Publications
Publication Information
| Title | Detailed analysis of excited state systematics in a lattice QCD calculation of gA |
| Authors | Jinchen He, David Brantley, Chia Cheng Chang, Ivan Chernyshev, Dean Howarth, Christopher Ko¨rber, Aaron Meyer, Henry Monge-Camacho, Enrico Rinaldi, C. Bouchard, M. Clark, Arjun Singh Gambhir, C. Monahan, Amy Nicholson, Pavlos Vranas, A Walker-Loud |
| JLAB number | JLAB-THY-21-3350 |
| LANL number | arXiv:2104.05226 |
| Other number | DOE/OR/23177-5168 |
| Document Type(s) | (Journal Article) |
| Associated with EIC: | No |
| Supported by Jefferson Lab LDRD Funding: | No |
| Funding Source: | Nuclear Physics (NP) |
|
Journal Compiled for Physical Review C Volume 105 Page(s) 065203 Refereed | |
| Publication Abstract: | Excited state contamination remains one of the most challenging sources of systematic uncertainty to control in lattice QCD calculations of nucleon matrix elements and form factors. Most lattice QCD collaborations advocate for the use of high-statistics calculations at large time-separations (tsep > 1 fm) in order to combat the signal-to-noise degradation. In this work we demonstrate that, for the nucleon axial charge, the alternative strategy of utilizing a large number of relatively low-statistics calculations at short to medium time separations (0.2 < tsep < 1 fm), combined with a multi-state analysis, provides a more robust and economical method of quantifying and controlling the excited state systematic uncertainty, including correlated late-time fluctuations that may bias the ground state. We also demonstrate that two classes of excited states largely cancel, leaving the third class, the transition matrix elements, as the dominant source of excited state contamination. On an a ? 0.09 fm, m? ? 310 MeV ensemble, we observe the expected exponential suppression of excited state contamination in the Feynman-Hellmann correlation function relative to the standard three-point function; the excited states of the regular three-point function reduce to the 1% level for tsep > 2 fm while for the Feynman-Hellmann correlation function, they are suppressed to 1% at tsep ? 1 fm. Independent analyses of the three-point and Feynman-Hellmann correlators yields consistent results for the ground state. However, a combined analysis allows for a more detailed and robust understanding of the excited state contamination, improving the demonstration that the ground state parameters are stable against variations in the excited state model, the number of excited states, and the truncation of early-time or late-time numerical data. |
| Experiment Numbers: | other |
| Group: | THEORY CENTER |
| Document: | |
| DOI: | https://doi.org/10.1103/PhysRevC.105.065203 |
| Accepted Manuscript: | PhysRevC.105.065203.pdf |
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