Updated Standard Model Prediction for $K\to \pi \nu \bar{\nu }$ and ${ϵ}_K$

Abstract

The rare $K\to \pi \nu \bar{\nu }$ decay modes and the parameter ${ϵ}_K$ that measures CP violation in Kaon mixing are sensitive probes of physics beyond the standard model. In this article we provide the updated standard-model prediction for the rare decay modes in detail, and summarise the status of standard-model prediction of ${ϵ}_K$. We find $\text{BR}(K^{+}\to {\pi }^{+}\nu \bar{\nu })=7.73(61)\times 10^{-11}$ and $\text{BR}(K_L\to {\pi }^0\nu \bar{\nu })=2.59(29)\times 10^{-11}$. The uncertainties are dominated by parametric input.

Comments: 8 pages, new Standard Model prediction, to be published in the proceedings of the BEAUTY2020 conference