Absorptive part of meson--baryon scattering amplitude and baryon polarization in chiral perturbation theory

TL;DR

This paper calculates the polarization of baryons in low-energy meson-baryon scattering using chiral perturbation theory, revealing significant polarization effects even near threshold energies.

Contribution

It provides analytical one-loop level calculations of absorptive amplitudes and explores baryon polarization in various meson-baryon processes within chiral perturbation theory.

Findings

Significant baryon polarization observed near threshold energies.

Analytical expressions for absorptive amplitudes at one-loop level.

Numerical results indicate sizable polarization in several processes.

Abstract

We compute the spin asymmetry and polarization of the final-state baryon in its rest frame in two-body meson--baryon low-energy scattering with unpolarized initial state, to lowest non-trivial order in BChPT. The required absorptive amplitudes are obtained analytically at one-loop level. We discuss the polarization results numerically for several meson--baryon processes. Even at low energies above threshold, where BChPT can reasonably be expected to be applicable, sizable values of polarization are found for some processes.