Transcript HESR…
Concept of the PANDA Detector for pp&pA at GSI • • • • • Physical motivation for hadron physics with pbars The antiproton facility Detector concept Selected simulation results Conclusions James Ritman Univ. Giessen Physical Motivation 1. Quantitative understanding of quark confinement Charmonium (Bettoni, Koch) 2. Do hadrons other than mesons and baryons exist? glueballs and/or hybrids (Peters) 3. The mass of hadrons is much larger than the sum of the valence current quark masses. (SBcS) p A interactions 4. Nuclear spectroscopy and the study of baryon-baryon interactions double hypernuclei (Pochodzalla) • Future options (Poster: Ganzhur&Koch) Overview talk by W. Henning The GSI p Facility HESR = High Energy Storage Ring • Production rate 2x107/sec • Pbeam = 1 - 15 GeV/c • Nstored = 5x1010 p High luminosity mode • Lumin. = 2x1032 cm-2s-1 • dp/p~10-4 (stochastic cooling) High resolution mode • dp/p~10-5 (el. cooling < 8 GeV/c) • Lumin. = 1031 cm-2s-1 General Purpose Detector Detector requests: • nearly 4p solid angle (partial wave analysis) • high rate capability (2107 annihilations/s) • good PID (g, e, m, p, K, p) • momentum resolution (~1%) • vertex info for D, K0S, L (ct = 317mm for D) • efficient trigger (e, m, K, D, L) • modular design (Hypernuclei experiments) Detector Concept target spectrometer DIRC: Detecting Internally Reflected Cherenkov light straw tube tracker mini drift chambers muon counter iron yoke Solenoidal magnet electromagnetic calorimeter micro vertex detector forward spectrometer Target • A fiber/wire target will be needed for D physics, • A pellet target is conceived: 1016 atoms/cm2 for D=20-40 mm 1 mm MVD Conversion Prob: ~3%, primary e+e- ~3.6% Central Tracking Detectors • MVD: (Si) 5 layers • Straw-Tubes: 15 skewed double-layers • Mini-Drift-Chambers example event: pp f f 4K Tracking Resolution Single track resolution Invariant mass resolution J/y m+m- Example reaction: pp J/y + F (s = 4.4 GeV/c2) F K+K- s(J/y) = 35 MeV/c2 s(F) = 3.8 MeV/c2 PID with DIRC (DIRC@BaBar) GEANT4 simulation for HESR: PbWO4 Calorimeter Length = 17 X0 APD readout (in field) pp J/Y h mm gg e/p-Separation Muon Detector Performance of Spectrometer Probability to measure the reaction: pp J / Y h J/Y ee ( s = 4.4 GeV ) J/Y m(m) Simulations Framework Event Generation (FS) DPM pbar + p background PndEvtGen selected channels PndSimApp GEANT4 modeling of the detector PndRecoApp tracking, EMC cluster finding, RICH ring finding,... PandaApp (FastSim) „user analysis“, PID, spectra, ... Summary • HESR: cooled antiprotons up to 15 GeV/c • Wide program in hadron physics • Detector concept • Selected simulation results Pressemitteilung 05.02.2003 Bulmahn gives green light for large-scale research equipment "We are securing an international top position for German basic research" … Together with European partners, the Gesellschaft für Schwerionenforschung (GSI) in Darmstadt is to develop further its equipment in a phased approach and become a leading European physics centre. At least 25% of the costs amounting to €675 million are to be shouldered by foreign partners. Neutral Vertex Finder Reaction: pp-2K0s |D0|>0.4 mm or |Z0|>0.5 mm for each track Kinematic refit (constraint=common vertex) 3-Momentum conservation p+ K0S pp+ p- p- Forward Spectrometer What Can Antiproton Beams Contribute to this Discussion? Much lower momentum for heavy produced particles (2GeV for “free”) (Mass shifts are smaller at high momentum) Open charm mass region (H atom of QCD) @HESR (single light quark) Well defined nuclear environment (T and r)