Decays of Pc into J/ψN and ηcN with heavy quark spin symmetry

We investigate the consequences of heavy quark spin symmetry (HQSS) on hidden-charm pentaquark Pc states. As has been proposed before, assuming the Pc(4440) and the Pc(4457) as S-wave D¯*Σc molecules, seven hadronic molecular states composed of D¯Σc, D¯Σc*, D¯*Σc, and D¯*Σc* can be obtained, with the D¯Σc molecule corresponding to the Pc(4312). These seven states can decay into J/ψN and ηcN, and we use HQSS to predict ratios of partial widths of the S-wave decays. For the decays into J/ψN, it is found that among all six Pc molecules with spin 1/2 or 3/2, at least four states decay much more easily into the J/ψN than the Pc(4312), and two of them couple dominantly to the D¯*Σc*. While no significant peak around the D¯*Σc* threshold is found in the J/ψp distribution, these higher Pc states either are produced with lower rates or some special production mechanism for the observed Pc states might play an important role, such as an intricate interplay between the production of pentaquarks and triangle singularities.