Evolution of twist-3 multi-parton correlation functions relevant to single transverse-spin asymmetry

Understand

We constructed two sets of twist-3 correlation functions that are responsible for generating the novel single transverse-spin asymmetry in the QCD collinear factorization approach.

• We derive evolution equations for these universal three-parton correlation functions.
• We calculate evolution kernels relevant to the gluonic pole contributions to the asymmetry at the order of $\alpha_s$.
• We find that all evolution kernels are infrared safe as they should be and have a lot in common to the DGLAP evolution kernels of unpolarized parton distributions.