HF minutes - 2018/08/02

1) Update on D+- in Run16 Au+Au@200 GeV - Jan Vanel
Jan obtained D+- efficiency from fast-sim using EvtGen and compared it to that using PYTHIA. A few bugs found in the previous efficiency evaluation with PYTHIA fast-sim. After removing bugs, the efficiency from two fast-sim are consistent and the D+/- RAA from Run16 is consistent with that from Run14. 

  • slide 6, question was is the Vz bin issue common in PYTHIA fast-sim, will it affect other people using PYTHIA fast-sim. The answer was no.
  • slide 11, suggested to compare the results to Xinyue and Robert's results
  • PAs have plan to extend the analysis to lower pt (0-1 GeV/c) with TMVA


2) Status report of D* in Run16 Au+Au@200 GeV - Yuanjing Ji
Yuanjing reported her first result on D* production in Run16 Au+Au data. The significance is similar between run14 and run16, but the background in run16 is about a factor of 3 higher in run16 compared to run14. 

  • slide 8, comparison of D0 from Yuanjing and Xiaolong. They use different methods. Yuanjing used fitting method, Xiaolong used bin-counting method with fixed mass-window. Need apple-to-apple comparison. Need also double check the error bars, especially at the highest pt bin.
  • Slide 10, looks like dca<1 cm should help to improve signal-to-background ratio. Yuanjing commented that she tried dca<1 cm but found the significance is similar. She will do further study.