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New Frontiers in Heavy-Ion Physics: the CBM experiment

New Frontiers in Heavy-Ion Physics: the CBM experiment. ICFP 2012 Kolymbari, Crete, Greece. Vassiliev Iouri , CBM Collaboration. TOF. ECAL. TRD. RICH. STS. PSD. GSI. SIS. CBM. MUCH. Physics case: Exploring the QCD phase diagram. The equation-of-state at high  B

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New Frontiers in Heavy-Ion Physics: the CBM experiment

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  1. New Frontiers in Heavy-Ion Physics: the CBM experiment ICFP 2012 Kolymbari, Crete, Greece Vassiliev Iouri , CBM Collaboration TOF ECAL TRD RICH STS PSD GSI SIS CBM MUCH

  2. Physics case: Exploring the QCD phase diagram The equation-of-state at high B • collective flow of hadrons • particle production at threshold energies (open charm) LHC RHIC Deconfinement phase transition at high B • excitation function and flow of strangeness (K, , , , ) • excitation function and flow of charm(J/ψ, ψ', D0, Ds, D, c) • charmoniumsuppression, for J/ψandψ' SPS-CERN CBM QCD critical endpoint • excitation function of event-by-event fluctuations (K/π,...) Onset of chiral symmetry restoration at high B • in-medium modifications of hadrons (,,e+e-(μ+μ-), D?, *?) Projects to explore the QCD phase diagram at large μB: RHIC energy-scan, NA61@SPS, MPD@NICAbulk observables CBM@FAIR/SIS-300bulk andrare observables, high statistic!

  3. Experiments on superdense nuclear matter Why CBM?

  4. D0, D+, Ds+ , c , D* The mission: J/,  SIS-300 SIS-100 P.Senger SPS Pb+Pb 30 A GeV D0, D+, c,J/ Lynnik et al., Nucl. Phys. A 786 (2007) 183

  5. Charm production at threshold R. Arnaldi et al. (NA60) charm in A+A at / near threshold: terra incognita high discovery potential, e.g. inmedium modifications of D mesons D T or  ? p + p →J /ψ + p + p 11.2 GeV p + n →Λc + D− + p 12.0 GeV p + p →D+ + D− + p + p 14.9 GeV • J/ and open charm suppression measured • charmonium in hot and very dense matter? • open charm in hot and very dense matter? Cold nuclear effects at low energy

  6. 700  160 p 53 K 32  KS ~1 - 0.022 - UrQMD event, central Au+Au @ 25AGeV  up to 107 Au+Au reactions/sec (J/ψ)  determination of (displaced) vertices with high resolution ( 50 m)  identification of leptons and hadrons  fast and radiation hard detectors  self-triggered readout electronics  high speed data acquisition and online event selection

  7. Welcome to the multi-core era! Intel E7-4860 Simulation & reconstruction 80k UrQMD 02.2012 80 cores GSI Developer’s World 2012 user’s World 2011

  8. central Au+Au @ 25AGeV 700  160 p 53 K 32  KS ~1 - 0.022 - simulation SIS-300 600 reconstructed tracks Ref. prim. eff = 96% All set eff = 86% dp/p = 1.2% SIMDized tracking + KFParticle CBM, STAR, ALICE… 10MHz Track finder, central: 62 ms/core mbias : 8 ms/core Particles finder, central: 10 ms/core mbias : 1.4 ms/core up to 80 cores/CPU Online: track finder, track fitter, PV finder, V0 (K0sand Λ) finder, -,- , *+, *-, K*,.. J/, D0, D+ ,, ,  ... finder reconstruction

  9. Bulk observables: K0s and Λ 80k central UrQMD events K0S  K0s 9

  10. Au+Au, strangeness: - and  - CBM, STAR trigger !? Secondary  from -, -  6 window KFParticle 80k central events, 2.5 hours 724 1187 p id eff = 0.9% 10

  11. KFParticle Finder (50 particles so far…) χ2fit – χ2 given by a track fit χ2prim – χ2 distance to a primary vertex (PV) χ2geo – χ2 given by a particle fit χ2topo – χ2 of a particle fitted to PV Tracks χ2fitcriterion Selected tracks χ2primcriterion Secondary tracks Primarytracks e+e- +- K0s, Λ and Λ candidates D0, D+ Ds , c candidates J, ‘ χ2geocriterion e+e- +- Selected K0s,Λ and Λ Store check mass ,, Selected K0s, Λ and Λ χ2topo zvertexcriteria D+* SecondaryΛ and Λ Primary K0s,Λ and Λ Ξ- , Ξ+, Ω- and Ω+ candidates Σ*+, Σ*+, Σ*- and Σ*-, K*0, K*0, K*- and K*+ candidates H-dibaryon candidates χ2geo , χ2topo , zvertexcriteria χ2geo , χ2topo , zvertexcriteria χ2geocriterion Selected Ξ- , Ξ+, Ω-and Ω+ Selected H Selected Σ*+, Σ*+, Σ*- and Σ*-, K*0, K*0, K*-and K*+ Store

  12. pC 30GeV bulk observables: K0s and Λ 0.8M events 12

  13. pAu 30GeV K0s and Λ 0.8M events 13

  14. C+C 10AGeV 6M events 52 - direct search no  generator p_id

  15. C+C 25AGeV I.Vassiliev, CBM 15

  16. 10 MHz IR, high statistic

  17. Up to 10 MHz IR, high statistic 17

  18. Charmonia (di-muon channel) 256 pads 3.5×8 mm2 GEM detectors J/measurements trigger Fe 20 20 20 30 35 100 cm 13.5 λI Straw tubes 7.5 λI low-mass vector meson measurements

  19. Charmonia (di-muon channel) Signal and background yields from physics event generators (HSD, UrQMD) Full event reconstruction based on realistic detector layout and response Au+Au 35 AGeV J/ψ → μ+μ- muons p+C 30 GeV few/hour signals ρ ω φ η ηDalitz lmvm muons 130 ρ/h 600 ω /h 90 φ/h ~600 J/ψ per hour

  20. Charmonia (di-electron channel) e+/- Rings:up to 100 per event~ 6cm diameter~ 20 photo electrons finding eff. 95.3% π+/- multi-anode PMT RICH + TRD: e identification efficiency 85 % π-suppression 104 glass mirror with Al+MgF2 high-rate TRD

  21. Charmonia (di-electron channel) Signal and background yields from physics event generators (HSD, UrQMD) Full event reconstruction based on realistic detector layout and response KFParticle - vertexing: Background suppression γ-conversion, π0 Dalitz Electron id: RICH and TRD π suppression: factor 104 dominant background: e from π0 Dalitz 4 1010 events

  22. Reconstruction of the Low-mass Signal : e+e- Reduction of physical background byreconstructing pairs from g-conversion(~3/event) and p0-Dalitz decays (~8/event) by means of their track topology Transverse momentum cut of single electron – powerful, but has to be taken with special care! Pair cuts, i.e. opening angle cut Track Segment p0e+e-g Identified e+/- All e+e-CB gmediume+e- Fakepair π0 γe+e-  π0e+e-ηγe+e- Track Fragment ρ e+e-  e+e-φ e+e- Invariant mass spectra D Before cuts Electron option After cuts Central Au+Au@25AGeV

  23. Reconstruction of Low-mass Sigal: Phase space coverage D r0  e+e– w  m+m- yCM yCM • Are the hadron properties influenced by the dense medium? • • Can we see an onset of chiral symmetry restoration? • • Measure short-lived vector mesons: decay in dense phase of collisions • • decay into lepton pairs: no interaction with medium • Electrons: no phase space limitation

  24. MissionOpen Charm: Primary vertex reconstruction Au+Au @ 25AGeV • Monolithic Active Pixel Sensors • (MAPS, also CMOS-Sensors) • Invented by industry (digital camera) • Modified for charged particle detection since 1999 by IPHC Strasbourg • Also foreseen for STAR… 450 primary tracks 450 tracks central 100 tracks mbias

  25. -electrons = reconstruction time ! Au+Au @ 25AGeV IR: 0.1MHz =300 Au ions t = 30 s Au 10.7 GeV (P.Zarubin) 0.1 MHz 0.2 MHz 0.4 MHz 0.8 MHz

  26. Open charm at SIS-100Invariant mass spectra p+C 30GeV D+  K- ++ MD+HSD=2.710-8 BR = 0.095 eff = 13.2 % eff = 11.6 % 3 cut 4 cut with PV BG suppressed 10-30 times! 15/03/12 26

  27. Invariant mass spectra p+C 30GeV 1012 central events D0  K- -++ 3 cut MD0HSD = 2.9(8.8)10-8 BR = 7.7% Eff = 1.7% K- D0 + 2geo + - 27

  28. Open charm (Au+Au @ 25 AGeV)z-vertex reconstruction D0K-+ 0.1 MHz

  29. Au+Au @ 25 AGeV 1.6k 0.6k 29

  30. Open charm properties table (25AGeV) 15/03/12 30 30

  31. CBM timeline CBM detector is an excellent device to measure not only bulk observables, but strangeness and rare (charm) probes with high statistic.

  32. The CBM Collaboration: 55 institutions, 450 members Germany: Frankfurt Univ. IKF Frankfurt Univ. FIAS GSI Darmstadt Giessen Univ. Heidelberg Univ. P.I. Heidelberg Univ. KIP Heidelberg Univ. ZITI HZ Dresden-Rossendorf Münster Univ. Tübingen Univ. Wuppertal Univ. Korea: Korea Univ. Seoul Pusan Nat. Univ. Romania: NIPNE Bucharest Univ. Bucharest Russia: IHEP Protvino INR Troitzk ITEP Moscow KRI, St. Petersburg Kurchatov Inst., Moscow LHEP, JINR Dubna LIT, JINR Dubna MEPHI Moscow Obninsk State Univ. PNPI Gatchina SINP MSU, Moscow St. Petersburg P. Univ. Ukraine: T. Shevchenko Univ. Kiev Kiev Inst. Nucl. Research Croatia: RBI, Zagreb Split Univ. China: CCNU Wuhan Tsinghua Univ. USTC Hefei Czech Republic: CAS, Rez Techn. Univ.Prague France: IPHC Strasbourg Hungaria: KFKI Budapest Budapest Univ. Norway: Univ. Bergen 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 IIT Kharagpur Gauhati Univ. Poland: AGH Krakow Jag. Univ. Krakow Silesia Univ. Katowice Warsaw Univ. 28/02/12 I.Vassiliev, CBM 32

  33. Highest net-baryon densities at FAIR [J. Randrup, J. Cleymans PRC74, 047901 (2006)]

  34. Au+Au 8AGeV p+C 30GeV pi+ 140.97 pi- 165.62 p 168.97 K+ 17.15 K- 2.34 K0 17.43 aK0 2.22 14.23 04.64 - 0.268 -0.005 pi+ 2.39 pi- 2.12 p 6.65 K+ 0.17 K- 0.08 K00.17 aK00.08  0.1 0 0.033 -0.0013 -0.0000 Au+Au 8AGeV SIS-100 p+C 30GeV SIS-100 2geo

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