Measurements of the Higgs boson production and decay rates and coupling strengths using $pp$ collision data at $\sqrt{s}=7$ and $8$ TeV in the ATLAS experiment

TL;DR

This paper reports combined measurements of the Higgs boson production, decay rates, and coupling strengths using LHC data at 7 and 8 TeV, confirming consistency with the Standard Model predictions for a 125.36 GeV Higgs boson.

Contribution

It provides a comprehensive analysis of Higgs boson properties across multiple decay channels and production modes, including off-shell and top-associated production, using combined ATLAS data.

Findings

Measured signal yield is 1.18 times the Standard Model expectation.

Results are compatible with the Standard Model for a 125.36 GeV Higgs.

Constraints on Higgs couplings and production modes are established.

Abstract

Combined analyses of the Higgs boson production and decay rates as well as its coupling strengths to vector bosons and fermions are presented. The combinations include the results of the analyses of the $H\to\gamma\gamma,\, ZZ^*,\, WW^*,\, Z\gamma,\, b\bar{b},\, \tau\tau$ and $\mu\mu$ decay modes, and the constraints on the associated production with a pair of top quarks and on the off-shell coupling strengths of the Higgs boson. The results are based on the LHC proton-proton collision datasets, with integrated luminosities of up to 4.7 $\mathrm{fb}^{-1}$ at $\sqrt{s}=7$ TeV and 20.3 $\mathrm{fb}^{-1}$ at $\sqrt{s}=8$ TeV, recorded by the ATLAS detector in 2011 and 2012. Combining all production modes and decay channels, the measured signal yield, normalised to the Standard Model expectation, is $1.18^{+0.15}_{-0.14}$. The observed Higgs boson production and decay rates are interpreted in a leading-order coupling framework, exploring a wide range of benchmark coupling models both with and without assumptions on the Higgs boson width and on the Standard Model particle content in loop processes. The data are found to be compatible with the Standard Model expectations for a Higgs boson at a mass of 125.36 GeV for all models considered.