The $P_{\psi s}^{\Lambda }(4338)$ pentaquark and its partners in the molecular picture

Abstract

The LHCb collaboration has detected a new hidden-charm pentaquark with the quantum numbers of a $\Lambda$ baryon: the $P_{\psi s}^{\Lambda }(4338)$. This pentaquark will be interpreted as a ${\bar{D}}_s{\Lambda }_c$-$\bar{D}{\Xi }_c$ resonance within a contact-range theory. Here we briefly comment on the relation of the new $P_{\psi s}^{\Lambda }(4338)$ with the $P_{\psi s}^{\Lambda }(4459)$. We find that the $P_{\psi s}^{\Lambda }(4338)$ and $P_{\psi s}^{\Lambda }(4459)$ both accept a common description in terms of the same parameters, which predicts the existence of a few additional $P_{\psi }^N$, $P_{\psi s}^{\Lambda }$, $P_{\psi s}^{\Sigma }$ and $P_{\psi ss}^{\Xi }$ molecular pentaquarks composed of a charmed antimeson and an antitriplet charmed baryon. The most robust of these predicted pentaquarks is a $P_{\psi s}^{\Lambda }$ with a mass in the $(4235-4255)\mathrm{MeV}$ range, while other two interesting ones are a $P_{\psi }^N(4150)$ and a $P_{\psi }^{\Sigma }(4335)$, the latter basically at the same mass as the $P_{\psi }^{\Lambda }(4338)$, with which it might mix owing to isospin symmetry breaking effects.

7 pages, 1 figure, 1 table, corresponds with the published version