Connecting Theory to Heavy Ion Experiment

TL;DR

This paper develops a theoretical framework to connect hyperon polarization measurements in heavy ion collisions with the underlying production mechanisms, including decay contributions and resonance effects.

Contribution

It introduces a derivation of polarization transfer coefficients and a method to compute the mean polarization of all detected hyperons, accounting for decay processes and resonance contributions.

Findings

Derived polarization transfer coefficients for hyperon decays

Computed mean polarization including decay and resonance effects

Provided a comprehensive formula linking theory to experimental polarization data

Abstract

Only a fraction of all $\Lambda$ and $\bar{\Lambda}$ hyperons detected in heavy ion collisions are produced from the hot and dense matter directly at the hadronization. These hyperons are called the {\em primary} hyperons. The rest of the hyperons are products of the decays of heavier hyperon states, which in turn are produced at the hadronization. As such, the polarization of only primary hyperons can be described with the formulae introduced in Sect. 8. For the rest of the hyperons, the polarization transfer in the decays has to be computed, and convoluted with the polarization of the mother hyperon. In this chapter, a derivation of the polarization transfer coefficients, as well as the computation of the mean polarization of all $\Lambda$ hyperons detected in the experiment, is presented. The chapter is concluded with the calculation of the resonance contributions to the global and local $\Lambda$ polarizations.