Universality of soft and collinear factors in hard-scattering factorization

The universality of fragmentation functions, soft factors and parton densities between e⁺ e^- annihilation, semi-inclusive deep inelastic scattering and the Drell-Yan process was analyzed. It was found that universality is applicable both to the basic definitions with lightlike Wilson lines and to the correct definitions with removal of rapidity divergences. Universality was modified by a time-reversal transformation of the soft function and parton densities between Drell-Yan and the other processes, whose only effect is the known reversal of sign for T-odd parton densities. It was concluded that the modifications of the definitions needed to remove rapidly divergences with lightlike Wilson lines do not affect the results.