Pion-nucleon scattering and the nucleon sigma term in an extended sigma model
| dc.creator | Dmitrasinovic, V. | |
| dc.creator | Myhrer, F. | |
| dc.date | 1999-11-11 | |
| dc.date.accessioned | 2026-07-07T11:35:46Z | |
| dc.date.available | 2026-07-07T11:35:46Z | |
| dc.description | A modified linear sigma model that allows for $g_A = 1.26$ by addition of vector and pseudovector $πN$ coupling terms was discussed by Bjorken and Nauenberg and by Lee. In this extended linear sigma model the elastic $π$N scattering amplitudes satisfy the relevant chiral low-energy theorems, such as the Weinberg-Tomozawa relation for the isovector scattering length and in some cases Adler's "consistency condition". The agreement of the isospin symmetric $πN$ scattering length with experiment is substantially improved in this extended sigma model as compared with the original one. We show that the nucleon sigma term ($Σ_N$) in the linear- and the extended sigma models with three different kinds of chiral symmetry breaking terms are identical. Within the tree approximation the formal operator expression for the $Σ_N$ term and the value extracted from the $πN$ scattering matrix coincide. Large values of $Σ_N$ are easily obtained without any $s\bar s$ content of the nucleon. Using chiral rotations the Lagrangian of this extended sigma model reproduces the lowest-order $πN$ chiral perturbation theory Lagrangian. | |
| dc.description | 21 pages, 1 postscript figure, submitted to Phys. Rev | |
| dc.identifier | https://arxiv.org/abs/hep-ph/9911320 | |
| dc.identifier | http://arxiv.org/abs/hep-ph/9911320 | |
| dc.identifier | Phys.Rev.C61:025205,2000 | |
| dc.identifier | doi:10.1103/PhysRevC.61.025205 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/198705 | |
| dc.subject | High Energy Physics - Phenomenology | |
| dc.subject | Nuclear Theory | |
| dc.title | Pion-nucleon scattering and the nucleon sigma term in an extended sigma model | |
| dc.type | text |