Independently parameterised momenta variables and Monte Carlo IR subtraction
Peter Cox, Tom Melia
Journal of High Energy Physics | SPRINGER | Published : 2018
We introduce a system of parameters for the Monte Carlo generation of Lorentz invariant phase space that is particularly well-suited to the treatment of the infrared divergences that occur in the most singular, Born-like configurations of 1 → n QCD processes. A key feature is that particle momenta are generated independently of one another, leading to a simple parameterisation of all such IR limits. We exemplify the use of these variables in conjunction with the projection to Born subtraction technique at next-to-next-to-leading order. The geometric origins of this parameterisation lie in a coordinate chart on a Grassmannian manifold.
Awarded by JSPS KAKENHI
We would like to thank Keith Hamilton, Brian Henning, Franz Herzog, Hitoshi Murayama, and Giulia Zanderighi for useful discussions, and Simon Badger and Brian Henning for comments on a draft version of this manuscript. This work is supported by the World Premier International Research Center Initiative (WPI), MEXT, Japan. TM is supported by JSPS KAKENHI Grant Number JP18K13533. TM is grateful to the Mainz Institute for Theoretical Physics (MITP) for its hospitality as this work was being finalised.