Hidden-Heavy Pentaquarks and Where to Find Them

Abstract

We provide a simple explanation for the observed hidden-charm pentaquarks as bound states in Born-Oppenheimer potentials. We identify $P_{c\bar{c}}(4312)^+$, $P_{c\bar{c}}(4440)^+$, and $P_{c\bar{c}}(4457)^+$ as heavy-quark spin states in a quartet of $c \bar{c}$ pentaquarks with $J^P$ quantum numbers $\frac{1}{2}^-$, $\frac{3}{2}^-$, and $\frac{5}{2}^-$. The quantum numbers of $P_{c\bar{c}}(4457)^+$ differ from most previous predictions. We also predict a fourth $c\bar{c}$ pentaquark with quantum numbers $\frac{3}{2}^-$ near the $\Sigma_c^\ast\bar{D}$ threshold. We identify $P_{c\bar{c}s}(4338)^0$ and $P_{c\bar{c}s}(4459)^0$ as heavy-quark spin states in a triplet of $c \bar{c}s$ pentaquarks with quantum numbers $\frac{1}{2}^-$ and either $\frac{1}{2}^-$ or $\frac{3}{2}^-$. We also predict a third $c\bar{c}s$ pentaquark with quantum numbers either $\frac{3}{2}^-$ or $\frac{1}{2}^-$ near the $\Xi_c\bar{D}^\ast$ threshold. We explain why the observed hidden-charm pentaquarks have narrow widths.