Phase-shift definition for pion-nucleon scattering from chiral perturbation theory

Chiral Perturbation Theory is considered as a very precise method when applied to pion-nucleon scattering near threshold and in the unphysical region since in these cases the pion momenta are small. In this framework, third order calculation yields a non-relativistic scattering amplitude with nine free parameters. From the fact that the resulting partial-wave amplitudes do not respect elastic unitarity relation, one has that the phase-shift definition is ambiguous. In this article, we present the comparison of the model with experimental data for two different phase-shift formulas and we conclude that the results are very sensitive to phase-shift definition.

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Bibliographic Details
Main Authors: Cavalcante,Isabela P., Borges,J. Sá
Format: Digital revista
Language:English
Published: Sociedade Brasileira de Física 2004
Online Access:http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-97332004000200024
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