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Photons+X meeting Update 16 Oct 2017

Photons+X meeting Update 16 Oct 2017. Photon+X Paper. Comments on V0.4 addressed and prepared to upload V0.5 on Monday 9 Oct Just as I was preparing to upload, noticed comments from Zach Marshall on V0.4 that had been uploaded within the past few hours.  Held off

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Photons+X meeting Update 16 Oct 2017

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  1. Photons+X meeting Update 16 Oct 2017

  2. Photon+X Paper • Comments on V0.4 addressed and prepared to upload V0.5 on Monday 9 Oct • Just as I was preparing to upload, noticed comments from Zach Marshall on V0.4 that had been uploaded within the past few hours.  Held off • Till asked about status; when I told him, he asked me to upload provision V0.5 • Received comments on V0.5 from Till and Remi • Most of those addressed. Status summarized on next page

  3. Photon+X Paper Preparation Status Several things are needed from Stefano • Limit contours with extended grid for squark-bino and wino-bino models • P0 and significance values for the 5 diphoton SRs • Noting 9 DOF degeneracy for squarks in squark-bino plot I need help with several things from Francisco/Hernan • Confirm reasons for insensitivity when neutralino mass is within 50 GeV of gluino mass • Confirm reason that A*e falls off for small neutralino mass • Check color consistency of limit contour plot (relative to diphoton plots) • Question about transfer factor uncertainties for CR constraints

  4. WH (H  ) Analysis Timeline Ed Board meeting Friday 1pm CERN time • 1l + bb • Diphoton • Need ~20 minute presentation https://indico.cern.ch/event/672985/

  5. WH (H  ) Analysis Status • Conversion from Kazuki’s private script to HistFitter is underway • Version 0.2 uploaded 9 October • Comments on current version (0.2) submitted by Tommaso on 13 October • One major comment will require (I believe) discussion by larger WH group, including Tommaso. • I’ll require help with a few other comments • See next slides

  6. WH (H  ) Analysis: SM WH Background Issue Current approach from V0.2 of Note: prompted the following comment from Tommaso (next slides)

  7. WH Background Comment (Tommaso) Conceptually, I don’t agree with the choice of ignoring the SM prediction and use the measurements. We have two goals (test the SM and test the SM+SUSY hypothesis). A deviation from the SM prediction is what we are interested to maximize our sensitivity to. In practice, the peaking background is very small and it is smaller than the non peaking background, so I am happy to assign a large uncertainty if we can justify it, it does not compromise sensitivity, and it saves time since we don’t have to compute the uncertainty (and make sure it’s reliable) on the theory prediction.  a) Effect on sensitivity : in SRa the 60% error on WH increases the uncertainty on the total background from 0.22 to 0.23. For SRd it increases from 1.10 to 1.67. The effect on significance on 150,0 (presumably a worst case because of the large SRd/SRa ratio) is 2.04 => 2.00 in SRa and 2.10 => 1.83 for SRd (all computed with BinomialExpZ). I think that’s small enough. 

  8. WH Background Comment Cont’d b) The justification of the procedure to assign an uncertainty from measurements is more questionable. We cannot use [43] in a paper, as it is a preliminary result. Beside, we are interested in WH, H=> gg. The rate of this divided by the SM prediction is most definitely NOT the product of the WH(bb) and ggF-H(gg) signal strenghts. Those depend on four unknowns, sigma(WH), sigma(ggF),  BR(H=> bb) and BR(H=>gg) where the latter two are uncorrelated. I don’t think you can derive an uncertainty on WH(gg) without theoretical assumptions on BSM modifications of the couplings. Also, you are using the relative uncertainty but not the central values. The WH(bb) measurement is certainly compatible with an enhancement of WH cross section by a factor of 2. How are we going to explain the error on the peaking background in a publication ? 

  9. WH Background Comment Cont’d The uncertainty also does not account for acceptance uncertainties, just cross section and BR. Presumably acceptance uncertainty for the selections you are doing are small compared to 60%. I would just write that we assign an uncertainty of 60% which covers the uncertainty on the theoretical predictions in the SM and the MSSM parameterspace not excluded by the run1 coupling measurements. We should check that the statement is true. I believe the uncertainty on the SM prediction is smaller than that. I guess that scale variations are what would be used for the acceptance uncertainty - the Higgs group should have a clear recipe for that. For the MSSM-SM difference the MSSM paper should have a scan of the parameters I think, so one should be able to check the possible deviation in sigma_WH*BR(gg). \\

  10. WH Background Disucssion Outcome Issue was discussed at WH meeting today Consensus that we should begin evaluation of four sources of WH uncertainty • SM uncertainties on WH production and H BF • A*e uncertainties due to theoretical uncertainties (PDF, scale) • A*e uncertainties due to experimental uncertainties • Constraints within MSSM on relevant SM-like Higgs couplings After that we can evaluate what to do (try to justify 60% or reoptimize…)

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