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CDS comments on supporting note

CDS comments on supporting note. Zhijun Liang. Comments from EB. What is GRL used ? WZjets_allchannels from W/Z group Does Alpgen and Sherpa MC signal samples include all the diagrams ? Yes, FSR/ISR/frag photons are included. How to treat Lar hole for electron and photons? In MC ,

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CDS comments on supporting note

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  1. CDS comments on supporting note Zhijun Liang

  2. Comments from EB • What is GRL used ? • WZjets_allchannelsfrom W/Z group • Does Alpgen and Sherpa MC signal samples include all the diagrams ? • Yes, FSR/ISR/frag photons are included. • How to treat Lar hole for electron and photons? • In MC , • Use pseudo-random run number to associate one MC event to one data taking period, • Use object quality Map of that data taking period for e/gamma selection

  3. Comments from EB • Where parton-> photon fragmentation effect is included? in Awg/zg, Cwg/zg? • The ALpgen/Sherpa simulation have included photon fragmentation diagram in Matrix element calculations, • Since we are using simulation Monte Carlo to calculate Awg/zg, Cwg/zg, • parton-> photon fragmentation effect has been included and taken care in Awg/zg, Cwg/zg. • (photon fragmentation contribution mainly have impact on Cwg/zg, almost no impact on Awg/zg).

  4. Comments from EW conveners • How do you treat Tau decay channel ? • Consider as background. • It is a tiny background, subtract them using Monte Carlo • Trigger matching and apply trigger scale factor? • tiny effect in electron channel. • Update this effect for muon channel in the note • only one lepton in the event for Wgamma? • Describe Z veto cut in more details , what is quality cut to veto events with two leptons. • Isolation scale factor and systematic • Scale factor =1 , move part of photon isolation discussion into electron isolation section

  5. Question on the plot Why MC error bar are large ? (include systematic error) What is error on data driven method, is that consistent with Egamma Recommendations ?

  6. Data driven photon efficiency Purity comes from MC ? Or Data ? What is the error bar on the purity?

  7. Question to muon channel photon jet background • You have mentioned the Muon isolation shape is determined from control regionsand normalized in the signal region. • How the normalization is implemented? • Did you just use ptcon/pt>0.2 region for normalization? • L659 - L664 You said template method is similar to ABCD method. Could you describe the difference in the note? • In ABCD method, you have a correction of the signal in BCD region, • did you apply the same correction in the template method?

  8. Question to electron channel photon jet background • Question: • I expect non-isolated electron to isolated electron is a measure of heavy flavor jet electron background. • To estimate light jet electron background, we normally use (!Medium & Loose) as denominator to extrapolate to Tight electron. Could you describe • Answer • Unlike muon channel, heavy flavor is not the main contribution. • Electron fake mainly comes from hadron fake ( some fraction of heavy flavor). • Both hadron fake and heavy flavor are likely to fail isolation cut • A cross check with (!Medium & Loose) needed (for pT(g)>15GeV) ?

  9. Question on the plot • What is the point for this plot ? • Can we have log scale plot ?

  10. Comments on cross section • i) page 52: I got really lost about Awg/zg description . • Could you define it on page 52 very explicitly. • My confusion is about "parton-level -> particle level" discussion

  11. Comments on ATGC • Sec 7/8 Zgamma/Wgamma aTGC • The method of TGC extraction between Wgma/Zgam is the same. • Please combine sec 7/8 to one section to have a common description of the methodology. • You have described in the order of Wgam/Zgam in earlier section. • Please continue this order in the TGC section.

  12. Open issue • Why muon channel need |Vz|<200mm, what is the efficiency of that cut ? • L973, MCFM is NLO in alpha_s, I think you need to make the argument clearer why to use the 0 jet bin. • l992: Is an estimate available on the theory error for the photon fraction from fragmentation?

  13. Open issue • Also two-dimensional fits for neutral and charged aTGCs, where you allow two aTGCs to vary and plot the 95% contours would be nice (CMS had that). However, if it would take too long, I would not insist on that. • L546 You stated that "fragmentation of pi0->2photon pass the photon isolation threshold is counted as part of the signal". • However, you have subtracted W+jet->photon background using data-driven method. • Don't you overestimate the acceptance and efficiency by including this fragmented photon as the signal?

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