Single spin asymmetries and gauge invariance in hard scattering processes

In this PhD-thesis effects from intrinsic transverse momentum are studied in several hard scattering processes with an emphasis on color gauge invariance. The thesis is intended for beginning PhD-students as well as for the experts.Comment: 160 pages, 138 figures, PhD thesi

New observables in longitudinal single-spin asymmetries in semi-inclusive DIS

We analyze longitudinal beam and target single-spin asymmetries in semi-inclusive deep inelastic scattering and in jet deep inelastic scattering, including all possible twist-3 contributions as well as quark mass corrections. We take into account the path-ordered exponential in the soft correlators and show that it leads to the introduction of a new distribution and a new fragmentation function contributing to the asymmetries.Comment: 8 page