Probing Anomalous FCNC Top-Higgs Yukawa Couplings at the Large Hadron Electron Collider

TL;DR

This study investigates the potential to detect anomalous flavor-changing neutral current top-Higgs couplings at the Large Hadron Electron Collider, providing sensitivity estimates for new physics beyond the Standard Model.

Contribution

It introduces a novel analysis of FCNC top-Higgs interactions at the LHeC, exploring specific production channels and decay modes to improve detection sensitivity.

Findings

Probing FCNC couplings down to 0.0162 at the LHeC.

Sensitivity to branching ratio of t→qH as low as 1.34×10⁻⁴.

Enhanced detection prospects for new physics in top-Higgs interactions.

Abstract

In this paper, we study the anomalous flavor changing neutral current Yukawa interactions between the top quark, the Higgs boson, and either an up or charm quark ($\rm tqH, q=u, c$). We probe these couplings in $\rm e^- p\rightarrow \nu_e \bar{t} \rightarrow \nu_e H \bar{q}$ and the channel $\rm e^- p \rightarrow \nu_e H b$. Both channels are induced by charged current interactions through $\rm e^- p$ collision at the Large Hadron Electron Collider(LHeC). We study the signatures with the Higgs decay modes $\rm H\rightarrow \gamma\gamma, b\bar{b}$ and $\tau^+\tau^-$. Our results show that the flavor changing couplings $\rm \kappa_{tqH}$ can be probed down to a value of 0.0162 in $\rm e^- p \rightarrow \nu_e \bar{t} \rightarrow \nu_e H \bar{q}$ with $\rm H\rightarrow b \bar{b}$ at a 14 TeV LHeC with a 150 GeV electron beam and 200 $\rm fb^{-1}$ luminosity. This value of the coupling corresponds to the branching ratio $\rm Br(t\rightarrow qH)=1.34 \times 0^{-4}$.