Polarized Bremsstrahlung in the Equivalent Photon Method

TL;DR

This paper introduces an efficient method for calculating polarized bremsstrahlung using the equivalent photon approach, revealing how polarization depends on radiation angles and momentum transfer.

Contribution

It presents a novel, simplified calculation technique for polarized bremsstrahlung based on the reduction of the matrix element, with detailed polarization distribution analysis.

Findings

Polarization can reach 100% with angular photon selection.

Without angular selection, polarization is limited to 50%.

Polarization distribution forms circles passing through two points.

Abstract

An economic technique for calculation of polarized bremsstrahlung process is proposed, assuming typical atomic momentum transfer $q\ll m$. The adopted approach is based on the natural reduction of the matrix element to the form $V^{\alpha}\gamma^{\alpha}+A_{5}\gamma ^{5}$. Polarization distribution in the fully differential cross-section is analyzed. It is found that at a given momentum transfer to the atom polarization in the plane of small radiation angles is oriented along circles passing through two common points. It is shown that with angular selection of radiated photons carried out, even with momentum transfers to the atom being integrated over, for particular radiation angles polarization may stay as high as 100%. Without angular selection of photons, only by control of the recoil, it is impossible to gain radiation polarization above 50%.