Evidence for higher order QED in e+ e- pair production at RHIC

TL;DR

This paper presents a new lowest order QED calculation for e+ e- pair production at RHIC, finds it overestimates data, but a higher order QED calculation aligns well with experimental results.

Contribution

It introduces a phenomenological approach to Coulomb dissociation in QED calculations for heavy ion collisions at RHIC.

Findings

Lowest order QED overestimates STAR data by nearly two standard deviations.

Higher order QED calculations are consistent with experimental measurements.

Highlights the importance of higher order effects in accurate QED modeling.

Abstract

A new lowest order QED calculation for RHIC e+ e- pair production has been carried out with a phenomenological treatment of the Coulomb dissociation of the heavy ion nuclei observed in the STAR ZDC triggers. The lowest order QED result for the experimental acceptance is nearly two standard deviations larger than the STAR data. A corresponding higher order QED calculation is consistent with the data.