2005/04/27 by T. E. O. Ericson, T.E.O. Ericson, Ericson, T. E. O. · 1 citation
Physics and Astronomy · #Atomic and Molecular Physics #FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #Nuclear physics research studies #Quantum Chromodynamics and Particle Interactions #hep-ph
paper · pdf · doi:10.48550/arxiv.hep-ph/0504258
10 pages, 1 eps figure. Invited talk to appear in Proceedings of EXA05, Vienna, Feb. 21-25 2005, Verlag der oesterreichischen Akademie des Wissenschaften
arxiv created 2005/04/27 · openalex publication_date 2005/04/27 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We discuss the electromagnetic corrections to the pion-nucleon scattering lengths generated by minimal e. m. coupling from a knowledge of the low energy expansion of the pion-nucleon elastic scattering amplitude as well as from the nucleon and delta pole terms, all a consequence of purely strong interactions. We assume the heavy baryon limit; the e.m. and axial form factors and the masses are used with their empirical values, such that there is no free parameter. The different terms have a clear physical and intuitive origin. In particular, a large isospin breaking contribution to the isoscalar term appears for the elastic charged-pion scattering lengths. We attempt a comparison to the results from chiral effective field theory (EFT) with a physical interpretation of the empirical constants in that approach. The results are applied to the energy shift and width of pionic hydrogen.