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

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 √ s = 5.02 TeV. The results are in good agreement with the measurements especially the transverse momentum distribution of the Z boson.

Production of Z bosons in the parton branching method

“…Predictions applying PB-TMDs for the calculation of Z-boson production in protonlead collisions have been recently reported in Ref. [45]. In the following we will describe how to use the PB TMD-parton distributions together with higher order calculations.…”

DIS with KaTie

“…For the study in [14] it was essential to have the possibility for different sets of transverse moment dependent PDFs (TMDs) for each of the scattering hadrons. This is achieved with, for example tmdTableDir = /home/user/projects/protongrids/ tmdpdf A = g gluon.dat tmdpdf A = u uQuark.dat tmdpdf A = u~uBar.dat tmdTableDir = /home/user/projects/iongrids/ tmdpdf B = g gluon.dat tmdpdf B = u uQuark.dat tmdpdf B = u~uBar.dat…”

“…In [10] it is pointed out how QED gauge invariance -an issue the non-triviality of which was highlighted recently in [11] -is ensured too. KaTie has been used in several recent phenomenological studies [12][13][14]. The fact that it can produce parton-level event files with space-like initial-state partons opens the possibility to match it with a parton shower without the need to compromise the kinematics [15].…”

Drell–Yan production with the CCFM-K evolution

“…Also, unlike collinear factorization, it lacks formal proof. Despite these facts, many theoretical and phenomenological analyses of the DY process were made [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37]. The theoretical improvement was accompanied by many experimental results from fixed-target [38][39][40][41] and collider [42][43][44][45][46] experiments.…”