Low-mass dilepton production in $pp$ and $AA$ collisions

TL;DR

This paper develops a QCD-based approach to describe low-mass dilepton production in proton-proton and heavy-ion collisions, accounting for nuclear effects and multiple scattering to improve understanding of QCD processes at low invariant masses.

Contribution

It introduces an extended factorized QCD formalism that incorporates nuclear-dependent power corrections for dilepton production in $AA$ collisions.

Findings

Effective description of low-mass dilepton transverse momentum distribution in $pp$ collisions.

Extension of the formalism to include nuclear effects in $AA$ collisions.

Insights into parton multiple scattering impacts on dilepton production.

Abstract

We adopt a factorized QCD formalism to describe the transverse momentum distribution of low-mass lepton pairs produced in $pp$ collisions, when the pair transverse momentum $Q_T \gg Q$, with the pair's invariant mass $Q$ as low as $Q \sim \Lambda_{\mathrm{QCD}}$. We extend this formalism to dilepton production in $AA$ collisions by including the nuclear-dependent power correction due to parton multiple scattering.