Search for the Higgs Boson Decaying to W+W in the Fully Leptonic Final State (shape-based)

This is a condensed description with plots for the analysis CMS-HIG-12-038

Abstract

We report a search for the Higgs boson decaying to W+W in pp collisions at sqrt(s) = 8 TeV. The data were collected at the LHC with the CMS detector, and correspond to an integrated luminosity of 5.1 fb−1. The W+W candidates are selected in events with two opposite charged leptons and large missing transverse energy. Upper limits on the Higgs boson production relative to the standard model Higgs expectation are derived. The Standard Model Higgs boson is excluded for a mass in the range [129 - 560] GeV at 95% confidence level when these results are combined together with the analysis performed at sqrt(s)=7 TeV.

Main Results

A search has been made for a Higgs boson decaying in a pair of W bosons in the CMS detector. The search for the Higgs boson in the fully leptonic final state is summarized here. Previous results in this final state were published by CMS based on the 2010 and 2011 datasets, excluding the presence of the Higgs boson in the mass range 129--270 GeV. With respect to the analysis described in HIG-12-017, the only difference is the inclusion of a multivariate analysis for the different-flavor final state in the 0-jet and 1-jet categories. The same-flavor final states have limited sensitivity to the signal and introduce a large systematic uncertainty due to the larger fake missing ET background in events with high pile-up. Thus we retain the simpler cut-based approach for the same-flavor final states. The search discussed here is performed over the mass range 110--600 GeV, and the data sample corresponds to 5.1fb-1 of integrated luminosity collected in 2012 at a center-of-mass energy of 8 TeV. Finally, the 7 TeV data sample is added to the analysis to obtain the combined 2011 and 2012 results.

  • Observed (expected) significance for mH = 125 GeV in terms of standad deviations ==> 2.2 (2.5)
  • best fit value of the signal strengh for mH = 125 GeV ==> 0.82 +/- 0.38

Tables

8 TeV cut-based analysis 8 TeV shape-based analysis 7 TeV + 8 TeV analysis
Higgs Mass Observed Median exp. 68% band 95% band Observed Median exp. 68% band 95% band Observed Median exp. 68% band 95% band
110 7.7 4.7 [ 2.3, 3.2] [ 6.7, 8.4] 6.6 4.9 [ 2.5, 3.4] [ 6.8, 8.4] 5.6 3.2 [ 1.6, 2.2] [ 4.7, 6.6]
115 4.3 2.7 [ 1.3, 1.9] [ 3.9, 5.6] 4.6 2.1 [ 0.9, 1.4] [ 3.2, 4.7] 3.8 1.4 [ 0.6, 0.9] [ 2.1, 3.1]
120 3.1 1.6 [ 0.8, 1.1] [ 2.3, 3.3] 3.5 1.6 [ 0.8, 1.1] [ 2.3, 3.2] 2.5 1.1 [ 0.5, 0.7] [ 1.6, 2.2]
125 1.9 1.1 [ 0.6, 0.8] [ 1.6, 2.2] 2.0 0.9 [ 0.5, 0.6] [ 1.4, 1.9] 1.5 0.7 [ 0.3, 0.5] [ 1.0, 1.4]
130 1.4 0.8 [ 0.4, 0.6] [ 1.1, 1.5] 1.3 0.8 [ 0.4, 0.6] [ 1.1, 1.5] 0.9 0.5 [ 0.3, 0.3] [ 0.7, 1.0]
135 1.0 0.6 [ 0.3, 0.4] [ 0.9, 1.2] 1.1 0.5 [ 0.3, 0.4] [ 0.8, 1.1] 0.8 0.4 [ 0.2, 0.2] [ 0.5, 0.7]
140 0.7 0.5 [ 0.3, 0.4] [ 0.7, 1.0] 0.8 0.4 [ 0.2, 0.3] [ 0.5, 0.8] 0.5 0.3 [ 0.1, 0.2] [ 0.4, 0.5]
150 0.7 0.3 [ 0.2, 0.3] [ 0.5, 0.6] 0.6 0.3 [ 0.2, 0.2] [ 0.4, 0.5] 0.4 0.2 [ 0.1, 0.1] [ 0.3, 0.4]
160 0.4 0.2 [ 0.1, 0.1] [ 0.3, 0.4] 0.3 0.2 [ 0.1, 0.1] [ 0.2, 0.3] 0.2 0.1 [ 0.1, 0.1] [ 0.2, 0.2]
170 0.4 0.2 [ 0.1, 0.1] [ 0.3, 0.4] 0.3 0.2 [ 0.1, 0.1] [ 0.2, 0.3] 0.2 0.1 [ 0.1, 0.1] [ 0.2, 0.2]
180 0.5 0.3 [ 0.2, 0.2] [ 0.4, 0.5] 0.4 0.2 [ 0.1, 0.2] [ 0.3, 0.4] 0.3 0.2 [ 0.1, 0.2] [ 0.3, 0.4]
190 0.8 0.4 [ 0.2, 0.3] [ 0.5, 0.8] 0.6 0.4 [ 0.2, 0.3] [ 0.5, 0.7] 0.4 0.3 [ 0.2, 0.2] [ 0.4, 0.5]
200 1.0 0.5 [ 0.2, 0.3] [ 0.7, 0.9] 0.9 0.4 [ 0.2, 0.3] [ 0.6, 0.8] 0.6 0.4 [ 0.2, 0.3] [ 0.5, 0.7]
250 2.2 0.9 [ 0.4, 0.6] [ 1.3, 1.9] 1.3 0.9 [ 0.5, 0.6] [ 1.2, 1.6] 0.8 0.7 [ 0.4, 0.6] [ 1.0, 1.3]
300 1.9 1.1 [ 0.6, 0.8] [ 1.7, 2.4] 1.0 1.0 [ 0.5, 0.7] [ 1.4, 1.9] 0.7 0.7 [ 0.4, 0.5] [ 1.0, 1.4]
350 1.3 1.1 [ 0.5, 0.7] [ 1.6, 2.3] 0.5 0.8 [ 0.4, 0.5] [ 1.1, 1.6] 0.4 0.6 [ 0.3, 0.4] [ 0.8, 1.2]
400 1.2 1.2 [ 0.6, 0.8] [ 1.8, 2.6] 0.4 0.7 [ 0.3, 0.4] [ 1.1, 1.7] 0.5 0.5 [ 0.2, 0.3] [ 0.8, 1.2]
450 1.1 1.3 [ 0.6, 0.8] [ 2.1, 3.2] 0.6 1.0 [ 0.4, 0.6] [ 1.5, 2.3] 0.5 0.7 [ 0.3, 0.4] [ 1.1, 1.6]
500 1.2 1.6 [ 0.6, 1.0] [ 2.6, 4.2] 0.8 1.3 [ 0.6, 0.9] [ 2.1, 3.3] 0.5 1.0 [ 0.4, 0.6] [ 1.5, 2.4]
550 1.7 2.3 [ 1.0, 1.5] [ 3.8, 6.2] 1.6 1.7 [ 0.7, 1.1] [ 2.8, 4.5] 1.0 1.2 [ 0.5, 0.7] [ 1.9, 3.1]
600 2.3 3.4 [ 1.5, 2.2] [ 5.7, 7.9] 2.3 3.0 [ 1.5, 2.0] [ 4.7, 7.1] 1.2 2.2 [ 1.0, 1.4] [ 3.5, 5.6]

Figures

histo_mva_125_0j_of.png BDT different-flavor H(125) 0-jet bin
histo_mva_125_1j_of.png BDT different-flavor H(125) 1-jet bin
limit8TeV_cut_from110to600_logx1_logy1.png cut-based 8 TeV limits, H(125) injected
limit8TeV_bdt_from110to600_logx1_logy1.png shape-based 8 TeV, H(125) injected limits
combined_from110to600_logx1_logy1.png 7+8 TeV shape-based limits, H(125) injected
limit8TeV_cut_from110to600_logx1_logy1_nosignalinjected.png cut-based 8 TeV limits
limit8TeV_bdt_from110to600_logx1_logy1_nosignalinjected.png shape-based 8 TeV limits
combined_from110to600_logx1_logy1_nosignalinjected.png 7+8 TeV shape-based limits
significance7p8TeV.png Expected and observed significance for the combined 7+8 TeV analysis
mlf7p8TeV.png Best fit value for sigma/sigmaSM for the combined 7+8 TeV analysis
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Topic revision: r2 - 2012-09-05 - GuillelmoCeballos
 
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