We calculate the soft function for the global event variable 1-jettiness at next-to-next-to-leading order (NNLO) in QCD. We focus specifically on the non-Abelian contribution, which, unlike the Abelian part, is not determined by the next-to-leading order result. The calculation uses the known general forms for the emission of one and two soft partons and is performed using a sector-decomposition method that is spelled out in detail. Results are presented in the form of numerical fits to the 1-jettiness soft function for LHC kinematics (as a function of the angle between the incoming beams and the final-state jet) and for generic kinematics (as a function of three independent angles). These fits represent one of the needed ingredients for NNLO calculations that use the N-jettiness event variable to handle infrared singularities.
@article{arxiv.1711.09984,
title = {The NNLO QCD soft function for 1-jettiness},
author = {John M. Campbell and R. Keith Ellis and Roberto Mondini and Ciaran Williams},
journal= {arXiv preprint arXiv:1711.09984},
year = {2018}
}