Roy-Steiner equations for pi N scattering

Abstract

Starting from hyperbolic dispersion relations for the invariant amplitudes of pion-nucleon scattering together with crossing symmetry and unitarity, one can derive a closed system of integral equations for the partial waves of both the s-channel (pi N --> pi N) and the t-channel (pi pi --> Nbar N) reaction, called Roy-Steiner equations. After giving a brief overview of the Roy-Steiner system for pi N scattering, we demonstrate that the solution of the t-channel subsystem, which represents the first step in solving the full system, can be achieved by means of Muskhelishvili-Omnès techniques. In particular, we present results for the P-waves featuring in the dispersive analysis of the electromagnetic form factors of the nucleon.

6 pages, 3 figures, proceedings for The 7th International Workshop on Chiral Dynamics, Jefferson Lab, Newport News, Virginia, USA, August 6-10, 2012

References in corpus (6)

• The pion-pion scattering amplitude. IV: Improved analysis with once subtracted Roy-like equations up to 1100 MeV
• Regge analysis of the pi pi scattering amplitude
• The size of the proton - closing in on the radius puzzle
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