$P_c$ pentaquarks with chiral tensor and quark dynamics

Abstract

We investigate the hidden-charm pentaquarks as superpositions of ${\Lambda }_c{\bar{D}}^{(\ast )}$ and ${\Sigma }_c^{(\ast )}{\bar{D}}^{(\ast )}$ (isospin $I=1/2$) meson-baryon channels coupled to a $uudc\bar{c}$ compact core by employing an interaction satisfying the heavy quark and chiral symmetries. Our model can consistently explain the masses and decay widths of $P_c^{+}(4312)$, $P_c^{+}(4440)$ and $P_c^{+}(4457)$ with the dominant components of ${\Sigma }_c\bar{D}$ and ${\Sigma }_c{\bar{D}}^{\ast }$ with spin parity assignments $J^P=1/2^{-},3/2^{-}$ and $1/2^{-}$, respectively. We analyze basic properties of the $P_c$'s such as masses and decay widths, and find that the mass ordering is dominantly determined by the quark dynamics while the decay widths by the tensor force of the one-pion exchange.

6 pages, 2 figures