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Simulation activities in India: students working on various topics..

Simulation activities in India: students working on various topics.. Partha(VECC), Hemen (GU) : Trigger, SIS100, physics simulation Bipasha (CU): dynamic range simulation, J/Psi physics at FAIR Arun: Geometry study Manish, Irshad (Jammu U)

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Simulation activities in India: students working on various topics..

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  1. Simulation activities in India: • students working on various topics.. • Partha(VECC), Hemen (GU) : Trigger, SIS100, physics simulation • Bipasha (CU): dynamic range simulation, J/Psi physics at FAIR • Arun: Geometry study • Manish, Irshad (Jammu U) • EVO meet every Thursday: co-ordinator: Z. Ahammed

  2. ARUN PRAKASH High Energy Physics Lab Department of Physics Banaras Hindu University Varanasi-221005 Study of Manual Segmentation of MuCh CBM-Muon Meeting(EVO)

  3. CBM-Muon Meeting(EVO) Outline • Manual Segmentation Study • Results • Future Plan

  4. Approach: • Reduce total no of pad sizes to 0.5 Milion • Single track (and muon) efficiency should not change with highest granularity case

  5. CBM-Muon Meeting(EVO) • Cbmroot trunk version • Embedded 1000 central events Au+Au at 25 AGeV • Standard MuCh: 13 layers • Total length : 3.4m Standard Geometry

  6. CBM-Muon Meeting(EVO) Manual Segmentation .2x.4 to 1.6 x 3.2 3 regions A Total no of pads: 577536 Rest all: 1.6 x 1.6 1 region

  7. CBM-Muon Meeting(EVO) Manual Segmentation(contd...) B No of pads: 1211392 .2 x .4 One region Rest all 1.6 x 1.6 (one region each)

  8. CBM-Muon Meeting(EVO) Manual Segmentation(contd...) C 2 regions: .2 x .4 .4 1.6 No of pads: 628736 Rest 1.6 x 1.6. 1 region

  9. CBM-Muon Meeting(EVO) Manual Segmentation(contd...) D 3 regions: .2 x .4 to.8 x 3.2 Total no of pads: 574464 Rest: 1.6 x 1.6, one region

  10. CBM-Muon Meeting(EVO) Manual Segmentation(contd...) E Total no of pads: 195840 3 regions: .2 x .4 to 1.6 to 3.2 3 regions: .8 x 1.6 to 3.2 to 3.2 2 regions: 1.6 x 3.2 to 3.2 to 3.2 Rest 3.2 x 3.2

  11. CBM-Muon Meeting(EVO) Efficiency of Muons(standard geo) Presented earlier

  12. Why no change in efficiency? • Can we work with largest pad size? • Take one region/station, double pad size for • every subsequent station • Change track selection criteria and see the effect

  13. Manual Segmentation

  14. 4 different pad sizes

  15. CBM-Muon Meeting(EVO) Future Plan • To look into other parameters like invariant mass, acceptance plot,momentum distribution etc. • Add clustering • Study auto-segmentation

  16. Bipasha Bhowmick University of Calcutta, Kolkata & Partha Pratim Bhaduri,VECC,Kolkata Dynamic Range of Much

  17. It is a term used frequently in numerous fields to describe the ratio between the smallest & largest possible values of a changeable quantity (such as measurable deposited energy) DYNAMIC RANGE

  18. Aim & algorithm • Dynamic range is a quantity essential for design of the read-out chips. • Determination of the energy deposition at each cell of the muon chambers ( in terms of MIP ,as muons give MIP signal). • Take different cell sizes (2mm. – 4cm.) & find out the fraction of multiple-hit cells & singly-hit cells for particles generated by UrQMD. • Optimize the cell size based on multi-hit fraction. • For the optimal cell size find cell energy deposition (E_dep) both for single muons (MIP spectra) & UrQMD particles. • Apply different MIP cuts & calculate the loss due to saturation. • Apply different hit cuts to observe the effect on tracking.

  19. Fraction of multiple-hit cells= (total # of cells having >1 hit)/ (total # of cells hit) Optimal cell-size : 4mm. for inner stations, 4cm. For outer stations (stn 12 onwards)

  20. Station# 1 Cell size : 4mm. Station# 12 Cell size: 4cm. Single muon energy deposition spectra : Fitted with Landau distribution MIP value : 0.197 KeV (MPV of the Landau)

  21. Station# 1 Cell size : 4mm. Station# 12 Cell size: 4cm. E_dep by UrQMD particles

  22. Saturation loss : part of the energy spectra above the selected energy deposition cut (in terms of MIP) value MIP cut: E_dep cut (keV)/MIP value(= 0.197 keV)

  23. Statistics : • UrQMD : 50 central events • Single muons : 50 events with 50 mu+ & 50 mu- in the momentum range 2.5GeV-25GeV generated at angle 2.5 to 25 degree using box-generator OBSEVATIONnumber of tracks is affected to a permissible amount(2.78% of the total tracks) if we reject 2% of the total hit in each station

  24. Comparison of percentage of track lost using different signals as input Varying the number of muon tracks added in embedding

  25. Trigger simulation Partha Pratim Bhaduri VECC, India

  26. Simulation CbmRoot Version: Trunk version Much geometry : Standard Geometry • 2 layers in 5 stations • Distance between layers 10 cm. • Gap between absorbers 20 cm • 3 layers at the last trigger station • Total 13 layers • Total length of Much 350 cm Signal : J/y decayed muons from Pluto Background : minimum bias UrQMD events for Au+ Au at 25 GeV/n Much Hit producer w/o cluster & avalanche L1(STS) & Lit (Much) tracking with branching Input : reconstructed Much hits Absorber thickness (cm): 20 20 20 30 35 100

  27. Take 3 hits from the trigger station with one from each of the 3 layers & fit with st. line both in X-Z & Y-Z plane passing through the origin (0. 0) i.e. X = m0*Z ; Y=m1*Z Make all possible combinations Find c2 & apply cut on both c2X & c2y Hit combination satisfying the cuts is called a triplet. Hits once used for formation of a triplet is not used further. Find m0 & m1 of the fitted st. lines Define a parameter α=√(m02+m12) Apply cut on α Trigger algorithm Trigger station (0,0,0) (0,0.0) Magnetic field 11 12 13

  28. Specification of cuts • Cut 1: at least 1 triplet/event • Cut 2 : at least 2 triplets/event • Cut 3 : at least one of the selected triplets satisfy alpha cut • Cut 4 : at least two of the selected triplets satisfy alpha cut • Events analyzed: 80k minimum bias UrQMD event for background suppression factor & 1k embedded minimum bias events for J/ reconstruction efficiency

  29. Event selection Set : 1 Cut Values : C2x,y<=0.2 α>=0.183

  30. Background suppression factor (B. S. F) B. S. F = Input events (80,000) / events survived

  31. Reconstructed J/ 1k embedded minimum bias events

  32. Trigger Cut 1 (Reconstructed J/ : 292)

  33. Trigger Cut 2 (Reconstructed J/ : 245)

  34. Trigger Cut 3 (Reconstructed J/ : 242)

  35. Trigger Cut 4 ( Reconstructed J/ : 153)

  36. Observation • Hit-triplets are made from last 3 layers of the trigger station, vertex included in the fitting. • Systematic study of background suppression & number of reconstructed J/y & its phase space distribution on cut by cut basis has been done. Statistics will be increased to reduce the statistical error further. • Using information from “Much-only” gives sufficient B. S.F (~1430). • With the application of the 4th trigger cut there is a decrease in signal reconstruction efficiency up to ~ 50 % • Cut by cut investigation shows even up to the 3rd trigger cut we have reasonable B. S. F (~879) but without decrease in signal reconstruction efficiency. • Phase space distribution of the triggered & un-triggered sample shows that all the trigger cuts are unbiased.

  37. Future Plans • Prepare a look-up table for different values of cut parameters & corresponding values of B. S.F & signal reconstruction efficiency. • Implementation of TRD in the present scheme. • Study pad resolution effect. • Formation of CbmMuchTrigger class to be run in chain.

  38. SIS-100 simulation • We have a HSD version with charm production, we are running that for generation of signal for SIS100 • Will vary muon geometry (no of stations/pad-sizes) • Arun (and Dr. Viyogi) will be at GSI working on this

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