Muon simulation for p+A system Preliminary studies with HSD Partha Pratim Bhaduri Subhasis Chattopadhyay VECC, Kolkata

Partha Pratim Bhaduri, Kolkata2 Motivation 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, Kolkata3 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 Partha Pratim Bhaduri, Kolkata4 J/Psi pseudo-rapidity distribution pC pO pS pCu pAu pC pO pS pCu pAu CMS Frame Laboratory Frame

J/Psi transverse momentum spectra Partha Pratim Bhaduri, Kolkata5 pC pO pS pCu pAu

HSD vs. Pluto (pseudo-rapidity distribution ) Partha Pratim Bhaduri, Kolkata6 HSD Pluto

Partha Pratim Bhaduri, Kolkata7 CMS 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):

Partha Pratim Bhaduri, Kolkata3rd CBM-India Collaboration Meet9 Analysis 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) >= No. of STS Hits associated with the global track >=4 3.No. of Much Hits associated with the global track >=10 4.Chi 2 primary <=2

Detector Acceptance Partha Pratim Bhaduri, Kolkata10 Raw HSD Layer # 1 Layer # 3 Layer # 5 Layer # 7 Layer # 9 Layer # 11

Invariant mass spectra Partha Pratim Bhaduri, Kolkata11 Embedded Reconstruction efficiency : 23.8 % Pure HSD Reconstruction efficiency : 25 % Negligible background effect

Partha Pratim Bhaduri, Kolkata3rd CBM-India Collaboration Meet12 Thank You