We extend the improved Collins–Soper–Sterman (iCSS) W+Y construction recently presented in  to the case of polarized observables, where we focus in particular on the Sivers effect in semi-inclusive deep-inelastic scattering. We further show how one recovers the expected leading-order collinear twist-3 result from a (weighted) qT-integral of the differential cross section. We are also able to demonstrate the validity of the well-known relation between the (TMD) Sivers function and the (collinear twist-3) Qiu–Sterman function within the iCSS framework. This relation allows for their interpretation as functions yielding the average transverse momentum of unpolarized quarks in a transversely polarized spin-[Formula presented] target. We further outline how this study can be generalized to other polarized quantities.
|Original language||English (US)|
|Number of pages||12|
|Journal||Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics|
|State||Published - Jun 10 2018|
All Science Journal Classification (ASJC) codes
- Nuclear and High Energy Physics