We present the Standard Model evaluation of the indirect CP violation parameter εK using inputs determined from lattice QCD together with experiment: ∣Vus∣, ∣Vcb∣, ξ0, and B^K. We use the Wolfenstein parametrization (∣Vcb∣, λ, ρˉ, ηˉ) for the CKM matrix elements. For the central value, we take the angle-only fit of the UTfit collaboration, and use ∣Vus∣ from the Kℓ3 and Kμ2 decays as an independent input to fix λ. 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 εK with exclusive Vcb (lattice QCD results) is lower than the experimental value by 3.6(2)σ. However, with inclusive Vcb (results of the heavy quark expansion), the tension between the SM prediction of εK and its experimental value disappears.
@article{arxiv.1503.06613,
title = {Current status of $\varepsilon_K$ with lattice QCD inputs},
author = {Jon A. Bailey and Yong-Chull Jang and Weonjong Lee and Sungwoo Park},
journal= {arXiv preprint arXiv:1503.06613},
year = {2015}
}
Comments
5 pages, 3 figures. arXiv admin note: substantial text overlap with arXiv:1503.05388