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arXiv · 2108.00017

Two-loop Electroweak Corrections to the Top-Quark Contribution to $\epsilon_K$

Joachim Brod·Sandra Kvedaraitė·Zachary Polonsky
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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 $-1\%$.

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Joachim Brod, Sandra Kvedaraitė, Zachary Polonsky. 2021-07-30. Two-loop Electroweak Corrections to the Top-Quark Contribution to $\epsilon_K$. https://doi.org/10.1007/jhep12(2021)198

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