The blog collects the information related to jpsi analysis using 2014 MTD triggered data.

Luminosity

• Jamie's luminosity tracker: http://www.star.bnl.gov/protected/common/common2014/trigger2014/lumiau200GeV/tracker.html
• As of May 27th, 2.02e3M di-muon events have been collected, which correspond to ~ 9nb^-1 of luminosity

Jpsi cross section

• In 200 GeV Au+Au collisions, the rapidity density of jpsi is (1.79±0.26)*10^-3at mid-rapidity (PRC 81, 034911). Given that the Au+Au cross section is 7.27 b, the cross section for jpsi in Au+Au collisions is about (13.01±1.89) mb at mid-rapidity.

Expected jpsi counts

• For 10M di-muon events, the total number of jpsi is about 5.8*1e5
• Branching ratio to di-muon channel: 5.93%
• MTD acceptance: 45% * 45% = 20.25%
• TPC tracking efficiency: 80% * 80% = 64%
• MTD trigger efficiency: ~ 70%
• 1 GeV/c pt cut on muon candidates: a few percentage
•