New strange pentaquarks
Marek Karliner, Jonathan L. Rosner
Abstract
The new strange pentaquarks observed by LHCb are very likely hadronic molecules consisting of ${\mathrm{\ensuremath{\Xi}}}_{c}\overline{D}$ and ${\mathrm{\ensuremath{\Xi}}}_{c}{\overline{D}}^{*}$. 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 nonstrange sector. The latter clearly are hadronic molecules consisting of ${\mathrm{\ensuremath{\Sigma}}}_{c}\overline{D}$ and ${\mathrm{\ensuremath{\Sigma}}}_{c}{\overline{D}}^{*}$. Following this line of thought, we predict three additional strange pentaquarks consisting of ${\mathrm{\ensuremath{\Xi}}}_{c}^{\ensuremath{'}}\overline{D}$ and ${\mathrm{\ensuremath{\Xi}}}_{c}^{\ensuremath{'}}{\overline{D}}^{*}$. The masses of these states are expected to be shifted upward by $M({\mathrm{\ensuremath{\Xi}}}_{c}^{\ensuremath{'}})\ensuremath{-}M({\mathrm{\ensuremath{\Xi}}}_{c})\ensuremath{\approx}110\text{ }\text{ }\mathrm{MeV}$ with respect to the corresponding known strange pentaquarks.