Neither quantum field theory nor S-Matrix theory have a well defined procedure for going over to an approximation that can be reliably used in non-relativistic models for nuclear physics. We meet the problem here by constructing a finite particle number relativistic scattering theory for (scalar) particles and mesons using integral equations of the Faddeev-Yakubovsky type. Restricted to N parti...

We consider an effective field theory of unstable particles (resonances) using the complex-mass renormalization. As an application we calculate the masses and the widths of the ρ meson and the Roper resonance.

We derive the leading order strangeness S = −2 baryon-baryon interactions in chiral effective field theory. The potential consists of contact terms without derivatives and of one-pseudoscalar-meson exchanges. The contact terms and the couplings of the pseudoscalar mesons to the baryons are related via SU(3)f symmetry to the S = −1 hyperonnucleon channels. We show that the chiral effective field...

Abstract Different representations of an effective, covariant theory of the hadronic interaction are examined. For this purpose we have introduced nucleon-meson vertices parametrized in terms of scalar combinations of hadronic fields, extending the conceptual frame of the Density Dependent Hadronic Field Theory. Nuclear matter properties at zero temperature are examined in the Mean Field Approx...

The present paper is aimed to developing an effective field theory in the GeV region to describe consistently both elastic and inelastic NN -scattering in a fully covariant way. In this development we employ our novel s-channel mechanism of NN -interaction at intermediate and short ranges assuming a formation of the sixquark bag dressed with basic meson fields such as π, σ, ρ and ω in the inter...

We argue that the low-lying scalar-meson nonet [1] makes part of a subset of a family of infinitely many scalar-meson nonets, which in turn makes part of a family of infinitely many quark-antiquark bound states and resonances. We outline the properties of this subset.