Triple-strangeness hidden-charm pentaquarks

Abstract

We investigate the possible existence of triple-strangeness hidden-charm pentaquark states in the off-shell coupled-channel formalism. The open-charm meson-baryon ${\bar{D}}_s\hat{I}{\text{c◯}}_c$, ${\bar{D}}_s\hat{I}{\text{c◯}}_c^{\ast }$, ${\bar{D}}_s^{\ast }\hat{I}{\text{c◯}}_c$, and ${\bar{D}}_s^{\ast }\hat{I}{\text{c◯}}_c^{\ast }$ channels are considered, together with the hidden-charm $J/\ddot{I}ˆ\hat{I}\text{c◯}$ channel. The two-body kernel Feynman amplitudes are constructed from an effective Lagrangian based on hidden local symmetry and heavy-quark spin symmetry. The coupled Blankenbecler-Sugar equation is solved in the partial-wave helicity basis. We observe two triple-strangeness hidden-charm pentaquark states: $P_{c\bar{c}sss}(4787)$ and $P_{c\bar{c}sss}(4841)$, both with $J^P=1/2^{-}$. The $P_{c\bar{c}sss}(4787)$ couples dominantly to the ${\bar{D}}_s^{\ast }\hat{I}{\text{c◯}}_c$ and ${\bar{D}}_s^{\ast }\hat{I}{\text{c◯}}_c^{\ast }$ channels, while the $P_{c\bar{c}sss}(4841)$ couples almost exclusively to the ${\bar{D}}_s^{\ast }\hat{I}{\text{c◯}}_c^{\ast }$ channel. The total transition cross sections of ${\bar{D}}_s^{(\ast )}\hat{I}{\text{c◯}}_c^{(\ast )}\to J/\ddot{I}ˆ\hat{I}\text{c◯}$ indicate that the $P_{c\bar{c}sss}(4787)$ is clearly visible in the $J/\ddot{I}ˆ\hat{I}\text{c◯}$ invariant mass spectrum, whereas the $P_{c\bar{c}sss}(4841)$ is obscured by cusp structures and background contributions.

11 pages, 6 figures. The revised version to be published in Physical Review D