Endre søk
Begrens søket
1 - 21 of 21
RefereraExporteraLink til resultatlisten
Permanent link
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Treff pr side
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sortering
  • Standard (Relevans)
  • Forfatter A-Ø
  • Forfatter Ø-A
  • Tittel A-Ø
  • Tittel Ø-A
  • Type publikasjon A-Ø
  • Type publikasjon Ø-A
  • Eldste først
  • Nyeste først
  • Skapad (Eldste først)
  • Skapad (Nyeste først)
  • Senast uppdaterad (Eldste først)
  • Senast uppdaterad (Nyeste først)
  • Disputationsdatum (tidligste først)
  • Disputationsdatum (siste først)
  • Standard (Relevans)
  • Forfatter A-Ø
  • Forfatter Ø-A
  • Tittel A-Ø
  • Tittel Ø-A
  • Type publikasjon A-Ø
  • Type publikasjon Ø-A
  • Eldste først
  • Nyeste først
  • Skapad (Eldste først)
  • Skapad (Nyeste først)
  • Senast uppdaterad (Eldste først)
  • Senast uppdaterad (Nyeste først)
  • Disputationsdatum (tidligste først)
  • Disputationsdatum (siste først)
Merk
Maxantalet träffar du kan exportera från sökgränssnittet är 250. Vid större uttag använd dig av utsökningar.
  • 1.
    Bargholtz, Chr
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Chernyshev, B.A
    Gerén, L
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Grebenev, V.N
    Gurov, Yu.B
    Karpuhkin, V.S
    Laukhin, I.V
    Martemyanov, B.V
    Matveev, V.A
    Lindberg, Karl
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Shafigullin, R.R
    Sopov, V.S
    Tegnér, Per-Erik
    Zartova, Irina
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Tagging of η mesons using the pd3Heη reaction near threshold2006Inngår i: Instruments and experimental techniques (New York), ISSN 0020-4412, E-ISSN 1608-3180, Vol. 49, nr 4, s. 461-467Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A zero-degree spectrometer for tagging η mesons on the CELSIUS/WASA facility is described, and its characteristics are presented. Tagging of η mesons is performed by detecting 3He ions produced by reaction pd3Heη close to the production threshold. The low background level (<2%) is in good agreement with the data obtained earlier on the SATURNE accelerator.

  • 2.
    Bargholtz, Christoph
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Gerén, Linda
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Lindberg, Karl
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Tegnér, Per-Erik
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Thörngren-Engblom, Pia
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Zartova, Irina
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
     Exclusive measurtement of two-pion production in the dd->4Heππ reaction2009Inngår i: Nuclear Physics A, ISSN 0375-9474, E-ISSN 1873-1554, Vol. 825, nr 1-2, s. 71-90Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The results from the first kinematically complete measurement of the reaction are reported. The aim was to investigate a long standing puzzle regarding the origin of the peculiar ππ-invariant mass distributions appearing in double pion production in light ion collisions, the so-called ABC effect. The measurements were performed at the incident deuteron energies of 712 MeV and 1029 MeV, with the WASA detector assembly at CELSIUS in Uppsala, Sweden. We report the observation of a characteristic enhancement at low ππ-invariant mass at 712 MeV, the lowest energy yet. At the higher energy, in addition to confirming previous experimental observations, our results reveal a strong angular dependence of the pions in the overall centre of mass system. The results are qualitatively reproduced by a theoretical model, according to which the ABC effect is described as resulting from a kinematical enhancement in the production of the pion pairs from two parallel and independent NNdπ sub-processes.

  • 3.
    Bargholtz, Christoph
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Gerén, Linda
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Lindberg, Karl
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Tegnér, Per-Erik
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Thörngren-Engblom, Pia
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Zartova, Irina
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
     Production of the ω meson in the pd -> 3He ω reaction at 1450 MeV and 1360 MeV2009Inngår i: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, ISSN ISSN 0556-2813, Vol. 79, nr 4, s. 044002-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The production of ω mesons in the pd→3Heω reaction has been studied at two energies near the kinematic threshold, Tp=1450 MeV and Tp=1360 MeV. The differential cross section was measured as a function of the ω c.m. angle at both energies over the whole angular range. Whereas the results at 1360 MeV are consistent with isotropy, strong rises are observed near both the forward and backward directions at 1450 MeV. Calculations made using a two-step model with an intermediate pion fail to reproduce the shapes of the measured angular distributions and also underestimate the total cross sections

  • 4.
    Bargholtz, Christoph
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum. kärnfysik.
    Gerén, Linda
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum. kärnfysik.
    Lindberg, Karl
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum. kärnfysik.
    Tegnér, Per-Erik
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum. kärnfysik.
    Zartova, Irina
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum. kärnfysik.
    Calén,, H.
    The Svedberg Laboratory, Uppsala, Sweden.
    Ekström,, C.
    The Svedberg Laboratory, Uppsala, Sweden.
    Fransson,, K.
    The Svedberg Laboratory, Uppsala, Sweden.
    Kupsc, À.
    The Svedberg Laboratory, Uppsala, Sweden.
    Marciniewski,, P.
    The Svedberg Laboratory, Uppsala, Sweden.
    Ruber,, R. J. M.Y.
    The Svedberg Laboratory, Uppsala, Sweden.
    Measurement of h meson decays into lepton-antilepton pairs2008Inngår i: Physical Review D. Particles and fields, ISSN 0556-2821, E-ISSN 1089-4918, Vol. 77, nr 3, s. 32004-32008Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A search for rare lepton decays of the η meson was performed using the WASA detector at CELSIUS. Two candidates for double Dalitz decay η→e+e-e+e- events are reported with a background of 1.3±0.2 events. This allows to set an upper limit to the branching ratio of 9.7×10-5 (90% CL). The branching ratio for the decay η→e+e-γ is determined to (7.8±0.5stat±0.8syst)×10-3 in agreement with world average value. An upper limit (90% CL) for the branching ratio for the η→e+e- decay is 2.7×10-5 and a limit for the sum of the η→μ+μ-μ+μ- and η→π+π-μ+μ- decays is 3.6×10-4.

  • 5.
    Bargholtz, Christoph
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum. kärnfysik.
    Gerén, Linda
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum. kärnfysik.
    Lindberg, Karl
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum. kärnfysik.
    Tegnér, Per-Erik
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum. kärnfysik.
    Zartova, Irina
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum. kärnfysik.
    Kupść, A.
    Department of Nuclear and Particle Physics, Uppsala University.
    Shafigullinc, R.R:
    Moscow Engineering Physics Institute (State University), .
    Properties of the WASA pellet target and a stored intermediate-energy beam2008Inngår i: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 587, nr 2-3, s. 178-187Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Experimental data from the reaction close to threshold have been used to investigate time-dependent properties of the WASA pellet target and the stored beam of 892.8 MeV protons in the CELSIUS accelerator. The detection of 3He ions in solid-state detectors provides an excellent almost background free trigger for η production. Pellet interactions with the surrounding material and with the beam lead to evaporation of deuterium gas into the beam pipe. Approximately 30% of the registered η decay events are due to interactions in deuterium gas outside the pellets. Due to beam–target interaction the beam is transversely heated and appears to acquire a component of a slightly lower energy.

  • 6.
    Bargholtz, Christoph
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Tegner, Per-Erik
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Zartova, Irina
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Jacewicz, M.
    Uppsala University, Uppsala, Sweden.
    Johansson, T
    Uppsala University, Uppsala, Sweden.
    Lindberg, Karl
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Keleta, S.
    Uppsala University, Uppsala, Sweden.
    Koch, I.
    Uppsala University, Uppsala, Sweden.
    Kullander, S.
    Uppsala University, Uppsala, Sweden.
    Schönning, K.
    Uppsala University, Uppsala, Sweden.
    Thörngren Engblom, P.
    Uppsala University, Uppsala, Sweden.
    Wolke, M.
    Uppsala University, Uppsala, Sweden.
    Calén, H.
    The Svedberg Laboratory, Uppsala, Sweden.
    Ekström, C.
    The Svedberg Laboratory, Uppsala, Sweden.
    Fransson, K.
    The Svedberg Laboratory, Uppsala, Sweden.
    Marciniewski, P.
    The Svedberg Laboratory, Uppsala, Sweden.
    Ruber, R.J.M.Y.
    The Svedberg Laboratory, Uppsala, Sweden.
    Gustafsson, L.
    Uppsala University, Uppsala, Sweden.
    Höistad, B.
    Uppsala University, Uppsala, Sweden.
    Kupść, A.
    The Svedberg Laboratory, Uppsala, Sweden.
    Measurement of the η -> π+π-e+e- branching ratio2007Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 644, nr 5-6, s. 299-303Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The reaction at threshold was used to provide a clean source of η mesons for decay studies with the WASA detector at CELSIUS. The branching ratio of the decay ηπ+πe+e is measured to be (4.3±1.3±0.4)×10−4.

  • 7. Lorente, A. Sanchez
    et al.
    Achenbach, P.
    Agnello, M.
    Bressani, T.
    Bufalino, S.
    Cederwall, B.
    Feliciello, A.
    Ferro, F.
    Gerl, J.
    Iazzi, F.
    Kavatsyuk, M.
    Kojouharov, I.
    Majling, L.
    Pantaleo, A.
    Palomba, M.
    Pochodzalla, J.
    Raciti, G.
    Saito, N.
    Saito, T. R.
    Schaffner, H.
    Sfienti, C.
    Szymanska, K.
    Tegner, Per - Erik
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Performance of HPGe detectors in high magnetic fields2007Inngår i: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 573, nr 3, s. 410-417Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A new generation of high-resolution hypernuclear gamma-spectroscopy experiments with high-purity germanium detectors (HPGe) are presently designed at the FINUDA spectrometer at DA Phi NE, the Frascati phi-factory, and at (P) over bar ANDA, the (p) over barp hadron spectrometer at the future FAIR facility. Both, the FINUDA and (P) over bar ANDA spectrometers are built around the target region covering a large solid angle. To maximise the detection efficiency the HPGe detectors have to be located near the target, and therefore they have to be operated in strong magnetic fields (B approximate to I T). The performance of HPGe detectors in such an environment has not been well investigated so far. In the present work VEGA and EUROBALL Cluster HPGe detectors were tested in the field provided by the ALADiN magnet at GSI. No significant degradation of the energy resolution was found, and a change in the rise time distribution of the pulses from preamplifiers was observed. A correlation between rise time and pulse height was observed and is used to correct the measured energy, recovering the energy resolution almost completely. Moreover, no problems in the electronics due to the magnetic field were observed.

  • 8.
    Makonyi, Karoly
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Marcks von Würtemberg, Klas
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Tegnér, Per-Erik
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Hansen, K.
    Isaksson, L.
    Lundin, M.
    Schroder, B.
    Balkeståhl, L.
    Fransson, K.
    Johansson, T.
    Rosenbaum, C.
    Wolke, M.
    Erni, W.
    Keshelashvili, I.
    Krushe, B.
    Evaluating vacuum phototriodes designed for the PANDA electromagnetic calorimeter2014Inngår i: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 763, s. 36-43Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this work properties of a vacuum phototriode (VPT) and preamplifier unit designed for the electromagnetic calorimeter of the PANDA experiment being built at FAIR are investigated. With the use of lead tungstate and lanthanium bromide scintillators the VPT properties are studied at low photon energies, from tens of key in the lanthanium bromide measurements and between 10 MeV and 60 MeV in the lead tungstate measurements. At these energies the noise of the VPT unit can be expected to influence its performance significantly. It is shown that the noise contribution to the measured energy resolution, under optimal conditions, is consistent with a fluctuation of (one standard deviation) approximately 200 electrons at the VPT anode. For a lead tungstate crystal this is equivalent to a noise of 1.2 MeV. For lanthanium bromide this makes it possible to use VPTs for gamma ray spectroscopy above a few hundreds of keV without noticeable effects on the energy resolution compared to measurements with a standard photomultiplier.

  • 9.
    Makonyi, Karoly
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Preston, Markus
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Tegnér, Per Erik
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Wölbing, Dirk
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Technical design report for the (P)over-barANDA Barrel DIRC detector2019Inngår i: Journal of Physics G: Nuclear and Particle Physics, ISSN 0954-3899, E-ISSN 1361-6471, Vol. 46, nr 4, artikkel-id 045001Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The (P) over bar ANDA (anti-Proton ANnihiliation at DArmstadt) experiment will be one of the four flagship experiments at the new international accelerator complex FAIR (Facility for Antiproton and Ion Research) in Darmstadt, Germany. (P) over bar ANDA will address fundamental questions of hadron physics and quantum chromodynamics using high-intensity cooled antiproton beams with momenta between 1.5 and 15 GeV/c and a design luminosity of up to 2 x 10(32) cm(-2) S-1. Excellent particle identification (PID) is crucial to the success of the (P) over bar ANDA physics program. Hadronic PID in the barrel region of the target spectrometer will be performed by a fast and compact Cherenkov counter using the detection of internally reflected Cherenkov light (DIRC) technology. It is designed to cover the polar angle range from 22 degrees to 140 degrees and will provide at least 3 standard deviations (s.d.) pi/K separation up to 3.5 GeV/c, matching the expected upper limit of the final state kaon momentum distribution from simulation. This documents describes the technical design and the expected performance of the (P) over bar ANDA Barrel DIRC detector. The design is based on the successful BaBar DIRC with several key improvements. The performance and system cost were optimized in detailed detector simulations and validated with full system prototypes using particle beams at GSI and CERN. The final design meets or exceeds the PID goal of clean pi/K separation with at least 3 s.d. over the entire phase space of charged kaons in the Barrel DIRC.

  • 10.
    Makonyi, Karoly
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Preston, Markus
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Tegnér, Per-Erik
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Wölbing, Dirk
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Feasibility studies of time-like proton electromagnetic form factors at PANDA at FAIR2016Inngår i: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 52, nr 10, artikkel-id 325Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Simulation results for future measurements of electromagnetic proton form factors at PANDA (FAIR) within the PandaRoot software framework are reported. The statistical precision with which the proton form factors can be determined is estimated. The signal channel (p) over barp -> e(+)e(-) is studied on the basis of two different but consistent procedures. The suppression of the main background channel, i.e. (p) over barp -> pi(+)pi(-), is studied. Furthermore, the background versus signal efficiency, statistical and systematical uncertainties on the extracted proton form factors are evaluated using two different procedures. The results are consistent with those of a previous simulation study using an older, simplified framework. However, a slightly better precision is achieved in the PandaRoot study in a large range of momentum transfer, assuming the nominal beam conditions and detector performance.

  • 11.
    Makonyi, Karoly
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Preston, Markus
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Tegnér, Per-Erik
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Wölbing, Dirk
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum. Stockholm Univ, Stockholm, Sweden.
    Feasibility study for the measurement of pi N transition distribution amplitudes at (P)over-barANDA in (P)over-barp -> J/psi pi(0)2017Inngår i: Physical Review D: covering particles, fields, gravitation, and cosmology, ISSN 2470-0010, E-ISSN 2470-0029, Vol. 95, nr 3, artikkel-id 032003Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The exclusive charmonium production process in (P) over barp annihilation with an associated pi 0 meson (p) over barp -> J/psi pi(0) is studied in the framework of QCD collinear factorization. The feasibility of measuring this reaction through the J/psi -> e(+) e(-) decay channel with the AntiProton ANnihilation at DArmstadt ((P) over bar ANDA) experiment is investigated. Simulations on signal reconstruction efficiency as well as the background rejection from various sources including the (P) over barp -> pi(+)pi(-)pi(0) and (p) over barp -> J/psi pi(0)pi(0) reactions are performed with PANDAROOT, the simulation and analysis software framework of the (P) over bar ANDA experiment. It is shown that the measurement can be done at (P) over bar ANDA with significant constraining power under the assumption of an integrated luminosity attainable in four to five months of data taking at the maximum design luminosity.

  • 12.
    Makonyi, Karoly
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Preston, Markus
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Tegnér, Per-Erik
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Wölbing, Dirk
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Study of doubly strange systems using stored antiprotons2016Inngår i: Nuclear Physics A, ISSN 0375-9474, E-ISSN 1873-1554, Vol. 954, s. 323-340Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Bound nuclear systems with two units of strangeness are still poorly known despite their importance for many strong interaction phenomena. Stored antiprotons beams in the GeV range represent an unparalleled factory for various hyperon-antihyperon pairs. Their outstanding large production probability in antiproton collisions will open the floodgates for a series of new studies of systems which contain two or even more units of strangeness at the PANDA experiment at FAIR. For the first time, high resolution gamma-spectroscopy of doubly strange Lambda Lambda-hypernuclei will be performed, thus complementing measurements of ground state decays of Lambda Lambda-hypernuclei at J-PARC or possible decays of particle unstable hypernuclei in heavy ion reactions. High resolution spectroscopy of multistrange Xi(-) -atoms will be feasible and even the production of Omega(-) -atoms will be within reach. The latter might open the door to the vertical bar S vertical bar = 3 world in strangeness nuclear physics, by the study of the hadronic Omega(-) -nucleus interaction. For the first time it will be possible to study the behavior of Xi(+) in nuclear systems under well controlled conditions.

  • 13.
    Makonyi, Karoly
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Tegnér, Per Erik
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    von Würtemberg, Klas Marcks
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Experimental access to Transition Distribution Amplitudes with the PANDA experiment at FAIR2015Inngår i: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 51, nr 8, artikkel-id 107Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Baryon-to-meson Transition Distribution Amplitudes (TDAs) encoding valuable new information on hadron structure appear as building blocks in the collinear factorized description for several types of hard exclusive reactions. In this paper, we address the possibility of accessing nucleon-to-pion (pi N) TDAs from (p) over barp -> e(+)e(-)pi(0) reaction with the future PANDA detector at the FAIR facility. At high center-of-mass energy and high invariant mass squared of the lepton pair q(2), the amplitude of the signal channel (p) over barp -> e(+)e(-)pi(0) admits a QCD factorized description in terms of pi N TDAs and nucleon Distribution Amplitudes (DAs) in the forward aid backward kinematic regimes. Assuming the validity of this factorized description, we perform feasibility studies for measuring (p) over barp -> e(+)e(-)pi(0) with the PANDA detector. Detailed simulations on signal reconstruction efficiency as well as on rejection of the most severe background channel, i.e. (p) over barp -> pi(+)pi(-)pi(0) were performed for the center-of-mass energy squared s = 5 GeV2 and s = 10 GeV2, in the kinematic regions 3.0 < q(2) < 4.3 GeV2 and 5 < q(2) < 9 GeV2, respectively, with a neutral pion scattered in the forward or backward cone vertical bar cos theta(pi 0)vertical bar > 0.5 in the proton-antiproton center-of-mass frame. Results of the simulation show that the particle identification capabilities of the PANDA detector will allow to achieve a background rejection factor of 5 . 10(7) (1 . 10(7)) at low (high) q(2) for s = 5 GeV2, and of 1 . 10(8) (6 . 10(6)) at low (high) q(2) for s = 10 GeV2, while keeping the signal reconstruction efficiency at around 40%. At both energies, a clean lepton signal can be reconstructed with the expected statistics corresponding to 2 of integrated luminosity. The cross sections obtained from the simulations are used to show that a test of QCD collinear factorization can be done at the lowest order by measuring scaling laws and angular distributions. The future measurement of the signal channel cross section with PANDA will provide a new test of the perturbative QCD description of a novel class of hard exclusive reactions and will open the possibility of experimentally accessing pi N TDAs.

  • 14.
    Makonyi, Karoly
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Tegnér, Per-Erik
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    von Wurtemberg, K. M.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Technical design report for the PANDA (AntiProton Annihilations at Darmstadt) Straw Tube Tracker2013Inngår i: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 49, nr 2, s. 25-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This document describes the technical layout and the expected performance of the Straw Tube Tracker (STT), the main tracking detector of the PANDA target spectrometer. The STT encloses a Micro-Vertex-Detector (MVD) for the inner tracking and is followed in beam direction by a set of GEM stations. The tasks of the STT are the measurement of the particle momentum from the reconstructed trajectory and the measurement of the specific energy loss for a particle identification. Dedicated simulations with full analysis studies of certain proton-antiproton reactions, identified as being benchmark tests for the whole PANDA scientific program, have been performed to test the STT layout and performance. The results are presented, and the time lines to construct the STT are described.

  • 15.
    Makonyi, Karolyn
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Preston, Markus
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Tegnér, Per-Erik
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Wölbing, Dirk
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Precision resonance energy scans with the PANDA experiment at FAIR: Sensitivity study for width and line shape measurements of the X(3872)2019Inngår i: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 55, nr 3, artikkel-id 42Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper summarises a comprehensive Monte Carlo simulation study for precision resonance energy scan measurements. Apart from the proof of principle for natural width and line shape measurements of very narrow resonances with PANDA, the achievable sensitivities are quantified for the concrete example of the charmonium-like X(3872) state discussed to be exotic, and for a larger parameter space of various assumed signal cross-sections, input widths and luminosity combinations. PANDA is the only experiment that will be able to perform precision resonance energy scans of such narrow states with quantum numbers of spin and parities that differ from JPC=1--.

  • 16.
    Marcks von Wurtemberg, Klas
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Geren, L.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Lundberg, Olof
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Tegnér, Per-Erik
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Fransson, K.
    Grape, S.
    Johansson, T.
    Thome, E.
    Wolke, M.
    Brudvik, J.
    Fissum, K.
    Hansen, K.
    Isaksson, L.
    Lundin, M.
    Schroder, B.
    The response of lead-tungstate scintillators (PWO) to photons with energies in the range 13 MeV-64 MeV2012Inngår i: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 679, s. 36-43Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The response of a matrix of 25 lead tungstate (PWO) scintillator detectors, operated at -25 degrees C, to photons in the range 13 MeV-64 MeV has been measured at the tagged-photon facility at MAX-lab, Lund. The tapered PWO crystals, each with a length of 200 mm and a cross-section of 24.4 x 24.4 mm(2) in the front end, read out by 19 mm photomultiplier tubes, were arranged in a 5 x 5 matrix. The response was measured for photons directed towards the centre of the central crystal as well as for photons directed towards the corner of the central crystal, where four crystals meet. The obtained energy resolution surpasses what has been published so far and is close to the limit given by Poisson statistics and escaped energy. For photons directed towards the centre(corner) of the central crystal the relative energy resolution, defined as (FWHM/2.35)/E-gamma, decreases from 7.3%(11.0%) at E-gamma = 13 MeV to 3.3%(3.6%) at E-gamma = 64 MeV. The reconstructed point of impact of a photon in this energy range is determined with an uncertainty (one standard deviation) of 7.3 +/- 0.1 mm.

  • 17. Petren, H.
    et al.
    Bargholtz, Christoph
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Bashkanov, M.
    Bogoslavsky, D.
    Calen, H.
    Clement, H.
    Demiroers, L.
    Ekstrom, C.
    Fransson, K.
    Faldt, G.
    Gerén, Linda
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Hoistad, B.
    Ivanov, G.
    Jacewicz, M.
    Jiganov, E.
    Johansson, T.
    Keleta, S.
    Khakimova, O.
    Koch, I.
    Kren, F.
    Kullander, S.
    Kupsc, A.
    Lindberg, Karl
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Marciniewski, P.
    Morosov, B.
    Pauly, C.
    Petukhov, Y.
    Povtorejko, A.
    Schonning, K.
    Scobel, W.
    Skorodko, T.
    Stepaniak, J.
    Tegnér, Per-Erik
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Engblom, Pia Thörngren
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Tikhomirov, V.
    Wilkin, C.
    Wolke, M.
    Zabierowski, J.
    Zartova, Irina
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Zlomanczuk, J.
    eta-meson production in proton-proton collisions at excess energies of 40 and 72 MeV2010Inngår i: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 82, nr 5, s. 55206-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The production of eta mesons in proton-proton collisions has been studied using the WASA detector at the CELSIUS storage ring at excess energies of Q = 40 MeV and Q = 72 MeV. The eta was detected through its 2 gamma decay in a near-4 pi electromagnetic calorimeter, whereas the protons were measured by a combination of straw chambers and plastic scintillator planes in the forward hemisphere. About 6.9 x 10(4) and 9.3 x 10(4) events were found at Q = 40 MeV and Q = 72 MeV, respectively, with background contributions of less than 5%. A simple parametrization of the production cross section in terms of low partial waves was used to evaluate the acceptance corrections. Strong evidence was found for the influence of higher partial waves. The Dalitz plots show the presence of p waves in both the pp and the eta {pp} systems and the angular distributions of the eta in the center-of-mass frame suggest the influence of d-wave eta mesons.

  • 18.
    Preston, Markus
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Tegnér, Per-Erik
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Calén, Hans
    Johansson, Tord
    Makónyi, Karoly
    Marciniewski, Pawel
    Kavatsyuk, Myroslav
    Schakel, Peter
    Measurements and Simulations of Single-Event Upsets in a 28-nm FPGA2017Inngår i: PoS - Proceedings of Science, ISSN 1824-8039, E-ISSN 1824-8039, Vol. 313Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Single-event upsets in the configuration memory of the 28-nm Xilinx Kintex-7 FPGA, used in the PANDA electromagnetic calorimeter, have been studied. Results from neutron and proton irradiations at energies up to 184 MeV are presented and compared with previous experimental results. In order to gain information about the energy-dependence of the single-event upset cross section, a GEANT4-based Monte Carlo simulation of upset mechanisms in nanometric silicon volumes has been developed. The results from this model are shown to agree with the experimental data for both neutrons and protons. Knowledge about the energy dependence of the cross section and of the particle flux at the location of the front-end modules in PANDA enables better estimates of the mean time between failures in the electromagnetic calorimeter. At PANDA, a total neutron flux of 1·102 cm−2 s−1 at the location of the front-end modules is expected at the lowest antiproton beam momentum and a luminosity of 1·1031 cm−2 s−1, leading to a predicted Mean Time Between Failures of 47 ± 10 hours per FPGA in the electromagnetic calorimeter.

  • 19. Schonning, K.
    et al.
    Bargholtz, Christoph
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Bashkanov, M.
    Berlowski, M.
    Bogoslawsky, D.
    Calen, H.
    Clement, H.
    Demiroers, L.
    Ekstrom, C.
    Fransson, K.
    Gerén, Linda
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Gustafsson, L.
    Hoistad, B.
    Ivanov, G.
    Jacewicz, M.
    Jiganov, E.
    Johansson, T.
    Keleta, S.
    Khakimova, O.
    Kren, F.
    Kullander, S.
    Kupsc, A.
    Kuzmin, A.
    Lindberg, Karl
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Marciniewski, P.
    Morosov, B.
    Oelert, W.
    Pauly, C.
    Petren, H.
    Petukhov, Y.
    Povtorejko, A.
    Scobel, W.
    Shafigullin, R.
    Shwartz, B.
    Skorodko, T.
    Sopov, V.
    Stepaniak, J.
    Tegnér, Per-Erik
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Engblom, Pia Thörngren
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Tikhomirov, V.
    Turowiecki, A.
    Wagner, G. J.
    Wilkin, C.
    Wolke, M.
    Zabierowski, J.
    Zartova, Irina
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Zlomanczuk, J.
    The pd -> He-3 eta pi(0) reaction at T-p=1450 MeV CELSIUS/WASA Collaboration2010Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 685, nr 1, s. 33-37Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The cross section for the pd -> He-3 eta pi(0) reaction has been measured at a beam energy of 1450 MeV using the WASA detector at the CELSIUS storage ring. The He-3 was detected in coincidence with four photons from the decays of the two mesons. The data indicate that the production mechanism involves the formation of the Delta(1232) isobar. Although the beam energy does not allow the full peak of this resonance to be seen, the invariant mass distributions Of all three pairs of final particles are well reproduced by a phase space Monte Carlo simulation weighted with the p-wave factor of the square of the pi(0) momentum in the He-3 pi(0) system.

  • 20. Schonning, K.
    et al.
    Bargholtz, Christoph
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Bashkanov, M.
    Berlowski, M.
    Bogoslawsky, D.
    Calen, H.
    Clement, H.
    Demiroers, L.
    Ekstrom, C.
    Fransson, K.
    Gerén, Linda
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Gustafsson, L.
    Hoistad, B.
    Ivanov, G.
    Jacewicz, M.
    Jiganov, E.
    Johansson, T.
    Keleta, S.
    Khakimova, O.
    Kren, F.
    Kullander, S.
    Kupsc, A.
    Kuzmin, A.
    Lindberg, Karl
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Marciniewski, P.
    Morosov, B.
    Oelert, W.
    Pauly, C.
    Petren, H.
    Petukhov, Y.
    Povtorejko, A.
    Scobel, W.
    Shafigullin, R.
    Shwartz, B.
    Skorodko, T.
    Sopov, V.
    Stepaniak, J.
    Tegnér, Per-Erik
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Engblom, Pia Thörngren
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Tikhomirov, V.
    Turowiecki, A.
    Wagner, G. J.
    Wolke, M.
    Zabierowski, J.
    Zartova, Irina
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Zlomanczuk, J.
    Production of eta and 3 pi mesons in the pd -> (HeX)-He-3 reaction at 1360 and 1450 MeV2010Inngår i: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 45, nr 1, s. 11-21Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The cross-sections of the pd -> He-3 eta, pd -> He-3 pi(0)pi(0)pi(0) and pd -> He-3 pi(+)pi(-)pi(0) reactions have been measured at the beam kinetic energies T-p = 1360 MeV and T-p = 1450 MeV using the CELSIUS/WASA detector setup. At both energies, the differential cross-section d sigma/d Omega of the eta meson in the pd -> He-3 eta reaction shows a strong forward-backward asymmetry in the CMS. The ratio between the pd -> He-3 pi(+)pi(-)pi(0) and pd -> He-3 pi(0)pi(0)pi(0) cross-sections has been analysed in terms of isospin amplitudes. The reconstructed invariant-mass distributions of the pi pi, He-3 pi and (3)He2 pi systems provide hints on the role of nucleon resonances in the 3 pi production process.

  • 21.
    Tegnér, Per-Erik
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Thörngren-Engblom, Pia
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
     The pp -> d pi(+)pi(0) reaction – a case of Delta Delta excitation without ABC effect2009Inngår i: International Journal of Modern Physics A, ISSN 0217-751X, E-ISSN 1793-656X, Vol. 24, nr 2-3, s. 561-563Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The ABC effect, a low-mass enhancement in the invariant ππ mass, is observed in double-pionic fusion reactions leading to a bound nuclear system in the final state. From previous measurements there have been indications that this phenomenon is resctricted to the σ channel of the ππ system. With exclusive measurements of the pp → dπ<sup>+</sup>π<sup>0</sup> reaction at T<sub>p</sub> = 1.1 GeV we demonstrate that, indeed, the ABC effect does not occur in the vector-isovector ππ channel (ρ channel) despite the fact that the ΔΔ excitation is oberved to be the dominant reaction process. We also show that this reaction is well described by a t-channel ΔΔ excitation with the subsequent decay into the vector-isovector ππ channel given by the ρ channel operator

1 - 21 of 21
RefereraExporteraLink til resultatlisten
Permanent link
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf