1) NPE v2 at 54 and 27 GeV - Yuanjing Ji

• slide 6, bottom-right plot, the v2 of charged hadrons in 54 GeV is systematically higher than that of PHENIX data although within uncertainty. This could be due to different methods. The error bars are dominated by systematic uncertainty.
• slide 11, Yuanjing plan to use hadron v2 from 62 GeV published results. Question was why don't use the one from the same dataset, the charged pion v2 shown in previous slides are quite precise. The answer is that at high-pt, there are contribution from contamination. Since the v2(pt) doesn't have strong collision energy dependence, it is OK to use 62GeV data for first-order. In later stage, probably use the one in the same dataset from someone else's study.
• slide 12, top-right plot, why the mean of |VzVPD-VzTPC) shift by about -100 cm? After the meeting, I find an explanation. Since the MB is defined by VPDAND, ZDCAND or BBC&TOF, there is significant events VPD is not fired, the default VzVPD for these events is -999 cm. Yuanjing will show the QA plot with |VzVPD-VzTPC|< 3cm cut
• slide 12, bottom-left plot, why there is no event cut out by VzDiff requirement? need to double check
• slid2 12-13, the |Vz|<35 cm cut efficiency is only ~1/3. Question was why not use wider Vz window at low energy where the Vz distribution is broad. The answers was shown in slide 13, left plot. There is supporting structure at about Vz~55 cm which produces significant photonic electron. Need think about it.
• slide 14, embedding request for Run18 27 GeV Au+Au.