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Thoughts on a proposed new (?) signature: X 126 () + Z(l + l - ) Why?

Thoughts on a proposed new (?) signature: X 126 () + Z(l + l - ) Why?. If ~x2 excess holds up, as it may be, all SM couplings are suspect! Associated production (pp  VH) “directly” probes VH coupling. Theory Postdoc Patrick Draper says:

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Thoughts on a proposed new (?) signature: X 126 () + Z(l + l - ) Why?

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  1. Thoughts on a proposed new (?) signature: X126() + Z(l+l-) Why? If ~x2 excess holds up, as it may be, all SM couplings are suspect! Associated production (pp  VH) “directly” probes VH coupling

  2. Theory Postdoc Patrick Draper says: “The inclusive cross section ratio in the SM for (Zh)/(h+X) with mh=126 is about 0.02.  If we crank up the coupling of h to vector bosons universally, we can increase the Zh rate, but we also increase the Wh and VBF rates. The ratio above asymptotes to about 0.15 in that case. I'm not sure what happens when efficiencies are included, but as a first guess we might then say that a Zh fraction of 0.2 or bigger would reflect a violation of custodial symmetry.” What might we do with the 2012 data in this vein?

  3. Start clean: try to get at ZH coupling through H and Zll as advertised in title. • Peaking backgrounds: Dan writes that • I looked at the following MC samples (scaled to 5 fb-1) • Z->nunu + ggZ->ee + gZ->mumu +g • On all of this I required 2 photons with pt reqs of 40 and 30 GeV. I then selected events were the mass of the 2 photons was within 121 to 131 GeV.For Z->nunu + gg this yields 0.28 +\- 0.09 events (normalized to 4.8 fb-1). Then that should correspond ~0.09+/-0.03 events for Z->ll + gg Z->ee + g and Z->mumu +g give 0.96 and 0.97, respectively. These are each based off only one event in each that sample that has two photons in the selected mass range. Note that no lepton acceptance cuts are applied. • NOTE: If either lepton is missed, or the photon is not from l   misid, event is eliminated from background.

  4. 2) Non-peaking backgrounds: • The 2011-2012 “higgs” will sit on a background of 10K events (in a 1265 GeV window). • How many of these have two leptons that are within 1 of the Z mass resolution? • Optimization • Lepton ID requirements • Size of Z-selection mass window • Photon ID • Other things? • This might be first step.

  5. Assume for the moment that the background is 0… • 5 fb-1 at 7 TeV  105 events in peak • 20 fb-1 at 8 TeV  ~500 events in peak • Assume no observation, 50% efficiency for dilepton pair • No more than 6 events from ZX; Zll. • No more than 90 events from ZX overall. • No more than ~20% of X is produced in association with a Z at 95% CL Getting interesting. What about Zqq? What about looking for W?

  6. Seems to me like a good thing to get into… • 2012: • Explore non-peaking backgrounds • Engineer measurements of Z with leptons and quarks • Maybe also Ws. • Starting to get into interesting region, I would guess PRL material if non-peaking backgorunds are in control. • Good lead-in into 14 TeV data; event rate of X is key! • Q: Should we convene a little effort and stake a flag in the ground on this right away?

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