Slide 1

Status of CBM muon studies I.Vassiliev, S.Gorbunov, I. Kisel and A.Kiseleva 16-Oct-06 Motivation Simulation tools cbmroot2 v06 Signal and background simulations new absorber materials, WFeC absorbers Tracking with thick absorbers J/ and , , reconstruction Low rapidity region coverage, momentum dependent tracking Summary Slide 2 Motivation NA60 experiment Sanja Damjanovic QM2005 Budapest, GSI 2006 ~ 1m Muon Spectrometer MWPCs Trigger Hodoscopes Toroidal Magnet Iron wall Hadron absorber ZDC Target area beam Matching in coordinate and momentum space Slide 3 Signal and Background simulation J/ BG: 10 4 central UrQmd events Signal: J/ , , and + - Y~ 3.5 @ NA60 N ch ~190 central Y~ 2.0 @ CBM N ch ~600 central Slide 4 V. Baublis: Signal and Background simulation MC a) 120 cm of Fe equivalent b) SF ~ 20 per track c) LMVM bg unavoidable 2 GeV 6 GeV Slide 5 Excellent tracking in the Sts detector exist L1 ACCUMULATED STAT : 10000 EVENTS Ref. Prim.efficiency99.653840594 Ref. Sec.efficiency64.21290678 Refsetefficiency95.934131272 Allsetefficiency91.515250531 Extra Prim.efficiency89.10941690 Extra Sec.efficiency47.43177569 Extraefficiency78.201119259 Cloneprobability00.01344 Ghostprobability00.4825374 MC tracks/event found:525 CA Track Finder time:1.15 (1.05 + 0.10) s/ev MAPS: Physical hits: 1063Hybrid: 633 MCPStrips:MCP: 2518 Background hits: 1865 614 hitsMCPS:2415 Total hits created: 2928True:2408 Lost hits: 31Fake:15897 Fake hits: 87 Slide 6 Muon track finding -- ++ Fe C MC points -> hits smeared with xy = 100 m Active Progressively Increasing Thickness Absorber z2tr < 50 m zpv = 4 m Slide 7 Muon track finding -hit bg-hit estimated hit position APIT Absorber Slide 8 Muon track finding -hit bg-hit estimated hit position Slide 9 Muon track finding -hit bg-hit estimated hit position Slide 10 Muon track finding -hit bg-hit estimated hit position W Reconstructed track: (NSts MCT + NMuch MCT ) > 70% Slide 11 1 Step Hit 2 and 3 lost Thick absorber detectors n Steps All hits found 22 GEANT3 engine trajectory Tracking with thick absorber Slide 12 Much detector C: 1.2 m W: 5 (cm) Fe: 10, 20, 30 (cm) Sts 16 active layers: (1+5*3) 7.1 nI, 43.4 X 0 7.3 nI, 54.9 X 0 ++ -- no W W Slide 13 Transport 1k central urqmd W Fe C Hits distribution 60/event particleReco- track/ev. p0.04 ++ 0.135 K+K+ 0.09 ++ 0.003 -- 0.1 K-K- 0.005 -- 0.002 all0.38 Slide 14 Transport 1k central urqmd + + - + - Background 29 events Eff = 15.6% Signal 156 events Slide 15 signal efficiencies 10k events Slide 16 no cuts except track's 2 and hits # (16)! signal/background ratios S/B ~ 1/5 ( ) S/B ~ 1/25 ( ) S/B ~ 1/500 ( ) BG: 10 6 central urqmd events Slide 17 RECO IM 13 &16 hits/track additional information min bias central Slide 18 mid rapidity coverage Slide 19 Variables and cuts. Cuts optimization J/ reconstruction variable Cut J/ Cut lmvm p1.0 GeV/c0.9 GeV/c ptpt 1.0 GeV/c0.23 GeV/c OA12 0 SP t [-2.4, -2.05] (GeV/c) 2 [-0.26, 0.13] Slide 20 Variables and cuts. Cuts optimization (GeV/c) 2 SP t = p x1 * p x2 + p y1 * p y2 Slide 21 J/ reconstruction Geometry 150cm Fe equivalent BG: 10 8 central urqmd events S/B ~ 30 Eff = 13% Eff = 24% Slide 22 Plastic scintillators wall MIP Eloss 2 MIP Eloss 3 MIP Eloss ++ -- other p (s) e-e- e-e- e-e- e+e+ MIPS! MIP e-e- Slide 23 Summary Vector mesons reconstruction with CBM muon detector looks very promising Using W as an absorber material allows significantly reduce hit density for the first Much layers; J/ and especially needs more absorber material All helps, comments and suggestions are cordially welcome