Search for $\text{H} \to \text{b}\bar{\text{b}}$ in association with a single top quark at CMS

TL;DR

This paper searches for Higgs boson production with a single top quark in proton-proton collisions at 13 TeV, aiming to understand Higgs couplings and the sign of the top Yukawa coupling using advanced machine learning techniques.

Contribution

It presents the first search for tH production in the H→bb decay mode at 13 TeV, constraining the Higgs coupling modifiers and exploring the parameter space with boosted decision trees.

Findings

Set upper limits on tH production cross section at 51 points in coupling parameter space.

Provided constraints on the Higgs-top and Higgs-vector boson coupling modifiers.

Enhanced understanding of the Higgs coupling structure and the top Yukawa sign.

Abstract

A search for the production of a Higgs boson in association with a single top quark (tH) is performed using the decay $\text{H} \to \text{b}\bar{\text{b}}$. This Higgs boson production mode is sensitive to the coupling modifiers of the Higgs boson to top quarks ($\kappa_{\text{t}}$) and to weak gauge bosons ($\kappa_{\text{V}}$) and thus can be used to lift the degeneracy regarding the sign of the top quark Yukawa coupling. The 2015 pp collisions data at a center-of-mass energy of 13 TeV are analyzed. Boosted decision trees are used to reconstruct and classify the events. Upper limits on the tH production cross section are determined at 51 different points in the $\kappa_{\text{t}} - \kappa_{\text{V}}$ plane.