Conventional vs gauge couplings in elastic π<i>N</i> scattering

Abstract

We perform a review on the importance of the Δ(1232 MeV) resonance in different processes, analyze the existing problems with the fields used to describe it theoretically and finally we make an analysis on the use of πNΔ alternative couplings in πN scattering. We compare numerically results for the elastic cross section obtained by using the conventional couplings, already adopted in several reaction calculations, with those obtained with the so called "spin-3/2 gauge invariant" vertexes suggested recently. Confronting with experimental cross section data, we see that these results are by no means equivalent and that the differences between them cannot be compensated by a readjustment of free parameters of background contributions. We find that the conventional couplings work better than the gauge ones in describing the data.