[RBRC seminar] TMD gluon distributions at NLO within high energy factorization
by
Martin Hentschinski
(Brookhaven National Laboratory)
→
US/Eastern
Description
We discuss Transverse Momentum Dependent (TMD) gluon distributions within the framework of Lipatov's high energy effective action. We provide a detailed discussion of both rapidity divergences related to the TMD definition and its soft factor on the one hand, and rapidity divergences due to high energy factorization on the other hand, and discuss common features and differences between Collins-Soper (CS) and Balitsky-Fadin-Kuarev-Lipatov (BFKL) evolution. While we confirm earlier results which state that the unpolarized and linearly polarized gluon TMD agree in the BFKL limit at leading order, we find that both distributions differ, once next-to-leading order corrections are being included. Unlike previous results, our framework allows us to recover the complete anomalous dimension associated with Collins-Soper-Sterman (CSS) evolution of the TMD distribution, including also single-logarithmic terms in the CSS evolution. We further discuss the relation of our result to a previously derived off-shell gluon-to-gluon splitting function.
