Improved dispersive analysis of the scalar form factor of the nucleon
Abstract
We present a coupled system of integral equations for the pi pi --> Nbar N and Kbar K --> Nbar N S-waves derived from Roy-Steiner equations for pion-nucleon scattering. We discuss the solution of the corresponding two-channel Muskhelishvili-Omnes problem and apply the results to a dispersive analysis of the scalar form factor of the nucleon fully including Kbar K intermediate states. In particular, we determine the corrections Delta_sigma and Delta_D, which are needed for the extraction of the pion-nucleon sigma term from pi N scattering, and show that the difference Delta_D - Delta_sigma=(-1.8 +/- 0.2) MeV is insensitive to the input pi N parameters.
Keywords
Cite
@article{arxiv.1211.1485,
title = {Improved dispersive analysis of the scalar form factor of the nucleon},
author = {Martin Hoferichter and Christoph Ditsche and Bastian Kubis and Ulf-G. Meißner},
journal= {arXiv preprint arXiv:1211.1485},
year = {2012}
}
Comments
6 pages, 3 figures, Proceedings for the 7th International Workshop on Chiral Dynamics, Newport News, Virginia, USA, August 6-10, 2012