Two-loop Electroweak Corrections to the Top-Quark Contribution to ${\epsilon }_K$

Abstract

The parameter ${\epsilon }_K$ measures $CP$ violation in the neutral kaon system. It is a sensitive probe of new physics and plays a prominent role in the global fit of the Cabibbo-Kobabyashi-Maskawa matrix. The perturbative theory uncertainty is currently dominated by the top-quark contribution. Here, we present the calculation of the full two-loop electroweak corrections to the top-quark contribution to ${\epsilon }_K$, including the resummation of QED-QCD logarithms. We discuss different renormalization prescriptions for the electroweak input parameters. In the traditional normalization of the weak Hamiltonian with two powers of the Fermi constant $G_F$, the top-quark contribution is shifted by $-1\%$.

26 pages, 6 figures

References in corpus (1)

• On epsilon_K beyond lowest order in the Operator Product Expansion