Publications
Publication Information
| Title | A per-cent-level determination of the nucleon axial coupling from quantum chromodynamics |
| Authors | Chia Cheng Chang, Amy Nicholson, Enrico Rinaldi, Evan Berkowitz, N. Garron, David Brantley, Henry Monge Camacho, Christopher Monahan, Christopher Bouchard, M. Clark, Balint Joo, T. Kurth, Konstantinos Orginos, Pavlos Vranas, Andre Walker-Loud |
| JLAB number | JLAB-THY-18-2759 |
| LANL number | 1805.12130 |
| Other number | (None) |
| Document Type(s) | (Journal Article) |
| Associated with EIC: | No |
| Supported by Jefferson Lab LDRD Funding: | No |
| Funding Source: | Nuclear Physics (NP) |
|
Journal Compiled for Nature Volume 558 Issue 7708 Page(s) 91-94 Refereed | |
| Publication Abstract: | The $\textit{axial coupling of the nucleon}$, $g_A$, is the strength of its coupling to the $\textit{weak}$ axial current of the Standard Model of particle physics, in much the same way as the electric charge is the strength of the coupling to the electromagnetic current. This axial coupling dictates the rate at which neutrons decay to protons, the strength of the attractive long-range force between nucleons and other features of nuclear physics. Precision tests of the Standard Model in nuclear environments require a quantitative understanding of nuclear physics rooted in Quantum Chromodynamics, a pillar of the Standard Model. The prominence of $g_A$ makes it a benchmark quantity to determine theoretically - a difficult task because quantum chromodynamics is non-perturbative, precluding known analytical methods. Lattice Quantum Chromodynamics provides a rigorous, non-perturbative definition of quantum chromodynamics that can be implemented numerically. It has been estimated that a precision of two percent would be possible by 2020 if two challenges are overcome: contamination of $g_A$ from excited states must be controlled in the calculations and statistical precision must be improved markedly. Here we report a calculation of $g_A^{QCD} = 1.271\pm0.013$, using an unconventional method inspired by the Feynman-Hellmann theorem that overcomes these challenges. |
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| Group: | THEORY CENTER |
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