Constraints and Implications on Higgs FCNC Couplings from Precision Measurement of $B_s\to {\mu }^{+}{\mu }^{-}$ Decay

Abstract

We study constraints and implications of the recent LHCb measurement of $\mathcal{B}(B_s\to {\mu }^{+}{\mu }^{-})$ for tree-level Higgs-mediated flavor-changing neutral current (FCNC) interactions. Combined with experimental data on $B_s$ mass difference $\Delta m_s$, the $h\to \mu \tau$, and the $h\to {\tau }^{+}{\tau }^{-}$ decay branching ratios from the LHC, we find that the Higgs FCNC couplings are severely constrained. The allowed regions for $B_s\to \mu \tau$, $\tau \tau$ and $h\to sb$ decays are obtained. Current data allow large CP violation in the $h\to {\tau }^{+}{\tau }^{-}$ decay. Consequences of the Cheng-Sher ansatz for the Higgs Yukawa couplings are discussed in some detail.

Comments: 21 pages, 5 figures. Updated the paper with new results from LHC on h to mu tau