Gluon penguin enhancements to inclusive charmless decays of b quark in the 2HDM with flavor changing couplings

TL;DR

This paper investigates how gluon penguin diagrams involving Higgs bosons in the Two-Higgs-Doublet Model enhance the inclusive charmless decays of the b quark, significantly increasing the $b o sg$ branching ratio compared to the Standard Model.

Contribution

It provides a detailed calculation of Higgs-induced gluon penguin contributions to b quark decays within the 2HDM with flavor-changing couplings, highlighting the dominant role of charged Higgs bosons.

Findings

The $BR(b o sg)$ can increase from 0.2% in the SM to over 4% in the 2HDM.

The contributions to $b o s q ar{q}$ and $b o s gg$ are numerically small.

Charged Higgs bosons significantly enhance gluonic b decays in the considered parameter space.

Abstract

We calculate the enhancements to the inclusive charmless decays of b quark, $b \to s g, s q\bar{q}, sgg$, from gluon penguin diagrams induced by the charged and neutral Higgs bosons $(H^{\pm}, h^0, H^0$, and A^0) in the Two-Higgs-Doublet Model with flavor-changing couplings. Within the considered parameter space, the new contributions from charged Higgs boson are dominant. After including the new contributions, the branching ratio $BR(b \to sg)$ (q^2 =0) can be increased form $\sim 0.2%$ in the standard model to 4.4% and 2.6% in the two-Higgs-doublet model for $m_{H^+}=100$ and 200 GeV, respectively. The new contribution to the decay mode $b \to s q \bar{q}$ with q=(u,d,s) is, however, numerically small and peaked at the lower q^2 region. The new contribution to $b \to s gg$ can also be neglected.