Rethinking the Pc(4457)+ as the PψΔ+(4457) isoquartet D¯⁎Σc molecule

Abstract

The nature of the Pc(4312), Pc(4440) and Pc(4457) pentaquarks is a fascinating theoretical question. Within the molecular picture their more usual interpretation is that of I=12 D¯Σc and D¯⁎Σc bound states. Here we argue in favor of interpreting the Pc(4457) pentaquark as a I=32 D¯⁎Σc bound state (with spin J=12) instead. Owing to isospin symmetry breaking effects, with this identification the partial decay width of the Pc(4457)+ into J/ψp will be of the same order of magnitude as the Pc(4312)+ and Pc(4440)+, in contrast with the considerably larger partial decay width in the I=12 scenario. In turn, this leads to a different hidden-charm molecular pentaquark spectrum, in which there are only four or five PψN bound states instead of the usual seven, which might explain why the predicted J=12 and 32 (I=12) D¯⁎Σc⁎ molecular partners of the Pc(4312) and Pc(4440) have not been observed.