Conventional vs gauge couplings in elastic pion N scattering

A. MARIANO; C. BARBERO; D. BADAGNANI

JOURNAL OF PHYSICS: CONFERENCE SERIES

IOP PUBLISHING LTD

Año: 2012 vol. 387 p. 1 - 6

1742-6588

  We perform a review on the importance of the Delta(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 pi N Delta alternative couplings in pi N 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.