TMD PDFs in Drell-Yan lepton pair production at LHC

TL;DR

This paper investigates the transverse momentum dependent (TMD) quark densities in the proton for unpolarized Drell-Yan lepton pair production at the LHC, using CCFM evolution and analyzing various kinematic distributions and correlations.

Contribution

It introduces a calculation of the TMD sea quark density via convolution with gluon distributions and analyzes dilepton production using an ${ m O}( ext{α}^2)$ amplitude including angular correlations.

Findings

Calculated TMD sea quark densities using CCFM evolution.

Analyzed dilepton invariant mass, transverse momentum, and rapidity distributions.

Compared theoretical predictions with CMS, ATLAS, and LHCb data.

Abstract

We consider the transverse momentum dependent (TMD) quark densities of the proton which are very important ingredients for unpolarized Drell-Yan (DY) lepton pair production. We calculate the TMD sea quark density as a convolution of the Catani-Ciafaloni-Fiorani-Marchesini (CCFM)-evolved gluon distribution and the TMD gluon-to-quark splitting function. Based on the ${\cal O}(\alpha^2)$ production amplitude $q^* + \bar q^* \to Z/\gamma^* \to l^+ + l^-$, calculated by taking into account the effective $q^*\bar q^* Z/\gamma^*$ - vertex, we analyze the distributions on the dilepton invariant mass, transverse momentum and rapidity and specific angular correlations between the produced leptons as measured by the CMS, ATLAS and LHCb collaborations. We briefly duscuss also the process of assiciated lepton pair and jet production in $pp$ collisions at the LHC.