Strangeness and Charm in the CBM Experiment

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Strangeness and Charm in the CBM Experiment
V. Friese Gesellschaft für Schwerionenforschung Da
rmstadt, Germany v.friese_at_gsi.de
for the CBM collaboration
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The QCD Phase Diagram and SIS 300

• Beam energy 10 45 AGeV
• highest baryon densities
• first order phase transition
• critical point ?

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Baryon Energy Densities _at_ SIS 300
C. Fuchs, E. Bratkovskaya, W. Cassing
Large energy and baryon densities accessible e gt
ecrit for large part of system evolution Similar
results from QGSM
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Trajectories in the Phase Diagram
3-Fluid Hydro calculation with hadron gas EOS
(Ivanov, Russkikh, Toneev, nucl-th/0503088) Early
phase not equilibrated Predicts reaching the
phase boundary for 10 AGeV 30 AGeV trajectory
near critical point
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Trajectories in the Phase Diagram (2)
UrQMD transport (hadrons, strings,
reonances)Stöcker, nucl-th/0506013 Qualitativ
agreement with 3-Fluid-Hydro Phase border in
reach, maybe critical point also
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Something's going on at low energies
K/p fluctuations exceed UrQMD
v2 underpredicted by UrQMD from 30 AGeV on
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CBM Physics Topics Observables
Equation-of-state at high ?B
collective flow of hadrons, particle
production at threshold energies (open charm)
Deconfined phase at high ?B ?
Strangeness production K, ?, ?, ?, ?
? Charmonium suppression ? Charmonium
(J/?, ?'), open charm (D0, D?)
Chiral symmetry restoration at high ?B ?
In-medium modifications of hadrons ?,
?, ? ? ee- , open charm, .....
1. order phase transition its critical
endpoint Event-by-event fluctuations
(K/p, pT, ...)
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CBM Experimental Programme
Systematic investigations AA collisions from 8
to 45 (35) AGeV, Z/A0.5 (0.4) pA collisions
from 8 to 90 GeV pp collisions from 8 to 90
GeV Beam energies up to 8 AGeV HADES
High rates, rare probes
Detector requirements Large geometrical
acceptance (azimuthal symmetry !) good hadron
and electron identification excellent vertex
resolution high rate capability of detectors, FEE
and DAQ
Large integrated luminosity High beam intensity
and duty cycle, Available for several month per
year
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The FAIR Facility
existing GSI facilities

• Primary beams
• 1012/s 1.5-2 GeV/u 238U28
• 4x1013/s 90 GeV protons
• 1010/s 238U 35 GeV/u ( Ni 45 GeV/u)

SIS 100/300
CBM

• Secondary beams
• rare isotopes 1.5 - 2 GeV/u
• factor 10 000 increased intensity
• antiprotons 3(0) - 30 GeV

• Storage and cooler rings
• e A Collider
• rare isotopes
• 1011 stored and cooled antiprotons
• 0.8 - 14.5 GeV

• Relativistic heavy-ion physics
• Hadron physics with antiproton beam
• Plasma physics with pulsed beams
• Nuclear structure with radioactive ion beams
• Atomic physics

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Experimental Challenges
25 AGeV AuAu, UrQMDGEANT4

• reconstruction of 1000 charges particles per
  event, kinematically focussed
• extremely rare probes D, J/? (10-5 10 -4)
• high rates up to 107/s (beam 109/s)
• displaced vertex determination accuracy 50 µm
• hadron lepton ID

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The CBM Detector

• Radiation hard Silicon Tracking System in dipole
  field
• Electron ID in RICHTRDECAL
• Hadron ID in TOF (RPC)
• ?, µ, p in ECAL
• High-speed DAQ and trigger system

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Detector RD
after 1 MRad
RD ongoing and promising
Charge ADC
Radiation hardness of pixel sensors
RICH optical layout Radiator gas, mirror
material, photodetectors
TRD rate capability
RPC rate capability and large area coverage
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Simulations Level of Reality
Full track reconstruction (STS) Pattern
recognition in RICH Primary secondary vertex
reconstruction Global tracking under work
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Acceptance for TOF-identified Hadrons
Bulk of hadrons can be identified by STS
TOF Improvement for kaons by RICH (?)
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Performance for Hyperons
?-
O-
?
7.7
6.7
15.8
Hyperons reconstructable almost background-free
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Performance for D mesons
AuAu _at_ 25 AGeV, 1012 events min bias, full
track and vertex reconstruction D multiplicity
taken from HSD, background UrQMD no PID of
secondaries
D0
D
80,000 D in 1012 min bias events 1 day of full
luminosity running 100 days with todays MAPS
performance
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Performance for J/?
via ee- assumed pion suppression 10-4 studies
ongoing
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Performance for Flavour Fluctuations
UrQMD AuAu, 25 AGeV
4 ? acceptance identified particles
K/ ? 3.2 ? 0.3 2.6 ? 0.6
p/ ? -5.3 ? 0.07 -5.9 ? 0.1
sensitive to fluctuations within 1
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The Muon Option
C/Fe absorbers detector layers
Promising for J/? Low efficiency for soft
muons Low efficiency for invariant masses below
0.5 GeV Very challenging muon detector (high
densities)
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The CBM Physics Group

• established June 2005
• 1st CBM Physics Workshop December 2005, GSI
• 2nd Physics Workshop June 2006, ECT Trento
• CBM Physics Book in 1 year

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CBM Status
Nov. 2001 FAIR Conceptual Design Report Jul.
2002 FAIR Recommendation by german
Wissenschaftsrat Feb. 2003 FAIR approved by
BMBF Jan. 2004 CBM Letter of Intent
approved "core experiment of FAIR" Jan. 2005
CBM Technical Status Report June 2005 CBM
Physics Group established March 2006 Fed.
Gouvernment FAIR in budgetary plan up to
2014 2007 CBM Technical Proposal
http//www.gsi.de/fair/experiments/CBM
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The CBM collaboration
Croatia RBI, Zagreb China Wuhan Univ. Hefei
Univ. Cyprus Nikosia Univ.   Czech
Republic CAS, Rez Techn. Univ. Prague France
IReS Strasbourg Hungaria KFKI Budapest Eötvös
Univ. Budapest India VECC Kolkata    
Romania NIPNE Bucharest Russia IHEP
Protvino INR Troitzk ITEP Moscow KRI, St.
Petersburg Kurchatov Inst., Moscow LHE, JINR
Dubna LPP, JINR Dubna LIT, JINR Dubna MEPHI
Moscow Obninsk State Univ. PNPI Gatchina SINP,
Moscow State Univ. St. Petersburg Polytec.
U. Ukraine Shevshenko Univ. , Kiev
Korea Korea Univ. Seoul Pusan National
Univ. Norway Univ. Bergen Germany Univ.
Heidelberg, Phys. Inst. Univ. HD, Kirchhoff Inst.
Univ. Frankfurt Univ. Kaiserslautern Univ.
Mannheim Univ. Münster FZ Rossendorf GSI
Darmstadt Poland Krakow Univ. Warsaw
Univ. Silesia Univ. Katowice   Portugal LIP
Coimbra
40 institutions, 350 Members