1 Physics of High Baryon Densities - The CBM experiment at FAIR Subhasis Chattopadhyay Variable Energy Cyclotron Centre, Kolkata for the CBM collaboration Outline:  CBM physics  CBM setup  Feasibility studies  Detector R&D CBM

2 RHIC result:  new state of matter = perfect liquid?  T f = 160 – 165 MeV L-QCD Predictions:  T C = 151 ± 7 ± 4 MeV ( μ B =0 ) (Z. Fodor, arXiv: hep-lat)  T C = 192 ± 7 ± 4 MeV ( μ B =0 ) (F. Karsch, arXiv: hep-lat)  crossover transition at μ B =0 (Z. Fodor, arXiv: hep-lat)  1. order phase transition with critical endpoint at μ B > 0 High-energy heavy-ion collision experiments: RHIC, LHC: cross over transition, QGP at high T and low ρ Low-energy RHIC: search for QCD-CP with bulk observables search for QCD-CP with bulk observables scan of the phase diagram with bulk and rare observables Exploring the QCD Phase diagram

3  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 ρ B ? (hot and dense hadronic medium, deconfined phase, phase transitions ?)  What are the in-medium properties of hadrons as a function of T and ρ B ? (restoration of chiral symmetry ?) Questions of QCD After RHIC & LHC we need measurements at large baryon density

4 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', D 0, 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?

5 Net-baryon densities in central Au+Au collisions at FAIR: consistent picture from transport models Compilation by J. Randrup, CBM Physics Book, in preparation see also I.C. Arsene et al., Phys. Rev. C 75 (2007) At FAIR energy: large baryon density will be achieved over long time

6 Elliptic flow at FAIR AMPT calculations: C.M. Ko at CPOD 2007 Measure flow for all particles over CBM energy range D J/  

7 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/ψψ'ψ' sequential dissociation?

8 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: D mesons

9 hep-ph/ 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: CERES Calculations: R. Rapp Data: In+In 158 AGeV, NA60 Calculations: H.v. Hees, R. Rapp  mesons

10 Measurements and Challenges

11 SIS 100/300 Multiplicity in central Au+Au collisions W. Cassing, E. Bratkovskaya, A. Sibirtsev, Nucl. Phys. A 691 (2001) 745 Rare particles with high statistics High beam intensity Interaction rate: 10 MHz Fast detectors/DAQ

12 Dipole magnet The Compressed Baryonic Matter Experiment Ring Imaging Cherenkov Detector Transition Radiation Detectors Resistive Plate Chambers (TOF) ECAL Silicon Tracking Station Tracking Detector Muon detection System

13 Full event reconstruction: 2 low-mass pixel, 6 micro-strip detectors proton identification via TOF Benchmark for Vertex-Tracker performance: D mesons and Λ C from Au+Au central collisions at 25 AGeV D and Λ C multiplicity from HSD Hadronic background from UrQMD τ = 123 μm/c D0D0 K-K- π+π+ D0D0 Λ C → π + K - p τ = 60 μm/c

14 Electron pairs in CBM J/ψ → e+e- ρ, ω, φ → e+e- Central Au+Au collisions at 25 AGeV particleS/Bε (%) ω φ ρ J/ψ1314 Ψ' Ψ' μm target Talk: C. Hoehne, parallel session XXIII Posters: T. Galatyuk K. Antipin

15 Central Au+Au collisions at 25 AGeV ρ, ω, φ → μ+μ- J/ψ, ψ' → μ+μ- particleS/Bε (%)σ (MeV) ω φ ρ J/ψ Ψ' Ψ'11627 Muon pairs in CBM Talk: C. Hoehne, parallel session XXIIIPoster: A. Kiseleva, P. Bhaduri

16 Annual yields at RHIC II & LHC from Tony Frawley RHIC Users mtg. at LHC: (10-50) x  ~10% of L 25% running time 10 weeks CBM Au+Au 25 AGeV B. Jacak QM2006

17 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 lines, 55 cm long, 100 µm pitch Material: 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

18 Fe Fe Fe Fe Fe cm cm0 cm 5 cm 260cm Chambers: high resolution gas detectors (major Indian participation) Challenges: High Rate High density Large background Muon detection system

19 GEM (fast high resolution detector) under test at VECC-Kolkata Resistive chain biasing 6 mm holes in the plexiglass top cover for Source. Gas Inlet source GEM assembly housed in ~60 cm x ~30 cm box Gas: Ar/CO2-70/30 Source: Ru106(ß) mesh – a 5-10 micron thick nichrome wire

20 Self-triggered fast readout chip for double-sided Silicon Strip detectors and GEM detectors (128 channels, 32 MHz) under test in the GSI Detlab. Poster: W. Mueller High speed DAQ Online Event selection

21 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

22 CBM Collaboration : 51 institutions, ~ 400 members Croatia: RBI, Zagreb Split Univ. China: CCNU Wuhan USTC Hefei Cyprus: Nikosia Univ. Czech Republic: CAS, Rez Techn. Univ. Prague France: IPHC Strasbourg Hungaria: KFKI Budapest Budapest Univ. 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 MSU, Moscow St. Petersburg P. Univ. Ukraine: Shevshenko Univ., Kiev India: Aligarh Muslim Univ. Panjab Univ. Rajasthan Univ. Univ. of Jammu Univ. of Kashmir Univ. of Calcutta B.H. Univ. Varanasi VECC Kolkata SAHA Kolkata IOP Bhubaneswar IlT Kharagpur Korea: Korea Univ. Seoul Pusan National Univ. Norway: Univ. Bergen Supported by EU FP6 Germany: Univ. Heidelberg, P.I. Univ. Heidelberg, KIP Univ. Frankfurt Univ. Mannheim Univ. Münster FZ Dresden GSI Darmstadt Poland: Jag. Univ. Krakow Warsaw Univ. Silesia Univ. Katowice AGH Krakow Portugal: LIP Coimbra CBM Collaboration Meeting in Strasbourg Sept. 2006

23 Backup slides

24 Phase space coverage  -meson 25 AGeV beam energy: midrapidity = 2 electrons: full coverage muons: acceptance forward shifted, weak for low-pt muons electrons 25 AGeV central AuAu