Study of the $C$ parity violating and strangeness changing $J/{\psi}$ ${\to}$ $PP$ weak decays

The $J/{\psi}$ weak decays are rare but possible within the standard model of elementary particles. Inspired by the potential prospects and sensitivity at the future intensity frontier, the $J/{\psi}$ ${\to}$ $PP$ weak decays are studied with the perturbative QCD approach, where $P$ denote the ground $SU(3)$ pseudoscalar meson. It is found that the $C$ parity violating $J/{\psi}$ ${\to}$ ${\eta}^{({\prime})}{\eta}^{({\prime})}$ decays have relatively large branching ratios, about the order of $10^{-11}$, which might be within the measurement capability and sensitivity of the future STCF experiment.