Search for Higgs boson pair production in the $\gamma\gamma b\bar{b}$ final state with 13 TeV $pp$ collision data collected by the ATLAS experiment

TL;DR

This paper reports a search for Higgs boson pair production in the gamma-gamma and b-bbar final state using 13 TeV proton-proton collision data from ATLAS, setting limits on production cross-sections and Higgs self-coupling.

Contribution

First search for Higgs pair production in gamma-gamma b-bbar channel at 13 TeV with ATLAS, providing new limits on cross-sections and Higgs self-coupling.

Findings

No significant excess observed over Standard Model expectations.

Set upper limits on non-resonant Higgs pair production cross-section.

Constrained Higgs self-coupling parameter within a specific range.

Abstract

A search is performed for resonant and non-resonant Higgs boson pair production in the $\gamma\gamma b\bar{b}$ final state. The data set used corresponds to an integrated luminosity of 36.1 fb$^{-1}$ of proton-proton collisions at a centre-of-mass energy of 13 TeV recorded by the ATLAS detector at the CERN Large Hadron Collider. No significant excess relative to the Standard Model expectation is observed. The observed limit on the non-resonant Higgs boson pair cross-section is 0.73 pb at 95% confidence level. This observed limit is equivalent to 22 times the predicted Standard Model cross-section. The Higgs boson self-coupling ($\kappa_\lambda = \lambda_{HHH} / \lambda_{HHH}^{\rm SM}$) is constrained at 95% confidence level to $-8.2 < \kappa_\lambda < 13.2$. For resonant Higgs boson pair production through X $\rightarrow$ HH $\rightarrow$ $\gamma\gamma b\bar{b}$, the limit is presented, using the narrow-width approximation, as a function of $m_X$ in the range 260 GeV $< m_X <$ 1000 GeV. The observed limits range from 1.1 pb to 0.12 pb over this mass range.