Angular distribution and forward-backward asymmetry of the Higgs-boson decay to photon and lepton pair

TL;DR

This paper analyzes the angular distribution and forward-backward asymmetry in Higgs decay to photon and lepton pairs, exploring potential signs of new physics through these observables.

Contribution

It introduces a detailed calculation of decay width and asymmetry in a model with mixed scalar and pseudoscalar Higgs couplings, constrained by existing decay data.

Findings

Nonzero forward-backward asymmetry indicates possible new physics effects.

Decay width and asymmetry depend on dilepton invariant mass and coupling parameters.

Results provide a basis for experimental tests of Higgs sector extensions.

Abstract

The Higgs-boson decay h -> gamma l+ l- for various lepton states l = (e, mu, tau) is analyzed. The differential decay width and forward-backward asymmetry are calculated as functions of the dilepton invariant mass in a model where the Higgs boson interacts with leptons and quarks via a mixture of scalar and pseudoscalar couplings. These couplings are partly constrained from data on the decays to leptons, h -> l+ l-, and quarks h -> q \bar{q} (where q = (c, b)), while the Higgs couplings to the top quark are chosen from the two-photon and two-gluon decay rates. Nonzero values of the forward-backward asymmetry will manifest effects of new physics in the Higgs sector. The decay width and asymmetry integrated over the dilepton invariant mass are also presented.