Exploration of the LHCb P_c states and possible resonances in a unitary coupled-channel model

We extend our previous study of the interactions of D̅^(*)Λ_c - D̅^(*)Σ_c^(*) within an analytic, unitary, coupled-channel approach by including the J/ψ p channel and performing fits to the J/ψ p invariant mass distributions in the Λ_b^0 → J/ψ p K^- decay by the LHCb Collaboration. We take into account the contributions of t-channel pseudoscalar and vector meson exchanges and u-channel baryon exchanges in this work, and a series of bound states and resonances with different spin-parities are dynamically generated. According to the results, four states have a significant impact on the physical observables, with two having a spin-parity of 1/2^- and the other two having 3/2^-. These states can be associated with the LHCb hidden-charm pentaquarks. We further provide the coupling strength between each pole and different channels, which provides some insights on how to search for them in future experiments. Moreover, we also search for poles in higher partial waves up to J=7/2 and find indications for the existence of several states with larger widths.