The Chiral Magnetic Effect and an experimental bound on the late time magnetic field strength

TL;DR

This paper compares methods for estimating the chiral magnetic effect in heavy ion collisions and uses hyperon polarization measurements to set bounds on the late-time magnetic field strength.

Contribution

It clarifies the main assumptions behind different estimation approaches and links experimental hyperon polarization data to magnetic field bounds.

Findings

Different approaches vary mainly in magnetic field persistence assumptions.

Hyperon polarization measurements constrain late-time magnetic field strength.

The analysis provides bounds on magnetic field magnitude from experimental data.

Abstract

We first compare different approaches to estimates of the magnitude of the chiral magnetic effect in relativistic heavy ion collisions and show that their main difference lies in the assumptions on the length of persistence of the magnetic field generated by the colliding nuclei. We then analyze recent measurements of the global polarization of $\Lambda$ and $\bar \Lambda$ hyperons in terms of the bounds they set on the magnitude of the late time magnetic field.