${\chi }_{QJ}\to {\ell }^{+}{\ell }^{-}$ within and beyond the Standard Model

Deshan Yang, Shuai Zhao

We revisit ${\chi }_{QJ}\to {\ell }^{+}{\ell }^{-}$ (with $J=0,1,2$ and $Q=b,c$) within the Standard Model (SM). The electro-magnetic contributions are given in color-singlet model with non-vanish…