Abstract

A measurement of the mass of the Higgs boson in the diphoton decay channel is presented. This analysis is based on 35.9fb−1 of proton-proton collision data collected during the 2016 LHC running period, with the CMS detector at a centre-of-mass energy of 13 TeV. A refined detector calibration and new analysis techniques have been used to improve the precision of this measurement. The Higgs boson mass is measured to be mH=125.78±0.26GeV. This is combined with a measurement of mH already performed in the H→ZZ→4ℓ decay channel using the same data set, giving mH=125.46±0.16GeV. This result, when further combined with an earlier measurement of mH using data collected in 2011 and 2012 with the CMS detector, gives a value for the Higgs boson mass of mH=125.38±0.14GeV. This is currently the most precise measurement of the mass of the Higgs boson.

Highlights

  • The independent observations of the Higgs boson by the ATLAS and CMS Collaborations [1,2,3] in proton-proton collisions at the CERN LHC was a key milestone in the understanding of the mechanism of electroweak symmetry breaking

  • The general strategy followed in this analysis is the same as that adopted in an earlier analysis by the CMS Collaboration of the Higgs boson properties in the diphoton channel [9]

  • We have developed a method to evaluate the systematic uncertainty of the photon energy scale due to radiation damage of the electromagnetic calorimeter (ECAL) crystals, and a simplified event categorisation is followed in the analysis

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Summary

Introduction

The independent observations of the Higgs boson by the ATLAS and CMS Collaborations [1,2,3] in proton-proton collisions at the CERN LHC was a key milestone in the understanding of the mechanism of electroweak symmetry breaking. The couplings of the Higgs boson to other elementary particles can be predicted by the standard model of particle physics once its mass is known. This motivates precise measurements of the mass of the Higgs boson (mH) in all available decay channels. The mass of the Higgs boson was measured to be 125.09 ± 0.24 GeV [4], in such a combined measurement performed with the data collected in 2011 and 2012 (Run 1) by the ATLAS and CMS Collaborations. The ATLAS collaboration have published a measurement of mH of 124.97 ± 0.24 GeV [6], using the combined 2016 and Run 1 data sets. The combined result and the procedure followed for this combination are described in this Letter

The CMS detector
Analysis strategy
Data and simulation
Photon reconstruction and identification
Photon energy calibration
Photon preselection and identification
Vertex selection
Event classification
Signal and background models
Signal model
Background model
Systematic uncertainties
Uncertainties in the photon energy scale estimated with electrons
Uncertainties due to differences between electrons and photons
Impact of the sources of uncertainty
Results
10 Summary
A The CMS Collaboration
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