Z boson production in proton-lead collisions at the LHC accounting for transverse momenta of initial partons

E Blanco,H Jung,A Kusina,K Kutak,A Van Hameren

doi:10.1103/physrevd.100.054023

Abstract

We perform a calculation of inclusive $Z$ boson production in proton-lead collisions at the LHC taking into account the transverse momenta of the initial partons. We use the framework of $k_T$-factorization combining transverse momentum dependent parton distributions (TMDs) with off-shell matrix elements. In order to do it we need to construct appropriate TMDs for lead nuclei which is done using the parton branching method. Our computations are compared with data from CMS taken at $\sqrt{s}=5.02$ TeV. The results are in good agreement with the measurements especially the transverse momentum distribution of the $Z$ boson.

Highlights

The production of Z bosons in hadron-hadron collisions is described in lowest order (LO) calculations as the annihilation of a pair qq → Z
We perform a calculation of inclusive Z boson production in proton-lead collisions at the LHC taking into account the transverse momenta of the initial partons
We use the framework of kT-factorization combining transverse momentum dependent parton distributions (TMDs) with off-shell matrix elements

Summary

INTRODUCTION

The production of Z bosons in hadron-hadron collisions is described in lowest order (LO) calculations as the annihilation of a pair qq → Z. In this paper we are in particular interested in exploring the transverse momentum structure of the partonic content of lead nucleus at relatively large values of its longitudinal momentum.1 To achieve this we extend the PB approach to the case of heavy nuclei, in particular to lead nucleus, and apply the newly constructed nuclear TMDs (nTMDs) together with off-shell matrix elements to calculations of Z boson production in pPb collisions at the LHC.. Nucleus, we calculate the cross section for the rapidity and pT spectrum of Drell-Yan pairs with an intermediate Z=γÃ boson state Such a final state, being a colorless particle, gives the opportunity for interesting investigations complementary to results obtained in studies of jet final states in [12,13]

NUCLEAR TMDS

RESULTS

Predictions for 8 TeV data

CONCLUSIONS