We study the single spin asymmetry in the lepton angular distribution of Drell-Yan processes in the framework of collinear factorization. The asymmetry has been studied in the past and different results have been obtained. In our study we take an approach different than that used in the existing study. We explicitly calculate the transverse-spin dependent part of the differential cross-section with suitable parton states. Because the spin is transverse, one has to take multi-parton states for the purpose. Our result agrees with one of the existing results. A possible reason for the disagreement with others is discussed.

Recently CLEO has studied the radiative decay of Υ into η ′ and an upper limit for the decay has been determined. Confronting with this upper limit, most of theoretical predictions for the decay fails. After briefly reviewing these predictions we re-examine the decay by separating nonperturbative effect related to the quarkonium and that related to η ′ or η, in which the later is parameterized by distribution amplitudes of gluons in η ′ . With this factorization approach we obtain theoretical predictions which are in agreement with experiment. Uncertainties in our predictions are discussed. The possibly largest uncertainties are from relativistic corrections for J/Ψ and the value of the charm quark mass. We argue that the effect of these uncertainties can be reduced by using quarkonium masses instead of using quark masses. An example of the reduction is shown with an attempt to explain the violation of the famous 14% rule in radiative decays of charmonia.

We analyze the structure of relativistic corrections in the inclusive production of polarized J/ from b-quark decay. The analysis is performed not only for the production channel in which the cc pair is a color singlet, but also for the channels in which the cc is a color octet. We find that the correction in the color-singlet channel at tree level is completely determined by the decay constant of J/, while in the color-octet channels the corrections are characterized by three matrix elements defined in NRQCD, whose numerical values are unknown. We discuss the impact of these corrections on polarized J/ production, and the impact is so significant that the predictions based on the analysis for the considered process may be unreliable. Finally, we propose an integrated spin observable to measure the polarization of J/.