Bs → μ+μ− in a two-Higgs-doublet model with flavour-changing up-type Yukawa couplings

Abstract

We present a Two-Higgs-Doublet Model in which the structure of the quark Yukawa matrices is governed by three spurions breaking the flavour symmetries of the quark Yukawa sector. The model naturally suppresses flavour-changing neutral current (FCNC) amplitudes in the down-type sector, but permits sizable FCNC couplings in the up sector. We calculate the branching ratio of Bs → μ+μ− to leading and next-to-leading order of QCD for the case with FCNC couplings of the heavy neutral Higgs bosons to up-type quarks and verify that all counterterms follow the pattern dictated by the spurion expansion of the Yukawa matrices. We find correlations between Bs → μ+μ−, b → sγ, and the Higgs masses. The \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${B}_{s}-{\\overline{B} }_{s}$$\\end{document} mixing amplitude is naturally suppressed in the model but can probe a portion of the parameter space with very heavy Higgs bosons.