Transversely polarized Drell-Yan asymmetry A_TT at NLO

TL;DR

This paper provides the first fully differential NLO QCD calculation for transversely polarized Drell-Yan processes, enabling better comparison with experiments and extraction of transversely polarized parton distributions.

Contribution

It introduces a new NLO calculation and Monte Carlo implementation for transversely polarized Drell-Yan, including analysis of QCD corrections and scenarios for polarized parton distributions.

Findings

QCD corrections significantly affect asymmetries

Corrections depend strongly on lepton kinematics

Two scenarios for transversely polarized PDFs are proposed

Abstract

We present the first fully differential next-to-leading order QCD calculation for lepton production in transversely polarized hadronic collisions, pp -> l X , where the lepton arises from the decay of an electroweak gauge boson. The calculation is implemented in the Monte-Carlo like code `CHE' that already includes the unpolarized and longitudinally polarized cross sections and may be readily used to perform a comparison to experimental data and to extract information on the related parton distributions. We analyze the perturbative stability of the cross-section and double spin asymmetry A_TT at RHIC kinematics. We find that the QCD corrections are non-negligible even at the level of asymmetries and that they strongly depend on the lepton kinematics. Furthermore, we present two scenarios for transversely polarized parton distributions, based on the de Florian-Sassot-Stratmann-Vogelsang (DSSV) set of longitudinally parton densities and fully evolved to NLO accuracy, that can be used for the evaluation of different observables involving transverse polarization.