PANDA Ulrich Wiedner, FAIR PAC meeting, March 14, 2005.

PANDA Collaboration At present a group of 340 physicists from 46 institutions of 14 countries 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 Spokesperson: Ulrich Wiedner - Uppsala Austria – Belaruz - China - Finland - France - Germany – Italy – Poland – Russia – Spain - Sweden – Switzerland - U.K. – U.S.A.. 3 new members Unfortunately we lost KVI.

Main Physics Goals Charmonium spectroscopy QCD exotics Hypernuclear Physics Charm in Nuclei … base program for the first few years.

The PANDA Detector

Layout of the detector (top view)

The Target Spectrometer

The Forward Spectrometer

Target Envisaged luminosity: L = 2 × cm –2 s –1 Required target thickness: 5 × cm –2 Luminosity: L = N pbar f x target Cluster jet target. Hydrogen pellet target. Targets for hypernuclear physics.

Pellet Target

Beam pipe and pellet pipe

Reminder: Droplets, Pellets, etc. Liquified hydrogen (H 2 ) Temp K (T f =13.96 K) Through nozzle (d~12 μ m) Droplets formed (d=38 μ m) Cooling by evaporation Vacuum injection, freezing: Droplets now called pellets (d~20 μ m) H 2 molecules The WASA Pellet TargetThe hydrogen path Liquid phase observed, before and after vac. inj. [m]

Pellet target: working principle and result 1 mm

Pellet test station

Pressure - a measure for the pellet rate Experimental pellet distributions

Vacuum measurements

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 µ m

Beam pipe pumping scheme

The Cluster Jet Target

The Cluster Jet Target Gas System

Slow Control

Targets for Hypernuclear Physics pp      MC simulation of   rescattering under large angles Primary target: Secondary target: stopping of  

Stopping points for   (INC calulations)

Secondary target: sandwich of C absorber and Si detectors

The Electromagnetic Calorimeter Required: Fast, high resolution scintillator for  between 10 MeV - 2 GeV Two possible solutions: PbWO 4 (PWO) crystals BGO crystals lower light yield slower and more expensive Crystal size: 2  2 cm 2  22 X 0

PWO crystals light yield of PANDA crystals better than as CMS crystals

Light yield: temperature dependant

Optical Transmission of crystals from different suppliers

Optical transmission after irradiation

For comparison: BGO crystals 60 Co Light yield ~ 8 times higher than PWO

Readout device: APD CMS uses 5x5 mm 2 APDs For PANDA: 10x10 mm 2 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.

Expected performance (PWO calorimeter) Measurements with a tagged photon beam in Mainz: deposited energy / GeV  t / ns

The Mechanical Design Barrel part: 2.5 m long, Ø 1.08 m, 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

Overall Integration

Individual tapered crystals

Design to reduce # of crystal shapes

segmentation of the 160 crystals into 16 slices

Single alveoli pack

Dead space zones

Concept and major components of a barrel slice

End cap design

Implementation of the EMC into PANDA

The Forward EMC Shashlyk modules composed of lead absorbers and scintillators

Some benchmark channel simulation results

Charmed hybrid (J PC =1 –+ ) channel Production mode: pp   g      c (     ) S-wave  J/     e + e – (µ + µ – )  

Invariant mass spectra  J/  cc gg

µ decay channel

Reconstruction efficiencies

Open charm channels  D*(2010) + D*(2010) – D* ±  D 0  ± D 0 decays

Reconstructed  (4040) mass

Summary The PANDA collaboration is healthy and eagerly waiting to build up the experiment and to do world-class physics.