Double Transverse-Spin Asymmetries for Drell-Yan Process in pp and pbar{p} Collisions: Role of Nonleading QCD Corrections at Small Transverse Momentum

We discuss the double-spin asymmetries in transversely polarized Drell-Yan process, calculating all-order gluon resummation corrections up to the next-to-leading logarithmic accuracy. This resummation is relevant when the transverse-momentum Q_T of the produced lepton pair is small, and reproduces the (fixed-order) next-to-leading QCD corrections upon integrating over Q_T. The resummation corrections behave differently between pp- and p\bar{p}-collision cases and are small for the latter case at the kinematics in the proposed GSI experiments. This fact allows us to predict large value of the double-spin asymmetries at GSI, using the recent empirical information on the transversity.