Simulating the mass spectrum of J/Ψ and Upsilon Ingrid von Glehn Angus Comrie University of Cape Town Supervisor: Galina Shabratova Veksler and Baldin Laboratory of High Energy Physics
ALICE ► Detector at LHC ► Studies heavy-ion collisions ► Large number of subdectectors ► UCT-CERN group focuses on Dimuon
MUON Detector
Grid Computing ► Large data volume from experiment ► Can be processed independently ► Split up tasks across processors in an organised fashion (tier model) ► ALICE Grid (ALIEN)
J/Ψ Suppression as a sign of QGP
Simulation ► ROOT: C++ interpreter and analysis package ► Pythia: Particle transport / event simulation ► AliROOT: Contains geometry of entire ALICE project
Simulating the mass spectrum of J/Ψ and Upsilon ► Generate events using Pythia, only consider dimuon decays ► Apply Gaussian smearing to angles and momentum of muon pair ► Smeared mass histogram
Results for J/Ψ (1000 events)
Results for Upsilon (50000 events)
Background for charm pair ► More realistic situation, consider more decays ► Get an idea of what to expect ► Can look at particle code histogram to see major decays
Background for charm pair π0π0 π±π± strange mesons eg. K charmed mesons eg. D c,c μ±μ±
Background
ALICE Experiment ► Can compare simulated data with experimental data ► Can simulate different decay processes and see which agrees with experiment ► Comparison of theoretical models