CBM – MUCH Simulation Activities in India - Status

1. CBM – MUCH SimulationActivities in India - Status Premomoy Ghosh Variable Energy Cyclotron Centre Calcutta, India

2. Detector C-absorber Fe-absorber W-absorber MuCh simulation activities at VECC prior to last collaboration meeting CWFe04 – (C75+W6)+C30+Fe40+(C80+W6) e.g. Fe40 means 40cm thick Iron absorber Total length = 257 cm Gap between detectors = 4.5 cm Detector Thickness – 1cm Premomoy Ghosh 10th. CBM Collaboration Meeting, Dresden

3. MuCh simulation status till last collaboration meeting Study of Different MuCh geometry layout at GSI, VECC, PNPI……… Priority to unidirectional activity suggested for an early result on MuCh feasibility study. Optimum MuCh geometry configuration – “much_compact” tagged with ToF, as studied at GSI for low mass vector meson. VECC to study J/Y & Y’ for geometries based on “much_compact” version – to maintain the concept of modular-geometry with minimum change in set-up for study of entire di-muon mass-spectrum. Premomoy Ghosh 10th. CBM Collaboration Meeting, Dresden

4. What is done at VECC since last meeting Studied three geometries with different total absorber (Fe) thickness 1) much_compact (125 cm) 2) much_medium (190 cm) 3) much_large (225 cm) All these versions have same number (15) of detector layers, gaps between detectors, between detector and absorber, distance (102.5 cm) from the target. Premomoy Ghosh 10th. CBM Collaboration Meeting, Dresden

5. 20 cm 20 cm 20 cm 30 cm 35 cm 20 cm 20 cm 20 cm 30 cm 100 cm 30 cm 30 cm 30 cm 30 cm 35 cm 100 cm Schematics of MuCh geometries much_compact 125 cm Fe much_medium 190 cm Fe much_large 225 cm Fe Premomoy Ghosh 10th. CBM Collaboration Meeting, Dresden

6. Framework & Tools cbmroot FEB07 version Au+Au 25 AGeV – central UrQMD events Pluto generated muons Sts geometry – Sts_2maps_6strips.geo Sts track reconstruction - CA Tracking / Kalman Filter MuCh track – Kalman Filter Extrapolation Newly developed classes for realistic detector layout by M. Ryzhinskiy and as used by A. Kiseleva are not included. Premomoy Ghosh 10th. CBM Collaboration Meeting, Dresden

7. Selection of Tracks • Reconstructed tracks satisfying • Number of STS-hits (NSts) >= 4 and • True-hits/(true+wrong+fake hits) >0.7 • Number of MUCH-hits (NMuch) >9 • Terminology • NMuch =15, i.e the track passing through all absorber layers, is termed "Hard" • NMuch =12, i.e is the track passing through four absorber layers is termed "Soft" In the following slides we present relevant results, in terms of Hit-density, Signal reconstruction efficiency and Signal / Background for J/Y, Y’ and w. Premomoy Ghosh 10th. CBM Collaboration Meeting, Dresden

8. Comparison of hit-densities Premomoy Ghosh 10th. CBM Collaboration Meeting, Dresden

9. Signal/Background for J/Y & Y’ - large much_large.geo Reconstructed IM from Hard Tracks (NMuch=15) only Super Event Analysis with initial 10k UrQMD central events S/B from extrapolated exponential fitting For J/Y S/BG = 10.2 e = 14 % s = 22 MeV For Y S/BG = 3.33 e = 28 % s = 26 MeV Premomoy Ghosh 10th. CBM Collaboration Meeting, Dresden

10. Signal/Background for J/Y & Y’ – largecontd. Opening Angle cut of 12 degrees does not help in improving S/BG. Premomoy Ghosh 10th. CBM Collaboration Meeting, Dresden

11. Signal/Background for w - large Hard Tracks in much_large.geo For w, S/BG = 0.56, e = 0.34 % , s = 7 MeV. Premomoy Ghosh 10th. CBM Collaboration Meeting, Dresden

12. Signal/Background for J/Y & Y’ - medium much_medium.geo Reconstructed IM from Hard Tracks (NMuch=15) only Super Event Analysis with initial 10k UrQMD central events S/B from extrapolated exponential fitting For J/Y S/BG = 5.4 e = 16 % s = 22 MeV For Y S/BG = 1.82 e = 31 % s = 26 MeV Premomoy Ghosh 10th. CBM Collaboration Meeting, Dresden

13. Signal/Background for w -medium Hard Tracks in much_medium.geo For w, S/BG = 0.34, e = 1 % , s = 7 MeV. Premomoy Ghosh 10th. CBM Collaboration Meeting, Dresden

14. Summary & Plan for near future • The numbers on S/BG, efficiency etc. presented here are good enough to conclude that J/Y and Y’ reconstruction through di-m channel is feasible. • Immediate plan is to implement realistic detector layout as studied at GSI. • For proper estimation of S/BG - Super-Event Analysis with higher statistics (simulated events) or some new method is needed. • Parallel effort for other layout options needs to be continued. • Momentum dependent muon identification with “detectors within absorber” geometry layout only is not feasible, as yet. • We plan to investigate the method involving information from ToF and by optimizing (reducing) magnetic field. • We hope to progress in a faster rate with the possibility of active participation of more Indian Collaborators. J/Y and Y’ : Low mass vector mesons: Premomoy Ghosh 10th. CBM Collaboration Meeting, Dresden

15. Latest Development in simualtion activities Simulation Group formed in India-CBM Collaboration Meeting at Kolkata on 30th-31st July 2007. Framework and other codes installed at following Institutes/ Universities. • University of Calcutta, Kolkata • Indian Institute of Technology, Kharagpur • Saha Institute of Nuclear Physics, Kolkata • Benaras Hindu University, Varanasi • Jammu University, Jammu • Kashmir University, Srinagar • Bhabha Atomic Research Centre • Institute of Physics, Bhubaneswar Premomoy Ghosh 10th. CBM Collaboration Meeting, Dresden