Role of T-odd functions in high energy hadronic collisions

I propose a simple model for predicting the enegy behavior of T-odd, chiral odd function $h_1^{\perp}$. Furthermore I illustrate a method for extracting $h_1^{\perp}$ and the transversity function from Drell-Yan. The method may be applied also to other reactions.Comment: Talk given at Brookhaven, Spin-200

Q^2 Dependence of the azimuthal Asymmetry in Unpolarized Drell-Yan

We study the azimuthal asymmetry of the unpolarized Drell-Yan in the framework of the T-odd functions. We find, on the basis of quite general arguments, that for |{\bf q}_{\perp}| << Q such an asymmetry decreases as Q^{-2}, where {\bf q}_{\perp} and Q are respectively the transverse momentum and the center-of-mass energy of the muon pair. The experimental results support this conclusion.Comment: 15 pages, 4 figures. Presented at "HiX2004", Marseille, July 26-28, 200

Transverse Spin Asymmetries in Drell-Yan Processes: p↑p→μ+μ−X\mathbf p^{\uparrow} p \to \mu^+ \mu^- X}

We consider two different spin asymmetries in Drell-Yan processes generated by the collisions of an unpolarized proton beam on transversely polarized protons: the muon helicity asymmetry and the left-right asymmetry. We calculate the asymmetries in the framework of the QCD improved parton model, taking into account the parton transverse momentum and considering the first order QCD corrections. The muon helicity asymmetry is sensitive to the quark transversity distribution and is nonvanishing even at zero order. On the contrary the left-right asymmetry vanishes at zero order but not at first order in the QCD coupling constant, as a result of gluon contribution