Eur. Phys. J. C (2018) 78: 687
https://doi.org/10.1140/epjc/s10052-018-6180-7

Regular Article - Theoretical Physics

The double-soft integral for an arbitrary angle between hard radiators

¹ IPPP, Durham University, Durham, UK
² Institute for Theoretical Particle Physics, KIT, Karlsruhe, Germany

^* e-mail: fabrizio.caola@durham.ac.uk

Received: 14 August 2018
Accepted: 22 August 2018
Published online: 29 August 2018

Abstract

We consider the double-soft limit of a generic QCD process involving massless partons and integrate analytically the double-soft eikonal functions over the phase-space of soft partons (gluons or quarks) allowing for an arbitrary relative angle between the three-momenta of two hard massless radiators. This result provides one of the missing ingredients for a fully analytic formulation of the nested soft-collinear subtraction scheme described in Caola et al. (Eur Phys J C 77(4):248, 2017).