Decays of Higgs Boson into Pseudoscalar Meson Pair of Different Flavours

TL;DR

This paper provides an exact calculation of the Higgs-penguin vertex in the Standard Model and applies it to rare Higgs decays into different-flavor pseudoscalar meson pairs, finding very small decay rates.

Contribution

It presents a precise one-loop calculation of the Higgs-penguin vertex and its application to flavor-changing Higgs decays, including renormalization details.

Findings

Decay rates for Higgs to Kpi and BK are very small.

The Higgs-penguin vertex depends on the Higgs mass.

Renormalization using Chia and Chong's prescription is effective.

Abstract

The flavour-changing quark-Higgs coupling does not arise at the tree level in the Standard Model. It is, however, induced by one-loop effects. In this paper, we present an exact calculation of the Higgs-penguin vertex in the tHooft-Feynman gauge. Renormalization of the vertex is effected by a prescription by Chia and Chong which gives an expression for the counter term identical to that obtained by employing Ward-Takahashi identity. The on-shell vertex function for the Higgs-penguin vertex is obtained, and its dependence on Higgs mass is investigated. Our calculation is applied to the following process: decays of Higgs boson into pseudoscalar meson pair of different flavours: Kpi and BK. The coupling of pseudoscalar meson to quark is effected through a gamma5 coupling. The decay rates are found to be very small.