Year: 2019
Type: preprint
Abstract: We present updated results for $\varepsilon_K$ determined directly from the standard model (SM) with lattice QCD inputs such as $\hat{B}_K$, $|V_{cb}|$, $|V_{us}|$, $ξ_0$, $ξ_2$, $ξ_\text{LD}$, $f_K$, and $m_c$. We find that the standard model with exclusive $|V_{cb}|$ and other lattice QCD inputs describes only 65\% of the experimental value of $|\varepsilon_K|$ and does not explain its remaining 35\%, which leads to a strong tension in $|\varepsilon_K|$ at the $4.6σ\sim 4.2σ$ 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 QCD sum rules.
Source: arXiv (Cornell University)
Institution: Los Alamos National Laboratory
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Award: G5706118672
OpenAlex ID: W4297911310