J / ψ Λ femtoscopy and the nature of P ψ s Λ ( 4338 )

Over the past two decades, numerous exotic hadron states have been discovered, yet their underlying nature remains unclear. It is widely acknowledged that understanding hadron-hadron interactions is essential to unraveling their properties. Hadron spectroscopy is a powerful tool for this endeavor, providing rich experimental data that can shed light on exotic systems. Recently, the LHCb experiment analyzed the process B − → J / ψ Λ p ¯ and observed a narrow peak in the J / ψ Λ invariant mass spectrum, regarding it as a candidate for a pentaquark. In this work, we extract the coupled-channel J / ψ Λ − D ¯ Ξ c − D ¯ s Λ c potential based on the J / ψ Λ invariant mass spectrum. Our results indicate the existence of a bound state below the D ¯ Ξ c mass threshold, corresponding to the experimentally measured state P c s ( 4338 ) . Furthermore, we predict the scattering lengths and momentum correlation functions for the J / ψ Λ and D ¯ Ξ c channels, which serve as theoretical references for future femtoscopy experiments.