Hidden-heavy Pentaquarks in the Born-Oppenheimer Approximation for QCD

Abstract

Hidden-heavy pentaquarks can be identified as bound states in diabatic Born-Oppenheimer potentials that are repulsive color-Coulomb potentials at short distance, cross below a heavy-hadron-pair threshold, and then approach that threshold at long distance. We identify the pentaquarks $P_{c\bar{c}}(4312)^+$, $P_{c\bar{c}}(4337)^+$, $P_{c\bar{c}}(4440)^+$, and $P_{c\bar{c}}(4457)^+$ as the ground-state quartet for $c \bar c$ in the two coupled potentials associated with a spin-$3/2$ adjoint baryon. We predict that their $J^P$ quantum numbers are $\frac{1}{2}^-$, $\frac{3}{2}^-$, $\frac{3}{2}^-$, and $\frac{5}{2}^-$, respectively. Our prediction for $P_{c\bar{c}}(4457)^+$ differs from almost all previous predictions. Our prediction that there are only four hidden-charm pentaquarks differs qualitatively from that of simple molecular models that there should be seven. We identify the strange hidden-charm pentaquarks $P_{c\bar{c}s}(4338)^0$ and $P_{c\bar{c}s}(4459)^0$ as two members of the ground-state triplet for $c \bar c$ in the potential associated with a spin-$1/2$ strange adjoint baryon. We also present model-independent predictions for pentaquark decays into charmonium plus a light baryon and into a charm baryon and a charm meson.