It is well-known that perturbative expansions of QFT observable suffer from infrared (IR) divergences both in the phase-space of real-emission contributions and in the loop amplitudes of virtual contributions.
Traditionally, the two are handled separately through a combination of local subtraction counterterm and dimensional regulation.
Local Unitarity is an alternative formulation using the Loop-Tree Duality (LTD) theorem and where the Kinoshita–Lee–Nauenberg (KLN) cancellation pattern is leveraged to achieve a direct cancellation of real-emission and loop IR divergences, independently for each forward scattering graph.
I will discuss our recent efforts in implementing Local Unitarity in gammaLoop, together with threshold regularisation techniques and local UV subtraction counterterms, aiming to obtain fixed-order predictions of differential corss-sections at a perturbative order only limited by the available computational resources (no obstacle from a theoretical standpoint).