Exploring charmonia ${\eta }_c(6S,7S)$ in the ${\Lambda }_c^{+}{\bar{\Lambda }}_c^{-}$ invariant mass spectrum of $B^0\to K_S^0{\Lambda }_c^{+}{\bar{\Lambda }}_c^{-}$

Cheng-Xi Liu, Jun-Zhang Wang, Xiang Liu

We analyze the $B^0\to K_S^0{\Lambda }_c^{+}{\bar{\Lambda }}_c^{-}$ decay recently observed by the LHCb Collaboration. The ${\Lambda }_c^{+}{\bar{\Lambda }}_c^{-}$ invariant-mass spectrum exhibits an accumulation near 4.63~Ge…