Physics of High Baryon Densities - The CBM experiment at FAIR
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Transcript of Physics of High Baryon Densities - The CBM experiment at FAIR
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Physics of High Baryon Densities - The CBM experiment at FAIR
Subhasis Chattopadhyay Variable Energy Cyclotron Centre, Kolkata
for the CBM collaboration
Outline:Outline:
CBM physics CBM physics CBM setup CBM setup Feasibility studiesFeasibility studies Detector R&D Detector R&D
CBM
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RHIC result: new state of matter = perfect liquid? Tf = 160 – 165 MeV
L-QCD Predictions: TC = 151 ± 7 ± 4 MeV ( μB=0 ) (Z. Fodor, arXiv:0712.2930 hep-lat) TC = 192 ± 7 ± 4 MeV ( μB=0 ) (F. Karsch, arXiv:0711.0661 hep-lat) crossover transition at μB=0 (Z. Fodor, arXiv:0712.2930 hep-lat) 1. order phase transition with critical endpoint at μB > 0
High-energy heavy-ion collision experiments:
RHIC, LHC: cross over transition, QGP at high T and low ρLow-energy RHIC: search for QCD-CP with bulk observables NA61@SPS: search for QCD-CP with bulk observables CBM@FAIR: scan of the phase diagram with bulk and rare observables
Exploring the QCD Phase diagram
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What is the equation-of-state of strongly interacting matter? (core collapse supernovae, neutron stars, early universe)
What is the structure of strongly interacting matter as a function of T and ρB ?
(hot and dense hadronic medium, deconfined phase, phase transitions ?)
What are the in-medium properties of hadrons as a function of T and ρB ? (restoration of chiral symmetry ?)
Questions of QCD
After RHIC & LHC we need measurements at large baryon density
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Onset of chiral symmetry restoration at high B
in-medium modifications of hadrons (,, e+e-(μ+μ-), D)
Deconfinement phase transition at high B
excitation function and flow of strangeness (K, , , , ) excitation function and flow of charm (J/ψ, ψ', D0, D, c)
The equation-of-state at high B
collective flow of hadrons particle production at threshold energies (open charm?)
QCD critical endpoint excitation function of event-by-event fluctuations (K/π,...)
CBM: detailed measurement over precise energy bins (pp, pA,
AA) FAIR beam energy range 2-45 AGeV (protons 90 GeV)
What do we need to measure?
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Net-baryon densities in central Au+Au collisions at FAIR:consistent picture from transport models
Compilation by J. Randrup, CBM Physics Book, in preparationsee also I.C. Arsene et al., Phys. Rev. C 75 (2007) 034902
At FAIR energy: large baryon density will be achieved over long time
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Elliptic flow at FAIR
AMPT calculations: C.M. Ko at CPOD 2007
Measure flow for all particles over CBM energy range
DJ/
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Quarkonium dissociation temperatures: (Digal, Karsch, Satz)
Measure excitation functions of J/ψ and ψ' in p+p, p+A and A+A collisions !
rescaled to 158 GeV
Probing the quark-pluon plasma with charmonium
J/ψ ψ'
sequential dissociation?
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L. Grandchamp, R. Rapp and G. E. Brown, J.Phys. G30 (2004) S1355
In-medium modifications
Mass modifications of D mesons and charmed hyperons affect the ratios ψ'/ψ and charmonium to open charm
A. Andronic, P. Braun-Munzinger, K. Redlich, J. Stachel, arXiv:0708.1488
D mesons
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hep-ph/0604269
Hadronic properties are expected to be affected by the enormous baryon densities
→ -meson is expected to melt at high baryon densities
In-medium modifications
no ρ,ω,φ → e+e- (μ+μ-) data between 2 and 40 AGeV no J/ψ, ψ' → e+e- (μ+μ-) data below 160 AGeV
Data: CERESCalculations: R. Rapp
Data: In+In 158 AGeV, NA60Calculations: H.v. Hees, R. Rapp
mesons
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Measurements and Challenges
11SIS100/300
Multiplicity in central Au+Au collisionsW. Cassing, E. Bratkovskaya, A. Sibirtsev, Nucl. Phys. A 691 (2001) 745
Rare particles with high statisticsHigh beam intensityInteraction rate: 10 MHzFast detectors/DAQ
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Dipolemagnet
The Compressed Baryonic Matter Experiment
Ring ImagingCherenkovDetector
Transition Radiation Detectors Resistive
Plate Chambers(TOF)
ECAL
SiliconTrackingStation
Tracking Detector
Muondetection System
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Full event reconstruction: • 2 low-mass pixel, 6 micro-strip detectors• proton identification via TOF
Benchmark for Vertex-Tracker performance: D mesons and ΛC from Au+Au central collisions at 25
AGeVD and ΛC multiplicity from HSDHadronic background from UrQMD
τ = 123 μm/cD0
K-
π+
D0
ΛC → π+K-p τ = 60 μm/c
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Electron pairs in CBM
J/ψ → e+e-
ρ, ω, φ → e+e-
Central Au+Au collisions at 25 AGeV
particle S/B ε (%)
ω 0.4 6.6
φ 0.32 9.4
ρ 0.008 4.7
J/ψ 13 14
Ψ' 0.3 19
25 μm target
Talk: C. Hoehne, parallel session XXIII
Posters: T. Galatyuk K. Antipin
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Central Au+Au collisions at 25 AGeV
ρ, ω, φ → μ+μ-J/ψ, ψ' → μ+μ-
particle S/B ε (%) σ (MeV)
ω 0.11 4 10
φ 0.06 7 12
ρ 0.002 3
J/ψ 18 13 21
Ψ' 1 16 27
Muon pairs in CBM
Talk: C. Hoehne, parallel session XXIII Poster: A. Kiseleva, P. Bhaduri
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Annual yields at RHIC II & LHCfrom Tony Frawley RHIC Users mtg.
at LHC: (10-50) x ~10% of L 25% running time
10 weeks CBMAu+Au 25 AGeV
B. Jacak QM2006
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R&D on the Silicon Tracking System
R&D effort:
micro-strip detector modules low-mass mechanics sectors of different strip lengths r/o electronics outside aperture 10 MHz full-frame readout
Design of low-mass detector modules
Micro-strip detector prototype CBM01, Cooperation GSI-CIS.
R&D on ultra-low-mass readout cables. Cooperation with SESRTIIE Kharkov.
1025 lines, 55 cm long, 100 µm pitch1025 lines, 55 cm long, 100 µm pitch
Material: 14 µm Al on 10 µm KaptonMaterial: 14 µm Al on 10 µm Kapton
sensor
cable
FEE
First mechanical module prototype, KINR Kiev.
Front-end electronics prototyping with n-XYTER chip, GSI-DETNI.
System design
Poster: J. Heuser
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Fe Fe Fe Fe Fe
20 20 2
0 30
35 cm
102.5 cm0 cm5 cm
260cm
Chambers: high resolution gas
detectors (major Indian
participation)
Challenges: High Rate High density Large background
Muon detection systemMuon detection system
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GEM (fast high resolution detector) under test at VECC-Kolkata
Resistive chain biasing
6 mm holes in the plexiglasstop cover for Source.
Gas Inlet
source
GEM assembly housed in ~60 cm x ~30 cm box
Gas: Ar/CO2-70/30Source: Ru106(ß)
mesh – a 5-10 micronthick nichrome wire
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Self-triggered fast readout chipfor double-sided Silicon Strip detectors and GEM detectors (128 channels, 32 MHz) under test in the GSI Detlab.
Poster: W. Mueller
High speed DAQOnline Event selection
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Summary and Conclusions
• Exploration of QCD phase diagram at high baryon densities • Precision measurement of excitation functions including rare probes in pp, pA and AA
• CBM: Next generation heavy ion experiment at reaction rates up to 10 MHz
• Fast detectors, High speed DAQ, online event selection
• Simulation shows the feasibility of rare probe measurements
• Detector R&D in progress
CBM
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CBM Collaboration : 51 institutions, ~ 400 membersCroatia: RBI, ZagrebSplit Univ.China:CCNU WuhanUSTC HefeiCyprus: Nikosia Univ. Czech Republic:CAS, RezTechn. Univ. PragueFrance: IPHC StrasbourgHungaria:KFKI BudapestBudapest Univ.
Romania: NIPNE BucharestRussia:IHEP ProtvinoINR TroitzkITEP MoscowKRI, St. PetersburgKurchatov Inst., MoscowLHE, JINR DubnaLPP, JINR DubnaLIT, JINR DubnaMEPHI MoscowObninsk State Univ.PNPI GatchinaSINP MSU, Moscow St. Petersburg P. Univ.Ukraine: Shevshenko Univ. , Kiev
India:Aligarh Muslim Univ.Panjab Univ. Rajasthan Univ.Univ. of Jammu Univ. of KashmirUniv. of CalcuttaB.H. Univ. VaranasiVECC KolkataSAHA KolkataIOP BhubaneswarIlT KharagpurKorea:Korea Univ. SeoulPusan National Univ.Norway:Univ. Bergen
Supported by EU FP6
Germany: Univ. Heidelberg, P.I.Univ. Heidelberg, KIP Univ. FrankfurtUniv. Mannheim Univ. MünsterFZ DresdenGSI DarmstadtPoland:Jag. Univ. KrakowWarsaw Univ.Silesia Univ. KatowiceAGH KrakowPortugal: LIP Coimbra
CBM Collaboration Meeting in Strasbourg Sept. 2006
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Backup slides
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Phase space coverage-meson
• 25 AGeV beam energy: midrapidity = 2
• electrons: full coverage
• muons: acceptance forward shifted, weak for low-pt
muonselectrons
25 AGeVcentral AuAu