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CDS comments on supporting note

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Presentation on theme: "CDS comments on supporting note"— Presentation transcript:

1 CDS comments on supporting note
Zhijun Liang

2 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 , 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
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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