Parton transverse momenta and Drell-Yan dilepton production

TL;DR

This paper calculates the differential cross section for Drell-Yan dilepton production using unintegrated parton distributions, analyzing transverse momentum and angular correlations, and compares results with experimental data.

Contribution

It introduces a detailed calculation incorporating Fermi motion and ladder emissions with unintegrated parton distributions fulfilling Kwieciński evolution, including higher-order contributions.

Findings

Distribution in dilepton transverse momentum depends on incident energy and virtuality.

Azimuthal correlations between leptons and jets are characterized.

Results show good agreement with R209 and UA1 experimental data.

Abstract

The differential cross section for the dilepton production is calculated including Fermi motion of hadron constituents as well as emission from the ladders in the formalism of unintegrated parton distributions. We use unintegrated parton distributions which fulfil Kwieci\'nski evolution equations. Both zeroth- and first-order (for matrix element) contributions are included. We calculate azimuthal angular correlations between charged leptons and deviations from the $p_t(l^+) = p_t(l^-)$ relation. We concentrate on the distribution in dilepton-pair transverse momentum. We find incident energy and virtuality dependence of the distribution in transverse momentum of the lepton pair. We study also azimuthal correlations between jet and dilepton pair and correlation in the $(p_{1t}(jet),p_{2t}(l^+ l^-))$ space. The results are compared with experimental data of the R209 and UA1 collaborations.