$T$-Odd Effects in Unpolarized Drell-Yan Scattering

Leonard P. Gamberg; Gary R. Goldstein

Paper

$T$-Odd Effects in Unpolarized Drell-Yan Scattering

Abstract

We consider the leading twist

-odd contributions as the dominant source of the

azimuthal asymmetry in unpolarized

dilepton production in Drell-Yan Scattering. This asymmetry contains information on the distribution of quark transverse spin in an unpolarized proton. In a parton-spectator framework we estimate these asymmetries at

center of mass energy. This azimuthal asymmetry is interesting in light of proposed experiments at GSI, where an anti-proton beam is ideal for studying the transversity properties of quarks due to the dominance of {\em valence} quark effects.