English

2019 Update on $\varepsilon_K$ with lattice QCD inputs

High Energy Physics - Lattice 2019-12-13 v2 High Energy Physics - Phenomenology

Abstract

We present updated results for εK\varepsilon_K determined directly from the standard model (SM) with lattice QCD inputs such as B^K\hat{B}_K, Vcb|V_{cb}|, Vus|V_{us}|, ξ0\xi_0, ξ2\xi_2, ξLD\xi_\text{LD}, fKf_K, and mcm_c. We find that the standard model with exclusive Vcb|V_{cb}| and other lattice QCD inputs describes only 65\% of the experimental value of εK|\varepsilon_K| and does not explain its remaining 35\%, which leads to a strong tension in εK|\varepsilon_K| at the 4.6σ4.2σ4.6\sigma \sim 4.2\sigma level between the SM theory and experiment. We also find that this tension disappears when we use the inclusive value of Vcb|V_{cb}| obtained using the heavy quark expansion based on QCD sum rules.

Keywords

Cite

@article{arxiv.1912.03024,
  title  = {2019 Update on $\varepsilon_K$ with lattice QCD inputs},
  author = {Jeehun Kim and Sunkyu Lee and Weonjong Lee and Yong-Chull Jang and Jaehoon Leem and Sungwoo Park},
  journal= {arXiv preprint arXiv:1912.03024},
  year   = {2019}
}

Comments

7 pages, 6 figures, 5 tables, Lattice 2019 proceeding, references augmented. arXiv admin note: text overlap with arXiv:1810.09761

R2 v1 2026-06-23T12:37:49.925Z