QCD Corrections in two-Higgs-doublet extensions of the Standard Model with Minimal Flavor Violation

TL;DR

This paper calculates QCD corrections in two-Higgs-doublet models with Minimal Flavor Violation, refining predictions for R_b and B->Xs gamma, and constraining charged Higgs couplings.

Contribution

It provides the first detailed QCD correction analysis for R_b and B->Xs gamma in these specific two-Higgs-doublet models with Minimal Flavor Violation.

Findings

QCD corrections make R_b prediction scheme-independent for top mass

Stronger lower bounds on tan(beta) in type-I and type-II models

Constraints on charged Higgs couplings to top and bottom quarks

Abstract

We present the QCD corrections to R_b and to the Delta B=1 effective Hamiltonian in models with a second Higgs field that couples to the quarks respecting the criterion of Minimal Flavor Violation, thus belonging either to the (1,2)_1/2 or to the (8,2)_1/2 representation of SU(3)xSU(2)xU(1). After the inclusion of the QCD corrections, the prediction for R_b becomes practically insensitive to the choice of renormalization scheme for the top mass, which for the type-I and type-II models translates in a more robust lower bound on tan(beta). The QCD-corrected determinations of Rb and BR(B->Xs gamma) are used to discuss the constraints on the couplings of a (colored) charged Higgs boson to top and bottom quarks.