Muon simulation for p+A systemPreliminary studies with HSD

Muon simulation for p+A systemPreliminary studies with HSD

Partha Pratim BhaduriSubhasis Chattopadhyay

VECC, Kolkata

Partha Pratim Bhaduri, Kolkata 2

MotivationMotivation

• The aim of the relativistic heavy-ion collisions is to study the onset of de-confinement and the properties of the de-confined media in the laboratory. Hence it is necessary to define unambiguous and experimentally viable probes for de-confinement.

• In this respect proton-nucleus (p+A) collisions must be a fundamental component of any heavy-ion physics program

• Defines the reference baseline relative to which we recognize HI specific phenomena

• p+A collisions provide a measure of the nuclear effects – helps in disentangling the “QGP” effect from the “non-QGP” effects. Here there is no formation time for the “secondary” medium , hence such collisions provide as essential tool to correctly account for the effect of the nuclear medium initially present.

Partha Pratim Bhaduri, Kolkata 3

System System

• The specifications of the system chosen are:

Target : Au , Cu, S, O, C Projectile : p (1, 1) Beam energy : 30 GeV Event generator used : HSD – 2.5 Events : 5,000 (ISUBS = 50, NUM = 100)

Results with HSD

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J/Psi pseudo-rapidity distribution

pCpOpSpCupAu

pCpOpSpCupAu

CMS Frame Laboratory Frame

J/Psi transverse momentum spectra

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pCpOpSpCupAu

HSD vs. Pluto (pseudo-rapidity distribution)

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HSD Pluto

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CMS Frame Laboratory Frame

Laboratory Frame

Muons decayed from J/Psi Isotropic decay in J/Psi rest frame

8

CbmRoot Version: Trunk version

Number of events : 4000

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 HSD for p+Au system for 30 GeV p beam

Background : central UrQMD events for p+ Au at 30 GeV/n

Much Hit producer w/o cluster & avalanche

L1(STS) & Lit (Much) tracking with branching

Simulation

Absorber thickness (cm):20 20 20 30 35 100

Partha Pratim Bhaduri, Kolkata 3rd CBM-India Collaboration Meet 9

AnalysisAnalysis

• Use the reconstructed data after the full tracking through the detector set-up.

• Reconstructed global tracks have to satisfy :

1. Fraction of true hits (truehits/(true hits+ wrong hits+fake hits) >= 0.72. No. of STS Hits associated with the global track >=43. No. of Much Hits associated with the global track >=104. Chi2 primary <=2

Detector Acceptance

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Raw HSDLayer # 1Layer # 3Layer # 5Layer # 7Layer # 9Layer # 11

Invariant mass spectra

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Embedded Reconstruction efficiency : 23.8 %

Pure HSDReconstruction efficiency : 25 %

Negligible background effect

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Thank You