Effective interactions for mesons and baryons in nuclei

A new method is proposed to construct the effective nuclear interactions which describe nuclear systems even beyond the pion threshold. The method is based on the unitary transformation, which assures Hermiticity of the effective interactions. The effective interactions are defined to be regular and include a meson-nucleon potential, an isobar transition potential, pion-production/annihilation operators, electromagnetic exchange current, and so on. The nucleon-nucleon potentials defined here are very similar to those in the formalism of Fukuda-Sawada-Taketani, that of Okubo, and that of Nishijima. The theory is a natural and sound extension of conventional nuclear theory and covers nuclear physics in low-and intermediate-energy regions.