Lattice QCD Calculation of Electroweak Box Contributions to Superallowed Nuclear and Neutron Beta Decays

Fuente: arXiv
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Autori principali: Ma, Peng-Xiang, Feng, Xu, Gorchtein, Mikhail, Jin, Lu-Chang, Liu, Keh-Fei, Seng, Chien-Yeah, Wang, Bi-Geng, Zhang, Zhao-Long
Natura: Preprint
Pubblicazione: 2023
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author Ma, Peng-Xiang
Feng, Xu
Gorchtein, Mikhail
Jin, Lu-Chang
Liu, Keh-Fei
Seng, Chien-Yeah
Wang, Bi-Geng
Zhang, Zhao-Long
author_facet Ma, Peng-Xiang
Feng, Xu
Gorchtein, Mikhail
Jin, Lu-Chang
Liu, Keh-Fei
Seng, Chien-Yeah
Wang, Bi-Geng
Zhang, Zhao-Long
contents We present the first lattice QCD calculation of the universal axial $γW$-box contribution $\square_{γW}^{VA}$ to both superallowed nuclear and neutron beta decays. This contribution emerges as a significant component within the theoretical uncertainties surrounding the extraction of $|V_{ud}|$ from superallowed decays. Our calculation is conducted using two domain wall fermion ensembles at the physical pion mass. To construct the nucleon 4-point correlation functions, we employ the random sparsening field technique. Furthermore, we incorporate long-distance contributions to the hadronic function using the infinite-volume reconstruction method. Upon performing the continuum extrapolation, we arrive at $\square_{γW}^{VA}=3.65(8)_{\mathrm{lat}}(1)_{\mathrm{PT}}\times10^{-3}$. Consequently, this yields a slightly higher value of $|V_{ud}|=0.97386(11)_{\mathrm{exp.}}(9)_{\mathrm{RC}}(27)_{\mathrm{NS}}$, reducing the previous $2.1σ$ tension with the CKM unitarity to $1.8σ$. Additionally, we calculate the vector $γW$-box contribution to the axial charge $g_A$, denoted as $\square_{γW}^{VV}$, and explore its potential implications.
format Preprint
id arxiv_https___arxiv_org_abs_2308_16755
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Lattice QCD Calculation of Electroweak Box Contributions to Superallowed Nuclear and Neutron Beta Decays
Ma, Peng-Xiang
Feng, Xu
Gorchtein, Mikhail
Jin, Lu-Chang
Liu, Keh-Fei
Seng, Chien-Yeah
Wang, Bi-Geng
Zhang, Zhao-Long
High Energy Physics - Lattice
High Energy Physics - Phenomenology
Nuclear Experiment
We present the first lattice QCD calculation of the universal axial $γW$-box contribution $\square_{γW}^{VA}$ to both superallowed nuclear and neutron beta decays. This contribution emerges as a significant component within the theoretical uncertainties surrounding the extraction of $|V_{ud}|$ from superallowed decays. Our calculation is conducted using two domain wall fermion ensembles at the physical pion mass. To construct the nucleon 4-point correlation functions, we employ the random sparsening field technique. Furthermore, we incorporate long-distance contributions to the hadronic function using the infinite-volume reconstruction method. Upon performing the continuum extrapolation, we arrive at $\square_{γW}^{VA}=3.65(8)_{\mathrm{lat}}(1)_{\mathrm{PT}}\times10^{-3}$. Consequently, this yields a slightly higher value of $|V_{ud}|=0.97386(11)_{\mathrm{exp.}}(9)_{\mathrm{RC}}(27)_{\mathrm{NS}}$, reducing the previous $2.1σ$ tension with the CKM unitarity to $1.8σ$. Additionally, we calculate the vector $γW$-box contribution to the axial charge $g_A$, denoted as $\square_{γW}^{VV}$, and explore its potential implications.
title Lattice QCD Calculation of Electroweak Box Contributions to Superallowed Nuclear and Neutron Beta Decays
topic High Energy Physics - Lattice
High Energy Physics - Phenomenology
Nuclear Experiment
url https://arxiv.org/abs/2308.16755