Higgs-induced flavor-changing neutral current as a source of new physics inb→stransitions

Abstract

The experimental study of $B$ mesons suggest the existence of some new physics contribution to the ${B}_{s}^{0}\ensuremath{-}{\overline{B}}_{s}^{0}$ mixing. We study the implications of a hypothesis that this contribution is generated by the Higgs-induced flavor-changing neutral currents (FCNC). We concentrate on the specific $b\ensuremath{\rightarrow}s$ transition which is described by two complex FCNC parameters, ${F}_{23}$ and ${F}_{32}$, and parameters in the Higgs sector. Model-independent constraints on these parameters are derived from the ${B}_{s}^{0}\ensuremath{-}{\overline{B}}_{s}^{0}$ mixing and are used to predict the branching ratios for ${\overline{B}}_{s}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$ and ${\overline{B}}_{d}\ensuremath{\rightarrow}\overline{K}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$ numerically by considering general variations in the Higgs parameters assuming that Higgs sector conserves $CP$. Taking the results on ${B}_{s}^{0}\ensuremath{-}{\overline{B}}_{s}^{0}$ mixing derived by the global analysis of UTfit group as a guide we present the general constraints on ${F}_{23}^{*}{F}_{32}$ in terms of the pseudoscalar mass ${M}_{A}$. The former is required to be in the range $\ensuremath{\sim}(1--5)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}11}{M}_{A}^{2}\text{ }\text{ }{\mathrm{GeV}}^{\ensuremath{-}2}$ if the Higgs-induced FCNC represent the dominant source of new physics. The phases of these couplings can account for the large $CP$ violating phase in the ${B}_{s}^{0}\ensuremath{-}{\overline{B}}_{s}^{0}$ mixing except when ${F}_{23}={F}_{32}$. The Higgs contribution to ${\overline{B}}_{s}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$ branching ratio can be large, close to the present limit while it remains close to the standard model value in case of the process ${\overline{B}}_{d}\ensuremath{\rightarrow}\overline{K}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$ for all the models under study. We identify and discuss various specific examples which can naturally lead to suppressed FCNC in the ${K}^{0}\ensuremath{-}{\overline{K}}^{0}$ mixing allowing at the same time the required values for ${F}_{23}^{*}$ and ${F}_{32}$.