This work presents a determination of the quark Collins-Soper kernel, which relates transverse-momentum-dependent parton distributions (TMDs) at different rapidity scales, using lattice Quantum Chromodynamics (QCD). This is the first lattice QCD calculation of the kernel at quark masses corresponding to a close-to-physical value of the pion mass, with next-to-next-leading logarithmic matching to TMDs from the corresponding lattice-calculable distributions, and includes a complete analysis of systematic uncertainties arising from operator mixing. The kernel is extracted at transverse momentum scales 240MeV≲qT≲1.6GeV with a precision sufficient to begin to discriminate between different phenomenological models in the non-perturbative region.
@article{arxiv.2307.12359,
title = {Collins-Soper kernel from lattice QCD at the physical pion mass},
author = {Artur Avkhadiev and Phiala Shanahan and Michael Wagman and Yong Zhao},
journal= {arXiv preprint arXiv:2307.12359},
year = {2024}
}