James Ritman Univ. Giessen Overview of the Proposed Antiproton Facility Antiproton production facility High Energy Storage Ring (HESR) Electron cooling Detector concept Simulations of the detector properties Conclusions

James Ritman Univ. Giessen

Antiproton Production 50 MeV Proton Linac 5 Hz, T=0.1 ms, 50 mA SIS 18, 5  protons up to 2 GeV SIS 100, 4-5 bunches up to 29 GeV Pbar production: 10 8 pbar / bunch Collector Ring 5 s cooling Storage in the NESR at 3 GeV for ~ 20 min. Reinject into SIS100 Experiments at HESR

James Ritman Univ. Giessen Antiproton Storage Ring Number of p in HESR5x10 10 p production rate2x10 7 /sec High luminosity mode: (stochastic cooling) Beam momentum GeV/c Luminosity < 2x10 32 cm -2 s -1  p/p~10 -4 High resolution mode: (electron cooling) Beam momentum GeV/c Luminosity ~ cm -2 s -1  p/p~ 10 -5

James Ritman Univ. Giessen Electron Cooling Momentum spread of beam can be reduced by superimposing the p beam with an electron beam of the same average velocity.

James Ritman Univ. Giessen Fokker-Plank Equation Electron cooling is described by the Fokker-Plank equation. where  (v) is the p velocity distribution, F is the cooling force, m the ion mass and D the diffusion constant. F(v) (v)(v) v

James Ritman Univ. Giessen General Purpose Detector Detector requests: nearly 4  solid angle (partial wave analysis) high rate capability (2  10 7 annihilations/s) good PID ( , e, , , K, p) momentum resolution (~1%) vertex reconstruction for D, K 0 S,  for D   c  m  efficient trigger (e, , K, D,  ) modular design (Hypernuclei experiments)

James Ritman Univ. Giessen

Micro Vertex Detector (MVD) Number of layers5 in barrel, 5 in endcap Thickness (single layer) 200  m Thickness (5 layers)1.25% of X 0 Resolution   z  25 … 100  m 7.2 mio. barrel pixels 50 x 300 μm 2 mio. forward pixels 100 x 150 μm 200 mm

James Ritman Univ. Giessen MVD Performance  D0) = 51  m  Z0) = 82  m Requirement: significantly better than 100  m (D   c  m, D 0  c  m)

James Ritman Univ. Giessen Straw Tube Tracker STT Number of double layers15 Skew angle of layer 1 and 150°0° Skew angle of layers 2-142°-3° Straw tube wall thickness 26  m Wire thickness 20  m Gas90 : 10 He and C 4 H 10 Length150 cm Tube diameters (1-5, 6-10, 11-15)4, 6, 8 mm Total number of tubes8734 Transverse resolution 150  m example event: pp    4K

James Ritman Univ. Giessen Mini Drift Chambers MDC Number of cathode planes2 chambers x 3 layers x 2 planes Orientation of wire planes0°, 60°, 120° Signal wire thickness 25  m Field wire thickness 100  m Cell size1 cm x 1cm, i.e channels Gas90:10 He and C 4 H 10 Resolution: 150  m

James Ritman Univ. Giessen Momentum Resolution Polar angle resolution    1 mrad P t resolution  P /P  1-2 % N.B. 2 T solenoid field in z-direction, i.e. no fringe field!

James Ritman Univ. Giessen Invariant Mass Resolution J/    +  -   +-  +-  (J/  = 35 MeV/c 2  (  = 3.8 MeV/c 2 Example reaction: pp  J/  +  (  s = 4.4 GeV/c 2 )

James Ritman Univ. Giessen PID with DIRC Concept similar to the existing DIRC at BaBar

James Ritman Univ. Giessen DIRC Parameters Angle coverage22° - 150° Quartz thickness and length 1.7 cm / 150 cm SensorsGas chambers with multi-pad readout, or PMTs

James Ritman Univ. Giessen Pion/Kaon Separation High kaon efficiency with about 1-2% pion misidentification probability.

James Ritman Univ. Giessen Pion/Kaon Acceptance The simulated data distributions below are for pions and kaons from the reaction p p  D + D - with T beam = 6.7 GeV/c  s = 4 GeV

James Ritman Univ. Giessen Electromagnetic Calorimeter Detector materialPbWO 4 Photo sensorsAvalanche Photo Diodes Crystal size  35 x 35 x 150 mm 3 (i.e 1.5 x 1.5 R M 2 x 17 X 0 ) Energy resolution 1.54 % /  E[GeV] % Time resolution   130 ps Total number of crystals7150

James Ritman Univ. Giessen Invariant Mass Resolution Example reaction: pp  J/     (  s = 4.4 GeV/c 2 ) m(  )= GeV/c 2  (  ) = GeV/c 2

James Ritman Univ. Giessen Electron Pion Separation  -Suppression e  Deposited energy = p*c   MIP, thus DE < p*c Above 0.4 GeV/c about of pions misidentified

James Ritman Univ. Giessen Muon Detector MUD PositionOutside iron yoke Covered angle  30° - 80°,  = 360° Bar thickness2 cm Flux return as hadron absorber is 50 cm thick in the transverse direction. Threshold is 1.3 GeV/c

James Ritman Univ. Giessen Muon Performance  identification  misidentification High muon efficiency above 1.3 GeV/c About 1% probability for  misidentification

James Ritman Univ. Giessen Summary & Outlook Antiproton facility HESR: high luminosity, electron cooled beam Detector concept Performance of detector components studied OPEN POINTS Background generator (  Dubna) Forward spectrometer Target …

James Ritman Univ. Giessen Antiproton Physics Study Group T. Barnes 8, D. Bettoni 6, R. Calabrese 6, W. Cassing 5, M. Düren 5, S. Ganzuhr 1, A. Gillitzer 7, O. Hartmann 2, V. Hejny 7, P. Kienle 9, H. Koch 1, W. Kühn 5, U. Lynen 2, R. Meier 11, V. Metag 5, P. Moskal 7, H. Orth 2, S. Paul 9, K. Peters 1, J. Pochodzalla 10, J. R. 5, M. Sapozhnikov 3, L. Schmitt 9, C. Schwarz 2, K. Seth 4, N. Vlassov 3, W. Weise 9, U. Wiedner 12

James Ritman Univ. Giessen General Purpose Detector Detector requests: nearly 4  solid angle high rate capability (2  10 7 annihilations/s) good PID ( ,e, , ,K,p) efficient trigger (e, ,K,D,  ) J/+-J/+- ‘+-‘+- pp  ‘pp (  s=3.6 GeV)  4K

James Ritman Univ. Giessen HESR Detector Pellet-Target: Atoms/cm  m MicroVertexDetektor: (Si) 5 layers Straw-Tubes: 15 skewed double layers RICH: DIRC and Aerogel (Proximityfocussing) Straw-Tubes + Mini-Drift-Chambers PbWO 4 -calorimeter 17X 0 2T-Solenoid & 2Tm-Dipole Muon filter EM- & H-cal. near 0°

James Ritman Univ. Giessen Target A fiber/wire target will be needed for D physics, A pellet target is conceived: atoms/cm  m Open point: heating of the beam 1 mm

James Ritman Univ. Giessen

Simulation Scheme Tools:ROOT for data handling and analysis PLUTO++for event generation (ROOT library) phase space / exp. distributions for certain reactions read in by Geant4 or processed directly in ROOT Geant4for detailed detector simulations currently used version: linked with ROOT to use ROOT file I/O PLUTO in ROOT Simulation in GEANT4 Fast Simu In ROOT Analysis with HAF