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Physics with anti protons at the future GSI facility

Physics with anti protons at the future GSI facility. Physics program Detector set-up. High Energy Storage Ring HESR. p. >> cooled anti protons >> internal target. e - cooler. detector. P max = 15 GeV/c L max = 2 ·10 32 cm -2 s -1 Ø < 100 μm Δ p/p < 10 -5. Glueballs

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Physics with anti protons at the future GSI facility

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  1. Physics with anti protons at the future GSI facility • Physics program • Detector set-up High Energy Storage Ring HESR p >> cooled anti protons >> internal target e- cooler detector Pmax = 15 GeV/c Lmax = 2·1032 cm-2 s-1 Ø < 100 μm Δ p/p < 10-5

  2. Glueballs Hybrids Physics program Charmonium spectroscopy Medium modifications of D mesons and J/Ψ in nuclei Hypernuclei CP violation

  3. Mass modifications of mesons pionic atoms π- 25 MeV π π+ KAOS/FOPI K+ K 100 MeV K- HESR D D- 50 MeV ? D+ vacuum nuclear medium ρ = ρ0 Medium modifications of D mesons and J/Ψ in nuclei Continuation of present GSI physics FOPI, KAOS, HADES, …HESR Signal: medium modification of production threshold, resonance width e.g. Ψ’, χ2 Absorption cross section of J/Ψ in nuclei (ρ=ρ0).

  4. Medium modifications Sibirtsev Nul. Phys. A 680 (2001) 274c Hayashigaki, Phys. Lett. B 487 (2000) 96 Look eg. for decay of Ψ’ DD

  5. Charmonium spectroscopy • Charmonium gives information about QCD confinement potential. • Many states are still missing. • pp: direct population of all states. • HESR allows investigation of states above DD threshold. • Cooled beams with Δp/p≤10-5 allow high precision scan of resonances. Crystal Ball e+e- 40 keV

  6. Charmonium spectroscopy high resolution helps to identify states

  7. Signal: exotic quantum numbers: partial wave analysis normal quantum numbers: model comparison (LGT) Glueballs Hybrids mixing with normal mesons charm sector: few resonances with small widths Meson Hybrid Glueball ggg qq qqg Normal meson: 2 fermions P = (-1)L+1 C = (-1)L+S Excited glue: bosonic degree of freedom → exotic quantum numbers eg. JPC=1-+, 0--, 0+-, 2+-… → normal quantum numbers

  8. Glueball, Hybrids

  9. _ X 3 GeV/c p X- Hypernuclei K+K Trigger • X-(dss)p(uud)L(uds)L(uds) • study of L L interaction secondary target

  10. Measure decay asymmetry of angular distribution of p relative to Λ-Hyperon momentum. Ip(θp) ~ 1+α cos(θp) for Λ Ip(θp) ~ 1+α cos(θp) for Λ CP conservation: α = α Signal for CP violation: Theoretical prediction: ~10-4 ~ 10-5 Experiment: 1010 reconstructed ΛΛ L=2·1032 cm-2 s-1 → >1 year running p + p → Λ +Λ ↓ ↓ pπ- pπ+ CP violation in Hyperon decay

  11. Detector requirements (simulations) Formation of Ψ’and decay in muons • Energy release of charmed hadrons high → large ptrans → large angles • High cm-velocity (fixed target) → high energies → small angles Ψ’→μ+μ- electrons similar → calorimeter for large angles. Ψ’→J/Ψ + X ↓ μ+μ-

  12. Detector requirements (PID) p+p → ΦΦ→ 4K s½ =3.6 GeV • Forward angles need π/K separation up to 3 GeV/c: Cherenkov n=1.02 • Backward: higher value of n.

  13. HESR-detector target spectrometer forward spectrometer Internal target top view Heavy charmed mesons decay in light products with large pt. Solenoid is important.

  14. side view HESR detector

  15. 2 mio. forward pixels 100 x 150 μm 7.2 mio. barrel pixels 50 x 300 μm beam pipe pellet pipe Central tracking: Microvertex Detector Readout: ASICs (ATLAS/CMS) 0.37% X0 or pixel one side – readout other side (TESLA)

  16. σZ0=82 μm σD0=51 μm y z D0 Z0 x MVD single track resolution (Geant 4) p p 8.5 GeV 2π+ 2π- Vertex resolution is sufficient for D-physics c(D) = 314 μm, c(D0) = 124 μm

  17. pp(s = 4.4 GeV/c2)  J/+f. TS momentum resolution (Geant 4) MVD straw tubes MDC σM= 1.2% ???

  18. Particle identification • PID from • 00<Θ<50 hadronic calorimeter • 50<Θ<220 Aerogel Cherenkov Counters • 220<Θ<1400 DIRC (BABAR@SLAC) DIRC thickness: 0.19 X0

  19. DIRC PID B = 0 Tesla: Cherenkov opening angle: Internal reflection → different vel. thresholds B = 2 Tesla: Azimuthal deflection → more homogeneous detection efficiency

  20. p p(s = 3.6 GeV/c2) ff. DIRC PID (Geant4) K efficiency misidentification of π as K PID+tracking

  21. Calorimeter 22o 140o 5o PbWO4 Length = 17 X0 APD readout (in field) σ(E) = 1.54% / E½ + 0.3% pp  J/Ψ+η γγ

  22. 10 e±/π±sep. 8 e+/- 6 Edep (GeV/c) 4 2 π+ 0 2 4 6 8 p (GeV/c) π+ probability 10-3 electron/pion separation  10-3 0 2 4 6 8 p (GeV/c)

  23. Pellet target • Frozen hydrogen pellets 20-40μm • Δx=±1 mm (±0.04o) • 60 m/s • 70000 pellets/sec. • 1014-1016 atoms/cm2 (avg.) 1 mm

  24. Costs

  25. Collaborations: Working group: LEAR, COSY, SATURNE community Munich Germany Bochum “ Giessen “ Dresden “ Erlangen “ Jülich “ Ferrara Italy Turin “ Krakow Poland Warsaw “ T. Barnes D. Bettoni R. Calabrese M. Düren S. Ganzhur V. Hejny H. Koch U. Lynen V. Metag H. Orth S. Paul K. Peters J. Pochodzalla J. Ritman L. Schmitt C. Schwarz K. Seth W. Weise U. Wiedner

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