Projected sensitivity for Standard Model Higgs boson searches at 7 and 8 TeV, and 1-10 fb^-1

Main Results

Projections are obtained using an expanded list of SM Higgs signatures, namely: H→WW→2l2v (+0/1 jets), VBF H→WW→2l2v, H→ZZ→4l, H→ZZ→2l2ν, H→ZZ→2l2b, H→γγ, VBF H→ττ, associate production VH→V(bb) (highly boosted), associate production ZH→Z(WW)→(ll)(lvjj), associate production WH→W(WW)→(lv)(lvjj) (same sign di-leptons). At sqrt(s)=7 TeV with L=5 fb^-1, CMS is expected to reach an exclusion sensitivity in the mass range from the LEP limits (114 GeV) to 600 GeV. At sqrt(s)=8 TeV with L=5 fb^-1, the observation sensitivity in the same mass range of 114-600 GeV is expected to be 3σ or higher, depending on the Higgs mass.

Public Note: NOTE-2010/008 The CMS physics reach in searches at 7 TeV YET TO BE UPDATED TO INCLUDE THE NEW PROJECTIONS

How these projections were obtained

The following describes the work flow for deriving these projections.

• Start out from public older results at 14 TeV and more recent (but not public) studies at 7 and 10 TeV.
• Re-scale signal and bkgd event counts to correspond to 7 and 8 TeV cross sections and integrated luminosities of 1-10 fb-1
• Cross sections:
  • signal: gg-fusion at NNLO+NNLL, VBF and VH at NLO, ttH at LO
  • all backgrounds at NLO
• No corrections for acceptance change when projecting event yields obtained in studies performed at different sqrt(s)
• No corrections for improvements in reconstruction (efficiencies, resolution) when projecting from older studies
• Systematic errors included (scaled with energy/luminosity according to our rough expectations)
• Statistical analysis:
  • Exclusions (95%CL): Bayesian limits with a flat prior for the typical expected ("Azimov") outcome: n_observed=_sum of all backgrounds_
  • Significance: Profile Likelihood method

Public plots and recommended conclusions for conferences:

The table on the left shows Hggs production and decay channels used for the purposes of these projections. The mass range used in the analyses is also shown. All analyses are based on the cut-and-count methodology (in some cases, the cut is applied on the MVA-output).

The plots on the left (eps format far left and near left) show the projected exclusion limits and the expected observation signifcance for a SM Higgs search at sqrt(s)=8 TeV and L=5 fb-1. Contributions of individual channels used in the overall combination are also shown. Beware that the relative roles of different channels is luminosity-dependent (at low luminosity, some channels have a very little signal yield and quickly lose sensitivity; at higher luminosities, some channels slow down in gaining sensitivity due to systematic errors).

The plots on the left (eps format far left and near left) show the projected exclusion limits and the expected observation signifcance for a SM Higgs search at sqrt(s)=7 and 8 TeV and a few selected luminosities. At sqrt(s)=7 TeV with L=5 fb-1, CMS is expected to reach an exclusion sensitivity in the mass range from the LEP limits (114 GeV) to 600 GeV. At sqrt(s)=8 TeV with L=5 fb-1, the observation sensitivity in the same mass range of 114-600 GeV is expected to be 3σ or higher, depending on the Higgs mass.

The plots on the left (eps format far left and near left) show the projected exclusion limits and the expected observation signifcance for a SM Higgs search at sqrt(s)=7 and 8 TeV and a few selected luminosities. These are same plots as above, but with the x-axis in the linear scale.

The plots on the left (eps format far left and near left) show the projected exclusion limits and the expected observation signifcance for a SM Higgs search at sqrt(s)=7 and 8 TeV and a few selected luminosities for the SM Higgs range 115-200 GeV.

The plots on the left (eps format far left and near left) show the projected exclusion limits and the expected observation signifcance for a SM Higgs search at sqrt(s)=7 and 8 TeV and L=1, 2, 5, 10 fb-1.

Full collection of public plots for 7 TeV in various formats can be found here

-- AndreyKorytov - 01-Nov-2010