Exploration of the hidden charm decays of $Z_{cs}(3985)$

Abstract

In the present work, we investigate the decays of $Z^-_{cs}(3985)$ in the $D_s^{-} D^{\ast0} + D_s^{\ast -}D^0$ molecular frame. By using an effective Lagrangian approach, the branching ratios of $Z^-_{cs}\rightarrow J/\psi K^-$ and $Z^-_{cs}\rightarrow \eta_c K^{\ast-}$ are estimated. It is found that the dominating decay mode of $Z^-_{cs}(3985)$ is open charm channel, while, the branching ratio of the hidden charm decay channels is about $20\%$. In particular, the branching ratios of $Z^-_{cs}\rightarrow J/\psi K^-$ and $Z^-_{cs}\rightarrow \eta_c K^{\ast-}$ are predicted to be of order of $10\%$. Moreover, our estimation indicates that the fraction of the quasi-two-body cascade decay via $Z_{cs}(3985)$ and the total cross section of $e^+ e^- \to K^+ K^- J/\psi$ around 4.68 GeV is $\left(6.8^{+10.5}_{-6.2} \right)\%$. All the predicted branching ratios in the present work could be tested by further measurements in BESIII and Belle II.