# Probing the linear polarization of photons in ultraperipheral heavy ion collisions

## TL;DR

This paper proposes measuring the linear polarization of electromagnetic fields in ultraperipheral heavy ion collisions by analyzing azimuthal asymmetries in dilepton production, which are predicted to be significant.

## Contribution

It introduces a method to probe electromagnetic field polarization in heavy ion collisions using azimuthal asymmetries in dilepton production.

## Key findings

- Asymmetries are sizable according to the equivalent photon approximation.
- The method provides a new way to study electromagnetic fields in heavy ion collisions.

## Abstract

We propose to measure the linear polarization of the external electromagnetic fields of a relativistic heavy ion through azimuthal asymmetries in dilepton production in ultraperipheral collisions. The asymmetries estimated with the equivalent photon approximation are shown to be sizable.