Q_T-Resummation for Polarized Semi-Inclusive Deep Inelastic Scattering
  We study the transverse-momentum distribution of hadrons produced in semi-inclusive deep-inelastic scattering. We consider cross sections for various combinations of the polarizations of the initial lepton and nucleon or the produced hadron, for which we perform the resummation of large double-logarithmic perturbative corrections arising at small transverse momentum. We present phenomenological results for the process $ep\to e\pi X$ for the typical kinematics in the COMPASS experiment. We discuss the impact of the perturbative resummation and of estimated non-perturbative contributions on the corresponding cross sections and their spin asymmetry. 
Yuji Koike, Junji Nagashima (Niigata Univ.) and Werner Vogelsang (BNL)