Attendance - Zach, Xiaozhi, Kunsu, Bingchu

 1) PHE Selection and RooFit by Kunsu- Slides

• Pi0 DCA_XY distribution with higher stats from HIJING shown, still disagreement with Xiaozhi's analysis (XB sees 10 um shift)
• Slide 5: the peak in the middle plot (difference between fit and data) not well understood yet, could come from lack of constraints on hadron contamination
• For Dalitz decay contribution to inclusive e during fit, use a scaled version of the pion fit (same shape, scaled to match)
• Using RooFit, to fit with multiple configurations (PHE from data, PHE from HIJING, PHE from HIJING with no explicit Dalitz contribution). PDF's shown on slide 4 as lines, made directly from histograms.
• For PHE from HIJING, "reverse" means a mirroring of the DCA_XY distribution about DCAXY=0, keeping only the value from the negative side. This was done to try to better match the simulated PHE shape to data. Request to see a plot of HIJING PHE, HIJING PHE Reversed, and Data DCA_XY so we can discuss whether this is an acceptable method.
• The B_fraction extraction is shown in many overlapping bins, will need to determine best binning later. Request to see same plots without reversing the HIJING. Noted that HIJING without Dalitz best agrees with Xiaozhi's results so far, but does not mean much yet.

2) DCA_XY Shifting and R_B update by Xiaozhi - Slides

• As noted before, still see a difference between HIJING Pion DCA_XY distributions from Kunsu.
• Still question why DCA_XY distribution is not symmetric for Pion/electron. Investigating the charge dependence of this.
• Fits not converging well, working on better constraints for PHE.