Information Content of Polarization Measurements

TL;DR

This paper introduces an information entropy-based method to quantify the informational value of polarization measurements in meson photoproduction, emphasizing practical measurement strategies over mathematical completeness.

Contribution

It develops a scheme using information entropy to assess the quality of polarization observable sets, highlighting the importance of measuring many observables in practice.

Findings

Complete measurement sets do not eliminate ambiguities with experimental uncertainties.

Measuring more observables improves the extraction of reaction amplitudes.

Information entropy provides a practical measure of measurement quality.

Abstract

Information entropy is applied to the state of knowledge of reaction amplitudes in pseudoscalar meson photoproduction, and a scheme is developed that quantifies the information content of a measured set of polarization observables. It is shown that this definition of information is a more practical measure of the quality of a set of measured observables than whether the combination is a mathematically complete set. It is also shown that when experimental uncertainty is introduced, complete sets of measurements do not necessarily remove ambiguities, and that experiments should strive to measure as many observables as practical in order to extract amplitudes.