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Experiment CBM – research program

Study the QCD Phase Diagram with CBM experiment to explore freeze-out phases and rare probes, such as high-pT particles and collective motion, towards reaching the Critical Point.

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Experiment CBM – research program

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  1. Physics motivation • Detector concept • Feasibility study • Status Experiment CBM – research program Paweł Staszel Jagiellonian University

  2. Diagram fazowy QCD

  3. QCD Phase Diagram scan with A+Acollisions 3 component hydrodynamics + hadron gas EOS: Critical Point reached at trajectory for ~30 AGeV (√sNN=7.74) Phase Boundary reached already at ~10 AGeV (√sNN=4.72) V.Toneev et al., nucl-th/0309008

  4. How to explore interesting regions of the QCD Phase Diagram Freeze-out phase can be studied by measurement of „soft” hadrons production (bulk observables)‏ • Information about earlier phases is carried by rare probes: • High pT particles • Particles decaying in to leptons • Particles build up of heavy quarks (J/ψ, D, Λc ....)‏ and by collective motion (flow) of the created soft medium. (e .g. v2 is sensitive to the quanta interaction just after the medium formation) large advantage from simultaneous flow measurement of “ordinary” hadrons and rare probes Lattice QCD calculations: Fedor & Katz, Ejiri et al.

  5. Experymental arguments for Phase Transition at low SPS energy NA49(QM 2004)‏ None monotonic behaviour of K+/+ ratio Effective temperature shows plateau in the range of SPS energy

  6. Hadrons in dense medium (->e+e-)‏ Top SPS: excess of e+e- pairs around 0.5 GeV (by factor of ~2.8)‏ 40AGeV: the excess rised up to ~4 → strong dependency on B Rapp-Wambach –  in-medium modification Rapp: “dropping mass” according to Brown-Rho scaling scenario Thermal model

  7. Hadrons in dense medium (->+-)‏ NA60, Nucl. Phys. A 774 (2006) 67 broadening of 0 spectral function (Rapp-Wambach)‏ contradiction with mass drop scenario (Brown-Rho scaling)‏ excess by factor of 4 over the “cocktail” with 25% systematic uncertainty !‏

  8. Open Charm in dense medium‏ Mishra et al, nucl-th/0308082 Reduction in the effective mass of D-meson can open D-Dbar decay channel for charmonium states → possible scenario for the J/Ψ suppression, CBM=> simultaneous measurement of J/Ψ and D-mesons

  9. J/Ψ suppression Better scaling is obtained in Npart; onset already at Npart~90, At lower energies (larger μB)one can expect onset of AS for more central collisions → dependency on energy density and μB Important measurement of open charm to verify other scenarios NA50, QM 2005 NA60 evidenced same effect in In+In Anomalous J/ψ suppresion (AS) on SPS, L – effective path in medium

  10. Elliptic flow • all particles flow (even these with charm!)‏ • scaling if taking the underlying number of quarks into account! • →like (all!) quarks flow and combine to hadrons at a later stage (hadronisation)‏ • data can only be explained assuming a • large, early built up pressure in a nearly • ideal liquid (low viscosity!)‏ [PHENIX, PRL.98:162301,2007] baryons n=3 mesons n=2 KET = mT-m

  11. Elliptic flow at SPS data at top SPS support hypothesis of early development of collectivity • influence of hadronic rescattering phase, resonance decay? • lack of complete thermalization, viscosity effect? • larger pt-range needed Pb+Pb collisions, √sNN = 17.3 GeV [NA49, G. Stefanek, PoS CPOD2006:030,2006]

  12. Event-by-event fluctuations • observation might become enormously difficult • correlation length  of sigma field, may become rather small for a finite lifetime of the fireball • large acceptance needed! 1st try to identify 1st order phase transition line fluctuations, correlations with large acceptance and particle identification [NA49 collaboration, arXiv:0810.5580v2 [nucl-ex]] [Stephanov, Rajagopal, Shuryak, PRD60, 114028 (1999)]

  13. Dynamical Fluctuations (by D. Kersan)‏ Measure the particle yields ratio in an event : K/  = RMS / MEAN Relative width of distribution : data2 = fin2 + exp2 + dyn2 background Event mixing: no two tracks coming from one real event mixed dyn2 = data2mixed2

  14. Dynamical Fluctuations in UrQMD RECO + PID 4

  15. Toy Model Toy Model features: Independent particle production with yields and kinematics from UrQMD Extra kaon multiplicity fluctuation Resonance decays

  16. Resonances in Toy Model – K* K*(892)0 K <K> = 41 <> = 363 Independently produced:

  17. Resonances in Toy Model –  <K> = 41 <> = 363 Independently produced: K+K  K0LK0S 00 0 + analytical formula

  18. Conclusion (fluctuation feasibility study)‏ Hadron ID and event-by-event fluctuations of the kaon to pion ratio were studied with full event reconstruction in CBM Kaons can be identified up to p = 3.5 GeV/c The current setup is sensitive to event-by-event fluctuations above 1 % Resonance decays influence the fluctuation measure; the effect obtained in a toy model is in agreement with analytical predictions

  19. CBM: Physics topics and Observables The equation-of-state at high B • collective flow of hadrons • particle production at threshold energies (open charm) 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)‏ charmonium suppression, sequential for J/ψ and ψ' ? corelated with open charm ? QCD critical endpoint • excitation function of event-by-event fluctuations (K/π,...)‏ predictions? clear signatures? →prepare to measure "everything": bulk particles and rare probes ⇒ probing medium with known overall characteristics → systematic studies! (pp, pA, AA, energy)‏ Onset of chiral symmetry restoration at highB • in-medium modifications of hadrons (,,e+e-(μ+μ-), D)‏

  20. Heavy Ion Experiments (selection)‏ C B GAP M upgrade LHC  Inner Tracker HPID RHIC SPS TPC SIS300 SIS 100AGS SIS18 Bevalac time (advance in technology)‏

  21. CBM Detector (->e+e-)‏ TRDs (4,6,8 m)‏ STS ( 5 – 100 cm)‏

  22. CBM Detector (->+-)‏ ECAL (12 m)‏ ABSORBER (1,5 m)‏ magnet TOF (10 m)‏ TRDs (4,6,8 m)‏ STS ( 5 – 100 cm)‏ beam

  23. Silicon Tracking Station – heart of CBM Challenge: high track density:  600 charged particles in  25o @10MHz • Tasks: • track reconstruction: 0.1 GeV/c < p  10-12 GeV/c p/p ~ 1% (p=1 GeV/c)‏ • primary and secondary vertex reconstruction (resolution  50 m)‏ • V0 track pattern recognition radiation hard and fast silicon pixel and strip detectors c = 312 m self triggered FEE high speed DAQ and trigger online track reconstruction!

  24. Simulation: rare probes di-electrons di-muons D0   J/ J/ c ' ' 24

  25. Simulation: bulk particles and hyperons‏ incl. TOF Ξ Ω Λ 10 35 AGeV

  26. Hiperons: PID from decay topology in STS  

  27. Status CBM Collaboration undergoes (phase) transition simulation → prototyping

  28. Successful test of CBM prototype detector systems with free-streaming read-out electronics using proton beams atGSI, September 28-30, 2008 2 Double-sided silicon microstrip detectors GSI and AGH Krakow KIP Heidelberg VECC Kolkata Double and triple GEM detectors Radiation tolerance studies for readout electronics Full readout and analysis chain: Go4 online Detector signals Analysis Front-end board with self-triggering n-XYTER chip Data Acquisition System Readout controller offline

  29. CBM hardware R&D Forward Calorimeter RICH mirror Silicon microstrip detector GEM dipole magnet MVD: Cryogenic operation in vacuum n-XYTER FEB RPC R&D

  30. CBM Collaboration China: Tsinghua Univ., Beijing CCNU Wuhan USTC Hefei Croatia: University of Split RBI, Zagreb Univ. Mannheim Univ. Münster FZ Rossendorf GSI Darmstadt Univ. Kashmir, Srinagar Banaras Hindu Univ., Varanasi Korea: Korea Univ. Seoul Pusan National Univ. Russia: IHEP Protvino INR Troitzk ITEP Moscow KRI, St. Petersburg Hungaria: KFKI Budapest Eötvös Univ. Budapest Norway: Univ. Bergen Kurchatov Inst. Moscow LHE, JINR Dubna LPP, JINR Dubna India: Aligarh Muslim Univ., Aligarh IOP Bhubaneswar Panjab Univ., Chandigarh Gauhati Univ., Guwahati Univ. Rajasthan, Jaipur Univ. Jammu, Jammu IIT Kharagpur SAHA Kolkata Univ Calcutta, Kolkata VECC Kolkata Cyprus: Nikosia Univ. Poland: Krakow Univ. Warsaw Univ. Silesia Univ. Katowice Kraków AGH (Inst. Nucl. Phys. Krakow)‏ LIT, JINR Dubna MEPHI Moscow Obninsk State Univ. PNPI Gatchina SINP, Moscow State Univ. St. Petersburg Polytec. U. Czech Republic: CAS, Rez Techn. Univ. Prague France: IPHC Strasbourg Portugal: LIP Coimbra Romania: NIPNE Bucharest Bucharest University Ukraine: INR, Kiev Shevchenko Univ. , Kiev Germany: Univ. Heidelberg, Phys. Inst. Univ. HD, Kirchhoff Inst. Univ. Frankfurt 55 institutions, > 400 members Dubna, Oct 2008

  31. Mapping the QCD phase diagram with heavy-ion collisions SIS300 net baryon density: B 4 ( mT/2h2c2)3/2 x [exp((B-m)/T) - exp((-B-m)/T)] baryons - antibaryons Lattice QCD calculations: Fedor & Katz, Ejiri et al.

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