Answer to Notes from Physics Coordination

• S11: for p-Pb, we normally give cross sections as the final result, will this be done here as well? Otherwise, we need to specify which event class it is (INEL,NSD, etc) and possibly correct the event count.
  • Answer: invariant cross section is calculated. (https://twiki.cern.ch/twiki/bin/view/Main/YieldToCrossSection)
• S11: check procedure that was used for the reference for RAA; we think we switch between the ALICE data and ATLAS data at pT= 12 GeV there. Use the same prescription if possible.
  • Answer: It is impossible because pT range of pp 7 TeV cross section measured at ALICE is not reached up to 12 GeV /c (0.5 < pT < 8 GeV /c).
  • I checked RpPb with several patterns of pp reference. (https://twiki.cern.ch/twiki/bin/view/Main/PpReference). And we have to determine which reference is bettter to use for preliminary result.
    • reanalyzed pp 7 TeV at ALICE + published pp 7 TeV at ALICE + ATLAS electron (already shown at Physics Forum)
    • reanalyzed pp 7 TeV at ALICE + published pp 7 TeV at ALICE + ATLAS muon
    • reanalyzed pp 7 TeV at ALICE + preliminary HFM at 8 TeV at ALICE
• S12: could consider to evaluate this systematic uncertainty using the inclusive electron spectra, on which a Barlow test could be done. This may be worth trying for the largest systematic uncertainties.
• S13: would expect a stronger pt dependence for the uncertainty on the hadron contamination. At high pt, the hadron contamination is large, up to 40%, so a 2% uncertainty means that we know the hadron contamination with a 5%precision. It might make more sense to assign a constant relative uncertainty on the hadron contamination itself and then propagate this to the final result.
• S16: why does the systematic uncertainty increase strongly from pt=1 GeV to pt=5 GeV? It looks like we are including statistical fluctuations in the systematics.
  • Answer: this comes from the systematic uncertainty on the(published) reference.