Λ and Σ resonances coupled to vector and pseudoscalar mesons

The vector and pseudoscalar meson-baryon systems have been studied in a coupled channel formalism recently, which has lead to findings of some important results. The formalism consists of obtaining a detailed vector meson-baryon interaction originating from the s-, t-, u-channel diagrams and a contact interaction, all derived from the Lagrangian invariant under the gauge of the hidden local symmetry (HLS). We find the contributions from all the diagrams (except s-channel) to be important, contrary to the systems involving light Goldstone bosons where Weinberg-Tomozawa interaction gives the dominant contribution. Further, the transitions between the pseudoscalar meson-baryon (PB) and vector meson-baryon (VB) channels is obtained consistently by extending the Kroll-Ruderman theorem by replacing the photon by a vector meson, assuming the vector meson dominance. We find that the low-lying resonances couple strongly to VB channels. This information can be very useful in studying processes like photoproduction of low-lying resonances. Further, we find dynamical generation of new states in PB-VB coupled systems which can be related to the known resonances: Λ(2000), Σ(1750), Σ(1940) and Σ(2000).