Study of $C$ 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 at the future intensity frontier, the $C$ parity violating $J/{\psi}$ ${\to}$ ${\pi}{\eta}^{({\prime})}$, ${\eta}{\eta}^{\prime}$ decays and the strangeness changing $J/{\psi}$ ${\to}$ ${\pi}K$, $K{\eta}^{({\prime})}$ decays are studied with the perturbative QCD approach. It is found that the $J/{\psi}$ ${\to}$ ${\eta}{\eta}^{\prime}$ 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.