Nucleon Isovector Axial Form Factors

Journal Article · 05 January 2024 · Physical Review. D.

DOI: https://doi.org/10.1103/PhysRevD.109.014503 · OSTI ID:2278895

Jang, Yong-Chull ^[1]; Gupta, Rajan  ^[2]; Bhattacharya, Tanmoy  ^[2]; Yoon, Boram ^[3]; Lin, Huey-Wen ^[4]

---

1. Brookhaven National Laboratory (BNL), Upton, NY (United States); Columbia Univ., New York, NY (United States)
2. Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
3. NVIDIA Corporation, Santa Clara, CA (United States)
4. Michigan State Univ., East Lansing, MI (United States)

We present results for the isovector axial vector form factors obtained using thirteen 2+1+1-flavor highly improved staggered quark (HISQ) ensembles generated by the MILC collaboration. The calculation of nucleon two- and three-point correlation functions has been done using Wilson-clover fermions. In the analysis of these data, we quantify the sensitivity of the results to strategies used for removing excited state contamination and invoke the partially conserved axial current relation between the form factors to choose between them. Our data driven analysis includes removing contributions from multihadron Nπ states that make significant contributions. Our final results are g_A = 1.292⁢(53)_stat⁢(24)_sys for the axial charge; g_S = 1.085⁢(50)_stat⁢(103)_sys and g_T = 0.991⁢(21)_stat⁢(10)_sys for the scalar and tensor charges; $$\langle$$r²A$$\rangle$$ = 0.439⁢(56)_stat⁢(34)_sys fm² for the mean squared axial charge radius, $${g}^*_P$$ = 9.03⁢(47)_stat⁢(42)_sys for the induced pseudoscalar charge; and g_πNN = 14.14⁢(81)_stat⁢(85)_sys for the pion-nucleon coupling. We also provide a parametrization of the axial form factor G_A⁡(Q²) over the range 0 ≤ Q² ≤ 1 GeV² for use in phenomenology and a comparison with other lattice determinations. We find that the various lattice data agree within 10% but are significantly different from the extraction of G_A⁡(Q²) from the v-deuterium scattering data.

• Research Organization: Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
• Sponsoring Organization: USDOE Laboratory Directed Research and Development (LDRD) Program; USDOE Office of Science (SC), High Energy Physics (HEP)
• Grant/Contract Number: 89233218CNA000001; AC05-00OR22725; AC02-05CH11231; AC52-06NA25396; LGT107; HEP133
• OSTI ID: 2278895
• Alternate ID(s): OSTI ID: 2426788
• Report Number(s): LA-UR-23-25225; TRN: US2503659
• Journal Information: Physical Review. D., Vol. 109, Issue 1; ISSN 2470-0010
• Publisher: American Physical Society (APS)Copyright Statement
• Country of Publication: United States
• Language: English