title: Calculation of transverse-momentum-dependent evolution for Sivers transverse single spin asymmetry measurements.
abstract: The Sivers transverse single spin asymmetry (TSSA) is calculated and compared at different scales using the transverse-momentum-dependent (TMD) evolution equations applied to previously existing extractions. We apply the Collins-Soper-Sterman (CSS) formalism, using the version recently developed by Collins. Our calculations rely on the universality properties of TMD functions that follow from the TMD-factorization theorem. Accordingly, the nonperturbative input is fixed by earlier experimental measurements, including both polarized semi-inclusive deep inelastic scattering (SIDIS) and unpolarized Drell-Yan (DY) scattering. It is shown that recent preliminary COMPASS measurements are consistent with the suppression prescribed by TMD evolution.
authors.affiliation: Nikhef Theory Group, Science Park 105, 1098XG Amsterdam, The Netherlands.
authors.forename: S Mert
authors.initials: SM
authors.lastname: Aybat
authors.forename: Alexei
authors.initials: A
authors.lastname: Prokudin
authors.forename: Ted C
authors.initials: TC
authors.lastname: Rogers