Numerical Multiloop Calculations: Sector Decomposition and QMC Integration in pySecDec

The FCC-ee will allow the experimental uncertainties on several important observables, such as the Electroweak Pseudo-Observables (EWPOs), to be reduced by up to two orders of magnitude compared to the previous generation LEP/SLC experiments [1, 2]. In order to be able to best exploit this unprecedented boost in precision, it is necessary also for theoretical predictions to be known with sufficient accuracy. In practice, this means that very high order perturbative corrections to electroweak precision observables and other processes will be required both in the Standard Model (SM) and potentially also in BSM scenarios. One of the key challenges for computing perturbative corrections is our ability to compute the Feynman integrals that appear in these multi-loop corrections. There has been very significant progress in this direction in recent years ranging from purely analytic approaches [3–17] to semi-analytic approaches based on expansions [18–23] and also via purely numerical methods [24–32].