2.76 TeV and 4 TeV Hydjet sample comparison

Introduction

Data samples are located under MIT T2 servers. In the DBS, dataset name is :

• 2.76 TeV (~ 1M events) : /Hydjet_Quenched_MinBias_2760GeV_MC_3XY_V24_GEN-SIM-RAW/davidlw-Hydjet_Quenched_MinBias_2760GeV_MC_3XY_V24_GEN-SIM-RAW-51550601a6965131c06787129d40c7a9/USER
• 4 TeV (~ 35000 events) : /Hydjet_MinBias_4TeV/Summer09-MC_31X_V9-v1/GEN-SIM-RAW

Used program :

• CMSSW : 3_4_1
• EDAnalyzer : CVS page.

Issue on 2.8 TeV :

• Number of muon per event is larger at 4 TeV and 2.76 TeV (~1/event) than at 2.8 TeV (~0.3/event).
• Related material is on the indico : slide
• pt hat hydjet cut in the samples (cut at 6 GeV/c for 2.8 TeV vs. 7 GeV/c in 4 TeV)

To do lists from HI di-lepton meeting:

• Check what cross section is used for Pythia input in HYDJET and compare with NLO expectations (integrated numbers should be enough). The theoretical calculations should give a pt, eta distribution. One needs to compare the spectra from hydjet to the one from theory and see how well they match, in what region. Does the change in pt hat cut modify the muon pt specta (and those measurable) ?
• Compare with HIJING (from Alice people) if the information is easy to access (but probably only at forward rapidity).

Mother particle comparison

• Transverse momentum (pt) trends are similar between 2.76 TeV and 4 TeV for same mom ID

Muon

List of all mother particle ID of muon

• % is calculated by this formula

J/psi

Because 4 TeV sample doesn't have enough J/psi, here is another plot from other 4 TeV sample. Original twiki site of this plot is here.

List of all mother particle ID of J/psi

Upsilon

Muon's rapidity, phi, pt distribution

• Because number of total event for each sample is different, normalization is done by this formula

J/psi's rapidity, phi, pt distribution

Upsilon's rapidity, phi, pt distribution

-- MiheeJo - 21 Mar 2010