1 Run15 centrality study using MB data - Yanfang Liu
a) Use "VPDMB-novtx" for MTD dimuon triggered events. Can also use "VPDMB-5-ssd" events. Do not use trigger ids 57, 27 since these events were taken before the triggers were elevated to physics triggers. 
b) For now, "ranking>0" cut will be used to select clean events. Once the procedure is established, we can come back to see if events with |TPC-VPD| < 6 cm but negative ranking can be used to gain statistics.
c) Slide 11: contact Daniel about how to select good signals from VPD
d) Slide 12: peak at 0 for ZdcSumAdcEast where Au nuclues goes. Is this due to efficiency?
e) Next step: work on Glauber model to check which detector gives best classification of centrality.