Angular Distributions of Drell-Yan Lepton Pairs at the Tevatron: Order $α_s^2$ Corrections and Monte Carlo Studies

Abstract

We investigate the angular distribution of the lepton pair in the process $p \bar{p} \rightarrow γ^{\ast} + X \rightarrow \ell^+\ell^- + X$, where the virtual photon is produced at high transverse momentum. The angular distribution of the leptons is very sensitive to possible nonperturbative effects, such as a nontrivial vacuum structure of QCD, and offers a good chance to test such effects. We present complete ${\cal O}(α_s^2)$ calculations of the decay lepton distributions in the lepton pair rest frame. An order ${\cal O}(α_s)$ Monte Carlo study of the lepton angular distributions, with acceptance cuts and energy resolution smearing applied to the leptons, is also presented.