pith. sign in

arxiv: 1503.06613 · v3 · pith:HOMCIG62new · submitted 2015-03-23 · ✦ hep-lat · hep-ph

Current status of varepsilon_K with lattice QCD inputs

classification ✦ hep-lat hep-ph
keywords varepsilonlatticeresultsvalueexperimentalinputslambdamodel
0
0 comments X
read the original abstract

We present the Standard Model evaluation of the indirect CP violation parameter $\varepsilon_K$ using inputs determined from lattice QCD together with experiment: $|V_{us}|$, $|V_{cb}|$, $\xi_0$, and $\hat{B}_K$. We use the Wolfenstein parametrization ($|V_{cb}|$, $\lambda$, $\bar{\rho}$, $\bar{\eta}$) for the CKM matrix elements. For the central value, we take the angle-only fit of the UTfit collaboration, and use $|V_{us}|$ from the $K_{\ell 3}$ and $K_{\mu 2}$ decays as an independent input to fix $\lambda$. For the error estimate, we use results of the global unitarity triangle fits from the CKMfitter and UTfit collaborations. We find that the Standard Model (SM) prediction of $\varepsilon_K$ with exclusive $V_{cb}$ (lattice QCD results) is lower than the experimental value by $3.6(2)\sigma$. However, with inclusive $V_{cb}$ (results of the heavy quark expansion), the tension between the SM prediction of $\varepsilon_K$ and its experimental value disappears.

This paper has not been read by Pith yet.

discussion (0)

Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.