Publications
Publication Information
Title | An accurate calculation of the nucleon axial charge with lattice QCD |
Authors | Evan Berkowitz, David Brantley, Christopher Bouchard, Chia Cheng Chang, M. Clark, N. Garron, Balint Joo, T. Kurth, Christopher Monahan, Henry Monge Camacho, Amy Nicholson, Konstantinos Orginos, Enrico Rinaldi, Pavlos Vranas, Andre Walker-Loud |
JLAB number | JLAB-THY-17-2485 |
LANL number | arXiv:1704.01114 |
Other number | DOE/OR/23177-4157 |
Document Type(s) | (Other) |
Associated with EIC: | No |
Supported by Jefferson Lab LDRD Funding: | No |
Funding Source: | Nuclear Physics (NP) |
Other Funding: | FG02-04ER41302 AC52-07NA27344 AC02-05CH11231 |
Other arXiv:1704.01114 | |
Publication Abstract: | We report on a lattice QCD calculation of the nucleon axial charge, $g_A$, using M\"{o}bius Domain-Wall fermions solved on the dynamical $N_f=2+1+1$ HISQ ensembles after they are smeared using the gradient-flow algorithm. The calculation is performed with three pion masses, $m_\pi\sim\{310,220,130\}$ MeV. Three lattice spacings ($a\sim\{0.15,0.12,0.09\}$ fm) are used with the heaviest pion mass, while the coarsest two spacings are used on the middle pion mass and only the coarsest spacing is used with the near physical pion mass. On the $m_\pi\sim220$ MeV, $a\sim0.12$ fm point, a dedicated volume study is performed with $m_\pi L \sim \{3.22,4.29,5.36\}$. Using a new strategy motivated by the Feynman-Hellmann Theorem, we achieve a precise determination of $g_A$ with relatively low statistics, and demonstrable control over the excited state, continuum, infinite volume and chiral extrapolation systematic uncertainties, the latter of which remains the dominant uncertainty. Our final determination at 2.6\% total uncertainty is $g_A = 1.278(21)(26)$, with the first uncertainty including statistical and systematic uncertainties from fitting and the second including model selection systematics related to the chiral and continuum extrapolation. The largest reduction of the second uncertainty will come from a greater number of pion mass points as well as more precise lattice QCD results near the physical pion mass. |
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Group: | THEORY CENTER |
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