Molecular P ψ pentaquarks from light-meson exchange saturation

Theoretical predictions of the spectrum of heavy meson-baryon bound states are a fundamental tool for disentangling the nature of the different pentaquark states that have been observed in experimental facilities. Here we explore this spectrum in a phenomenological model that describes the heavy meson-baryon interaction in terms of a contact-range interaction, where the coupling strength is saturated by the exchange of light scalar and vector mesons, i.e., σ , ρ , and ω exchanges. Saturation determines the couplings modulo an unknown proportionality constant that can be calibrated from a molecular candidate. If we use the P ψ N ( 4312 ) as input, we predict a series of molecular pentaquarks including the P ψ N ( 4440 ) and P ψ N ( 4457 ) , the recent P ψ s Λ ( 4338 ) and the P ψ s Λ ( 4459 ) .