Implications of the HyperCP Data on $B$ and $τ$ decays

Abstract

If the HyperCP three events for the decay of $Σ^+\to pμ^+μ^-$ are explained by a new pseudoscalar (axial-vector) boson $X_{P(A)}$ with a mass of 214.3 MeV, we study the constraints on the couplings between $X_{P(A)}$ and fermions from the experimental data in $K$ and $B$ processes. Some implications of the new particle on flavor changing $B$ and $τ$ decays are given. Explicitly, we show that the decay branching ratios of $B_{s}\toϕX_{P(A)}\to ϕμ^{+}μ^{-}$, $B_{d}\to K_{0}^{*}(1430){P(A)}\to K_{0}^{*}(1430)μ^{+}μ^{-}$ and $τ\toμX_{P(A)}\toμμ^{+}μ^{-}$ can be as large as $2.7 (2.8)\times 10^{-6}$, $7.4 (7.5)\times 10^{-7}$ and $1.7 (0.14)\times 10^{-7}$, respectively.