Nucleus-nucleus collisions at the future facility in Darmstadt -
Compressed Baryonic Matter at GSI
Outline:
Dense baryonic matter: fundamental physics Experimental observables Technical challenges and (possible) solutions
Peter Senger
States of strongly interacting matter
baryons hadrons partons
Compression + heating = quark-gluon plasma (pion production)
Neutron stars Early universe
Exploring the phase diagram of strongly interacting matter
CERN-SPS, RHIC, LHC: high temperature, low baryon density
GSI (SIS300): moderate temperature, high baryon density
B 3-80 , T 130 MeV
Fundamental questions:
Equation-of-state at high densities: stability of neutron stars, supernova dynamics
deconfinement
In-medium hadron properties: chiral symmetry restoration, origin of hadron masses?
Creating high baryon densities in the laboratoryby heavy-ion collisions
Transport calculationsB. Friman, W. Nörenberg, V.D. Toneev Eur. Phys. J. A3 (1998) 165
SIS300
Pion multiplicities per participating nucleons
SIS100/300
Statistical hadron gas modelP. Braun-Munzinger et al.
Nucl. Phys. A 697 (2002) 902
Experimental situation : Strangeness enhancement ?Experimental situation : Strangeness production
in central Au+Au and Pb+Pb collisions
New results from NA49 (CERN Courier Oct. 2003)
SIS100300
SIS100300
Comparison of experimental data to results of transport codes E.L. Bratkovskaya, W. Cassing, M. van Leeuwen, S. Soff, H. Stöcker, nucl-th/0307098
“Flow generated by extra pressure generated by partonic interactions in the early phase of a central Au+Au/Pb+Pb collision”
Mapping the QCD phase diagram with heavy-ion collisions
B 6 0
B 0.3 0
baryon density: B 4 ( mT/2)3/2 x
[exp((B-m)/T) - exp((-B-m)/T)] baryons - antibaryons
Analysis of particle ratios with statistical model: chemical freeze-out
P. Braun-Munzinger
SIS300
gasliquid
coexistence
C. R. Allton et al, hep-lat 0305007
Lattice QCD : maximal baryon number density fluctuations at TC for q = TC (B 500 MeV)
CBM physics topics and observables
1. In-medium modifications of hadrons onset of chiral symmetry restoration at high B
measure: , , e+e- open charm (D mesons) 2. Strangeness in matter (strange matter?) enhanced strangeness production ?
measure: K, , , , 3. Indications for deconfinement at high B anomalous charmonium suppression ?
measure: J/, D
softening of EOS
measure flow excitation function 4. Critical point event-by-event fluctuations 5. Color superconductivity precursor effects ??
Note: In heavy ion collisions
(, , ) e+e- not measured from 2 – 40 AGeV
J/ not measured below 158 AGeV
D mesons not measured at all
pn
++
K
e+
e-
p
Looking into the fireball …
… using penetrating probes:
short-lived vector mesons decaying into electron-positron pairs
Measure spectral functions of vector mesons via their decay into electron-positron pairs (penetrating probes!)using Ring Imaging Cherenkov detectors
NA45/CERES @ CERN-SPS
CH4 radiator gas: thr= 32
HADES @ GSI
C4F10 radiator gas: thr= 18.3UV-det.: fast CsI cathode
Invariant mass of electron-positron pairs from Pb+Au at 40 AGeVCERES Collaboration S. Damjanovic and K. Filimonov, nucl-ex/0109017
≈185 pairs!
Signatures of the quark-pluon plasma ?
Anomalous suppression of charmonium (J/) ???
central collisions 25 AGeV Au+Au 158 AGeV Pb+Pb
J/ multiplicity 1.5·10-5 1·10-3 beam intensity 2·108/s 2·107/sinteractions 8·106/s (4%) 2·106/s (10%)central collisions 8·105/s 2·105/sJ/ rate 12/s 200/s 6% J/e+e- (+-) 0.7/s 12/sspill fraction 0.8 0.25 acceptance 0.25 0.1J/ measured 0.14/s 0.3/s 8·104/week 1.8·105/week
J/ experiments: a count rate estimate10 50 120 210 Elab [GeV]
Charmed mesons
Some hadronic decay modes
D (c = 317 m):D+ K0+ (2.90.26%)
D+ K-++ (9 0.6%)
D0 (c = 124.4 m):D0 K-+ (3.9 0.09%)
D0 K-+ + - (7.6 0.4%)
experimental challenges:low production cross sectionlarge combinatorial backgroundmeasure displaced vertex with resolution of 30m
D meson production in pN collisions
SIS18 SIS100/
300
Meson production in central Au+Au collisionsW. Cassing, E. Bratkovskaya, A. Sibirtsev, Nucl. Phys. A 691 (2001) 745
Observables:p, , K, , , , , , , , D, J/(3-diff. cross sect., correlations, dileptonic decays)exotica: strange clusters, pentaquarks, …
The experimental program of CBM:
Collision systems:A+A collisions from 8 to 45 (35) AGeV, Z/A=0.5 (0.4) p+A collisions from 8 to 90 GeVp+p collisions from 8 to 90 GeVBeam energies up to 8 AGeV: HADESAccelerator:SIS300High beam intensity and duty cycle,Excellent beam quality, no halo !Available for several month per year
Experimental challenges
107 Au+Au reactions/sec (beam intensities up to 109 ions/sec, 1 % interaction target)
determination of (displaced) vertices with high resolution ( 30 m)
identification of electrons and hadrons
Central Au+Au collision at 25 AGeV:URQMD + GEANT4
160 p 400 -
400 + 44 K+ 13 K-
The CBM Experiment
Radiation hard Silicon pixel/strip detectors in a magnetic dipole field
Electron detectors: RICH & TRD & ECAL: pion suppression up to 105
Hadron identification: RPC, RICH
Measurement of photons, π, η, and muons: electromagn. calorimeter (ECAL)
High speed data acquisition and trigger system
CBM in GEANT4
CBM R&D working packages Feasibility, Simulations
D Kπ(π)GSI Darmstadt, Czech Acad. Sci., RezTechn. Univ. Prague
,ω, e+e-
Univ. KrakowJINR-LHE Dubna
J/ψ e+e-
INR Moscow
Hadron ID Heidelberg Univ,Warsaw Univ.Kiev Univ. NIPNE BucharestINR Moscow
GEANT4: GSI
TrackingKIP Univ. HeidelbergUniv. MannheimJINR-LHE Dubna
Design & constructionof detectors
Silicon PixelIReS StrasbourgFrankfurt Univ.,GSI Darmstadt,RBI Zagreb,Krakow Univ. LBNL Berkeley
Silicon StripSINP Moscow State U.CKBM St. PetersburgKRI St. Petersburg
RPC-TOFLIP Coimbra, Univ. Santiago de Com.,Univ. Heidelberg,GSI Darmstadt,NIPNE BucharestINR MoscowFZ RossendorfIHEP ProtvinoITEP Moscow
Fast TRDJINR-LHE, DubnaGSI Darmstadt,Univ. MünsterINFN Frascati
Straw tubesJINR-LPP, DubnaPNPI GatchinaFZ RossendorfFZ Jülich
ECAL ITEP Moscow GSI Darmstadt
RICH IHEP Protvino GSI Darmstadt
Trigger, DAQKIP Univ. HeidelbergUniv. MannheimGSI DarmstadtJINR-LIT, DubnaKFKI BudapestSilesia Univ.
MagnetJINR-LHE, DubnaGSI Darmstadt
AnalysisGSI Darmstadt,Heidelberg Univ,
Data Acquis.,Analysis
EU FP6 Hadron Physics (2004 – 2006)
Joint Research Projects (approved):
• Fast gaseous detectors • Advanced TOF Systems• Future DAQ and trigger systems
Network activities (approved):
• CBMnet
CBM Participation in EU Programmes:
INTAS-GSI (2004-2005)
approved projects:
• Transition Radiation Detectors JINR LHE Dubna, NC PHEP Minsk, INFN Frascati, GSI Darmstadt • Straw tube tracker: JINR LPP Dubna, LPI Moscow, PNPI Gatchina, TU Warsaw, FZ Rossendorf, FZ Jülich
• Resistive Plate Chambers INR Troitzk, IHEP Protvino, ITEP Moscow, LIP Coimbra, Univ. Heidelberg
• Electromagnetic calorimeter ITEP Moscow, Polimersintez Wladimir, Univ. Krakow, GSI Darmstadt
New call EU FP6 (opened Nov.03, closed Mar04):
• Design of new facilities • Construction of new facilities
CBM R&D Collaboration : 38 institutions , 15 countriesCroatia:
RBI, Zagreb
Cyprus: Nikosia Univ. Czech Republic:Czech Acad. Science, RezTechn. Univ. Prague France: IReS Strasbourg
Germany: Univ. Heidelberg, Phys. Inst.Univ. HD, Kirchhoff Inst. Univ. FrankfurtUniv. Mannheim Univ. MarburgUniv. MünsterFZ RossendorfGSI Darmstadt
Russia:CKBM, St. PetersburgIHEP ProtvinoINR TroitzkITEP MoscowKRI, St. PetersburgKurchatov Inst., MoscowLHE, JINR DubnaLPP, JINR DubnaLIT, JINR DubnaPNPI GatchinaSINP, Moscow State Univ.
Spain: Santiago de Compostela Univ. Ukraine: Shevshenko Univ. , Kiev
USA: LBNL Berkeley
Hungaria:KFKI BudapestEötvös Univ. Budapest
Italy: INFN CataniaINFN Frascati
Korea:Korea Univ. SeoulPusan Univ.
Poland:Krakow Univ.Warsaw Univ.Silesia Univ. Katowice Portugal: LIP Coimbra
Romania: NIPNE Bucharest