Study of Gamma + Pi --> Pi + Pi

TL;DR

This paper investigates the gamma plus pion to two pions scattering process using theoretical principles like axial anomaly, unitarity, and analyticity, deriving an integral equation and solving it with an iterative method that includes multiple scattering effects.

Contribution

It introduces a novel integral equation approach for the process, incorporating multiple scattering effects within the vector meson dominance framework.

Findings

Derived an integral equation for the lowest partial wave amplitude.

Solved the equation using an iterative method.

Included multiple scattering effects in the analysis.

Abstract

The problem of Gamma + Pi --> Pi + Pi is studied using the axial anomaly, elastic unitarity, analyticity and crossing symmetry. Single variable dispersion relation is assumed. Using elastic unitarity relation, an integral equation equation for the lowest partial wave amplitude is obtained. The solution for this integral equation is obtained by an iteration procedure corresponding to that obtained from the vector meson dominance model but with multiple scattering effects taken into account.