Independently Parameterised Momenta Variables and Monte Carlo IR Subtraction

Understand

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 $1\to n$ 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.