Drell-Yan phenomenology in the color dipole picture revisited

TL;DR

This paper revisits Drell-Yan process phenomenology in proton-proton collisions using the color dipole model, including Z0 contributions and azimuthal correlations, aligning well with data and highlighting saturation effects.

Contribution

It extends the color dipole framework to include Z0 contributions and azimuthal correlations, providing new insights into saturation effects in Drell-Yan processes.

Findings

Reasonable agreement with experimental data across energies.

Azimuthal correlation functions show double-peak structure sensitive to saturation.

Z0 contribution becomes relevant at high dilepton invariant masses.

Abstract

An extensive phenomenological study of the Drell-Yan (DY) process in $pp$ collisions at various energies is performed in the color dipole framework. Besides previously studied $\gamma^*$ production we have also included the $Z^0$ contribution relevant at large dilepton invariant masses. We investigate the DY cross section differential in invariant mass, rapidity and transverse momentum of the dilepton pair in $pp$ collisions at RHIC and LHC. We consider three different phenomenological models for the dipole cross section and found a reasonable agreement with the available data. As a further test of the color dipole formalism, we also study the correlation function in azimuthal angle between the dilepton pair and a forward pion $\Delta\phi$ for different energies, dilepton rapidites and invariant masses. The characteristic double-peak structure of the correlation function around $\Delta \phi\simeq \pi$ found for very forward pions and low-mass dilepton pairs is sensitive to the saturation effects and can be tested by future DY measurements in $pp$ collisions.