Exploring pion emission properties of (strange) hidden-charm molecular pentaquarks in a chiral quark model

Abstract The internal structure of the exotic $$P_c$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>P</mml:mi> <mml:mi>c</mml:mi> </mml:msub> </mml:math> and $$P_{cs}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>P</mml:mi> <mml:mrow> <mml:mi>cs</mml:mi> </mml:mrow> </mml:msub> </mml:math> pentaquarks remains an open question. To address this, we demonstrate that pion emission serves as a sensitive probe by calculating its properties within a molecular scenario using the chiral quark model and coupled-channel effects. Our results reveal a strong dependence of the decay widths on the internal structure and spatial wave functions within the molecular framework. Notably, the relative ratios of the decay widths among different spin-parity assignments are found to be much more robust against model parameter variations than the absolute values, providing a clean discriminator for quantum numbers. We therefore expect this study to stimulate experimental measurements of these decays, which are crucial for determining the nature of these states and guiding the search for further molecular partners.