Lattice QCD Calculation of Electroweak Box Contributions to Superallowed Nuclear and Neutron Beta Decays.
Phys Rev Lett
; 132(19): 191901, 2024 May 10.
Article
en En
| MEDLINE
| ID: mdl-38804936
ABSTRACT
We present the first lattice QCD calculation of the universal axial γW-box contribution â¡_{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 four-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 â¡_{γW}^{VA}=3.65(7)_{lat}(1)_{PT}×10^{-3}. Consequently, this yields a slightly higher value of |V_{ud}|=0.973 86(11)_{exp}(9)_{RC}(27)_{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 â¡_{γW}^{VV}, and explore its potential implications.
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Banco de datos:
MEDLINE
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En
Revista:
Phys Rev Lett
Año:
2024
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Article
País de afiliación:
China