CBM physics analysis with KFParticle Vassiliev Iouri CBM

CBM physics analysis with KFParticle Vassiliev Iouri , CBM Collaboration Nov. 30 CERN 2012 TRD TOF ECAL RICH STS GSI PSD SIS CBM MUCH 1

Physics case: Exploring the QCD phase diagram Deconfinement phase transition at high B • excitation function and flow of strangeness (K, , . . . H , 3ΛH…) • excitation function and flow of charm (J/ψ, ψ', D 0, Ds, D , c) • charmonium suppression, for J/ψ and ψ' LHC RHIC SPS-CERN CBM Onset of chiral symmetry restoration at high B • in-medium modifications of hadrons ( , , e+e-(μ+μ-), D? , *? ) QCD critical endpoint • excitation function of event-byevent fluctuations (K/π, . . . ) The equation-of-state at high B • collective flow of hadrons • particle production at threshold energies (open charm) Projects to explore the QCD phase diagram at large μB: RHIC energy-scan, NA 61@SPS, MPD@NICA bulk observables 2 CBM@FAIR/SIS-300 bulk and rare observables, high statistic!

Experiments on superdense nuclear matter Why CBM? Experiment Energy range (Au/Pb beams) Reaction rates Hz STAR@RHIC BNL s. NN = 7 – 200 Ge. V NA 61@SPS CERN Ekin= 20 – 160 A Ge. V s. NN= 6. 4 – 17. 4 Ge. V (limitation by detector) MPD@NICA Dubna s. NN= 4. 0 – 11. 0 Ge. V ~1000 CBM@FAIR Darmstadt Ekin= 2. 0 – 35 A Ge. V s. NN= 2. 7 – 8. 3 Ge. V 1 – 800 (limitation by luminosity) 80 (design luminosity of cm-2 s-1 for heavy ions) 1027 105 – 107 (limitation by detector) 3

700 160 p 53 K 32 KS ~1 0. 022 - Ur. QMD event, central Au+Au @ 25 AGe. V 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 4 online event selection

central Au+Au @ 25 AGe. V 700 160 p 53 K 32 KS ~1 0. 022 - simulation SIS-300 reconstruction 10 MHz SIMDized (tracking + KFParticle) central: 62 (TF) + 11. 7 (PF) ms/core mbias : 8 (TF) + 1. 5 (PF) ms/core up to 80 cores/CPU 600 reconstructed tracks Ref. prim. eff = 96% All set eff = 86% dp/p = 1 % 5

KF Particle Finder for the CBM Experiment Tracks: e±, μ±, π±, K±, p± secondary and primary 6/14

KFParticle Finder (50 particles so far…) Tracks χ2 fit – χ2 given by a track fit χ2 prim – χ2 distance to a primary vertex (PV) χ2 geo – χ2 given by a particle fit χ2 topo – χ2 of a particle fitted to PV Selected tracks Secondary tracks MVD χ2 prim criterion χ2 geo criterion Primary tracks e + e - + - K 0 s, Λ and Λ candidates D 0 , D+ D s , c candidates χ2 geo criterion Selected K 0 s, Λ and Λ Store check mass Selected D+* RICH p. ID χ2 fit criterion To. F p. ID s, Λ and Λ Secondary Λ and Λ Ξ- , Ξ+, Ω- and Ω+ candidates χ2 geo , χ2 topo , zvertex criteria Selected Ξ- , Ξ+, Ω- and Ω+ K 0 χ2 topo zvertex criteria Primary K 0 s, Λ and Λ H-dibaryon candidates Store + - J , ‘ , , To. F p. ID Σ*+, Σ*- and Σ*-, K*0, K*- and K*+ candidates χ2 geo , χ2 topo , zvertex criteria Selected H e+ e- χ2 geo criterion Selected Σ*+, Σ*- and Σ*-, K*0, K*- and K*+ 7

Bulk observables: K 0 s and Λ 5 M(!) central Ur. QMD events K 0 S 8 8

Au+Au, strangeness: - and - CBM, STAR trigger !? Secondary from -, 6 window KFParticle 5 M central events, 1 day Direct search 1187 Eff=0. 55% S/B=0. 1 9 PLUTO generator 9

Au+Au, strangeness: - and - 1 M central events, 1 day 10 10

SIS-100 C+C 10 AGe. V 6 M events p_id 11

Charmonia (di-electron channel) e+/- π+/- finding eff. 95. 3% multi-anode PMT glass mirror with Al+Mg. F 2 Rings: up to 100 per event ~ 6 cm diameter ~ 20 photo electrons high-rate TRD RICH + TRD: e identification efficiency π-suppression 12 85 % 104

Charmonia (di-electron channel) Signal and background yields from physics event generators (HSD, Ur. QMD) Full event reconstruction based on realistic detector layout and response Electron id: RICH and TRD KFParticle - vertexing: Background suppression γ-conversion, π0 Dalitz 4 1010 events 13

Reconstruction of the Low-mass Signal : e+e • Reduction of physical background by Dreconstructing pairs from g-conversion (~3/event) and 0 -Dalitz decays (~8/event) by means of their track topology Invariant mass spectra Before cuts Track Segment Electron option 0 e+e-g KF Pa gmedium e+e- Identified e+/- rtic le Fake pair Track Fragment • Transverse momentum cut of single electron – powerful, but has to be taken with special care! • Pair cuts, i. e. opening angle cut Central Au+Au@25 AGe. V After cuts All e+e. CB π0 γe+e π0 e+eη γe+eρ e+eφ e+e-

Charmonia (di-muon channel) J/ measurements GEM detectors m 0 c 0 1 20 20 20 30 35 trigger Fe 13. 5 λI 256 pads 3. 5× 8 mm 2 Straw tubes 7. 5 λI low-mass vector meson measurements 15

Charmonia (di-muon channel) Signal and background yields from physics event generators (HSD, Ur. QMD) Full event reconstruction based on realistic detector layout and response Au+Au 35 AGe. V J/ψ → μ+μS/B ratio e [%] M [Me. V] 0. 08 3. 7 10 0. 03 6 12 0. 001 2. 7 lmvm muons p+C 30 Ge. V few/hour signals ρ ω φ η ηDalitz 130 ρ/h 600 ω /h 90 φ/h ~600 J/ψ per hour 16

Open charm decay topology D+ K- 2 prim 1 2 geo + + 2 prim 2 2 topo PV Target plane L 2 prim 3 cτ = 60… 312 μm ! I. Vassiliev, CBM 17

Mission Open Charm: Primary vertex reconstruction Au+Au @ 25 AGe. V 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 18

KFParticle Zvertex geo > 350 m I. Vassiliev, CBM 19 19

KFParticle Zvertex < 2 mm Duplets cut I. Vassiliev, CBM 20 20

KFParticle χ2 topological constrained fit 2. 0 -3. 0 PV 2 prim 2 topo D+ 2 geo K + + 21 21

PV 2 prim 2 topo D+ 2 geo K + + charm KFParticle impact parameter < 3 (20 m) I. Vassiliev, CBM 22 22

p+C 30 Ge. V Invariant mass spectra 1012 central events D 0 K - - + + 3 cut MD 0 HSD = 2. 9(8. 8) 10 -8 BR = 7. 7% Eff = 1. 7% 2 geo D 0 K + + - eff = 11. 6 % 4 cut D+ K- + + 23 23

Au+Au @ 25 AGe. V -electrons = reconstruction time ! IR: 0. 1 MHz = 300 Au ions t = 30 s Au 10. 7 Ge. V (P. Zarubin) 0. 1 MHz 0. 2 MHz 0. 4 MHz 0. 8 MHz 24

Au+Au @ 25 AGe. V 1. 6 k 0. 6 k 25 25

Strange and Hyper matter in the Lab ? s s d su u Λ Λ Does strange matter exist in the form of heavy multi-strange objects? J. Steinheimer, K. Gudima, A. Botvina, Mishustin, M. Bleicher, H. Stöcker ar. Xiv: 1203. 2547 v 2 [nucl-th] 11 -Jul-2012 CBM detector is an excellent device to measure not only bulk observables, but 26 strangeness and rare (charm) probes with high statistic. 9/24/2020

CBM timeline 2010 2011 R&D detectors & read-out systems 2012 2013 2014 2015 construction detectors & read -out systems 2016 2017 installation, commissioning 2018 2019 first data taking 27 2020

he CBM Collaboration: 55 institutions, 450 members 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 Univ. Norway: Univ. Bergen 28/02/12 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 I. Vassiliev, CBM India: Russia: Poland: Ukraine: Aligarh Muslim Univ. Panjab Univ. Rajasthan Univ. of Jammu Univ. of Kashmir Univ. of Calcutta B. H. Univ. Varanasi VECC Kolkata SAHA Kolkata IOP Bhubaneswar IIT Kharagpur Gauhati Univ. 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. AGH Krakow Jag. Univ. Krakow Silesia Univ. Katowice Warsaw Univ. T. Shevchenko Univ. Kiev Inst. Nucl. Research 28 28

The core detectors: Silicon Tracking System § 8 low-mass tracking stations § 4 m 2 of silicon microstrip detectors σ =32 m § layout optimized for efficient track reconstruction and high momentum resolution. 2. 4 Ge. V protons detailed GEANT models with active and passive materials 29

Reconstruction of Low-mass Sigal: Phase space coverage D 0 e+ e– The Low-mass signal + - y. CM O Electrons: no phase space limitation

Open charm (Au+Au @ 25 AGe. V) z-vertex reconstruction D 0 K- + 0. 1 MHz 31

10 MHz IR, high statistic p. Au 30 Ge. V KS 0 + - - decay channel - + p - -p - MHSD 0. 26 0. 28 ? ? 0. 0027 BR(%) 69. 2 63. 9 87. 0 ~100 total eff. (%) 10. 5 4. 65 ? ? 1. 6 S/B 2 16. 7 27 1. 4 1. 1 >10 Yield/central int. 0. 027 0. 013 0. 34 E-3 0. 24 E-3 32 0. 11 E-4

Up to 10 MHz IR, high statistic Au+Au 8 AGe. V KS 0 - decay channel - + p - -p - K- p - MHSD 9. 8 14. 2 0. 27 0. 005 BR(%) 69. 2 63. 9 ~100 67. 8 9 14. 3 2. 3 0. 8 S/B 2 1. 5 1. 4 6. 4 0. 1 Yield/central int. 0. 61 1. 3 0. 006 2. 7 E-5 Au+Au 25 AGe. V KS 0 - decay channel - + p - -p - K- p - MHSD 26. 2 28 0. 96 0. 022 BR(%) 69. 2 63. 9 ~100 67. 8 total eff. (%) 10. 4 12 1. 1 0. 55 S/B 2 0. 61 1. 4 6. 5 0. 4 Yield/central int. 1. 88 2. 14 0. 01 8. 2 E-5 total eff. (%) 33 33

Open charm properties table (25 AGe. V) D 0+D 0 D++D- Ds+ c + p K- + decay channel K- + + K-K+ + MHSD 1. 5· 10 -4 4. 2· 10 -5 5. 4· 10 -6 MSM 8. 2· 10 -4 8. 4· 10 -5 1. 4· 10 -4 4. 9· 10 -4 BR(%) 3. 8 9. 5 5. 3 5. 0 geo. acc. (%) 29. 2 40. 1 32. 8 71 z-resolution ( m) 52 56 60 69 total eff. (%) 3. 95 4. 75 1. 0 0. 05 m (Me. V/c 2) ~11 ~11 S/B 2 0. 16/0. 5 1. 24/2. 5 5. 0 0. 6 Yield/1012 mb HSD 14 k+41 k 47 k+89 k 0. 7 k Yield/1012 mb SHM 78 k+225 k 95 k+179 k 15/03/12 19 k 3. 2 k 34 34 34