Centrality dependence of dilepton production via $\gamma \gamma$ processes from Wigner distributions of photons in nuclei

TL;DR

This paper introduces a novel method using Wigner distributions of photons to calculate dilepton production in nuclear collisions, achieving excellent agreement with experimental data without free parameters or additional mechanisms.

Contribution

It presents a new formalism for calculating dilepton distributions from photon-photon fusion in nuclear collisions based on Wigner distributions.

Findings

Accurate predictions of dilepton invariant mass, transverse momentum, and acoplanarity distributions.

Good agreement with STAR, ALICE, and ATLAS experimental data.

Method does not require free parameters or additional rescattering mechanisms.

Abstract

We propose a new complete method, based on the Wigner distributions of photons, how to calculate differential distributions of dileptons created via photon-photon fusion in semicentral ($b<2R_A$) $AA$ collisions. The formalism is used to calculate different distributions of invariant mass, dilepton transverse momentum and acoplanarity for different regions of centrality. The results of calculation are compared with recent STAR, ALICE and ATLAS experimental data. Very good agreement with the data is achieved without free parameters and without including additional mechanisms such as a possible rescattering of leptons in the quark-gluon plasma.