Constraints on the Higgs boson total width using H*(126) -> ZZ events

TL;DR

This paper constrains the Higgs boson total decay width by analyzing off-shell ZZ production in 2012 CMS data, setting an upper limit of 4.2 times the Standard Model prediction at 95% confidence.

Contribution

It introduces a method combining on-shell and off-shell measurements to improve constraints on the Higgs width using LHC data.

Findings

Upper limit on Higgs width: Gamma_H < 4.2 x Gamma_H^SM

Combined analysis of 4l and 2l2nu channels enhances sensitivity

Uses maximum-likelihood fit of invariant mass and kinematic distributions

Abstract

Constraints are set on the Higgs boson decay width, Gamma_H, using off-shell production and decay to ZZ in the four-lepton (4l), or two-lepton-two-neutrino (2l2nu) final states. The analysis is based on the data collected in 2012 by the CMS experiment at the LHC, corresponding to an integrated luminosity L = 19.7 fb^{-1} at sqrt(s) = 8 TeV. A maximum-likelihood fit of invariant mass and kinematic discriminant distributions in the 4l case and of transverse mass or missing energy distributions in the 2l2nu case is performed. The result of it, combined with the 4l measurement near the resonance peak, leads to an upper limit on the Higgs boson width of Gamma_H < 4.2 x Gamma_H^SM at the 95% confidence level, assuming Gamma_H^SM = 4.15 MeV.