Measurement of the Higgs boson mass in the $H \rightarrow ZZ^* \rightarrow 4\ell$ decay channel using 139 fb$^{-1}$ of $\sqrt{s}=13$ TeV $pp$ collisions recorded by the ATLAS detector at the LHC

TL;DR

This paper reports a precise measurement of the Higgs boson mass using the four-lepton decay channel with data from the ATLAS detector at 13 TeV, employing advanced calibration and neural network techniques.

Contribution

It introduces an improved momentum calibration, an analytic model for invariant mass resolution, and a deep neural network for signal-background discrimination in Higgs mass measurement.

Findings

Measured Higgs mass: 124.99 GeV with uncertainties

Combined measurement with previous data: 124.94 GeV

Enhanced analysis techniques improve precision

Abstract

The mass of the Higgs boson is measured in the $H \rightarrow ZZ^* \rightarrow 4\ell$ decay channel. The analysis uses proton-proton collision data from the Large Hadron Collider at a centre-of-mass energy of 13 TeV recorded by the ATLAS detector between 2015 and 2018, corresponding to an integrated luminosity of 139 fb$^{-1}$. The measured value of the Higgs boson mass is $124.99\pm0.18\text{(stat.)}\pm0.04\text{(syst.)}$ GeV and is based on improved momentum-scale calibration for muons relative to previous publications. The measurement also employs an analytic model that takes into account the invariant-mass resolution of the four-lepton system on a per-event basis and the output of a deep neural network discriminating signal from background events. This measurement is combined with the corresponding measurement using 7 and 8 TeV $pp$ collision data, resulting in a Higgs boson mass measurement of $124.94\pm0.17\text{(stat.)}\pm0.03\text{(syst.)}$ GeV.