Eur. Phys. J. C (2018) 78: 234
https://doi.org/10.1140/epjc/s10052-018-5732-1

Regular Article - Theoretical Physics

The NNLO QCD soft function for 1-jettiness

¹ Fermilab, P.O. Box 500, Batavia, IL, 60510, USA
² Department of Physics, Institute for Particle Physics Phenomenology, University of Durham, Durham, DH1 3LE, UK
³ Department of Physics, University at Buffalo, The State University of New York, Buffalo, NY, 14260, USA

^* e-mail: rmondini@buffalo.edu

Received: 2 February 2018
Accepted: 12 March 2018
Published online: 19 March 2018

Abstract

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.