terms of group-theoretic objects. In particular, we shall discuss the relation between the construction of spinning blocks in any dimension through differential operators acting on seed blocks and the action of left/right invariant vector fields on the conformal group.

  • 304. Schornerus, Volker
    et al.
    Sobko, Evgeny
    Stockholm University, Nordic Institute for Theoretical Physics (Nordita).
    Isachenkov, Mikhail
    Harmony of spinning conformal blocks2017In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, no 3, article id 085Article in journal (Refereed)
    Abstract [en]

    Conformal blocks for correlation functions of tensor operators play an increasingly important role for the conformal bootstrap programme. We develop a universal approach to such spinning blocks through the harmonic analysis of certain bundles over a coset of the conformal group. The resulting Casimir equations are given by a matrix version of the Calogero-Sutherland Hamiltonian that describes the scattering of interacting spinning particles in a 1-dimensional external potential. The approach is illustrated in several examples including fermionic seed blocks in 3D CFT where they take a very simple form.

  • 305.
    Sjörs, Stefan
    et al.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Mörtsell, Edvard
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Spherically symmetric solutions in massive gravity and constraints from galaxies2013In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, no 2, p. 080-Article in journal (Refereed)
    Abstract [en]

    In this paper, analytical solutions describing static and spherically symmetric sources in the decoupling limit of massive gravity are derived. We analyze the model parameter range and specify when a Vainshtein mechanism is possible. Furthermore, we use gravitational lensing and velocity dispersion data from galaxies to put constraints on the mass scale of the graviton. The result for the inverse graviton mass scale lambda(g) = h/(cm(g)), in units of the Hubble radius r(H) = c/H-0, is of the order lambda(g)/r(H) greater than or similar to 0.01 - 0.02 at 95% confidence level.

  • 306.
    Stål, Oscar
    et al.
    Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC). Stockholm University, Faculty of Science, Department of Physics.
    Weiglein, G.
    Zeune, L.
    Improved prediction for the mass of the W boson in the NMSSM2015In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, no 9, article id 158Article in journal (Refereed)
    Abstract [en]

    Electroweak precision observables, being highly sensitive to loop contributions of new physics, provide a powerful tool to test the theory and to discriminate between different models of the underlying physics. In that context, the W boson mass, M-W, plays a crucial role. The accuracy of the M-W measurement has been significantly improved over the last years, and further improvement of the experimental accuracy is expected from future LHC measurements. In order to fully exploit the precise experimental determination, an accurate theoretical prediction for M-W in the Standard Model (SM) and extensions of it is of central importance. We present the currently most accurate prediction for the W boson mass in the Next-to-Minimal Supersymmetric extension of the Standard Model (NMSSM), including the full one-loop result and all available higher-order corrections of SM and SUSY type. The evaluation of M-W is performed in a flexible framework, which facilitates the extension to other models beyond the SM. We show numerical results for the W boson mass in the NMSSM, focussing on phenomenologically interesting scenarios, in which the Higgs signal can be interpreted as the lightest or second lightest CP-even Higgs boson of the NMSSM. We find that, for both Higgs signal interpretations, the NMSSM M-W prediction is well compatible with the measurement. We study the SUSY contributions to M-W in detail and investigate in particular the genuine NMSSM effects from the Higgs and neutralino sectors.

  • 307.
    Widén, Erik
    Stockholm University, Nordic Institute for Theoretical Physics (Nordita). Uppsala University, Sweden.
    One-point functions in beta-deformed N=4 SYM with defect2018In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, no 11, article id 114Article in journal (Refereed)
    Abstract [en]

    We generalize earlier results on one-point functions in N = 4 SYM with a codimension one defect, dual to the D3-D5-brane setup in type IIB string theory on AdS(5)xS(5), to a similar setup in the beta-deformed version of the theory. The treelevel vacuum expectation values of single-trace operators in the two-scalar-subsector are expressed as overlaps between a matrix product state (MPS) and Bethe states in the corresponding twisted spin-chain picture. We comment on the properties of this MPS and present the simplest analytical overlaps and their behavior in a certain limit (of large k). Importantly, we note that the deformation alters earlier interpretations of the MPS as an integrable boundary state, seemingly obstructing simpli fi cations of the overlaps analogous to the compact determinant formula found in the non-deformed theory. The results are supplemented with some supporting numerical results for operators of length eight with four excitations.

  • 308.
    Young, Donovan
    Stockholm University, Nordic Institute for Theoretical Physics (Nordita).
    Form factors of chiral primary operators at two loops in ABJ(M)2013In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, no 6, p. 049-Article in journal (Refereed)
    Abstract [en]

    We calculate the colour-ordered form factor for chiral primary operators built from J scalar fields of ABJ(M) theory to J scalar final states. We work in the 't Hooft limit and show that the leading quantum correction is O(lambda(2)), where lambda is the 't Hooft coupling. We evaluate this leading correction using standard Feynman diagrams and dimensional regularization, and find that the leading divergence is 1/epsilon(2) where the spacetime dimension is d = 3 - 2 epsilon. We further find that the result respects maximal transcendentality.

  • 309. Young, Donovan
    et al.
    Zarembo, Konstantin
    Stockholm University, Nordic Institute for Theoretical Physics (Nordita). Uppsala University, Sweden; IETP, Moscow, Russia.
    Holographic dual of the Eguchi-Kawai mechanism2014In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, no 6, p. 030-Article in journal (Refereed)
    Abstract [en]

    The holographic dual of N = 2*, D = 4 supersymmetric Yang-Mills theory has many features common to 5d CFT. We interpret this as a manifestation of Eguchi-Kawai mechanism.

  • 310.
    Åsman, Barbro
    et al.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Bendtz, Katarina
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Bohm, Christian
    Stockholm University, Faculty of Science, Department of Physics.
    Clément, Christophe
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Eriksson, Daniel
    Stockholm University, Faculty of Science, Department of Physics.
    Gellerstedt, Karl
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Hellman, Sten
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Holmgren, Sven-Olof
    Stockholm University, Faculty of Science, Department of Physics.
    Johansen, M.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Johansson, K. E.
    Stockholm University, Faculty of Science, Department of Physics.
    Jon-And, Kerstin
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Khandanyan, Hovhannes
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Kim, Hyeon Jin
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Klimek, Pawel
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Lundberg, Johan
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Lundberg, Olle
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Milstead, David
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Moa, Torbjörn
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Ohm, Christian
    CERN, Geneva, Switzerland.
    Papadelis, Aras
    Stockholm University, Faculty of Science, Department of Physics.
    Sellden, Björn
    Stockholm University, Faculty of Science, Department of Physics.
    Silverstein, Samuel
    Stockholm University, Faculty of Science, Department of Physics.
    Sjölin, Jörgen
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Strandberg, Sara
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Tylmad, Maja
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Yang, Zhaoyu
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Search for third generation scalar leptoquarks in pp collisions at root s=7 TeV with the ATLAS detector2013In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, no 6, p. 033-Article in journal (Refereed)
    Abstract [en]

    A search for pair-produced third generation scalar leptoquarks is presented, using proton-proton collisions at root s = 7 TeV at the LHC. The data were recorded with the ATLAS detector and correspond to an integrated luminosity of 4.7 fb(-1). Each leptoquark is assumed to decay to a tau lepton and a b-quark with a branching fraction equal to 100%. No statistically significant excess above the Standard Model expectation is observed. Third generation leptoquarks are therefore excluded at 95% confidence level for masses less than 534 GeV.

  • 311.
    Åsman, Barbro
    et al.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Bendtz, Katarina
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Bohm, Christian
    Stockholm University, Faculty of Science, Department of Physics.
    Clément, Christophe
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Eriksson, Daniel
    Stockholm University, Faculty of Science, Department of Physics.
    Gellerstedt, Karl
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Hellman, Sten
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Holmgren, Sven-Olof
    Stockholm University, Faculty of Science, Department of Physics.
    Johansen, M.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Johansson, K. E.
    Stockholm University, Faculty of Science, Department of Physics.
    Jon-And, Kerstin
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Khandanyan, Hovhannes
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Kim, Hyeon Jin
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Klimek, Pawel
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Lundberg, Johan
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Lundberg, Olle
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Milstead, David
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Moa, Torbjörn
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Ohm, Christian
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC). CERN, Geneva, Switzerland.
    Papadelis, Aras
    Stockholm University, Faculty of Science, Department of Physics.
    Sellden, Björn
    Stockholm University, Faculty of Science, Department of Physics.
    Silverstein, Samuel
    Stockholm University, Faculty of Science, Department of Physics.
    Sjölin, Jörgen
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Strandberg, Sara
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Yang, Zhaoyu
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Measurement of ZZ production in pp collisions at root s=7 TeV and limits on anomalous ZZZ and ZZ gamma couplings with the ATLAS detector2013In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, no 3, p. 128-Article in journal (Refereed)
    Abstract [en]

    A measurement of the ZZ production cross section in proton-proton collisions at root s = 7 TeV using data recorded by the ATLAS experiment at the Large Hadron Collider is presented. In a data sample corresponding to an integrated luminosity of 4.6 fb(-1) collected in 2011, events are selected that are consistent either with two Z bosons decaying to electrons or muons or with one Z boson decaying to electrons or muons and a second Z boson decaying to neutrinos. The ZZ((*)) -> l(+)l(-)l'(+)l'(-) and ZZ -> l(+)l(-) nu(nu) over bar cross sections are measured in restricted phase-space regions. These results are then used to derive the total cross section for ZZ events produced with both Z bosons in the mass range 66 to 116 GeV, sigma(tot)(ZZ) = 6.7 +/- 0.7 (stat.) (+0.4)(-0.3) (syst.) +/- 0.3 (lumi.) pb, which is consistent with the Standard Model prediction of 5.89(-0.18)(+0.22) pb calculated at next-to-leading order in QCD. The normalized differential cross sections in bins of various kinematic variables are presented. Finally, the differential event yield as a function of the transverse momentum of the leading Z boson is used to set limits on anomalous neutral triple gauge boson couplings in ZZ production.

  • 312.
    Åsman, Barbro
    et al.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Bendtz, Katarina
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Bohm, Christian
    Stockholm University, Faculty of Science, Department of Physics.
    Clément, Christophe
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Eriksson, Daniel
    Stockholm University, Faculty of Science, Department of Physics.
    Gellerstedt, Karl
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Hellman, Sten
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Holmgren, Sven-Olof
    Stockholm University, Faculty of Science, Department of Physics.
    Johansen, M.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Johansson, K. E.
    Stockholm University, Faculty of Science, Department of Physics.
    Jon-And, Kerstin
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Khandanyan, Hovhannes
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Kim, Hyeon Jin
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Klimek, Pawel
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Lundberg, Olle
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Milstead, David
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Moa, Torbjörn
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Ohm, Christian
    Cern.
    Papadelis, Aras
    Stockholm University, Faculty of Science, Department of Physics.
    Sellden, Björn
    Stockholm University, Faculty of Science, Department of Physics.
    Silverstein, Samuel
    Stockholm University, Faculty of Science, Department of Physics.
    Sjölin, Jörgen
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Strandberg, Sara
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Tylmad, Maja
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Yang, Zhaoyu
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Lundberg, Johan
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Measurements of the pseudorapidity dependence of the total transverse energy in proton-proton collisions at root s=7 TeV with ATLAS2012In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, no 11, p. 033-Article in journal (Refereed)
    Abstract [en]

    This paper describes measurements of the sum of the transverse energy of particles as a function of particle pseudorapidity, eta, in proton-proton collisions at a centre-of-mass energy, root s = 7 TeV using the ATLAS detector at the Large Hadron Collider. The measurements are performed in the region \eta\ < 4.8 for two event classes: those requiring the presence of particles with a low transverse momentum and those requiring particles with a significant transverse momentum. In the second dataset measurements are made in the region transverse to the hard scatter. The distributions are compared to the predictions of various Monte Carlo event generators, which generally tend to underestimate the amount of transverse energy at high \eta\.

  • 313.
    Åsman, Barbro
    et al.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Bendtz, Katarina
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Bohm, Christian
    Stockholm University, Faculty of Science, Department of Physics.
    Clément, Christophe
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Eriksson, Daniel
    Stockholm University, Faculty of Science, Department of Physics.
    Gellerstedt, Karl
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Hellman, Sten
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Holmgren, Sven-Olof
    Stockholm University, Faculty of Science, Department of Physics.
    Johansen, M.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Johansson, K. E.
    Stockholm University, Faculty of Science, Department of Physics.
    Jon-And, Kerstin
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Khandanyan, Hovhannes
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Kim, Hyeon
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Klimek, Pawel
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Lundberg, Johan
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Lundberg, Olle
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Milstead, David
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Moa, Torbjörn
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Ohm, Christian
    CERN, Geneva, Switzerland.
    Papadelis, Aras
    Stockholm University, Faculty of Science, Department of Physics.
    Sellden, Björn
    Stockholm University, Faculty of Science, Department of Physics.
    Silverstein, Samuel
    Stockholm University, Faculty of Science, Department of Physics.
    Sjölin, Jörgen
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Strandberg, Sara
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Tylmad, Maja
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Yang, Zhaoyu
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Search for charged Higgs bosons through the violation of lepton universality in t(t)over-bar events using pp collision data at root s=7 TeV with the ATLAS experiment2013In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, no 3, p. 076-Article in journal (Refereed)
    Abstract [en]

    In several extensions of the Standard Model, the top quark can decay into a bottom quark and a light charged Higgs boson H+, t -> bH(+), in addition to the Standard Model decay t -> bW. Since W bosons decay to the three lepton generations equally, while H+ may predominantly decay into tau nu, charged Higgs bosons can be searched for using the violation of lepton universality in top quark decays. The analysis in this paper is based on 4.6 fb(-1) of proton-proton collision data at root s = 7 TeV collected by the ATLAS experiment at the Large Hadron Collider. Signatures containing leptons (e or mu) and/or a hadronically decaying tau (tau(had)) are used. Event yield ratios between e+ tau(had) and e + mu, as well as between mu + tau(had) and mu + e, final states are measured in the data and compared to predictions from simulations. This ratio-based method reduces the impact of systematic uncertainties in the analysis. No significant deviation from the Standard Model predictions is observed. With the assumption that the branching fraction B(H+ -> tau nu) is 100%, upper limits in the range 3.2%-4.4% can be placed on the branching fraction B(t -> bH(+)) for charged Higgs boson masses m(H+) in the range 90-140GeV. After combination with results from a search for charged Higgs bosons in t (t) over bar decays using the tau(had) + jets final state, upper limits on B(t -> bH(+)) can be set in the range 0.8%-3.4%, for m(H+) in the range 90-160GeV.

  • 314.
    Åsman, Barbro
    et al.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Bendtz, Katarina
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Bohm, Christian
    Stockholm University, Faculty of Science, Department of Physics.
    Clément, Christophe
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Eriksson, Daniel
    Stockholm University, Faculty of Science, Department of Physics.
    Gellerstedt, Karl
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Hellman, Sten
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Holmgren, Sven-Olof
    Stockholm University, Faculty of Science, Department of Physics.
    Johansen, M.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Johansson, K. E.
    Stockholm University, Faculty of Science, Department of Physics.
    Jon-And, Kerstin
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Kim, Hyeon
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Klimek, Pawel
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Lundberg, Johan
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Lundberg, Olle
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Milstead, David
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Moa, Torbjörn
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Ohm, Christian
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Papadelis, Aras
    Stockholm University, Faculty of Science, Department of Physics.
    Sellden, Björn
    Stockholm University, Faculty of Science, Department of Physics.
    Silverstein, Samuel
    Stockholm University, Faculty of Science, Department of Physics.
    Sjölin, Jörgen
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Strandberg, Sara
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Tylmad, Maja
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Yang, Zhaoyu
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    A search for flavour changing neutral currents in top-quark decays in pp collision data collected with the ATLAS detector at root s=7 TeV2012In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, no 9, p. 139-Article in journal (Refereed)
    Abstract [en]

    A search for flavour changing neutral current (FCNC) processes in top-quark decays by the ATLAS Collaboration is presented. Data collected from pp collisions at the LHC at a centre-of-mass energy of root s = 7 TeV during 2011, corresponding to an integrated luminosity of 2.1 fb(-1), were used. A search was performed for top-quark pair-production events, with one top quark decaying through the t -> Zq FCNC (q = u, c) channel, and the other through the Standard Model dominant mode t -> Wb. Only the decays of the Z boson to charged leptons and leptonic W-boson decays were considered as signal. Consequently, the final-state topology is characterised by the presence of three isolated charged leptons, at least two jets and missing transverse momentum from the undetected neutrino. No evidence for an FCNC signal was found. An upper limit on the t -> Zq branching ratio of BR(t -> Zq) < 0.73% is set at the 95% confidence level.

  • 315.
    Åsman, Barbro
    et al.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Bendtz, Katarina
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Bohm, Christian
    Stockholm University, Faculty of Science, Department of Physics.
    Clément, Christophe
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Eriksson, Daniel
    Stockholm University, Faculty of Science, Department of Physics.
    Gellerstedt, Karl
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Hellman, Sten
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Holmgren, Sven-Olof
    Stockholm University, Faculty of Science, Department of Physics.
    Johansen, M.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Johansson, K. E.
    Stockholm University, Faculty of Science, Department of Physics.
    Jon-And, Kerstin
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Kim, Hyeon
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Klimek, Pawel
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Lundberg, Johan
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Milstead, David
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Moa, Torbjörn
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Ohm, Christian
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Papadelis, Aras
    Stockholm University, Faculty of Science, Department of Physics.
    Sellden, Björn
    Stockholm University, Faculty of Science, Department of Physics.
    Silverstein, Samuel
    Stockholm University, Faculty of Science, Department of Physics.
    Sjölin, Jörgen
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Strandberg, Sara
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Tylmad, Maja
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Yang, Zhaoyu
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Hunt for new phenomena using large jet multiplicities and missing transverse momentum with ATLAS in 4.7fb(-1) of root s=7 TeV proton-proton collisions2012In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, no 7, p. 167-Article in journal (Refereed)
    Abstract [en]

    Results are presented of a search for new particles decaying to large numbers of jets in association with missing transverse momentum, using 4.7 fb(-1) of pp collision data at root s = 7 TeV collected by the ATLAS experiment at the Large Hadron Collider in 2011. The event selection requires missing transverse momentum, no isolated electrons or muons, and from >= 6 to >= 9 jets. No evidence is found for physics beyond the Standard Model. The results are interpreted in the context of a MSUGRA/CMSSM supersymmetric model, where, for large universal scalar mass m(0), gluino masses smaller than 840 GeV are excluded at the 95% confidence level, extending previously published limits. Within a simplified model containing only a gluino octet and a neutralino, gluino masses smaller than 870 GeV are similarly excluded for neutralino masses below 100 GeV.

  • 316.
    Åsman, Barbro
    et al.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Bendtz, Katarina
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Bohm, Christian
    Stockholm University, Faculty of Science, Department of Physics.
    Clément, Christophe
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Eriksson, Daniel
    Stockholm University, Faculty of Science, Department of Physics.
    Gellerstedt, Karl
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Hellman, Sten
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Holmgren, Sven-Olof
    Stockholm University, Faculty of Science, Department of Physics.
    Johansen, M.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Johansson, K. E.
    Stockholm University, Faculty of Science, Department of Physics.
    Jon-And, Kerstin
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Kim, Hyeon
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Klimek, Pawel
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Lundberg, Johan
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Milstead, David
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Moa, Torbjörn
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Ohm, Christian
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Papadelis, Aras
    Stockholm University, Faculty of Science, Department of Physics.
    Sellden, Björn
    Stockholm University, Faculty of Science, Department of Physics.
    Silverstein, Samuel
    Stockholm University, Faculty of Science, Department of Physics.
    Sjölin, Jörgen
    Stockholm University, Faculty of Science, Department of Physics.
    Strandberg, Sara
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Tylmad, Maja
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Yang, Zhaoyu
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Search for charged Higgs bosons decaying via H-+/- -> tau nu in t(t)over-bar events using pp collision data at root s=7 TeV with the ATLAS detector2012In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, no 6, p. 039-Article in journal (Refereed)
    Abstract [en]

    The results of a search for charged Higgs bosons are presented. The analysis is based on 4.6 fb(-1) of proton-proton collision data at root s = 7TeV collected by the ATLAS experiment at the Large Hadron Collider, using top quark pair events with a tau lepton in the final state. The data are consistent with the expected background from Standard Model processes. Assuming that the branching ratio of the charged Higgs boson to a tau lepton and a neutrino is 100%, this leads to upper limits on the branching ratio of top quark decays to a b quark and a charged Higgs boson between 5% and 1% for charged Higgs boson masses ranging from 90GeV to 160GeV, respectively. In the context of the m(h)(max) scenario of the MSSM, tan beta above 12-26, as well as between 1 and 2-6, can be excluded for charged Higgs boson masses between 90GeV and 150GeV.

  • 317.
    Åsman, Barbro
    et al.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Bendtz, Katarina
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Bohm, Christian
    Stockholm University, Faculty of Science, Department of Physics.
    Clément, Christophe
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Eriksson, Daniel
    Stockholm University, Faculty of Science, Department of Physics.
    Gellerstedt, Karl
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Hellman, Sten
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Holmgren, Sven-Olof
    Stockholm University, Faculty of Science, Department of Physics.
    Johansen, M.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Johansson, K. E.
    Stockholm University, Faculty of Science, Department of Physics.
    Jon-And, Kerstin
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Kim, Hyeon
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Klimek, Pawel
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Lundberg, O.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Milstead, David
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Moa, Torbjörn
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Ohm, Christian
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Papadelis, Aras
    Stockholm University, Faculty of Science, Department of Physics.
    Sellden, Björn
    Stockholm University, Faculty of Science, Department of Physics.
    Silverstein, Samuel
    Stockholm University, Faculty of Science, Department of Physics.
    Sjölin, Jörgen
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Strandberg, Sara
    Stockholm University, Faculty of Science, Department of Physics.
    Tylmad, Maja
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Yang, Zhaoyu
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Measurement of the W boson polarization in top quark decays with the ATLAS detector2012In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, no 6, p. 088-Article in journal (Refereed)
    Abstract [en]

    This paper presents measurements of the polarization of W bosons in top quark decays, derived from t (t) over bar events with missing transverse momentum, one charged lepton and at least four jets, or two charged leptons and at least two jets. Data from pp collisions at a centre-of-mass energy of 7 TeV were collected with the ATLAS experiment at the LHC and correspond to an integrated luminosity of 1.04 fb(-1). The measured fractions of longitudinally, left-and right-handed polarization are F-0 = 0.67 +/- 0.07, F-L = 0.32 +/- 0.04 and F-R = 0.01 +/- 0.05, in agreement with the Standard Model predictions. As the polarization of the W bosons in top quark decays is sensitive to the Wtb vertex Lorentz structure and couplings, the measurements were used to set limits on anomalous contributions to the Wtb couplings.

  • 318.
    Åsman, Barbro
    et al.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Bendtz, Katarina
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Bohm, Christian
    Stockholm University, Faculty of Science, Department of Physics.
    Clément, Christophe
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Eriksson, Daniel
    Stockholm University, Faculty of Science, Department of Physics.
    Gellerstedt, Karl
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Hellman, Sten
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Holmgren, Sven-Olof
    Stockholm University, Faculty of Science, Department of Physics.
    Johansen, Marianne
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Johansson, K. E.
    Stockholm University, Faculty of Science, Department of Physics.
    Jon-And, Kerstin
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Khandanyan, Hovhannes
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Kim, Hyeon
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Klimek, Pawel
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Lundberg, Johan
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Lundberg, Olof
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Milstead, David A.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Moa, Torbjörn
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Ohm, Christian C.
    CERN.
    Papadelis, Aras
    Stockholm University, Faculty of Science, Department of Physics.
    Sellden, Björn
    Stockholm University, Faculty of Science, Department of Physics.
    Silverstein, Samuel B.
    Stockholm University, Faculty of Science, Department of Physics.
    Sjölin, Jörgen
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Strandberg, Sara
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Tylmad, Maja
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Yang, Zhaoyu
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    ATLAS search for new phenomena in dijet mass and angular distributions using pp collisions at root s=7 TeV2013In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, no 1, p. 029-Article in journal (Refereed)
    Abstract [en]

    Mass and angular distributions of dijets produced in LHC proton-proton collisions at a centre-of-mass energy root s = 7TeV have been studied with the ATLAS detector using the full 2011 data set with an integrated luminosity of 4.8 fb(-1). Dijet masses up to similar to 4.0TeV have been probed. No resonance-like features have been observed in the dijet mass spectrum, and all angular distributions are consistent with the predictions of QCD. Exclusion limits on six hypotheses of new phenomena have been set at 95% CL in terms of mass or energy scale, as appropriate. These hypotheses include excited quarks below 2.83 TeV, colour octet scalars below 1.86TeV, heavy W bosons below 1.68 TeV, string resonances below 3.61 TeV, quantum black holes with six extra space-time dimensions for quantum gravity scales below 4.11 TeV, and quark contact interactions below a compositeness scale of 7.6 TeV in a destructive interference scenario.

  • 319.
    Åsman, Barbro
    et al.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Bendtz, Katarina
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Bohm, Christian
    Stockholm University, Faculty of Science, Department of Physics.
    Clément, Christophe
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Eriksson, Daniel
    Stockholm University, Faculty of Science, Department of Physics.
    Gellerstedt, Karl
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Hellman, Sten
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Holmgren, Sven-Olof
    Stockholm University, Faculty of Science, Department of Physics.
    Johansen, Marianne
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Johansson, K. E.
    Stockholm University, Faculty of Science, Department of Physics.
    Jon-And, Kerstin
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Khandanyan, Hovhannes
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Kim, Hyeon
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Klimek, Pawel
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Lundberg, Johan
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Lundberg, Olof
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Milstead, David A.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Moa, Torbjörn
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Ohm, Christian C.
    CERN.
    Papadelis, Aras
    Stockholm University, Faculty of Science, Department of Physics.
    Sellden, Björn
    Stockholm University, Faculty of Science, Department of Physics.
    Silverstein, Samuel B.
    Stockholm University, Faculty of Science, Department of Physics.
    Sjölin, Jörgen
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Strandberg, Sara
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Tylmad, Maja
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Yang, Zhaoyu
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Measurement of isolated-photon pair production in pp collisions at root s=7 TeV with the ATLAS detector2013In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, no 1, p. 086-Article in journal (Refereed)
    Abstract [en]

    The ATLAS experiment at the LHC has measured the production cross section of events with two isolated photons in the final state, in proton-proton collisions at root s = 7 TeV. The full data set collected in 2011, corresponding to an integrated luminosity of 4.9 fb(-1), is used. The amount of background, from hadronic jets and isolated electrons, is estimated with data-driven techniques and subtracted. The total cross section, for two isolated photons with transverse energies above 25 GeV and 22 GeV respectively, in the acceptance of the electromagnetic calorimeter (vertical bar eta vertical bar < 1.37 and 1.52 < vertical bar eta vertical bar 2.37) and with an angular separation Delta R > 0.4, is 44.0(-4.2)(+3.2) pb. The differential cross sections as a function of the di-photon invariant mass, transverse momentum, azimuthal separation, and cosine of the polar angle of the largest transverse energy photon in the Collins-Soper di-photon rest frame are also measured. The results are compared to the prediction of leading-order parton-shower and next-to-leading-order and next-to-next-to-leading-order parton-level generators.

  • 320.
    Åsman, Barbro
    et al.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Bendtz, Katarina
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Bohm, Christian
    Stockholm University, Faculty of Science, Department of Physics.
    Clément, Christophe
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Eriksson, Daniel
    Stockholm University, Faculty of Science, Department of Physics.
    Gellerstedt, Karl
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Hellman, Sten
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Holmgren, Sven-Olof
    Stockholm University, Faculty of Science, Department of Physics.
    Johansen, Marianne
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Johansson, K. E.
    Stockholm University, Faculty of Science, Department of Physics.
    Jon-And, Kerstin
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Khandanyan, Hovhannes
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Kim, Hyeon
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Klimek, Pawel
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Lundberg, Johan
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Lundberg, Olof
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Milstead, David A.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Moa, Torbjörn
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Ohm, Christian C.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Papadelis, Aras
    Stockholm University, Faculty of Science, Department of Physics.
    Sellden, Björn
    Stockholm University, Faculty of Science, Department of Physics.
    Silverstein, Samuel B.
    Stockholm University, Faculty of Science, Department of Physics.
    Sjölin, Jörgen
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Strandberg, Sara
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Tylmad, Maja
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Yang, Zhaoyu
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Search for a heavy top-quark partner in final states with two leptons with the ATLAS detector at the LHC2012In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, no 11, article id 094Article in journal (Refereed)
    Abstract [en]

    The results of a search for direct pair production of heavy top-quark partners in 4.7 fb(-1) of integrated luminosity from p p collisions at root s = 7 TeV collected by the ATLAS detector at the LHC are reported. Heavy top-quark partners decaying into a top quark and a neutral non-interacting particle are searched for in events with two leptons in the final state. No excess above the Standard Model expectation is observed. Limits are placed on the mass of a supersymmetric scalar top and of a spin-1/2 top-quark partner. A spin-1/2 top-quark partner with a mass between 300 GeV and 480 GeV, decaying to a top quark and a neutral non-interacting particle lighter than 100 GeV, is excluded at 95% confidence level.

  • 321.
    Åsman, Barbro
    et al.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Bendtz, Katarina
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Bohm, Christian
    Stockholm University, Faculty of Science, Department of Physics.
    Clément, Christophe
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Eriksson, Daniel
    Stockholm University, Faculty of Science, Department of Physics.
    Gellerstedt, Karl
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Hellman, Sten
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Holmgren, Sven-Olof
    Stockholm University, Faculty of Science, Department of Physics.
    Johansen, Marianne
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Johansson, K. E.
    Stockholm University, Faculty of Science, Department of Physics.
    Jon-And, Kerstin
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Khandanyan, Hovhannes
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Kim, Hyeon
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Klimek, Pawel
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Lundberg, Johan
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Lundberg, Olof
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Milstead, David A.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Moa, Torbjörn
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Ohm, Christian C.
    CERN.
    Papadelis, Aras
    Stockholm University, Faculty of Science, Department of Physics.
    Sellden, Björn
    Stockholm University, Faculty of Science, Department of Physics.
    Silverstein, Samuel B.
    Stockholm University, Faculty of Science, Department of Physics.
    Sjölin, Jörgen
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Strandberg, Sara
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Tylmad, Maja
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Yang, Zhaoyu
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Search for direct chargino production in anomaly-mediated supersymmetry breaking models based on a disappearing-track signature in pp collisions at root s=7 TeV with the ATLAS detector2013In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, no 1, p. 131-Article in journal (Refereed)
    Abstract [en]

    A search for direct chargino production in anomaly-mediated supersymmetry breaking scenarios is performed in p p collisions at root s = 7 TeV using 4.7 fb(-1) of data collected with the ATLAS experiment at the LHC. In these models, the lightest chargino is predicted to have a lifetime long enough to be detected in the tracking detectors of collider experiments. This analysis explores such models by searching for chargino decays that result in tracks with few associated hits in the outer region of the tracking system. The transverse-momentum spectrum of candidate tracks is found to be consistent with the expectation from the Standard Model background processes and constraints on chargino properties are obtained.

  • 322.
    Åsman, Barbro
    et al.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Bendtz, Katarina
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Bohm, Christian
    Stockholm University, Faculty of Science, Department of Physics.
    Clément, Christophe
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Eriksson, Daniel
    Stockholm University, Faculty of Science, Department of Physics.
    Gellerstedt, Karl
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Hellman, Sten
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Holmgren, Sven-Olof
    Stockholm University, Faculty of Science, Department of Physics.
    Johansen, Marianne
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Johansson, K. E.
    Stockholm University, Faculty of Science, Department of Physics.
    Jon-And, Kerstin
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Khandanyan, Hovhannes
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Kim, Hyeon
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Klimek, Pawel
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Lundberg, Johan
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Lundberg, Olof
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Milstead, David A.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Moa, Torbjörn
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Ohm, Christian C.
    CERN.
    Papadelis, Aras
    Stockholm University, Faculty of Science, Department of Physics.
    Sellden, Björn
    Stockholm University, Faculty of Science, Department of Physics.
    Silverstein, Samuel B.
    Stockholm University, Faculty of Science, Department of Physics.
    Sjölin, Jörgen
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Strandberg, Sara
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Tylmad, Maja
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Yang, Zhaoyu
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Search for resonances decaying into top-quark pairs using fully hadronic decays in pp collisions with ATLAS at root s=7 TeV2013In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, no 1, p. 116-Article in journal (Refereed)
    Abstract [en]

    A search for resonances produced in 7 TeV proton-proton collisions and decaying into top-quark pairs is described. In this Letter events where the top-quark decay produces two massive jets with large transverse momenta recorded with the ATLAS detector at the Large Hadron Collider are considered. Two techniques that rely on jet substructure are used to separate top-quark jets from those arising from light quarks and gluons. In addition, each massive jet is required to have evidence of an associated bottom-quark decay. The data are consistent with the Standard Model, and limits can be set on the production cross section times branching fraction of a Z' boson and a Kaluza-Klein gluon resonance. These limits exclude, at the 95% credibility level, Z' bosons with masses 0.70-1.00 TeV as well as 1.28-1.32 TeV and Kaluza-Klein gluons with masses 0.70-1.62 TeV.

  • 323.
    Åsman, Barbro
    et al.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Bendtz, Katarina
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Bohm, Christian
    Stockholm University, Faculty of Science, Department of Physics.
    Clément, Christophe
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Eriksson, Daniel
    Stockholm University, Faculty of Science, Department of Physics.
    Gellerstedt, Karl
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Hellman, Sten
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Holmgren, Sven-Olof
    Stockholm University, Faculty of Science, Department of Physics.
    Johansen, Marianne
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Johansson, K. E.
    Stockholm University, Faculty of Science, Department of Physics.
    Jon-And, Kerstin
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Khandanyan, Hovhannes
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Kim, Hyeon
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Klimek, Pawel
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Lundberg, Johan
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Lundberg, Olof
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Milstead, David A.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Moa, Torbjörn
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Ohm, Christian C.
    CERN.
    Papadelis, Aras
    Stockholm University, Faculty of Science, Department of Physics.
    Sellden, Björn
    Stockholm University, Faculty of Science, Department of Physics.
    Silverstein, Samuel B.
    Stockholm University, Faculty of Science, Department of Physics.
    Sjölin, Jörgen
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Strandberg, Sara
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Tylmad, Maja
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Yang, Zhaoyu
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Search for the neutral Higgs bosons of the minimal supersymmetric standard model in pp collisions at root s=7 TeV with the ATLAS detector2013In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, no 2, p. 095-Article in journal (Refereed)
    Abstract [en]

    A search for neutral Higgs bosons of the Minimal Supersymmetric Standard Model (MSSM) is reported. The analysis is based on a sample of proton-proton collisions at a centre-of-mass energy of 7 TeV recorded with the ATLAS detector at the Large Hadron Collider. The data were recorded in 2011 and correspond to an integrated luminosity of 4.7 fb(-1) to 4.8 fb(-1). Higgs boson decays into oppositely-charged in muon or tau lepton pairs are considered for final states requiring either the presence or absence of b-jets. No statistically significant excess over the expected background is observed and exclusion limits at the 95% confidence level are derived. The exclusion limits are for the production cross-section of a generic neutral Higgs boson, phi, as a function of the Higgs boson mass and for h/A/H production in the MSSM as a function of the parameters m(A) and tan beta in the m(h)(max) scenario for m(A) in the range of 90 GeV to 500 GeV.

  • 324.
    Åsman, Barbro
    et al.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Bendtz, Katarina
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Bohm, Christian
    Stockholm University, Faculty of Science, Department of Physics.
    Clément, Christophe
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Eriksson, Daniel
    Stockholm University, Faculty of Science, Department of Physics.
    Gellerstedt, Karl
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Hellman, Sten
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Holmgren, Sven-Olof
    Stockholm University, Faculty of Science, Department of Physics.
    Johansen, Marianne
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Johansson, K. E.
    Stockholm University, Faculty of Science, Department of Physics.
    Jon-And, Kerstin
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Khandanyan, Hovhannes
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Kim, Hyeon
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Klimek, Pawel
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Lundberg, Johan
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Lundberg, Olof
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Milstead, David A.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Moa, Torbjörn
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Papadelis, Aras
    Stockholm University, Faculty of Science, Department of Physics.
    Sellden, Björn
    Stockholm University, Faculty of Science, Department of Physics.
    Silverstein, Samuel B.
    Stockholm University, Faculty of Science, Department of Physics.
    Sjölin, Jörgen
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Strandberg, Sara
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Tylmad, Maja
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Yang, Zhaoyu
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Search for high-mass resonances decaying to dilepton final states in pp collisions at root s=7 TeV with the ATLAS detector2012In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, no 11, p. 138-Article in journal (Refereed)
    Abstract [en]

    The ATLAS detector at the Large Hadron Collider is used to search for high-mass resonances decaying to an electron-positron pair or a muon-antimuon pair. The search is sensitive to heavy neutral Z' gauge bosons, Randall-Sundrum gravitons, Z* bosons, techni-mesons, Z/gamma bosons, and bosons predicted by Torsion models. Results are presented based on an analysis of pp collisions at a center-of-mass energy of 7 TeV corresponding to an integrated luminosity of 4.9 fb(-1) in the e(+)e(-) channel and 5.0 fb(-1) in the mu(+)mu(-) channel. A Z' boson with Standard Model-like couplings is excluded at 95% confidence level for masses below 2.22 TeV. A Randall-Sundrum graviton with coupling k root M-P1 = 0.1 is excluded at 95% confidence level for masses below 2.16 Tev. Limits on the other models are also presented, including Technicolor and Minimal Z' Models.

  • 325.
    Åsman, Barbro
    et al.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Bendtz, Katarina
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Bohm, Christian
    Stockholm University, Faculty of Science, Department of Physics.
    Clément, Christophe
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Eriksson, Daniel
    Stockholm University, Faculty of Science, Department of Physics.
    Gellerstedt, Karl
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Hellman, Sten
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Holmgren, Sven-Olof
    Stockholm University, Faculty of Science, Department of Physics.
    Johansen, Marianne
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Johansson, K. Erik
    Stockholm University, Faculty of Science, Department of Physics.
    Jon-And, Kerstin
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Khandanyan, Hovhannes
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Kim, Hyeon
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Klimek, Pawel
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Lundberg, Johan
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Lundberg, Olof
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Milstead, David A.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Moa, Torbjörn
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Ohm, Christian C.
    CERN.
    Papadelis, Aras
    Stockholm University, Faculty of Science, Department of Physics.
    Plucinski, Pawel
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Sellden, Björn
    Stockholm University, Faculty of Science, Department of Physics.
    Silverstein, Samuel B.
    Stockholm University, Faculty of Science, Department of Physics.
    Sjölin, Jörgen
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Strandberg, Sara
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Tylmad, Maja
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Yang, Zhaoyu
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Measurement of the cross-section for W boson production in association with b-jets in pp collisions at root s=7 TeV with the ATLAS detector2013In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, no 6, p. 084-Article in journal (Refereed)
    Abstract [en]

    This paper reports a measurement of the W+b-jets (W+b+X and W+b (b) over bar +X) production cross-section in proton-proton collisions at a centre-of-mass energy of 7 TeV at the LHC. These results are based on data corresponding to an integrated luminosity of 4.6 fb(-1), collected with the ATLAS detector. Cross-sections are presented as a function of jet multiplicity and of the transverse momentum of the leading b-jet for both the muon and electron decay modes of the W boson. The W+b-jets cross-section, corrected for all known detector effects, is quoted in a limited kinematic range. Combining the muon and electron channels, the fiducial cross-section for W+b-jets is measured to be 7.1 +/- 0.5 (stat) +/- 1.4 (syst) pb, consistent with the next-to-leading order QCD prediction, corrected for non-perturbative and double-parton interactions (DPI) contributions, of 4.70 +/- 0.09 (stat) (+0.60)(-0.49) (scale) +/- 0.06 (PDF) +/- 0.16 (non-pert) (+0.52)(-0.38) (DPI) pb.

  • 326.
    Åsman, Barbro
    et al.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Bendtz, Katarina
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Bohm, Christian
    Stockholm University, Faculty of Science, Department of Physics.
    Clément, Christophe
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Eriksson, Daniel
    Stockholm University, Faculty of Science, Department of Physics.
    Gellerstedt, Karl
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Hellman, Sten
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Holmgren, Sven-Olof
    Stockholm University, Faculty of Science, Department of Physics.
    Johansen, Marianne
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Johansson, K. Erik
    Stockholm University, Faculty of Science, Department of Physics.
    Jon-And, Kerstin
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Khandanyan, Hovhannes
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Kim, Hyeon
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Klimek, Pawel
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Lundberg, Johan
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Lundberg, Olof
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Milstead, David A.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Moa, Torbjörn
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Ohm, Christian C.
    CERN.
    Papadelis, Aras
    Stockholm University, Faculty of Science, Department of Physics.
    Sellden, Björn
    Stockholm University, Faculty of Science, Department of Physics.
    Silverstein, Samuel B.
    Stockholm University, Faculty of Science, Department of Physics.
    Sjölin, Jörgen
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Strandberg, Sara
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Tylmad, Maja
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Yang, Zhaoyu
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Search for pair production of massive particles decaying into three quarks with the ATLAS detector in root s=7 TeV pp collisions at the LHC2012In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, no 12, p. 086-Article in journal (Refereed)
    Abstract [en]

    A search is conducted for hadronic three-body decays of a new massive coloured particle in root s = 7 TeV p p collisions at the LHC using an integrated luminosity of 4.6 fb(-1) collected by the ATLAS detector. Supersymmetric gluino pair production in the context of a model with R-parity violation is used as a benchmark scenario. The analysis is divided into two search channels, each optimised separately for their sensitivity to high-mass and low-mass gluino production. The first search channel uses a stringent selection on the transverse momentum of the six leading jets and is performed as a counting experiment. The second search channel focuses on low-mass gluinos produced with a large boost. Large-radius jets are selected and the invariant mass of each of the two leading jets is used as a discriminant between the signal and the background. The results are found to be consistent with Standard Model expectations and limits are set on the allowed gluino mass.

  • 327.
    Åsman, Barbro
    et al.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Bendtz, Katarina
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Bohm, Christian
    Stockholm University, Faculty of Science, Department of Physics.
    Clément, Christophe
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Eriksson, Daniel
    Stockholm University, Faculty of Science, Department of Physics.
    Gellerstedt, Karl
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Hellman, Sten
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Holmgren, Sven-Olof
    Stockholm University, Faculty of Science, Department of Physics.
    Johansen, Marianne
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Johansson, K. Erik
    Stockholm University, Faculty of Science, Department of Physics.
    Jon-And, Kerstin
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Khandanyan, Hovhannes
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Kim, Hyeon
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Klimek, Pawel
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Lundberg, Johan
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Lundberg, Olof
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Milstead, David A.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Moa, Torbjörn
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Ohm, Christian C.
    CERN.
    Papadelis, Aras
    Stockholm University, Faculty of Science, Department of Physics.
    Sellden, Björn
    Stockholm University, Faculty of Science, Department of Physics.
    Silverstein, Samuel B.
    Stockholm University, Faculty of Science, Department of Physics.
    Sjölin, Jörgen
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Strandberg, Sara
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Tylmad, Maja
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Yang, Zhaoyu
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Search for R-parity-violating supersymmetry in events with four or more leptons in root s=7 TeV pp collisions with the ATLAS detector2012In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, no 12, p. 124-Article in journal (Refereed)
    Abstract [en]

    A search for new phenomena in final states with four or more leptons (electrons or muons) is presented. The analysis is based on 4.7 fb(-1) of root s = 7TeV proton-proton collisions delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in two signal regions: one that requires moderate values of missing transverse momentum and another that requires large effective mass. The results are interpreted in a simplified model of R-parity-violating supersymmetry in which a 95% CL exclusion region is set for charged wino masses up to 540GeV. In an R-parity-violating MSUGRA/CMSSM model, values of m(1/2) up to 820GeV are excluded for 10 < tan beta < 40.

  • 328.
    Åsman, Barbro
    et al.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Bendtz, Katarina
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Bohm, Christian
    Stockholm University, Faculty of Science, Department of Physics.
    Clément, Christophe
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Eriksson, Daniel
    Stockholm University, Faculty of Science, Department of Physics.
    Gellerstedt, Karl
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Hellman, Sten
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Holmgren, Sven-Olof
    Stockholm University, Faculty of Science, Department of Physics.
    Johansen, Marianne
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Johansson, K. Erik
    Stockholm University, Faculty of Science, Department of Physics.
    Jon-And, Kerstin
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Khandanyan, Hovhannes
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Kim, Hyeon
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Klimek, Pawel
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Lundberg, Johan
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Lundberg, Olof
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Milstead, David A.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Moa, Torbjörn
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Ohm, Christian C.
    CERN.
    Papadelis, Aras
    Stockholm University, Faculty of Science, Department of Physics.
    Sellden, Björn
    Stockholm University, Faculty of Science, Department of Physics.
    Silverstein, Samuel B.
    Stockholm University, Faculty of Science, Department of Physics.
    Sjölin, Jörgen
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Strandberg, Sara
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Tylmad, Maja
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Yang, Zhaoyu
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Time-dependent angular analysis of the decay B-s(0) -> J/psi phi and extraction of Delta Gamma(s) and the CP-violating weak phase phi(s) by ATLAS2012In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, no 12, p. 072-Article in journal (Refereed)
    Abstract [en]

    A measurement of B-s(0) -> J/psi phi decay parameters, including the CP-violating weak phase phi(s) and the decay width difference Delta Gamma(s) is reported, using 4.9 fb(-1) of integrated luminosity collected in 2011 by the ATLAS detector from LHC pp collisions at a centre-of-mass energy root s = 7 TeV. The mean decay width Gamma(s) and the transversity amplitudes vertical bar A(0)(0)vertical bar(2) and vertical bar A(parallel to)(0)vertical bar(2) are also measured. The values reported for these parameters are: phi(s) = 0.22 +/- 0.41 (stat.) +/- 0.10 (syst.) rad Delta Gamma(s) = 0.053 +/- 0.021 (stat.) +/- 0.010 (syst.) ps(-1) Gamma(s) = 0.677 +/- 0.007 (stat.) +/- 0.004 (syst.) ps(-1) vertical bar A(0)(0)vertical bar(2) = 0.528 +/- 0.006 (stat.) +/- 0.009 (syst.) vertical bar A(parallel to)(0)vertical bar(2) = 0.220 +/- 0.008 (stat.) +/- 0.007 (syst.) where the values quoted for phi(s) and Delta Gamma(s) correspond to the solution compatible with the external measurements to which the strong phase delta(perpendicular to) is constrained and where is Delta Gamma(s) constrained to be positive. The fraction of S-wave KK or f(0) contamination through the decays B-s(0) -> J/psi K+K- (f(0)) is measured as well and is found to be consistent with zero. Results for phi(s) and Delta Gamma(s) are also presented as 68%, 90% and 95% likelihood contours, which show agreement with Standard Model expectations.

  • 329.
    Åsman, Barbro
    et al.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Bendtz, Katarina
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Bohm, Christian
    Stockholm University, Faculty of Science, Department of Physics.
    Clément, Christophe
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Eriksson, Daniel
    Stockholm University, Faculty of Science, Department of Physics.
    Gellerstedt, Karl
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Hellman, Sten
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Holmgren, Sven-Olof
    Stockholm University, Faculty of Science, Department of Physics.
    Johansen, Marianne
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Johansson, K. Erik
    Stockholm University, Faculty of Science, Department of Physics.
    Jon-And, Kerstin
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Kim, Hyeon
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Klimek, Pawel
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Lundberg, Johan
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Lundberg, Olof
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Milstead, David A.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Moa, Torbjörn
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Ohm, Christian C.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Papadelis, Aras
    Stockholm University, Faculty of Science, Department of Physics.
    Sellden, Björn
    Stockholm University, Faculty of Science, Department of Physics.
    Silverstein, Samuel B.
    Stockholm University, Faculty of Science, Department of Physics.
    Sjölin, Jörgen
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Strandberg, Sara
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Tylmad, Maja
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Yang, Zhaoyu
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    A search for t(t)over-bar resonances in lepton plus jets events with highly boosted top quarks collected in pp collisions at root s=7 TeV with the ATLAS detector2012In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, no 9, p. 041-Article in journal (Refereed)
    Abstract [en]

    A search for resonant production of high-mass top-quark pairs is performed on 2.05 fb(-1) of proton-proton collisions at root s = 7 TeV collected in 2011 with the ATLAS experiment at the Large Hadron Collider. This analysis of the lepton+jets final state is specifically designed for the particular topology that arises from the decay of highly boosted top quarks. The observed t (t) over bar invariant mass spectrum is found to be compatible with the Standard Model prediction and 95% credibility level upper limits are derived on the t (t) over bar production rate through new massive states. An upper limit of 0.7 pb is set on the production cross section times branching fraction of a narrow 1 TeV resonance. A Kaluza-Klein gluon with a mass smaller than 1.5 TeV is excluded.

  • 330.
    Åsman, Barbro
    et al.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Bendtz, Katarina
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Bohm, Christian
    Stockholm University, Faculty of Science, Department of Physics.
    Clément, Christophe
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Eriksson, Daniel
    Stockholm University, Faculty of Science, Department of Physics.
    Gellerstedt, Karl
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Hellman, Sten
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Holmgren, Sven-Olof
    Stockholm University, Faculty of Science, Department of Physics.
    Johansen, Marianne
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Johansson, K. Erik
    Stockholm University, Faculty of Science, Department of Physics.
    Jon-And, Kerstin
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Kim, Hyeon
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Klimek, Pawel
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Lundberg, Johan
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Lundberg, Olof
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Milstead, David A.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Moa, Torbjörn
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Ohm, Christian C.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Papadelis, Aras
    Stockholm University, Faculty of Science, Department of Physics.
    Sellden, Björn
    Stockholm University, Faculty of Science, Department of Physics.
    Silverstein, Samuel B.
    Stockholm University, Faculty of Science, Department of Physics.
    Sjölin, Jörgen
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Strandberg, Sara
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Tylmad, Maja
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Yang, Zhaoyu
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Search for the Standard Model Higgs boson in the H -> tau(+)tau(-) decay mode in root s=7 TeV pp collisions with ATLAS2012In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, no 9, p. 070-Article in journal (Refereed)
    Abstract [en]

    A search for the Standard Model Higgs boson decaying into a pair of tau leptons is reported. The analysis is based on a data sample of proton-proton collisions collected by the ATLAS experiment at the LHC and corresponding to an integrated luminosity of 4.7 fb(-1). No significant excess over the expected background is observed in the Higgs boson mass range of 100-150GeV. The observed (expected) upper limits on the cross section times the branching ratio for H -> tau(+)tau(-) are found to be between 2.9 (3.4) and 11.7 (8.2) times the Standard Model prediction for this mass range.

  • 331.
    Åsman, Barbro
    et al.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Bendtz, Katarina
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Bohm, Christian
    Stockholm University, Faculty of Science, Department of Physics.
    Clément, Christophe
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Eriksson, Daniel
    Stockholm University, Faculty of Science, Department of Physics.
    Gellerstedt, Karl
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Hellman, Sten
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Holmgren, Sven-Olof
    Stockholm University, Faculty of Science, Department of Physics.
    Johansen, Marianne
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Johansson, K. Erik
    Stockholm University, Faculty of Science, Department of Physics.
    Khandanyan, Hovhannes
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Kim, Hyeon
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Klimek, Pawel
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Lundberg, Johan
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Lundberg, Olof
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Milstead, David A.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Moa, Torbjörn
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Ohm, Christian C.
    CERN, Geneva, Switzerland.
    Papadelis, Aras
    Stockholm University, Faculty of Science, Department of Physics.
    Sellden, Björn
    Stockholm University, Faculty of Science, Department of Physics.
    Silverstein, Samuel B.
    Stockholm University, Faculty of Science, Department of Physics.
    Sjölin, Jörgen
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Strandberg, Sara
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Tylmad, Maja
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Yang, Zhaoyu
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Search for anomalous production of prompt like-sign lepton pairs at root s=7 TeV with the ATLAS detector2012In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, no 12, p. 007-Article in journal (Refereed)
    Abstract [en]

    An inclusive search for anomalous production of two prompt, isolated leptons with the same electric charge is presented. The search is performed in a data sample corresponding to 4.7 fb(-1) of integrated luminosity collected in 2011 at root s = 7TeV with the ATLAS detector at the LHC. Pairs of leptons (e(+/-)e(+/-), e(+/-)mu(+/-), and mu(+/-)mu(+/-)) with large transverse momentum are selected, and the dilepton invariant mass distribution is examined for any deviation from the Standard Model expectation. No excess is found, and upper limits on the production cross section of like-sign lepton pairs from physics processes beyond the Standard Model are placed as a function of the dilepton invariant mass within a fiducial region close to the experimental selection criteria. The 95% confidence level upper limits on the cross section of anomalous e(+/-)e(+/-), e(+/-)mu(+/-), or mu(+/-)mu(+/-) production range between 1.7 fb and 64 fb depending on the dilepton mass and flavour combination.

  • 332.
    Åsman, Barbro
    et al.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Bendtz, Katarina
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Bohm, Christian
    Stockholm University, Faculty of Science, Department of Physics.
    Clément, Christophe
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Gellerstedt, Karl
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Hellman, Sten
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Holmgren, Sven-Olof
    Stockholm University, Faculty of Science, Department of Physics.
    Johansen, Marianne
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Johansson, K. Erik
    Stockholm University, Faculty of Science, Department of Physics.
    Jon-And, Kerstin
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Khandanyan, Hovhannes
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Kim, Hyeon
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Klimek, Pawel
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Lundberg, Johan
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Lundberg, Olof
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Milstead, David A.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Moa, Torbjörn
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Ohm, Christian C.
    CERN.
    Papadelis, Aras
    Stockholm University, Faculty of Science, Department of Physics.
    Sellden, Björn
    Stockholm University, Faculty of Science, Department of Physics.
    Silverstein, Samuel B.
    Stockholm University, Faculty of Science, Department of Physics.
    Sjölin, Jörgen
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Strandberg, Sara
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Yang, Zhaoyu
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Search for dark matter candidates and large extra dimensions in events with a jet and missing transverse momentum with the ATLAS detector2013In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, no 4Article in journal (Refereed)
    Abstract [en]

    A search for new phenomena in events with a high-energy jet and large missing transverse momentum is performed using data from proton-proton collisions at root s = 7 TeV with the ATLAS experiment at the Large flatiron Collider. Four kinematic regions are explored using a dataset corresponding to an integrated luminosity of 4.7 fb(-1). No excess of events beyond expectations from Standard Model processes is observed, and limits are set on large extra dimensions and the pair production of dark matter particles.

  • 333.
    Åsman, Barbro
    et al.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Bohm, Christian
    Stockholm University, Faculty of Science, Department of Physics.
    Clément, Christophe
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Eriksson, Daniel
    Stockholm University, Faculty of Science, Department of Physics.
    Gellerstedt, Karl
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Hellman, Sten
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Hidvegi, Attila
    Stockholm University, Faculty of Science, Department of Physics.
    Holmgren, Sven-Olof
    Stockholm University, Faculty of Science, Department of Physics.
    Johansen, Marianne
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Johansson, Erik
    Stockholm University, Faculty of Science, Department of Physics.
    Jon-And, Kerstin
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Lesser, Jonas
    Stockholm University, Faculty of Science, Department of Physics.
    Lundberg, Johan
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Milstead, David
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Moa, Torbjörn
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Nordkvist, Björn
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Ohm, Christian
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Papadelis, Aras
    Stockholm University, Faculty of Science, Department of Physics.
    Ramstedt, M.
    Stockholm University, Faculty of Science, Department of Physics.
    Selldén, Björn
    Stockholm University, Faculty of Science, Department of Physics.
    Silverstein, Samuel
    Stockholm University, Faculty of Science, Department of Physics.
    Sjölin, Jörgen
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Strandberg, Sara
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Tylmad, Maja
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Yang, Zhaoyu
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Measurement of $W\gamma$ and $Z\gamma$ Production in Proton-Proton Collisions at $\sqrt{s}=7$ TeV with the ATLAS Detector2011In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, Vol. 09, p. 072-Article in journal (Refereed)
    Abstract [en]

    We present studies of W and Z bosons with associated high energy photons produced in pp collisions at root s = 7 TeV. The analysis uses 35 pb(-1) of data collected by the ATLAS experiment in 2010. The event selection requires W and Z bosons decaying into high pT leptons (electrons or muons) and a photon with E(T) > 15 GeV separated from the lepton(s) by a distance Delta R(l, gamma) > 0.7 in eta-phi space. A total of 95 (97) pp -> e(+/-)nu gamma + X (pp -> mu(+/-)nu gamma + X) and 25 (23) pp -> e(+)e(-)gamma + X (pp -> mu(+)mu(-)gamma + X) event candidates are selected. The kinematic distributions of the leptons and photons and the production cross sections are measured. The data are found to agree with Standard Model predictions that include next-to-leading-order O(alpha alpha(s)) contributions.

  • 334.
    Åsman, Barbro
    et al.
    Stockholm University, Faculty of Science, Department of Physics.
    Bohm, Christian
    Stockholm University, Faculty of Science, Department of Physics.
    Clément, Christophe
    Stockholm University, Faculty of Science, Department of Physics.
    Eriksson, Daniel
    Stockholm University, Faculty of Science, Department of Physics.
    Gellerstedt, Karl
    Stockholm University, Faculty of Science, Department of Physics.
    Hellman, Sten
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Hidvégi, Attila
    Stockholm University, Faculty of Science, Department of Physics.
    Hillert, Sonja
    Stockholm University, Faculty of Science, Department of Physics.
    Holmgren, Sven-Olof
    Stockholm University, Faculty of Science, Department of Physics.
    Johansen, Marianne
    Stockholm University, Faculty of Science, Department of Physics.
    Johansson, Erik
    Stockholm University, Faculty of Science, Department of Physics.
    Jon-And, Kerstin
    Stockholm University, Faculty of Science, Department of Physics.
    Lesser, Jonas
    Stockholm University, Faculty of Science, Department of Physics.
    Milstead, David
    Stockholm University, Faculty of Science, Department of Physics.
    Moa, Torbjörn
    Stockholm University, Faculty of Science, Department of Physics.
    Nordkvist, Björn
    Stockholm University, Faculty of Science, Department of Physics.
    Ohm, Christian
    Stockholm University, Faculty of Science, Department of Physics.
    Ramstedt, Magnus
    Stockholm University, Faculty of Science, Department of Physics.
    Selldén, Björn
    Stockholm University, Faculty of Science, Department of Physics.
    Silverstein, Samuel
    Stockholm University, Faculty of Science, Department of Physics.
    Sjölin, Jörgen
    Stockholm University, Faculty of Science, Department of Physics.
    Tylmad, Maja
    Stockholm University, Faculty of Science, Department of Physics.
    Yang, Zhaoyu
    Stockholm University, Faculty of Science, Department of Physics.
    Performance of the ATLAS Detector using First Collision Data2010In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, no 9, p. 056-Article in journal (Refereed)
  • 335.
    Åsman, Barbro
    et al.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Bohm, Christian
    Stockholm University, Faculty of Science, Department of Physics.
    Clément, Christophe
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Eriksson, Daniel
    Stockholm University, Faculty of Science, Department of Physics.
    Gellerstedt, Karl
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Hellman, Sten
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Hidvégi, Attila
    Stockholm University, Faculty of Science, Department of Physics.
    Holmgren, Sven-Olof
    Stockholm University, Faculty of Science, Department of Physics.
    Johansen, Marianne
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Johansson, Erik
    Stockholm University, Faculty of Science, Department of Physics.
    Jon-And, Kerstin
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Lesser, Jonas
    Stockholm University, Faculty of Science, Department of Physics.
    Lundberg, Johan
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Milstead, David
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Moa, Torbjörn
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Nordkvist, Björn
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Ohm, Christian
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Papadelis, Aras
    Stockholm University, Faculty of Science, Department of Physics.
    Ramstedt, Magnus
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Selldén, Björn
    Stockholm University, Faculty of Science, Department of Physics.
    Silverstein, Samuel
    Stockholm University, Faculty of Science, Department of Physics.
    Sjölin, Jörgen
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Strandberg, Sara
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Tylmad, Maja
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Yang, Zhaoyu
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Inclusive Search for Same-Sign Dilepton Signatures in pp Collisions at $\sqrt{s}=7$ TeV with the ATLAS Detector2011In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, Vol. 10, p. 107-Article in journal (Refereed)
    Abstract [en]

    An inclusive search is presented for new physics in events with two isolated leptons (e or μ) having the same electric charge. The data are selected from events collected from pp collisions at Ös = 7 \sqrt {s} = 7 TeV by the ATLAS detector and correspond to an integrated luminosity of 34 pb−1. The spectra in dilepton invariant mass, missing transverse momentum and jet multiplicity are presented and compared to Standard Model predictions. In this event sample, no evidence is found for contributions beyond those of the Standard Model. Limits are set on the cross-section in a fiducial region for new sources of same-sign high-mass dilepton events in the ee, and μμ channels. Four models predicting same-sign dilepton signals are constrained: two descriptions of Majorana neutrinos, a cascade topology similar to supersymmetry or universal extra dimensions, and fourth generation d-type quarks. Assuming a new physics scale of 1 TeV, Majorana neutrinos produced by an effective operator V with masses below 460 GeV are excluded at 95% confidence level. A lower limit of 290 GeV is set at 95% confidence level on the mass of fourth generation d-type quarks.

  • 336.
    Åsman, Barbro
    et al.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Bohm, Christian
    Stockholm University, Faculty of Science, Department of Physics.
    Clément, Christophe
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Eriksson, Daniel
    Stockholm University, Faculty of Science, Department of Physics.
    Gellerstedt, Karl
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Hellman, Sten
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Hidvégi, Attila
    Stockholm University, Faculty of Science, Department of Physics.
    Holmgren, Sven-Olof
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Johansen, Marianne
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Johansson, Erik
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Jon-And, Kerstin
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Lesser, Jonas
    Stockholm University, Faculty of Science, Department of Physics.
    Milstead, David
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Moa, Torbjörn
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Nordkvist, Björn
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Ohm, Christian
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Ramstedt, Magnus
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Selldén, Björn
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Silverstein, Samuel
    Stockholm University, Faculty of Science, Department of Physics.
    Sjölin, Jörgen
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Strandberg, Sara
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Tylmad, Maja
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Yang, Zhaoyu
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Measurement of the $W\to\ell\nu$ and $Z/gamma^\ast\to\ell\ell$ Production Cross Sections in Proton-Proton Collisions at $\sqrt{s}=7$ TeV with the ATLAS Detector2010In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, no 12, p. 060-Article in journal (Refereed)
    Abstract [en]

    First measurements of the W →ν and Z/γ * ℓℓ (ℓ = e, μ) production cross sections in proton-proton collisions at Ös = 7  \textTeV s=7TeV are presented using data recorded by the ATLAS experiment at the LHC. The results are based on 2250 W →ν and 179 Z/γ * → ℓℓ candidate events selected from a data set corresponding to an integrated luminosity of approximately 320 nb. The measured total W and Z/γ -boson production cross sections times the respective leptonic branching ratios for the combined electron and muon channels are sW\texttot Wtot. BR(W → ℓν) = 9.96 ± 0.23(stat) ± 0.50(syst) ± 1.10(lumi) nb and sZ / g \texttot totZ BR(Z/γ → ℓℓ) = 0.82 ± 0.06 (stat) ± 0.05 (syst) ± 0.09(lumi) nb (within the invariant mass window 66 < m ℓℓ < 116GeV). The W/Z cross-section ratio is measured to be 11.7 ± 0.9(stat) ± 0.4(syst). In addition, measurements of the W + and W production cross sections and of the lepton charge asymmetry are reported. Theoretical predictions based on NNLO QCD calculations are found to agree with the measurements

  • 337.
    Åsman, Barbro
    et al.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Bohm, Christian
    Stockholm University, Faculty of Science, Department of Physics.
    Clément, Christophe
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Eriksson, Daniel
    Stockholm University, Faculty of Science, Department of Physics.
    Gellerstedt, Karl
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Hellman, Sten
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Hidvégi, Attila
    Stockholm University, Faculty of Science, Department of Physics.
    Holmgren, Sven-Olof
    Stockholm University, Faculty of Science, Department of Physics.
    Johansen, Marianne
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Johansson, K. Erik
    Stockholm University, Faculty of Science, Department of Physics.
    Jon-And, Kerstin
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Lesser, Jonas
    Stockholm University, Faculty of Science, Department of Physics.
    Lundberg, Johan
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Milstead, David A.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Moa, Torbjörn
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Nordkvist, Björn
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Ohm, Christian C.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Papadelis, Aras
    Stockholm University, Faculty of Science, Department of Physics.
    Ramstedt, Magnus
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Sellden, Björn
    Stockholm University, Faculty of Science, Department of Physics.
    Silverstein, Samuel B.
    Stockholm University, Faculty of Science, Department of Physics.
    Sjölin, Jörgen
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Strandberg, Sara
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Tylmad, Maja
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Yang, Zhaoyu
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Measurement of dijet production with a veto on additional central jet activity in pp collisions at root s=7 TeV using the ATLAS detector2011In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, Vol. 09, p. 053-Article in journal (Refereed)
    Abstract [en]

    A measurement of jet activity in the rapidity interval bounded by a dijet system is presented. Events are vetoed if a jet with transverse momentum greater than 20 GeV is found between the two boundary jets. The fraction of dijet events that survive the jet veto is presented for boundary jets that are separated by up to six units of rapidity and with mean transverse momentum 50 < <(p)over bar>T < 500 GeV. The mean multiplicity of jets above the veto scale in the rapidity interval bounded by the dijet system is also presented as an alternative method for quantifying perturbative QCD emission. The data are compared to a next-to-leading order plus parton shower prediction from the POWHEG-BOX, an all-order resummation using the HEJ calculation and the PYTHIA, HERWIG++ and ALPGEN event generators. The measurement was performed using pp collisions at root s = 7 TeV using data recorded by the ATLAS detector in 2010.

  • 338.
    Åsman, Barbro
    et al.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Bohm, Christian
    Stockholm University, Faculty of Science, Department of Physics.
    Clément, Christophe
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Eriksson, Daniel
    Stockholm University, Faculty of Science, Department of Physics.
    Gellerstedt, Karl
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Hellman, Sten
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Hidvégi, Attila
    Stockholm University, Faculty of Science, Department of Physics.
    Holmgren, Sven-Olof
    Stockholm University, Faculty of Science, Department of Physics.
    Johansen, Marianne
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Johansson, K. Erik
    Stockholm University, Faculty of Science, Department of Physics.
    Jon-And, Kerstin
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Lesser, Jonas
    Stockholm University, Faculty of Science, Department of Physics.
    Lundberg, Johan
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Milstead, David A.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Moa, Torbjörn
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Nordkvist, Björn
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Ohm, Christian C.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Papadelis, Aras
    Stockholm University, Faculty of Science, Department of Physics.
    Ramstedt, Magnus
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Selldén, Björn
    Stockholm University, Faculty of Science, Department of Physics.
    Silverstein, Samuel
    Stockholm University, Faculty of Science, Department of Physics.
    Sjölin, Jörgen
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Strandberg, Sara
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Tylmad, Maja
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Yang, Zhaoyu
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Search for new phenomena in final states with large jet multiplicities and missing transverse momentum using root s=7 TeV pp collisions with the ATLAS detector2011In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, Vol. 11, p. 099-Article in journal (Refereed)
    Abstract [en]

    Results are presented of a search for any particle(s) decaying to six or more jets in association with missing transverse momentum. The search is performed using 1.34 fb(-1) of root s = 7TeV proton-proton collisions recorded by the ATLAS detector during 2011. Data-driven techniques are used to determine the backgrounds in kinematic regions that require at least six, seven or eight jets, well beyond the multiplicities required in previous analyses. No evidence is found for physics beyond the Standard Model. The results are interpreted in the context of a supersymmetry model (MSUGRA/CMSSM) where they extend previous constraints.

  • 339.
    Åsman, Barbro
    et al.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Bohm, Christian
    Stockholm University, Faculty of Science, Department of Physics.
    Clément, Christophe
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Eriksson, Daniel
    Stockholm University, Faculty of Science, Department of Physics.
    Gellerstedt, Karl
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Hellman, Sten
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Holmgren, Sven-Olof
    Stockholm University, Faculty of Science, Department of Physics.
    Johansen, M.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Johansson, K. E.
    Stockholm University, Faculty of Science, Department of Physics.
    Jon-And, Kerstin
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Kim, Hyeon
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Klimek, Pawel
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Lesser, J.
    Stockholm University, Faculty of Science, Department of Physics.
    Lundberg, Johan
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Milstead, David
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Moa, Torbjörn
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Nordkvist, Björn
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Ohm, Christian
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Papadelis, Aras
    Stockholm University, Faculty of Science, Department of Physics.
    Sellden, Björn
    Stockholm University, Faculty of Science, Department of Physics.
    Silverstein, Samuel
    Stockholm University, Faculty of Science, Department of Physics.
    Sjölin, Jörgen
    Stockholm University, Faculty of Science, Department of Physics.
    Tylmad, Maja
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Yang, Zhaoyu
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Forward-backward correlations and charged-particle azimuthal distributions in pp interactions using the ATLAS detector2012In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, no 7, p. 019-Article in journal (Refereed)
    Abstract [en]

    Using inelastic proton-proton interactions at root s = 900 GeV and 7 TeV, recorded by the ATLAS detector at the LHC, measurements have been made of the correlations between forward and backward charged-particle multiplicities and, for the first time, between forward and backward charged-particle summed transverse momentum. In addition, jet-like structure in the events is studied by means of azimuthal distributions of charged particles relative to the charged particle with highest transverse momentum in a, selected kinematic region of the event. The results are compared with predictions from tunes of the PYTHIA and HERWIG++ Monte Carlo generators, which in most cases are found to provide a reasonable description of the data.

  • 340.
    Åsman, Barbro
    et al.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Bohm, Christian
    Stockholm University, Faculty of Science, Department of Physics.
    Clément, Christophe
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Eriksson, Daniel
    Stockholm University, Faculty of Science, Department of Physics.
    Gellerstedt, Karl
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Hellman, Sten
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Holmgren, Sven-Olof
    Stockholm University, Faculty of Science, Department of Physics.
    Johansen, Marianne
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Johansson, Erik K.
    Stockholm University, Faculty of Science, Department of Physics.
    Jon-And, Kerstin
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Kim, Hyeon
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Klimek, Pawel
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Lesser, J.
    Stockholm University, Faculty of Science, Department of Physics.
    Lundberg, Johan
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Milstead, David A.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Moa, Torbjörn
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Nordkvist, Björn
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Ohm, Christian C.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Papadelis, Aras
    Stockholm University, Faculty of Science, Department of Physics.
    Sellden, Björn
    Stockholm University, Faculty of Science, Department of Physics.
    Silverstein, Samuel B.
    Stockholm University, Faculty of Science, Department of Physics.
    Sjölin, Jörgen
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Strandberg, Sara
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Tylmad, Maja
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Yang, Zhaoyu
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Jet mass and substructure of inclusive jets in root s=7 TeV pp collisions with the ATLAS experiment2012In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, no 5, p. 128-Article in journal (Refereed)
    Abstract [en]

    Recent studies have highlighted the potential of jet substructure techniques to identify the hadronic decays of boosted heavy particles. These studies all rely upon the assumption that the internal substructure of jets generated by QCD radiation is well understood. In this article, this assumption is tested on an inclusive sample of jets recorded with the ATLAS detector in 2010, which corresponds to 35 pb(-1) of pp collisions delivered by the LHC at root s = 7 TeV. In a subsample of events with single pp collisions, measurements corrected for detector efficiency and resolution are presented with full systematic uncertainties. Jet invariant mass, k(t) splitting scales and N-subjettiness variables are presented for anti-k(t) R = 1.0 jets and Cambridge-Aachen R = 1.2 jets. Jet invariant-mass spectra for Cambridge-Aachen R = 1.2 jets after a splitting and filtering procedure are also presented. Leading-order parton-shower Monte Carlo predictions for these variables are found to be broadly in agreement with data. The dependence of mean jet mass on additional pp interactions is also explored.

  • 341.
    Åsman, Barbro
    et al.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Bohm, Christian
    Stockholm University, Faculty of Science, Department of Physics.
    Clément, Christophe
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Eriksson, Daniel
    Stockholm University, Faculty of Science, Department of Physics.
    Gellerstedt, Karl
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Hellman, Sten
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Holmgren, Sven-Olof
    Stockholm University, Faculty of Science, Department of Physics.
    Johansen, Marianne
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Johansson, K. Erik
    Stockholm University, Faculty of Science, Department of Physics.
    Jon-And, Kerstin
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Kim, Hyeon
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Klimek, Pawel
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Lesser, J.
    Stockholm University, Faculty of Science, Department of Physics.
    Lundberg, Johan
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Milstead, David
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Moa, Torbjörn
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Nordkvist, Björn
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Ohm, Christian C.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Papadelis, Aras
    Stockholm University, Faculty of Science, Department of Physics.
    Sellden, Björn
    Stockholm University, Faculty of Science, Department of Physics.
    Silverstein, Samuel B.
    Stockholm University, Faculty of Science, Department of Physics.
    Sjölin, Jörgen
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Strandberg, Sara
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Tylmad, Maja
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Yang, Zhaoyu
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Measurement of inclusive two-particle angular correlations in pp collisions with the ATLAS detector at the LHC2012In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, no 5, p. 157-Article in journal (Refereed)
    Abstract [en]

    We present a measurement of two-particle angular correlations in proton-proton collisions at root s = 900 GeV and 7 TeV. The collision events were collected during 2009 and 2010 with the ATLAS detector at the Large Hadron Collider using a single-arm minimum bias trigger. Correlations are measured for charged particles produced in the kinematic range of transverse momentum p(T) > 100 MeV and pseudorapidity vertical bar eta vertical bar < 2.5. A complex structure in pseudorapidity and azimuth is observed at both collision energies. Results are compared to PYTHIA 8 and HERWIG++ as well as to the AMBT2B, DW and Perugia 2011 tunes of PYTHIA 6. The data are not satisfactorily described by any of these models.

  • 342.
    Åsman, Barbro
    et al.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Bohm, Christian
    Stockholm University, Faculty of Science, Department of Physics.
    Clément, Christophe
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Eriksson, Daniel
    Stockholm University, Faculty of Science, Department of Physics.
    Gellerstedt, Karl
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Hellman, Sten
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Holmgren, Sven-Olof
    Stockholm University, Faculty of Science, Department of Physics.
    Johansen, Marianne
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Johansson, K. Erik
    Stockholm University, Faculty of Science, Department of Physics.
    Jon-And, Kerstin
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Kim, Hyon
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Klimek, Pawel
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Lesser, J.
    Stockholm University, Faculty of Science, Department of Physics.
    Lundberg, Johan
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Milstead, David A.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Moa, Torbjörn
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Nordkvist, Björn
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Ohm, Christian C.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Papadelis, Aras
    Stockholm University, Faculty of Science, Department of Physics.
    Sellden, Björn
    Stockholm University, Faculty of Science, Department of Physics.
    Silverstein, Samuel B.
    Stockholm University, Faculty of Science, Department of Physics.
    Sjölin, Jörgen
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Strandberg, Sara
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Tylmad, Maja
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Yang, Zhaoyu
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Search for same-sign top-quark production and fourth-generation down-type quarks in pp collisions at root s=7 TeV with the ATLAS detector2012In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, no 4, p. 069-Article in journal (Refereed)
    Abstract [en]

    A search is preseritecl for same-sign top-quark production and down-type heavy quarks of charge -1/3 in events with two isolated leptons (c or mu) that have the same electric charge, at least two jets and large missing transverse momentum. The data are selected from pp collisions at root s = 7 TeV recorded by the ATLAS detector and correspond to an integrated luminosity of 1.04 fb(-1). The observed data are consistent with expectations from Standard Model processes. Upper limits are set at 95% confidence level on the cross section of new sources of same-sign top-quark pair production of 1.4-2.0 pb depending on the assumed mediator mass. Upper limits are also set on the pair-production cross-section for new heavy down-type quarks; a lower limit of 450 GeV is set at 95% confidence level on the mass of heavy down-type quarks under the assumption that they decay 100% of the time to Wt.

  • 343.
    Åsman, Barbro
    et al.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Bohm, Christian
    Stockholm University, Faculty of Science, Department of Physics.
    Clément, Christophe
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Eriksson, Daniel
    Stockholm University, Faculty of Science, Department of Physics.
    Gellerstedt, Karl
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Hellman, Sten
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Holmgren, Sven-Olof
    Stockholm University, Faculty of Science, Department of Physics.
    Johansen, Marianne
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Johansson, K. Erik
    Stockholm University, Faculty of Science, Department of Physics.
    Kim, Hyeon
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Klimek, Pawel
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Lesser, J.
    Stockholm University, Faculty of Science, Department of Physics.
    Lundberg, Johan
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Milstead, David A.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Moa, Torbjörn
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Nordkvist, Björn
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Ohm, Christian C.
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Papadelis, Aras
    Stockholm University, Faculty of Science, Department of Physics.
    Sellden, Björn
    Stockholm University, Faculty of Science, Department of Physics.
    Silverstein, Samuel B.
    Stockholm University, Faculty of Science, Department of Physics.
    Sjölin, Jörgen
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Strandberg, Sara
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Tylmad, Maja
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Yang, Zhaoyu
    Stockholm University, Faculty of Science, Department of Physics. Stockholm University, Faculty of Science, The Oskar Klein Centre for Cosmo Particle Physics (OKC).
    Measurement of the cross section for top-quark pair production in pp collisions at root s=7 TeV with the ATLAS detector using final states with two high-p(T) leptons2012In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, no 5, p. 059-Article in journal (Refereed)
    Abstract [en]

    A measurement is reported of the production cross section of top-quark pairs (\ttbar{}) in proton-proton collisions at a center-of-mass energy of 7 TeV recorded with the ATLAS detector at the LHC. Candidate events have a signature consistent with containing two isolated leptons, large missing transverse momentum, and at least two jets. Using a data sample corresponding to an integrated luminosity of 0.70 fb−1, a \ttbar{} production cross section $\sigma{\ttbar{}}$ = 176 ± 5(stat.)+14 −11(syst.) ± 8(lum.) pb is measured for an assumed top-quark mass of mt = 172.5 GeV. This measurement is in good agreement with Standard Model predictions.

4567 301 - 343 of 343
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