Double-strangeness hidden-charm pentaquarks

Abstract

We investigate the possible existence of double-strangeness hidden-charm pentaquark states, denoted as $P_{c\bar{c}ss}$, within an off-shell coupled-channel formalism. Eleven meson-baryon channels with total strangeness $S=-2$ are constructed by combining charmed mesons and singly charmed baryons. The two-body scattering amplitudes are derived from an effective Lagrangian that respects heavy-quark spin symmetry, hidden local symmetry, and flavor SU(3) symmetry. The Bethe-Salpeter equation is solved using the Blankenbecler-Sugar reduction scheme, and resonances are identified as poles in the scattering amplitudes on the complex energy plane. We find five negative-parity $P_{c\bar{c}ss}$ states with spins $J=1/2$, $3/2$, and $5/2$, all located below their relevant thresholds. Three positive-parity states are also found: two with $J=1/2$ and one with $J=3/2$, lying above the thresholds with substantial widths. The coupling strengths of each resonance to relevant meson-baryon channels are extracted. The sensitivity of the results to the cutoff parameter $\hat{I}{›}_0=\hat{I}›-m$ is examined. These results provide theoretical predictions that may assist future experimental searches for $P_{c\bar{c}ss}$ states in the $J/\ddot{I}ˆ\hat{I}ž$ channel.

17 pages, 6 figures. Final version for publication