Skip to main content

Matter-Antimatter Asymmetry in Neutral Kaons

Date:
Location:
Blazer Dining Hall Rm 339
Speaker(s) / Presenter(s):
Zach Polonsky (University of Cincinnati)

The parameter εK is an important measure of the imbalance between matter and antimatter in the neutral kaon system. In particular, εK provides a sensitive probe of new physics and plays a critical role in the global fit of the Cabibbo-Kobayashi-Maskawa matrix. As one of the first discovered sources of CP violation, it has been extensively measured in experiment to per-mil precision. The theoretical calculation of εK, however, has historically been plagued by large perturbative errors arising from charm-quark corrections. These errors were larger than the expected magnitude of higher-order electroweak corrections in perturbation theory, rendering these contributions irrelevant. Recently, it was discovered that a simple re-parameterization of the theory drastically reduces perturbative errors, making these higher-order electroweak calculations worth-while. We present the two-loop electroweak contributions from the top quark to εK. In the traditional normalization of the weak Hamiltonian, this results in a -1% shift in the top quark contribution.

Event Series: