Search for the standard model Higgs boson decaying to a W pair in the fully leptonic final state in pp collisions at sqrt(s) = 7 TeV

TL;DR

This CMS study searches for the SM Higgs boson decaying to W+W− in the fully leptonic final state using 4.6 fb−1 of 7 TeV data. It employs 0-, 1-, and 2-jet categories with both cut-based and multivariate analyses, including a VBF-sensitive 2-jet selection. Data-driven background estimations and rigorous systematics underpin the results, which show no excess over SM expectations. Consequently, a broad Higgs mass range is excluded at 95% CL, with the 0- and 1-jet analyses covering 129–238 GeV and 129–270 GeV, respectively, and the mH ≈ 130 GeV point yielding limits near the SM prediction.

Abstract

A search for the standard model Higgs boson decaying to W+W- in pp collisions at sqrt(s) = 7 TeV is reported. The data are collected at the LHC with the CMS detector, and correspond to an integrated luminosity of 4.6 inverse femtobarns. The W+W- candidates are selected in events with two charged leptons and large missing transverse energy. No significant excess of events above the standard model background expectations is observed, and upper limits on the Higgs boson production relative to the standard model Higgs expectation are derived. The standard model Higgs boson is excluded in the mass range 129-270 GeV at 95% confidence level.

Figures (4)

• Figure 1: Azimuthal angle difference between the two selected leptons in the 0-jet (top) and 1-jet (bottom) categories, for a $m_{{H}\xspace}= 130\,\text{Ge\spaceV}\xspace$ SM Higgs boson and for the main backgrounds at the $\mathrm{W^+}{}\mathrm{W^-}$ selection level.
• Figure 2: Dilepton mass in the 0-jet (top) and 1-jet (bottom) categories, for a $m_{{H}\xspace}=130\,\text{Ge\spaceV}\xspace$ SM Higgs boson and for the main backgrounds. The cut-based ${H}\xspace\to\mathrm{W^+}{}\mathrm{W^-}$ selection, except for the requirement on the dilepton mass itself, is applied.
• Figure 3: BDT classifier distributions for signal and background events for a $m_{{H}\xspace}=130\,\text{Ge\spaceV}\xspace$ SM Higgs boson and for the main backgrounds at the $\mathrm{W^+}{}\mathrm{W^-}$ selection level: (upper-left) 0-jet bin same-flavour final state, (upper-right) 1-jet bin same-flavour final state, (lower-left) 0-jet bin opposite-flavour final state, (lower-right) 1-jet bin opposite-flavour final state.
• Figure 4: Expected and observed 95% CL upper limits on the cross section times branching fraction, $\sigma_{{H}\xspace} \times \mathrm{BR}({H}\xspace \to \mathrm{W^+}{}\mathrm{W^-})$, relative to the SM Higgs expectation, using cut-based (top) and multivariate BDT (bottom) event selections. Results are obtained using the CL$_{s}$ approach.