Top-quark pair production as a probe of light top-philic scalars and anomalous Higgs interactions

TL;DR

This paper explores how virtual scalar exchanges in top-quark pair production at the LHC can serve as sensitive probes for light top-philic scalars and anomalous Higgs-top interactions, offering a new avenue for detecting physics beyond the Standard Model.

Contribution

It extends previous studies by providing a comprehensive analysis of scalar effects on top pair production, including both light scalars and anomalous Higgs couplings, with updated constraints.

Findings

Current data can effectively constrain light top-philic scalars.

Virtual scalar effects significantly impact top pair production observables.

Constraints on anomalous Higgs-top Yukawa couplings are improved.

Abstract

We compute the effects due to the virtual exchange (or the soft emission) of a scalar particle with generic couplings to the top quark in $t\bar t$ pair production at the LHC. We apply the results to two cases of interest, extending and completing previous studies. First, we consider the indirect search for light ($m_S<2 m_t$) top-philic scalars with CP-even and/or CP-odd interactions. Second, we investigate how to set constraints on anomalous Yukawa couplings of the Higgs boson to the top quark. Our results show that the current precision of experimental data together with the accuracy of the SM predictions make such indirect determinations a powerful probe for new physics.