New strange pentaquarks

Abstract

The new strange pentaquarks observed by LHCb are very likely hadronic molecules consisting of $\Xi_c \bar D$ and $\Xi_c \bar D^{*}.$ We discuss the experimental evidence supporting this conclusion, pointing out the similarities and differences with the $P_c(4312)$, $P_c(4440)$ and $P_c(4457)$ pentaquarks in the non-strange sector. The latter clearly are hadronic molecules consisting of $\Sigma_c \bar D$ and $\Sigma_c \bar D^{*}.$ Following this line of thought, we predict three additional strange pentaquarks, consisting of $\Xi_c^{\prime} \bar D$ and $\Xi_c^{\prime} \bar D^{*}.$ The masses of these states are expected to be shifted upwards by $M(\Xi_c^{\prime})-M(\Xi_c) \approx 110$ MeV with respect to the corresponding known strange pentaquarks.