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arXiv · 2312.02986

2023 Update of $\varepsilon_K$ with lattice QCD inputs

Seungyeob Jwa·Jeehun Kim·Sunghee Kim·Sunkyu Lee·Weonjong Lee·Jaehoon Leem·Jeonghwan Pak·Sungwoo Park
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Abstract

We report recent progress on $\varepsilon_K$ evaluated directly from the standard model (SM) with lattice QCD inputs such as $\hat{B}_K$, $|V_{cb}|$, $|V_{us}|$, $|V_{ud}|$, $\xi_0$, $\xi_2$, $\xi_\text{LD}$, $f_K$, and $m_c$. We find that the standard model with exclusive $|V_{cb}|$ and lattice QCD inputs describes only 66\% of the experimental value of $|\varepsilon_K|$ and does not explain its remaining 34\%, which corresponds to a strong tension in $|\varepsilon_K|$ at the $4.9\sigma \sim 3.9\sigma$ level between the SM theory and experiment. We also find that this tension disappears when we use the inclusive value of $|V_{cb}|$ obtained using the heavy quark expansion based on the QCD sum rule approach.

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Seungyeob Jwa, Jeehun Kim, Sunghee Kim, Sunkyu Lee, Weonjong Lee, Jaehoon Leem, Jeonghwan Pak, Sungwoo Park. 2023-11-20. 2023 Update of $\varepsilon_K$ with lattice QCD inputs. https://arxiv.org/abs/2312.02986

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