First analytic results for two-loop five-particle amplitudes with one massive leg
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https://fisica-unimi.zoom.us/j/93801268810?pwd=NHB5c2N3aVhFVlNSSllGeWNLNUxCQT09
The physics exploitation of the precision data collected at the LHC requires highly accurate theory predictions. For many processes, Next-to-Next-to-Leading Order (NNLO) corrections in QCD are required. NNLO cross sections for many 2->2 processes are available, and dramatic progress has recently culminated in the first NNLO predictions for a 2->3 process with massless particles. Processes with external massive particles are of great phenomenological interest as well. The main bottleneck is the analytic computation of two-loop scattering amplitudes.
I present the very first analytic computation of a two-loop five-particle amplitude with one external massive leg. We consider the production of a W-boson in association with a pair of b-quarks. We compute the two-loop QCD corrections to the ud->Wbb amplitude for an on-shell W-boson using the leading colour and massless bottom quark approximations. We perform an integration-by-parts reduction of the unpolarised squared matrix element using finite field reconstruction techniques, and identify an independent basis of special functions that allows an analytic subtraction of the infrared and ultraviolet poles. This basis is valid for all planar two-loop integral topologies for five-particle scattering with an off-shell leg.