Role of t-channel meson exchange in S-wave pi N and K N scattering

TL;DR

This paper investigates the role of t-channel meson exchanges, particularly rho and sigma, in low-energy S-wave pi N and K N scattering using a K-matrix approach, highlighting their significant impact on scattering dynamics.

Contribution

It demonstrates the crucial influence of t-channel rho and sigma exchanges in S-wave pi N and K N scattering, emphasizing their different effects on isospin channels.

Findings

T-channel rho exchange determines isospin structure.

T-channel sigma exchange contributes significantly to scattering.

Rho exchange causes attraction in low isospin, repulsion in high isospin.

Abstract

The low-energy S-wave pi N and K N scatterings are studied by the K-matrix approach within the meson exchange framework. The t-channel meson exchanges, especially rho and sigma exchanges, are found to play a very important role in these two processes. The t-channel rho exchange determines the isospin structure of the scattering amplitudes, it gives attractive force in the low isospin state but repulsive force in the high isospin state. The t-channel sigma exchange gives a very large contribution in these two processes, while it is negligible in meson-meson S-wave scatterings.