Speaker
Description
In the context of infrared subtraction algorithms beyond NLO, it is necessary
to consider nested infrared limits of scattering amplitudes, in which several particles
become soft or collinear in a strongly-ordered sequence, as well as mixed real-virtual
contributions. I will discuss these configurations from the point of view of infrared factorisation,
and provide general definitions of strongly-ordered soft and collinear kernels in terms
of gauge-invariant operator matrix elements, leading to the construction of local subtraction
counterterms for strongly-ordered configurations. Because of their factorised structure,
these counterterms, upon integration, cancel the infrared poles of real-virtual contributions
by construction, streamlining an important sector of subtraction algorithms to any order.
