Search for the associated production of a Higgs boson with a single top quark in proton-proton collisions at sqrt(s) = 8 TeV

TL;DR

This study searches for Higgs boson production with a single top quark at 8 TeV, using multiple decay channels and advanced analysis techniques, setting new limits on anomalous tHq production for the first time.

Contribution

It introduces the first experimental limits on anomalous tHq production in proton-proton collisions at 8 TeV, employing diverse decay modes and multivariate analysis methods.

Findings

No excess of signal events observed.

Set upper limits on tHq production cross section.

Optimized analysis for non-standard Yukawa coupling.

Abstract

This paper presents the search for the production of a Higgs boson in association with a single top quark (tHq), using data collected in proton-proton collisions at a center-of-mass energy of 8 TeV corresponding to an integrated luminosity of 19.7 inverse femtobarns. The search exploits a variety of Higgs boson decay modes resulting in final states with photons, bottom quarks, and multiple charged leptons, including tau leptons, and employs a variety of multivariate techniques to maximize sensitivity to the signal. The analysis is optimized for the opposite sign of the Yukawa coupling to that in the standard model and corresponding to a large enhancement of the signal cross section. In the absence of an excess of candidate signal events over the background predictions, 95% confidence level observed (expected) upper limits on anomalous tHq production are set, ranging between 600 (450) fb and 1000 (700) fb depending on the assumed diphoton branching fraction of the Higgs boson. This is the first time that results on anomalous tHq production have been reported.