Speaker
Description
The hidden-charm pentaquark candidates observed in the
(J/\psi p) invariant-mass spectrum provide an important opportunity to
investigate the interplay between hadronic molecular dynamics and compact
multiquark configurations. We study these structures using a spin-resolved
coupled-channel model for the decay
(\Lambda_b\to K^-J/\psi p). The calculation incorporates the relevant
(\Sigma_c^{()}\bar{D}^{()}) and
(\Lambda_c\bar{D}^{(*)}) channels, including both (S)- and (D)-wave
interactions generated by one-pion exchange, together with an effective
compact five-quark component. By fitting the projected (J/\psi p) spectrum
and analyzing its spin decomposition, interaction dependence, and pole
structure, we find that the observed peaks do not arise from a single
universal mechanism. The (P_c(4312)) is predominantly associated with
(J^P=1/2^-) (\Sigma_c\bar{D}) molecular dynamics, whereas the structures
near (P_c(4380)) and (P_c(4440)) are mainly generated by
(J^P=3/2^-) open-charm coupled-channel dynamics. In contrast, the narrow
(P_c(4457)) receives a substantial compact five-quark contribution in the
(J^P=1/2^-) sector. These results suggest a state-dependent interplay
between open-charm threshold dynamics and compact short-distance components
in the hidden-charm pentaquark spectrum.
