We describe a constraint analysis for the interaction of the vector-meson octet with the baryon octet. Applying Diracs Hamiltonian method, we verify that the standard interaction in terms of two independent SU(3) structures is consistent at the class
ical level. We argue how the requirement of self consistency with respect to perturbative renormalizability may lead to relations among the renormalized coupling constants of the system.
We address the issue of a consistent power counting scheme in manifestly Lorentz-invariant baryon chiral perturbation theory. We discuss the inclusion of vector mesons in the calculation of the nucleon electromagnetic form factors. We comment on the
chiral expansion of the nucleon mass to order O(q**6).
We consider a symmetry-preserving approach to the nucleon-nucleon scattering problem in the framework of the higher-derivative formulation of baryon chiral perturbation theory. Within this framework the leading-order amplitude is calculated by solvin
g renormalizable equations and corrections are taken into account perturbatively.
In the framework of effective field theory we show that, at two-loop order, the mass and width of the Delta resonance defined via the (relativistic) Breit-Wigner parametrization both depend on the choice of field variables. In contrast, the complex-v
alued position of the pole of the propagator is independent of this choice.
