TMD distributions depending on the azimuthal angle provide a non-trivial example of observables that start at subleading order in the power expansion. They also have a long history, for example in 1978 Cahn showed that quark transverse momentum gives rise to an azimuthal cos(phi) asymmetry of the outgoing hadrons in semi-inclusive DIS (SIDIS). Such subleading distributions also are an...
We will present our results for TMD factorization at sub-leading power and focus on the matching of the large and small transverse momentum contribution in semi-inclusive deep inelastic scattering process (SIDIS and Drell Yan). We investigate their connection, paying special attention to azimuthal distributions such as the Cahn effect. Our results have consequences for the extension of...
