Collinear matching for Sivers function at next-to-leading order

Abstract

We evaluate the light-cone operator product expansion for the unpolarized transverse momentum dependent (TMD) operator in the background-field technique up twist-3 inclusively. The next-to-leading order (NLO) matching coefficient for the Sivers function is derived. The method, as well as many details of the calculation, are presented.

Comments: 46 page, 8 figured; ver2: Updated discussions on rapidity divergences and scheme-dependance, many minor changes