Measurement of the Higgs boson mass and width using the four-lepton final state in proton-proton collisions at $\sqrt{s}$ = 13 TeV

TL;DR

This paper presents the most precise measurement of the Higgs boson mass and constrains its width using four-lepton decay data from proton-proton collisions at 13 TeV, confirming consistency with the Standard Model.

Contribution

It provides the most precise single measurement of the Higgs mass and a new upper limit on its width, combining on- and off-shell production data with previous analyses.

Findings

Higgs boson mass measured as 125.04 ± 0.12 GeV

Higgs width constrained to less than 330 MeV at 95% CL

Off-shell production excluded at 3.8 standard deviations

Abstract

A measurement of the Higgs boson mass and width via its decay to two Z bosons is presented. Proton-proton collision data collected by the CMS experiment, corresponding to an integrated luminosity of 138 fb$^{-1}$ at a center-of-mass energy of 13 TeV is used. The invariant mass distribution of four leptons in the on-shell Higgs boson decay is used to measure its mass and constrain its width. This yields the most precise single measurement of the Higgs boson mass to date, 125.04 $\pm$ 0.12 GeV, and an upper limit on the width $\Gamma_\mathrm{H}$ $\lt$ 330 MeV at 95% confidence level. A combination of the on- and off-shell Higgs boson production decaying to four leptons is used to determine the Higgs boson width, assuming that no new virtual particles affect the production, a premise that is tested by adding new heavy particles in the gluon fusion loop model. This result is combined with a previous CMS analysis of the off-shell Higgs boson production with decay to two leptons and two neutrinos, giving a measured Higgs boson width of 3.0 $^{+2.0}_{-1.5}$ MeV, in agreement with the standard model prediction of 4.1 MeV. The strength of the off-shell Higgs boson production is also reported. The scenario of no off-shell Higgs boson production is excluded at a confidence level corresponding to 3.8 standard deviations.