SEMINAR

Pion Production Reactions in Nucleon-Nucleon Collisions

Verónica Malafaia

(CFTP-IST)

Sala P7, IST, Edifício Pós-Graduação
Tuesday, January 10th, 2006 at 04:00 PM

Abstract

We discuss the validity of the frequently used Distorted Wave Born Approximation for pion production. We link it to time-ordered perturbation theory (TOPT) starting from Feynman diagrams. The S-matrix technique, shown to reproduce the results of TOPT for the re-scattering mechanism in pi0 production, is used to calculate charged as well as neutral pion production reactions from NN scattering, from the same set of underlying processes and interactions. The chiral perturbation theory piN scattering amplitude is used. For the nucleon-nucleon distortions a newly developed realistic potential within the Bonn family of potentials, valid well above the pion production threshold, is considered. The pi+ production cross section strength, problematic in other approaches, is well described.