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

9th September,2009CBM-Muon Meeting(EVO)2 Study of Manual Segmentation of MuCh ARUN PRAKASH High Energy Physics Lab Department of Physics Banaras Hindu University Varanasi

9th September,2009CBM-Muon Meeting(EVO)3 Outline Manual Segmentation Study Results Future Plan

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

9th September,2009CBM-Muon Meeting(EVO)5 Standard Geometry  Cbmroot trunk version  Embedded 1000 central events Au+Au at 25 AGeV  Standard MuCh: 13 layers  Total length : 3.4m

9th September,2009CBM-Muon Meeting(EVO)6 Manual Segmentation A.2x.4 to 1.6 x regions Rest all: 1.6 x region Total no of pads:

9th September,2009CBM-Muon Meeting(EVO)7 Manual Segmentation(contd...) B.2 x.4 One region Rest all 1.6 x 1.6 (one region each) No of pads:

9th September,2009CBM-Muon Meeting(EVO)8 Manual Segmentation(contd...) C 2 regions:.2 x Rest 1.6 x region No of pads:

9th September,2009CBM-Muon Meeting(EVO)9 Manual Segmentation(contd...) D 3 regions:.2 x.4 to.8 x 3.2 Rest: 1.6 x 1.6, one region Total no of pads:

9th September,2009CBM-Muon Meeting(EVO)10 Manual Segmentation(contd...) E 3 regions:.2 x.4 to 1.6 to regions:.8 x 1.6 to 3.2 to regions: 1.6 x 3.2 to 3.2 to 3.2 Rest 3.2 x 3.2 Total no of pads:

9th September,2009CBM-Muon Meeting(EVO)11 Efficiency of Muons(standard geo) Presented earlier

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

Manual Segmentation STATION PAD SIZE(cm) A0.25x x x0.60.8x x1.25 B0.5x0.50.9x0.91.2x1.21.6x x2.5 C1.0x1.01.8x1.82.4x2.43.2x x5.0 D 6.0x6.07.0x7.08.0x8.09.0x x10.0

4 different pad sizes PAD SIZE (1 st ) PARAMETERS 0.25X0.25(A)0.5X0.5(B)1X1(C)5X5(D) # of Digis # of Global track # of Much Track (8hits)Eff (STS+MUCH) (6hits)Eff (STS+MUCH) Eff(10hits) (STS+MUCH) 0.89 Total no of pads2,400,480691,040170,37615,768

9th September,2009CBM-Muon Meeting(EVO)15 Future Plan To look into other parameters like invariant mass, acceptance plot,momentum distribution etc. Add clustering Study auto-segmentation

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

DYNAMIC RANGE ● DYNAMIC RANGE 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)

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.

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)

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

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

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(= keV)

 OBSEVATION number 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 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

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

Trigger simulation Partha Pratim Bhaduri VECC, India

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/  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 Simulation Absorber thickness (cm):

Trigger algorithm 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 = m 0 *Z ; Y=m 1 *Z Make all possible combinations Find  2 & apply cut on both  2 X &  2 y Hit combination satisfying the cuts is called a triplet. Hits once used for formation of a triplet is not used further. Find m 0 & m 1 of the fitted st. lines Define a parameter α=√(m 0 2 +m 1 2 ) Apply cut on α Magnetic field (0,0,0) (0,0.0) Trigger station

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

Event Input Cut-1 Cut-2Cut-3 cut-4 Pluto10k UrQMD80k Event selection Set : 1 Cut Values :  2 x,y <=0.2 α>=0.183

Background suppression factor (B. S. F) Cut Events survived Statistical Error B. S. F % ~ % ~ % ~ % ~1430 B. S. F = Input events (80,000) / events survived

Reconstructed J/  Trigger cut Reconstruction efficiency (%) no cut 29.3 % Cut % Cut % Cut % Cut % 1k embedded minimum bias events

Trigger Cut 1 (Reconstructed J/  : 292)

Trigger Cut 2 (Reconstructed J/  : 245)

Trigger Cut 3 (Reconstructed J/  : 242)

Trigger Cut 4 ( Reconstructed J/  : 153)

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 4 th trigger cut there is a decrease in signal reconstruction efficiency up to ~ 50 % Cut by cut investigation shows even up to the 3 rd 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.

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.

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