Analytic Two-Loop Five-Parton QCD Amplitudes from Numerical Unitarity

by Vasily Sotnikov

Monday 3 Jun 2019, 14:15 → 15:15 Europe/Berlin

313 (MPI Meeting rooms)

I present the recent calculation of analytic form of all two-loop five-parton helicity amplitudes required for the computation of NNLO QCD corrections to the production of three jets at hadron colliders in the leading-color approximation. I discuss how a combination of numerical evaluation of amplitudes through numerical unitarity with a dedicated algorithm of multivariate rational function reconstruction allows to obtain the analytic form of the amplitudes from exact numerical evaluations over finite fields. Their systematic simplification using multivariate partial-fraction decomposition leads to a particularly compact form. With these methods, a sample with a size comparable to that required for numerical Monte-Carlo integration is sufficient to produce analytic expressions. The approach is robust and flexible, opening the possibilities to tackle a number of important Standard Model processes in the future.