Implication of the HyperCP boson $X^0$ (214 MeV) in the flavour changing neutral current processes

We analyze the inclusive $b(c) to s(u) mu^+ mu^-$ and the exclusive $B(D^+) to K(pi^+) mu^+ mu^-$ flavour changing neutral current decays in the light of HyperCP boson $X^0$ of mass 214 MeV recently observed in the hyperon decay $Sigma^+ to p mu^+ mu^-$. Using the branching ratio data of the above inclusive and exclusive decays, we obtain constraints on $g_1 (h_1)$ and $g_2 (h_2)$, the scalar and pseudo-scalar coupling constants of the $b-s-X^0 (c-u-X^0)$ vertices.