Speaker
Description
Scattering amplitudes are the fundamental building blocks of collider observables. Comparing high precision measurements with theory predictions requires computing them to high perturbative order. The growth in the number of loops significantly increases the complexity of the problem. Using novel methods allowed us to compute QCD corrections to four-point massless processes at the state-of-the-art three-loop order. In this talk, I will argue that employing a recently proposed projector method reduces the amount of independent Lorentz tensor structures. I will also discuss the derivation of a complete set of Master Integrals in all the relevant physical regions. It is based on regularity properties of the underlying Feynman integrals, which were observed before. I will present our results for the diphoton production in gluon fusion channel. Finally, I will show an application of this amplitude to LHC phenomenology. This particular process is a leading background for Higgs production in the discovery channel. Because of the interference with the signal, it can put new bounds on the Higgs width.
