Physikalisches Institut

WASA (Wide Angle Shower Apparatus) is a large-acceptance detector for charged and neutral particles. It had been installed at the CELSIUS storage ring in Uppsala (Sweden). In 2005 the detector was moved to continue its work at the Cooler Synchrotron COSY at Forschung Zentrum Jülich. It was installed in summer 2006 and has successfully taken several beam times since then. A number of important modifications of the detector elements have been done.

The program of WASA@COSY comprises rare decays of "eta-meson" and "eta' -meson", isospin violating processes in particle reactions as well as the search for exotic processes.

With regard to the latter two-pion production in nucleon-nucleon collisions has been studied out. The comparison of the behavior of pion-pion production in isoscalar, isovector and isotensor channels had been performed.

ABC effect:

The ABC-effect in double-pionic fusion reactions is studied in the exclusive experiments for different beam particles, different targets and different energies. We find that the ABC effect is the result of a narrow exotic resonance in the basic pn->dπ π process which survive even in nuclei

see: -Article in http://prl.aps.org/toc/PRL/v106/i24

- Cover Page http://prl.aps.org/covers/106/24

COSY Annual Report 2008 in Forschungzentrum Jülich - Chapter Physics at COSY / 1.2.2 Two-Pion production in NN collisions - from the ABC-effect to the ABC-resonance


the ANNUAL REPORT 2008 of the INSTITUTE OF NUCLEAR PHYSICS, FZJ JUELICH,
is available: http://www.fz-juelich.de/ikp/publications/AR2008/en/contents.shtml

and Proceedings of the PANIC08 239-241; see also arxiv.org/pdf/0906.2328

Publications

  1. Measurement of the eta->3pi0 Dalitz Plot Distribution with the WASA Detector at COSY
    WASA-at-COSY Collaboration (P. Vlasov et al.)
    accepted Physics Letters B
    nucl-ex/0811.2763
  2. Results on eta/eta-prime Decays from Hadron Machines
    CELSIUS/WASA and WASA-at-COSY Collaborations (A. Kupsc et al.)
    Nucl.Phys.Proc.Suppl.181-182:221-225,2008
    spires-hep entry
    doi:10.1016/j.nuclphysbps.2008.09.040

  3. Proceedings of SCADRON70
    M. Büscher: The Light Scalar Mesons a0/f0(980) at COSY-Jülich,
    AIP Conf.Proc.1030:40-45,2008
    hep-ph/0804.2452
    DOI:10.1063/1.2973542

  4. Proceedings of MENU2007
    SLAC eConf C070910
    * M. Wolke: Rare Eta Meson Decays with WASA-at-COSY
    * C. Pauly: 3pi0 final states with WASA at CELSIUS and COSY
    * B.R. Jany: EtaPrime Decays with WASA at COSY
    * C.F. Redmer: In search of the box anomaly with the WASA-at-COSY facility
    * L.Yurev, M.Janusz: From charged tracks to ChPT anomalies
    * T.Tolba: Preparations for a Pellet Tracking System

  5. Proceedings of Symposium on Meson Physics at COSY-11 and WASA-at-COSY
    AIP Conf.Proc.950
    * M. Hodana: Dynamics of the eta meson production in proton-proton collisions
    * P. Podkopal: Charge symmetry breaking in d d ---> alpha pi0
    * M. Janusz: Studies of the eta ---> pi+ pi- e+ e- decay channel
    * P. Vlasov: Status of the analysis of the p p ---> p p (eta --->3pi0) reaction

  6. News from COSY
    H. Machner (FZJ)
    GHP Newsletter January 2006

  7. Strangeness physics with the WASA detector at COSY
    A. Gillitzer, D. Grzonka (FZJ)
    Int.J.Mod.Phys.A20:539-542,2005
    spires-hep entry
    doi:10.1142/S0217751X05021725
  8. Experiments with the WASA detector at COSY
    J. Ritman (Giessen U. & Julich, Forschungszentrum)
    Int.J.Mod.Phys.A20:525-531,2005
    spires-hep entry
    doi:10.1142/S0217751X05021695
  9. WASA AT COSY
    S. Schadmand (FZJ))
    Proceedings of Eta05 Workshop, Cracow, Poland, 15-18 Sep 2005.
    Acta Phys.Slov.56:351-355,2006
    physics/0511167

  10. WASA gets a new home at COSY (January 2005)
    CERN Courier

  11. Proposal for the Wide Angle Shower Apparatus (WASA) at COSY-Julich: WASA at COSY
    WASA-at-COSY Collaboration (H.-H. Adam et al.)
    nucl-ex/0411038