Effects of the nature of PccÌ…(4440)+ on the interpretation of PccÌ…(4457)+ via a model-selection approach

Abstract

The nature of the LHCb hidden-charm pentaquarks remains a topic of debate in hadron physics. In this work, we continue our series of studies by analyzing the two-peak structure P_ccÌ… (4440)⁺ and P_ccÌ… (4457)⁺ and probing their pole structures. A set of deep neural networks were trained using simulated line shapes with enhancement caused by independent poles of the S-matrix configured to appear close to the relevant threshold. Our model-selection results suggest that a pole-shadow pair structure in the second and third energy Riemann sheets is favored for the P_ccÌ… (4457)⁺, corresponding to a true resonance in a two-channel scattering system, regardless of the true nature of P_ccÌ… (4440)⁺. We also identified the proper energy regions to perform future analyses.