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The CBM heavy-quark program

NEW TRENDS IN HIGH-ENERGY PHYSICS (experiment, phenomenology, theory) Alushta, Crimea, Ukraine, September 3 - 10, 2011. Iouri Vassiliev CBM Collaboration. The CBM heavy-quark program. Physics case: Exploring the QCD phase diagram. The equation-of-state at high  B

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The CBM heavy-quark program

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  1. NEW TRENDS IN HIGH-ENERGY PHYSICS(experiment, phenomenology, theory) Alushta, Crimea, Ukraine, September 3 - 10, 2011 Iouri Vassiliev CBM Collaboration The CBM heavy-quark program

  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, D, c) • charmonium suppression, 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. The mission: D0, D+, Ds+ , c , D* J/,  SIS-300 P.Senger SIS-100 SPS Pb+Pb 30 A GeV D0, D+, J/ I.Vassiliev, CBM

  4. Charm production at threshold D HSD simulations • J/ and open charm suppression measured • charmonium in hot and very dense matter? • open charm in hot and very dense matter? Nuclear effects at low energy I.Vassiliev, CBM

  5. 791 mc track  697 reco Ref primary eff = 94.6% central Au+Au 25AGeV 80 ms lxir039  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 I.Vassiliev, CBM

  6. SIMDized tracking 700  160 p 53 K 32  27 KS0 ~1 - 0.022 - 697 reconstructed tracks Ref. prim. eff = 96% All set eff = 88% dp/p = 1.2% Finder: 80 ms Fitter: 1.6 ms PV : 51.2 ms K0S : 32.8 ms Total 165.6 ms/16 cpu front view Online: track finder, track fitter, PV finder, V0 finder,-,- finder

  7. 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

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

  9. 256 pads 3.5×8 mm2 Muon detection GEM detectors J/y measurements trigger Fe 20 20 20 30 35 100 cm ≡ 13.5 λI Straw tubes ≡ 7.5 λI low-mass vector meson measurements

  10. 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 25 AGeV p+C 30 GeV J/ψ, ψ' 3.8 1010 events J/ψ → μ+μ- 6 J/ψ recorded in 1010 events (b=0) (20 J/ψ per hour)

  11. Open charm. Sensors for the MVD • 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 ILC, STAR… Best values reached

  12. Micro Vertex Detecor (MVD) Development • first station 5cm downstream of target • high position resolution! Chip-on-polyamide first demonstrator tested in beam! • Monolithic Acitive Pixel Sensors in commercial CMOS process • CBM: 5 µm single point resolution

  13. Development of the Silicon Tracking System (STS) Sensor development: double-sided micro-strips, stereo angle 15o, pitch 60 μm 300 μm thick, bonded to ultra-thin micro-cables, radiation hardness Prototypes: full CBM sensor, ultrathin cables STS in thermal enclosure Detector planes: ultra-light weight ladder structure

  14. K- p + p e- e+ - MC -electrons p+C 30GeV SIS-100 K- p + XY Rear View p RECO MC e- e+ - 50 pile up + -electrons by 100k protons Reconsruction time << 1ms 22.09.2014 14

  15. Primary vertex reconstruction pC 30 GeV K- D+ + 2geo + 4.5 tracks central, 1 track mbias 22.09.2014 15

  16. 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! 22.09.2014 I.Vassiliev, CBM 16

  17. 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 + - with PV BG suppressed 22.09.2014 I.Vassiliev, CBM 17

  18. Primary vertex reconstruction Au+Au @ 25AGeV 450 primary tracks 50 ms 450 tracks central 100 tracks mbias

  19. -electrons! IR: 0.1MHz =300 Au ions t = 30 s 479 12389

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

  21. Open charm Reconstruction Quality Control K0S 2prim > 3 eff~12.0% 2geo < 3  q>0  proton mass 2prim > 3 Outer acc. Inner Eff =10.4% 2geo < 3

  22. Open charm Reconstruction Quality Control 22

  23. Strategy: background suppression keeping maximum of efficiency single track parameters based cuts: χ2primimpact parameter value 6.0-7.5 IP impact parameter cut (upper value) 0.5 mm protons ID by TOF track transverse momentum pt > 0.3 GeV/c (D0 only) multiple track (particle) parameters based cuts: χ2GEOgeometrical constrained fit 3.0 χ2TOPOtopological constrained fit 2.0-3.0 charm particle to primary vertex DCA < 20(30) m Zvertex< 2(3.5) mmc I.Vassiliev, CBM 23

  24. χ2primimpact parameter value 6.5-7.5 2 = r2/2 r  pv I.Vassiliev, CBM 24

  25. χ2geogeometrical constrained fit 3.0 K 2geo  I.Vassiliev, CBM 25

  26. Zvertex geo > 350 m I.Vassiliev, CBM 26

  27. χ2topotopological constrained fit 2.0-3.0 K- 2prim D+ PV + 2topo + 2geo 27

  28. charm particle impact parameter < 20 m I.Vassiliev, CBM 28

  29. Zvertex < 2 mm (new cut) Duplets cut I.Vassiliev, CBM 29

  30. Invariant mass spectra Au+Au @ 25 AGeV 1.6k 600 I.Vassiliev, CBM

  31. Invariant mass spectra Au+Au @ 25 AGeV I.Vassiliev, CBM

  32. Invariant mass spectra Au+Au @ 25 AGeV. C+C @ 25AGeV I.Vassiliev, CBM

  33. Open charm properties table (25AGeV) 22.09.2014 I.Vassiliev, CBM 33

  34. D0K-+(K-++-) D+K-+ + DsK- K++ c pK-+ DVT K- 2prim Open Charm Triggers PV D+ + DKT 2topo + 2geo D+ Background Background

  35. Open Charm Trigger-algorithm L1CATrackFinder SIMD  RFmb = 125 RFcen = 14 L1KFTrackFitter SIMD  Charm Track Candidates Selection χ2prim > N N = 3 ☻ accepted Charm Pairsχ22geo< 3.0, zv <1 cm χ2topo < 3.0, minv > 1.3 GeV ☺D0 rejected accepted ☺ D+c Ds ☻ Charm Tripletsχ23geo+topo < 3.0

  36. Detached Vertex Trigger: RFmb = 125 RFcen = 14 I.Vassiliev, CBM

  37. CBM timeline

  38. 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. I.Vassiliev, CBM 15st CBM Collaboration Meeting, April 12-16, 2010, GSI Darmstadt

  39. high (net-)baryon and energy densities created in central Au+Au collisions Highest net-baryon densities at FAIR [J. Randrup, J. Cleymans PRC74, 047901 (2006)]

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