Hidden-strange molecular states and the N? bound states via a QCD van der Waals force

摘要

In this work, we study the hidden-strange molecular states composed of a baryon and a vector meson in a coupled-channel N ρ ? N ω ? N ? ? Λ K * ? Σ K * interaction. With the help of the effective Lagrangians which coupling constants are determined by the SU(3) symmetry, the interaction is constructed and inserted into the quasipotential Bethe-Salpeter equation to search for poles in the complex plane, which correspond to molecular states. Two poles are found with a spin parity 3 / 2 ? near the N ρ and the Σ K * thresholds, which can be related to the N ( 1700 ) and the N ( 2100 ) , respectively. No pole near the N ? threshold can be found if direct interaction between a nucleon and ? meson is neglected according to the OZI rule. After introducing the QCD van der Waals force between a nucleon and ? meson, a narrow state can be produced near the N ? threshold. Inclusion of the QCD van der Waals force changes the line shape of the invariant mass spectrum in the N ? channel leading to a worse agreement with the present low-precision data. Future experiments at BelleII, JLab, and other facilities will be very helpful to clarify the existence of these possible hidden-strange molecular states.