Abstract
We present a thorough analysis of unpolarized Drell–Yan (DY) pair production in pion–nucleus scattering. On the nucleus side, we use nuclear parton distributions along with parametrisations of the nucleon partonic transverse distribution available in the literature. Partonic longitudinal and transverse distributions of the pion are those obtained in a recent calculation in a Nambu–Jona Lasinio (NJL) framework, with Pauli–Villars regularization. The scale of the NJL model is determined with a minimisation procedure comparing NLO predictions based on NJL evolved pion distributions to rapidity differential DY cross sections data. The resulting distributions are then used to describe, up to next-to-leading logarithmic accuracy, the transverse momentum spectrum of dilepton pairs up to a transverse momentum of 2 GeV. With no additional parameters, fair agreement is found with available pion–nucleus data, confirming the virtues of the NJL description of pion parton structure. We find sizable evolution effects on the shape of the distributions and on the generated average transverse momentum of the dilepton pair. We furthermore discuss the possibility of gaining information about the behavior of the pion unpolarized transverse momentum dependent parton distribution from pion nucleus DY data.
Highlights
The cross section for DY pair production, differential in the transverse momentum of the pair, qT, is a suitable observable for this kind of studies
We present a thorough analysis of unpolarized Drell–Yan (DY) pair production in pion–nucleus scattering
In this paper we study the DY unpolarized pair production in pion–nucleus scattering, to next-to-leading logarithmic (NLL) perturbative accuracy, up to a transverse momentum of the produced lepton pair of 2 GeV
Summary
The cross section for DY pair production, differential in the transverse momentum of the pair, qT , is a suitable observable for this kind of studies. Global fits of DY production at different energies have given access to the non perturbative proton transverse structure [12,13]. Both aspects have received increasing attention due to the formalisation of new and old concepts in the TMD language [14,15,16,17]. A fit to the qT spectrum of DY pairs produced in pion–nucleus collisions has been recently presented in Ref. In this paper we study the DY unpolarized pair production in pion–nucleus scattering, to next-to-leading logarithmic (NLL) perturbative accuracy, up to a transverse momentum of the produced lepton pair of 2 GeV.
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