2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/163785We investigate the emergence of single spin asymmetries (SSA) in hard processes using transverse momentum dependent (TMD) distribution and fragmentation functions. Specifically, the description of SSA involves time reversal-odd functions. Process-dependence (non-universality) in measurements of SSA can be attributed to the non-trivial gauge link structure in the TMD correlator. Finding the appropriate gauge links, however, also enables us to characterize the non-universality4 pages, 1 figure, contribution to DIS2008 (April 2008), London (UK)High Energy Physics - Phenomenologytext