Speaker
Description
Collins-Soper (CS) evolution kernel is critical to relate transverse-momentum-dependent parton distribution functions (TMDPDFs) at different scales. When the parton transverse momentum is small, q_T \sim \Lambda_{QCD}, the CS kernel is non-perturbative; the determination of the CS kernel in the non-perturbative regime can only be done through experiment or first-principles calculations. I will review how lattice QCD can be used to compute the CS kernel through Large-Momentum Effective Theory, how results from lattice calculations compare with phenomenological fits, and provide an update on ongoing efforts to improve the precision of current lattice QCD results from forward matrix elements with a complementary approach via quasi-TMD wavefunctions.
