Meson-baryon scattering and Lambda(1405) in resummed baryon chiral perturbation theory
We investigated the meson-baryon scattering using time-order perturbation theory (TOPT) based on covariant baryon ChPT. Renormalized scattering amplitudes are obtained by solving the integral equations with the full off-shell dependence of effective potentials and applying subtractive renormalization. Our formalism has been successfully applied to the pion-nucleon scattering and extended to the meson-baryon scattering in the S=-1 sector. We obtained the two-pole structure of Lambda(1405) state.