Electroweak bosonic 2-loop corrections to the Z-pole precision observables

Abstract

Precision measurements of properties of the electroweak W - and Z-bosons provide strong constraints on the Standard Model (SM) and extensions thereof. This sensitivity crucially depends on the availability of accurate theoretical predictions for these quantities, including higher-order radiative corrections. This contribution gives a brief overview of available calculations and compares the estimate of theory uncertainties with the projected experimental precision of future e(+)e(-) collider proposals. Then it is shown how numerical Mellin-Barnes integrals can be used to evaluate higher-order loop integrals that depend on three or more independent mass and momentum scales. As a concrete physical application, the complete two-loop corrections to Z -> b (b) over bar are considered.