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.

Comments: 6 pages, 3 figures, 2 tables; v2: new references, changed plot color scheme, small edits; v3: new and updated figures, new references, edited text