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Johansen, Marianne
Alternative names
Publications (10 of 255) Show all publications
Åsman, B., Bendtz, K., Bohm, C., Hellman, S., Johansen, M., Lundberg, J., . . . Sjölin, J. (2016). The ATLAS Data Acquisition and High Level Trigger system. Journal of Instrumentation, 11, Article ID P06008.
Open this publication in new window or tab >>The ATLAS Data Acquisition and High Level Trigger system
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2016 (English)In: Journal of Instrumentation, ISSN 1748-0221, E-ISSN 1748-0221, Vol. 11, article id P06008Article in journal (Refereed) Published
Abstract [en]

This paper describes the data acquisition and high level trigger system of the ATLAS experiment at the Large Hadron Collider at CERN, as deployed during Run 1. Data flow as well as control, configuration and monitoring aspects are addressed. An overview of the functionality of the system and of its performance is presented and design choices are discussed.

Keywords
Control and monitor systems online, Data acquisition concepts, Online farms and, online filtering, Trigger concepts and systems (hardware and software)
National Category
Physical Sciences
Identifiers
urn:nbn:se:su:diva-132414 (URN)10.1088/1748-0221/11/06/P06008 (DOI)000379239700020 ()
Available from: 2016-08-12 Created: 2016-08-11 Last updated: 2022-03-23Bibliographically approved
Abulaiti, Y., Åsman, B., Bendtz, K., Bohm, C., Clément, C., Eriksson, D., . . . Yang, Z. (2014). Measurement of the inclusive isolated prompt photons cross section in pp collisions at root s=7 TeV with the ATLAS detector using 4.6 fb(-1). Physical Review D, 89(5), 052004
Open this publication in new window or tab >>Measurement of the inclusive isolated prompt photons cross section in pp collisions at root s=7 TeV with the ATLAS detector using 4.6 fb(-1)
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2014 (English)In: Physical Review D, ISSN 1550-7998, E-ISSN 1550-2368, Vol. 89, no 5, p. 052004-Article in journal (Refereed) Published
Abstract [en]

A measurement of the cross section for the production of isolated prompt photons in pp collisions at a center-of-mass energy root s = 7 TeV is presented. The results are based on an integrated luminosity of 4.6 fb(-1) collected with the ATLAS detector at the LHC. The cross section is measured as a function of photon pseudorapidity eta(gamma) and transverse energy E-T(gamma) in the kinematic range 100 <= E-T(gamma) < 1000 GeV and in the regions vertical bar eta(gamma)vertical bar < 1.37 and 1.52 <= vertical bar eta(gamma)vertical bar < 2.37. The results are compared to leading-order parton-shower Monte Carlo models and next-to-leading-order perturbative QCD calculations. Next-to-leading-order perturbative QCD calculations agree well with the measured cross sections as a function of E-T(gamma) and eta(gamma) .

National Category
Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:su:diva-103986 (URN)10.1103/PhysRevD.89.052004 (DOI)000334304700002 ()
Note

AuthorCount:2916;

Available from: 2014-06-02 Created: 2014-05-27 Last updated: 2022-03-23Bibliographically approved
Abulaiti, Y., Åsman, B., Bendtz, K., Bohm, C., Clément, C., Eriksson, D., . . . Yang, Z. (2014). Muon reconstruction efficiency and momentum resolution of the ATLAS experiment in proton-proton collisions at root s=7 TeV in 2010. European Physical Journal C, 74(9), Article ID 3034.
Open this publication in new window or tab >>Muon reconstruction efficiency and momentum resolution of the ATLAS experiment in proton-proton collisions at root s=7 TeV in 2010
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2014 (English)In: European Physical Journal C, ISSN 1434-6044, E-ISSN 1434-6052, Vol. 74, no 9, article id 3034Article in journal (Refereed) Published
Abstract [en]

This paper presents a study of the performance of the muon reconstruction in the analysis of proton-proton collisions at root s = 7TeV at the LHC, recorded by the ATLAS detector in 2010. This performance is described in terms of reconstruction and isolation efficiencies and momentum resolutions for different classes of reconstructed muons. The results are obtained from an analysis of J/psi meson and Z boson decays to dimuons, reconstructed from a data sample corresponding to an integrated luminosity of 40 pb(-1). The measured performance is compared to Monte Carlo predictions and deviations from the predicted performance are discussed.

National Category
Physical Sciences
Identifiers
urn:nbn:se:su:diva-115643 (URN)10.1140/epjc/s10052-014-3034-9 (DOI)000350141000001 ()
Note

AuthorCount:2926;

Available from: 2015-04-01 Created: 2015-03-27 Last updated: 2022-03-23Bibliographically approved
Abulaiti, Y., Åsman, B., Bendtz, K., Bohm, C., Clément, C., Eriksson, D., . . . Yang, Z. (2014). Study of heavy-flavor quarks produced in association with top-quark pairs at root s=7 TeV using the ATLAS detector. Physical Review D, 89(7), 072012
Open this publication in new window or tab >>Study of heavy-flavor quarks produced in association with top-quark pairs at root s=7 TeV using the ATLAS detector
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2014 (English)In: Physical Review D, ISSN 1550-7998, E-ISSN 1550-2368, Vol. 89, no 7, p. 072012-Article in journal (Refereed) Published
Abstract [en]

Using a sample of dilepton top-quark pair ((tt) over bar) candidate events, a study is performed of the production of top-quark pairs together with heavy-flavor (HF) quarks, the sum of (tt) over bar + b + X and (tt) over bar + c + X, collectively referred to as (tt) over bar + HF. The data set used corresponds to an integrated luminosity of 4.7 fb(-1) of proton-proton collisions at a center-of-mass energy of 7 TeV recorded by the ATLAS detector at the CERN Large Hadron Collider. The presence of additional HF (b or c) quarks in the (tt) over bar sample is inferred by looking for events with at least three b-tagged jets, where two are attributed to the b quarks from the (tt) over bar decays and the third to additional HF production. The dominant background to (tt) over bar + HF in this sample is (tt) over bar + jet events in which a light-flavor jet is misidentified as a heavy-flavor jet. To determine the heavy-and light-flavor content of the additional b-tagged jets, a fit to the vertex mass distribution of b-tagged jets in the sample is performed. The result of the fit shows that 79 +/- 14 (stat) +/- 22 (syst) of the 105 selected extra b-tagged jets originate from HF quarks, 3 standard deviations away from the hypothesis of zero (tt) over bar + HF production. The result for extra HF production is quoted as a ratio (R-HF) of the cross section for (tt) over bar + HF production to the cross section for (tt) over bar production with at least one additional jet. Both cross sections are measured in a fiducial kinematic region within the ATLAS acceptance. R-HF is measured to be [6.2 +/- 1.1(stat) +/- 1.8 (syst)]% for jets with p(T) > 25 GeV and vertical bar eta vertical bar < 2.5, in agreement with the expectations from Monte Carlo generators.

National Category
Physical Sciences
Identifiers
urn:nbn:se:su:diva-104423 (URN)10.1103/PhysRevD.89.072012 (DOI)000335235200001 ()
Note

AuthorCount:2923;

Available from: 2014-06-17 Created: 2014-06-10 Last updated: 2022-03-23Bibliographically approved
Åsman, B., Bendtz, K., Bohm, C., Clément, C., Eriksson, D., Gellerstedt, K., . . . Yang, Z. (2014). The differential production cross section of the phi(1020) meson in root s=7 TeV pp collisions measured with the ATLAS detector. European Physical Journal C, 74(7), 2895
Open this publication in new window or tab >>The differential production cross section of the phi(1020) meson in root s=7 TeV pp collisions measured with the ATLAS detector
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2014 (English)In: European Physical Journal C, ISSN 1434-6044, E-ISSN 1434-6052, Vol. 74, no 7, p. 2895-Article in journal (Refereed) Published
Abstract [en]

A measurement is presented of the phi x BR(phi -> K+ K-) production cross section at root s = 7 TeV using pp collision data corresponding to an integrated luminosity of 383 mu b(-1), collected with the ATLAS experiment at the LHC. Selection of phi(1020) mesons is based on the identification of charged kaons by their energy loss in the pixel detector. The differential cross section is measured as a function of the transverse momentum, pT, phi, and rapidity, y(phi), of the phi(1020) meson in the fiducial region 500 < pT,phi < 1200MeV, vertical bar y phi| < 0.8, kaon p(T), (K) > 230 MeV and kaon momentum p(K) < 800 MeV. The integrated phi(1020)-meson production cross section in this fiducial range is measured to be sigma(phi) x BR(phi -> K+ K-) = 570 +/- 8 (stat) +/- 66 (syst) +/- 20 (lumi) mu b.

National Category
Physical Sciences
Identifiers
urn:nbn:se:su:diva-106582 (URN)10.1140/epjc/s10052-014-2895-2 (DOI)000338719300001 ()
Note

AuthorCount:2906;

Available from: 2014-08-14 Created: 2014-08-12 Last updated: 2022-03-23Bibliographically approved
Åsman, B., Bendtz, K., Bohm, C., Clément, C., Eriksson, D., Gellerstedt, K., . . . Yang, Z. (2013). A search for high-mass resonances decaying to tau(+)tau(-) in pp collisions at root s=7 TeV with the ATLAS detector. Physics Letters B, 719(4-5), 242-260
Open this publication in new window or tab >>A search for high-mass resonances decaying to tau(+)tau(-) in pp collisions at root s=7 TeV with the ATLAS detector
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2013 (English)In: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 719, no 4-5, p. 242-260Article in journal (Refereed) Published
Abstract [en]

This Letter presents a search for high-mass resonances decaying into tau(+)tau(-) final states using proton-proton collisions at root s = 7 TeV produced by the Large Hadron Collider. The data were recorded with the ATLAS detector and correspond to an integrated luminosity of 4.6 fb(-1). No statistically significant excess above the Standard Model expectation is observed; 95% credibility upper limits are set on the cross section times branching fraction of Z' resonances decaying into tau(+)tau(-) pairs as a function of the resonance mass. As a result, Z' bosons of the Sequential Standard Model with masses less than 1.40 TeV are excluded at 95% credibility.

Keywords
Exotics, Z ', Ditau, Resonance, Search
National Category
Physical Sciences
Identifiers
urn:nbn:se:su:diva-89527 (URN)10.1016/j.physletb.2013.01.040 (DOI)000315316900005 ()
Funder
Swedish Research CouncilKnut and Alice Wallenberg Foundation
Note

AuthorCount:2911;

Available from: 2013-05-03 Created: 2013-04-29 Last updated: 2022-03-23Bibliographically approved
Åsman, B., Bendtz, K., Bohm, C., Clément, C., Eriksson, D., Gellerstedt, K., . . . Yang, Z. (2013). A search for prompt lepton-jets in pp collisions at root s=7 TeV with the ATLAS detector. Physics Letters B, 719(4-5), 299-317
Open this publication in new window or tab >>A search for prompt lepton-jets in pp collisions at root s=7 TeV with the ATLAS detector
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2013 (English)In: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 719, no 4-5, p. 299-317Article in journal (Refereed) Published
Abstract [en]

We present a search for a light (mass < 2 GeV) boson predicted by Hidden Valley supersymmetric models that decays into a final state consisting of collimated muons or electrons, denoted lepton-jets. The analysis uses 5 fb(-1) of root s = 7 TeV proton-proton collision data recorded by the ATLAS detector at the Large Hadron Collider to search for the following signatures: single lepton-jets with at least four muons; pairs of lepton-jets, each with two or more muons; and pairs of lepton-jets with two or more electrons. This study finds no statistically significant deviation from the Standard Model prediction and places 95% confidence-level exclusion limits on the production cross section times branching ratio of light bosons for several parameter sets of a Hidden Valley model.

National Category
Physical Sciences
Identifiers
urn:nbn:se:su:diva-89525 (URN)10.1016/j.physletb.2013.01.034 (DOI)000315316900008 ()
Funder
Swedish Research CouncilKnut and Alice Wallenberg Foundation
Note

AuthorCount:2886;

Available from: 2013-05-03 Created: 2013-04-29 Last updated: 2022-03-23Bibliographically approved
Åsman, B., Bendtz, K., Bohm, C., Clément, C., Eriksson, D., Gellerstedt, K., . . . Yang, Z. (2013). ATLAS search for new phenomena in dijet mass and angular distributions using pp collisions at root s=7 TeV. Journal of High Energy Physics (JHEP) (1), 029
Open this publication in new window or tab >>ATLAS search for new phenomena in dijet mass and angular distributions using pp collisions at root s=7 TeV
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2013 (English)In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, no 1, p. 029-Article in journal (Refereed) Published
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.

Keywords
Hadron-Hadron Scattering
National Category
Physical Sciences
Identifiers
urn:nbn:se:su:diva-89251 (URN)10.1007/JHEP01(2013)029 (DOI)000315583200029 ()
Funder
Swedish Research CouncilKnut and Alice Wallenberg Foundation
Note

AuthorCount:2903;

Available from: 2013-04-17 Created: 2013-04-17 Last updated: 2022-03-23Bibliographically approved
Åsman, B., Bendtz, K., Bohm, C., Clément, C., Eriksson, D., Gellerstedt, K., . . . Yang, Z. (2013). Characterisation and mitigation of beam-induced backgrounds observed in the ATLAS detector during the 2011 proton-proton run. Journal of Instrumentation, 8, P07004
Open this publication in new window or tab >>Characterisation and mitigation of beam-induced backgrounds observed in the ATLAS detector during the 2011 proton-proton run
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2013 (English)In: Journal of Instrumentation, ISSN 1748-0221, E-ISSN 1748-0221, Vol. 8, p. P07004-Article in journal (Refereed) Published
Abstract [en]

This paper presents a summary of beam-induced backgrounds observed in the ATLAS detector and discusses methods to tag and remove background contaminated events in data. Trigger-rate based monitoring of beam-related backgrounds is presented. The correlations of backgrounds with machine conditions, such as residual pressure in the beam-pipe, are discussed. Results from dedicated beam-background simulations are shown, and their qualitative agreement with data is evaluated. Data taken during the passage of unpaired, i.e. non-colliding, proton bunches is used to obtain background-enriched data samples. These are used to identify characteristic features of beam-induced backgrounds, which then are exploited to develop dedicated background tagging tools. These tools, based on observables in the Pixel detector, the muon spectrometer and the calorimeters, are described in detail and their efficiencies are evaluated. Finally an example of an application of these techniques to a monojet analysis is given, which demonstrates the importance of such event cleaning techniques for some new physics searches.

Keywords
Pattern recognition, cluster finding, calibration and fitting methods, Performance of High Energy Physics Detectors, Accelerator modelling and simulations (multi-particle dynamics, single-particle dynamics), Analysis and statistical methods
National Category
Physical Sciences
Identifiers
urn:nbn:se:su:diva-93586 (URN)10.1088/1748-0221/8/07/P07004 (DOI)000322572900015 ()
Projects
Atlas Collaboration
Note

AuthorCount:2913;

Available from: 2013-09-10 Created: 2013-09-10 Last updated: 2022-03-23Bibliographically approved
Abulaiti, Y., Åsman, B., Bendtz, K., Bohm, C., Clément, C., Eriksson, D., . . . Yang, Z. (2013). Dynamics of isolated-photon plus jet production in pp collisions at root s=7 TeV with the ATLAS detector. Nuclear Physics B, 875(3), 483-535
Open this publication in new window or tab >>Dynamics of isolated-photon plus jet production in pp collisions at root s=7 TeV with the ATLAS detector
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2013 (English)In: Nuclear Physics B, ISSN 0550-3213, E-ISSN 1873-1562, Vol. 875, no 3, p. 483-535Article in journal (Refereed) Published
Abstract [en]

The dynamics of isolated-photon plus jet production in pp collisions at a centre-of-mass energy of 7 TeV has been studied with the ATLAS detector at the LHC using an integrated luminosity of 37 pb(-1). Measurements of isolated-photon plus jet bin-averaged cross sections are presented as functions of photon transverse energy, jet transverse momentum and jet rapidity. In addition, the bin-averaged cross sections as functions of the difference between the azimuthal angles of the photon and the jet, the photon jet invariant mass and the scattering angle in the photon jet centre-of-mass frame have been measured. Next-to-leading-order QCD calculations are compared to the measurements and provide a good description of the data, except for the case of the azimuthal opening angle.

Keywords
QCD, Photon, Jet
National Category
Physical Sciences
Identifiers
urn:nbn:se:su:diva-95073 (URN)10.1016/j.nuclphysb.2013.07.025 (DOI)000324601700001 ()2-s2.0-85042012072 (Scopus ID)
Projects
ATLAS Collaboration
Funder
Knut and Alice Wallenberg FoundationSwedish Research CouncilEU, European Research Council
Note

AuthorCount:2916;

Other Funding Agencies: 73 from various countries

Available from: 2013-10-23 Created: 2013-10-21 Last updated: 2022-10-06Bibliographically approved
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