Speaker
Description
Future electron-position colliders, such as CEPC and FCC-ee, have the capability
to dramatically improve the experimental precision for W and Z-boson masses and
couplings. This would enable indirect probes of physics beyond the Standard Model at
multi-TeV scales. For this purpose, one must complement the experimental measurements with equally precise calculations for the theoretical predictions of these quantities
within the Standard Model, including three-loop electroweak corrections. This article
reports on the calculation of a subset of these corrections, stemming from diagrams
with three closed fermion loops to the following quantities: the prediction of the W-boson mass from the Fermi constant, the effective weak mixing angle, and partial and
total widths of the Z boson. The numerical size of these corrections is relatively modest, but non-negligible compared to the precision targets of future colliders. In passing,
an error is identified in previous results for the two-loop corrections to the Z width,
with a small yet non-zero numerical impact.
