Unravelling the non-standard top and Higgs couplings in associated top-Higgs production at the High-luminosity LHC

TL;DR

This paper investigates how non-standard top and Higgs couplings influence associated top-Higgs production at the HL-LHC, focusing on top polarization and decay observables to probe anomalous interactions.

Contribution

It introduces a detailed analysis of production and decay observables sensitive to anomalous top and Higgs couplings in $pp\to thj$ at 14 TeV HL-LHC, highlighting the interplay of these couplings.

Findings

Anomalous couplings significantly affect top polarization.

Decay-lepton angular distributions reveal sensitivity to couplings.

Asymmetries can probe real and imaginary parts of couplings.

Abstract

We study the sensitivities of non-standard top and Higgs couplings in the $pp\to thj$ process at the 14 TeV high-luminosity run of Large Hadron Collider (HL-LHC). We calculate top polarization and construct various lab-frame observables to study their sensitivities on anomalous couplings at HL-LHC. Both anomalous Wtb and hVV couplings contribute in the production process. However, only the former contributes in top decay and only the latter takes part in Higgs decay. We study this interesting interplay of couplings in the production and decay observables. In production, these couplings significantly affect the top polarization. As a measure of top polarization, we look at decay-lepton angular distributions in the laboratory frame and study the effect of anomalous couplings on these distributions. We construct certain asymmetries to study the sensitivity of these distributions to top quark couplings. In particular, real and imaginary parts of an hVV coupling and real part of a Wtb coupling f2R significantly alter the top polarization and, in turn, affect the decay-lepton distributions in laboratory frame.