Transcript HESR…

Concept of the PANDA
Detector for pp&pA at GSI
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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
(2107 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: pp-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)