2023 Update of $\varepsilon_K$ with lattice QCD inputs

Author:

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

Keyword:

High Energy Physics - Lattice, High Energy Physics - Lattice (hep-lat), High Energy Physics - Phenomenology (hep-ph)

journal:

date:

2023-11-20 00:00:00

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.

PDF: 2023 Update of $\varepsilon_K$ with lattice QCD inputs.pdf