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

In this work, we study the hidden-strange molecular states composed of a baryon and a vector meson in a coupled-channel N rho-N omega-N phi-Lambda K*-Sigma 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 rho and the Sigma K* thresholds, which can be related to the N(1700) and the N(2100), respectively. No pole near the N phi threshold can be found if direct interaction between a nucleon and phi meson is neglected according to the OZI rule. After introducing the QCD van der Waals force between a nucleon and phi meson, a narrow state can be produced near the N phi threshold. Inclusion of the QCD van der Waals force changes the line shape of the invariant mass spectrum in the N phi 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.