Motivation; CBM experimental setup, MVD+STS; Open charm at SIS 100; He cooling (no Beam Pipe)

CBM Split sts K- + + MVD MAPS Open charm physics at CBM I.Vassiliev, D0, D+, Ds+ , c , D* • Motivation; • CBM experimental setup, MVD+STS; • Open charm at SIS 100; • He cooling (no Beam Pipe) • Open charm at SIS 300 • D0K-+, D+K-+ +, Ds+ K+K-+; and +c pK-+ • Open charm trigger; • {Ξ0Λ}b detectability study • Summary D+

CBM Split Charm production at threshold energies (motivation) Input to hadronic transport models (HSD): Parameterization of measured cross sections O. Linnyk et al., Nucl. Phys. A786 (2007) 183 No data: (why?) X-sections, flow(s), pt, y; D0/D+, D0/Ds, D0/c ratios

10 stations (5, 10,30,35,40,50,60,75, 95,100 cm) 2 first in vacuum MAPS: 300 and 500 (m), with 10x10m cell size Strip-detectors (400m), 60 m strip-pitch, 1cm (min.) strip length; Realistic hit producers; -electrons in, no pile-up and clusters for the MAPS detectors CBM Split MVD 100K p+C

CBM Split 44h 11h 05.10.09 4

CBM Split Fast SIMDized CA tracking in STS by I.Kisel p+C 30GeV XZ Top View MC RECO 1.125s eff = 97.9% RefPrim efficiency : 0.999 RefSec efficiency : 0.895 Refset efficiency : 0.991 Allset efficiency : 0.932 Clone probability : 0.023 05.10.09 5

CBM Split Fast SIMDized CA tracking in STS p+C 30GeV XY Rear View K- MC RECO p + p e- e+ - 05.10.09 6

CBM Split Fast SIMDized CA tracking in STS p+C 30GeV 50 pile-up 05.10.09 7

CBM Split Invariant mass resolution 05.10.09 8

CBM Split Z vertex resolution 05.10.09 I.Vassiliev, Dubna, May-09 9

CBM Split primary vertex reconstruction pC background control K- D+ + 2geo + 4.5 tracks central, 1 track mbias 05.10.09 10

CBM Split

CBM Split Open charm z-vertex reconstruction v221 5 cm 10 cm 05.10.09 12

CBM Split Invariant mass spectra HERA-B p+A 920GeV 2weeks @ 1.5MHz particles ID by RICH 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! 05.10.09 13

Simulation studies with He, no beam pipe (AuHe minbias) He He CBM Split

Simulation studies with He, no beam pipe (AuHe minbias) Acc(%) Efficiency (%) CBM Split

Simulation studies with He, no beam pipe (AuHe minbias) Acc(%) S/BG ~0.15 and rapidly decreasing with Z A. Kotynia CBM Split

CBM Split RefPrim efficiency : 0.979 (0.93) 0.88 RefSec efficiency : 0.833 Refset efficiency : 0.961 Allset efficiency : 0.905 Clone probability : 0.032 Ghost probability : 0.044 698 reco tracks Au+Au 25AGeV 1.125s eff = 97.9% 0.077s eff = 95.3% 534 mc track 771 mc track 698 tracks 509 tracks

CBM Split sv K- pv + - 5.5 µm primary vertex reconstruction UrQMD background control

CBM Split secondary vertex reconstruction D0 z-vertex resolution vs second MAPS z-position 3-d MAPS realistic sv K- pv + 500 m - 5.5 µm

CBM Split Open charm z-vertex reconstruction realistic MAPS D0K-+

CBM Split Strategy: background suppression keeping maximum of efficiency single track parameters based cuts: • χ2primon the impact parameter value 6.5-7.5 ! • IP impact parameter cut (upper value) 1mm • track momentum cut p > 1.0 GeV/c • track transverse momentum pt > (0.2-0.5) GeV/c multiple track (particle) parameters based cuts: • χ2GEOgeometrical constrained fit 3.0 • χ2TOPOtopological constrained fit 2.0 • signal particle primary vertex DCA < 30 m

CBM Split D0 and D0 @ 25AGeV minv spectra 1010 events

CBM Split D+ and D- @ 25AGeV minv spectra

CBM Split Ds+ @ 25AGeV minv spectra K+K-+ (5.3 ± 0.8)% +(4.5 ± 0.4)% -> K+K-(2.2 ± 0.2)% K+K*(892), K*(892) ->K-+(2.5)%

CBM Split Ds+ @ 25AGeV minv spectra

CBM Split Open Charm Trigger-algorithm CbmL1TrackFinder RFmb = 125 RFcen = 14 CbmL1TrackFitter Charm Track Candidates Selection χ2prim > 3 ☻ Charm Pairsχ22geo< 3.0, zv <1 cm χ2topo < 3.0, minv > 1.3 GeV ☺D0 ☻ ☺ D+c Ds Charm Tripletsχ23geo+topo < 3.0

CBM Split Detached Vertex Trigger: first results

CBM Split Open charm properties table (25AGeV)

{Ξ0Λ}b -dibaryon detectability study in the CBM experiment {Ξ0Λ}b→ΛΛ→ pπ-pπ- STS π- p p p MAPS π- Λ p π- Λ Λ {Ξ0Λ}b π- Λ {Ξ0Λ}b

Event topology: p π- p Λprim π- χ2topo Λ2 pv {Ξ0Λ}b Λ1 χ2topo p π-

{Ξ0Λ}b-dibaryon signal and ΛΛ-background z vertex distribution We use all cuts except cut on z vertex Distribution was fitted with exponent Integral under exponent from 3 to  was calculated. To estimate amount of ΛΛ candidates for 1012 events integral was multiplied by 108

Reconstructed invariant mass distribution with theoretically predicted parameters 50K 50K

Reconstructed invariant mass detectability level (multiplicity  few10-6) 50 M = 7·10-6

CBM Split Summary CBM detector is suitable for the Open charm measuring at SIS 100 and SIS 300 energies He inside MVD and STS isn’t good for the Open charm New Primary vertex finder has been developed New KFParticle CBM detector can collect about 50K {Ξ0Λ}b -dibaryons per 1012 central collisions Au+Au 25 AGeV Detectability limit is about few·10-6H-dibaryons per central event Plans: -electrons, pile-up, clustering in the MAPS, new detector geometries and passive materials;

Motivation; CBM experimental setup, MVD+STS; Open charm at SIS 100; He cooling (no Beam Pipe)