Aspects of TMD evolution of azimuthal asymmetries

Abstract

In this contribution TMD evolution of azimuthal asymmetries, in particular of the Sivers and double Collins asymmetries, is addressed. A comparison of the scale dependence is made between asymmetries described with TMD factorization at low transverse momentum and those described with collinear factorization at high transverse momentum. Finally, the advantages of Bessel weighting are discussed: convergence of transverse momentum integrals, suppression of large transverse momentum contributions, and well-defined lattice QCD evaluations of Bessel-weighted TMDs including proper gauge links.

9 pages, 2 figures, to appear in the proceedings of the QCD Evolution Workshop (QCD2013), Thomas Jefferson National Accelerator Facility, Newport News, VA, May 6-10, 2013