English

2022 Update on $\varepsilon_K$ with lattice QCD inputs

High Energy Physics - Lattice 2023-02-07 v2 High Energy Physics - Phenomenology

Abstract

We present recent updates 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 5.1σ3.9σ5.1\sigma \sim 3.9\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 the QCD sum rule approach, although this inclusive tension is small (1.4σ\approx 1.4\sigma) but keeps increasing as time goes on.

Keywords

Cite

@article{arxiv.2301.12375,
  title  = {2022 Update on $\varepsilon_K$ with lattice QCD inputs},
  author = {Sunghee Kim and Sunkyu Lee and Weonjong Lee and Jaehoon Leem and Sungwoo Park},
  journal= {arXiv preprint arXiv:2301.12375},
  year   = {2023}
}

Comments

10 pages, 6 figures, 8 tables, Lattice 2022 proceeding. arXiv admin note: substantial text overlap with arXiv:2202.11473, arXiv:1912.03024, acknowledgement updated

R2 v1 2026-06-28T08:25:11.076Z