PANDA Ulrich Wiedner, FAIR PAC meeting, March 14, 2005.
PANDA Collaboration • At present a group of 340 physicists from46 institutions of 14 countries Austria – Belaruz - China - Finland - France - Germany – Italy – Poland – Russia – Spain - Sweden – Switzerland - U.K. – U.S.A.. 3 new members Basel, Beijing, Bochum, Bonn, Catania, Cracow, Dresden, Edinburg, Erlangen, Ferrara, Frankfurt, Genova, Giessen, Glasgow, GSI, Inst. of Physics Helsinki, FZ Jülich, JINR, Katowice, Lanzhou, LNF, Mainz, Milano, Minsk, TU München, Münster, Northwestern, BINP Novosibirsk, Pavia, Piemonte Orientale, IPN Orsay, IHEP Protvino, PNPI St. Petersburg, Stockholm, Dep. A. Avogadro Torino, Dep. Fis. Sperimentale Torino, Torino Politecnico,Trieste, TSL Uppsala, Tübingen, Uppsala, Valencia, SINS Warsaw, TU Warsaw, AAS Wien Unfortunately we lost KVI. Spokesperson: Ulrich Wiedner - Uppsala http://www.gsi.de/panda
Main Physics Goals • Charmonium spectroscopy • QCD exotics • Hypernuclear Physics • Charm in Nuclei … base program for the first few years.
Target Luminosity: L = Npbar • f • xtarget Envisaged luminosity: L = 2×1032 cm–2s–1 Required target thickness: 5×1015 cm–2 Hydrogen pellet target. Cluster jet target. Targets for hypernuclear physics.
1 mm Pellet target: working principle and result
Pressure - a measure for the pellet rate Experimental pellet distributions
Predicted beam pipe vacuum pumps at both ends of PANDA additional pumping between solenoid and dipole
Pellet tracking system under investigation: line scan camera provides online information on pellet position <100 µm
pp Targets for Hypernuclear Physics Primary target: Secondary target: stopping of MC simulation of rescattering under large angles
lower light yield slower and more expensive The Electromagnetic Calorimeter Required: Fast, high resolution scintillator for between 10 MeV - 2 GeV Two possible solutions: PbWO4 (PWO) crystals BGO crystals Crystal size: 22 cm2 22 X0
PWO crystals light yield of PANDA crystals better than as CMS crystals
For comparison: BGO crystals 60Co Light yield ~ 8 times higher than PWO
Readout device: APD CMS uses 5x5 mm2 APDs For PANDA: 10x10 mm2 APDs being developed by Hamamatsu Preliminary tests show no significant differences. Alternative readout devices like the PLANACON hybrid photomultiplier have been tested but show sensitivity to magnetic fields.
st / ns Expected performance (PWO calorimeter) Measurements with a tagged photon beam in Mainz: deposited energy / GeV
The Mechanical Design Barrel part: 2.5 m long, Ø 1.08 m, 11360 crystals End caps: upstream: Ø 0.68 m, 816 crystals downstream: Ø ~2 m, 6864 crystals Cooling to -25 C, temperature stabilized to ±0.1 C
The Forward EMC Shashlyk modules composed of lead absorbers and scintillators
pp g c()S-wave J/ e+e– (µ+µ–) Charmed hybrid (JPC=1–+) channel Production mode:
Invariant mass spectra J/ c g