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Towards an understanding of isospin violation in pion-nucleon scattering

Nadia Fettes·Ulf-G. Meißner
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Abstract

We investigate isospin breaking in low-energy pion-nucleon scattering in the framework of chiral perturbation theory. This work extends the systematic analysis of [1] to the energy range above threshold. Various relations, which identically vanish in the limit of isospin symmetry, are used to quantify isospin breaking effects. We study the energy dependence of the S- and P-wave projections of these ratios and find dramatic effects in the S-waves of those two relations which are given in terms of isoscalar quantities only. This effect drops rather quickly with growing center-of-mass energy.

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Nadia Fettes, Ulf-G. Meißner. 2000-08-17. Towards an understanding of isospin violation in pion-nucleon scattering. https://doi.org/10.1103/physrevc.63.045201

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