Spin degrees and Polarization Observables in Electromagnetic Reactions

TL;DR

This paper reviews the role of spin degrees and polarization observables in electromagnetic reactions, emphasizing the density matrix formalism and methods to determine complete sets of observables for reaction analysis.

Contribution

It introduces a comprehensive formalism for polarization phenomena and discusses strategies to identify complete sets of polarization observables in electromagnetic processes.

Findings

Density matrix formalism effectively describes polarization phenomena.

Explicit examples for spin-1/2 and spin-1 systems are provided.

Guidelines for determining complete sets of polarization observables are discussed.

Abstract

After a brief introduction into the general importance of polarization observables for the analysis of a reaction, the basic density matrix formalism for the description of polarization phenomena is outlined and illustrated by explicit examples for spin one-half and one. Then various electromagnetic processes like photoreactions and electron scattering are discussed in some detail. Finally, the question of how to determine a complete set of polarization observables providing the maximum information on a reaction is considered.