Higgs boson decay to lepton pair and photon and possible non-Hermiticity of the Yukawa interaction

TL;DR

This paper investigates how non-Hermitian, mixed scalar and pseudo-scalar Higgs-fermion interactions affect lepton pair production in Higgs decay, revealing significant impacts on observable asymmetries.

Contribution

It introduces a model with non-Hermitian Higgs-fermion couplings and analyzes their effects on decay observables, highlighting potential experimental signatures.

Findings

Non-Hermitian interactions significantly alter forward-backward asymmetry.

Large effects observed for top quark couplings on electron and muon pairs.

Differential decay width depends on the nature of Higgs-fermion coupling.

Abstract

The production of lepton pairs in the Higgs boson decay $h \to \ell^+ \ell^- \gamma$ is studied. The emphasis is put on the structure of the Higgs boson interaction with the fermions. This interaction is chosen as a mixture of the scalar and pseudo-scalar couplings, and, in addition, it is supposed to be non-Hermitian. We study prediction of this model for the observables in the $h \to \ell^+ \ell^- \gamma$ decay for the $e^+ e^-$, $\mu^+ \mu^-$ and $\tau^+ \tau^-$ pairs. The differential decay width and lepton forward-backward asymmetry are calculated as functions of the dilepton invariant mass for several sets of $h f \bar{f}$ coupling constants. The influence of non-Hermitian $h f \bar{f}$ interaction on the forward-backward asymmetry is studied, and large influence of a possible non-Hermiticity of the Higgs interaction with the top quarks on forward-backward asymmetry for $e^+ e^-$ and $\mu^+ \mu^-$ pairs is stressed.