The QCD factorization in SIDIS is considered in close analogy to the analysis of the Drell-Yan process. A special role of the (weighted) average over produced hadron transverse momentum is stressed. The case of Single Spin Asymmetry (SSA) due to the Collins-type fragmentation function is analyzed and its twist-3 nature is uncovered. The analysis of the sources of imaginary phases and respective cuts in hadronic kinematic variables leads to the effective character (nonuniversality) of T-odd distribution functions, contrary to universality of T-odd fragmentation functions.

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