Search for the associated production of charm quarks and a Higgs boson decaying into a photon pair with the ATLAS detector

TL;DR

This paper reports a search for Higgs boson production with charm quarks in proton-proton collisions, focusing on Higgs decays to photon pairs, using ATLAS data at 13 TeV, setting upper limits and measuring cross-sections.

Contribution

It introduces a novel analysis approach using Gaussian process regression for background modeling in Higgs-charm associated production searches.

Findings

Upper limit on cross-section: 10.6 pb at 95% CL

Measured cross-section: 5.3 ± 3.2 pb

Analysis demonstrates feasibility of charm-tagged Higgs searches

Abstract

A search for the production of a Higgs boson and one or more charm quarks, in which the Higgs boson decays into a photon pair, is presented. This search uses proton-proton collision data with a centre-of-mass energy of $\sqrt{s}=13$ TeV and an integrated luminosity of 140 fb$^{-1}$ recorded by the ATLAS detector at the Large Hadron Collider. The analysis relies on the identification of charm-quark-containing jets, and adopts an approach based on Gaussian process regression to model the non-resonant di-photon background. The observed (expected, assuming the Standard Model signal) upper limit at the 95% confidence level on the cross-section for producing a Higgs boson and at least one charm-quark-containing jet that passes a fiducial selection is found to be 10.6 pb (8.8 pb). The observed (expected) measured cross-section for this process is $5.3 \pm 3.2~\text{pb}$ ($2.9 \pm 3.1~\text{pb}$).