Measurement of the Higgs boson mass with $H \rightarrow \gamma\gamma$ decays in 140 fb$^{-1}$ of $\sqrt{s}=13$ TeV $pp$ collisions with the ATLAS detector

TL;DR

This paper reports the most precise measurement of the Higgs boson mass using the $H o \gamma\gamma$ decay channel with 140 fb$^{-1}$ of data from the ATLAS detector at 13 TeV, achieving an uncertainty of 1.1 per mille.

Contribution

It presents an improved photon energy calibration and combines data from 13 TeV with previous runs to enhance measurement precision.

Findings

Higgs boson mass measured as 125.17 GeV with 0.11 GeV statistical and 0.09 GeV systematic uncertainties.

The combined measurement yields a Higgs mass of 125.22 GeV with the smallest uncertainty from a single decay channel.

Achieved the most precise Higgs mass measurement to date from a single decay channel.

Abstract

The mass of the Higgs boson is measured in the $H\to\gamma\gamma$ decay channel, exploiting the high resolution of the invariant mass of photon pairs reconstructed from the decays of Higgs bosons produced in proton-proton collisions at a centre-of-mass energy $\sqrt{s}=13$ TeV. The dataset was collected between 2015 and 2018 by the ATLAS detector at the Large Hadron Collider, and corresponds to an integrated luminosity of 140 fb$^{-1}$. The measured value of the Higgs boson mass is $125.17 \pm 0.11 \mathrm{(stat.)} \pm 0.09 \mathrm{(syst.)}$ GeV and is based on an improved energy scale calibration for photons, whose impact on the measurement is about four times smaller than in the previous publication. A combination with the corresponding measurement using 7 and 8 TeV $pp$ collision ATLAS data results in a Higgs boson mass measurement of $125.22 \pm 0.11 \mathrm{(stat.)} \pm 0.09 \mathrm{(syst.)}$ GeV. With an uncertainty of 1.1 per mille, this is currently the most precise measurement of the mass of the Higgs boson from a single decay channel.