Weak neutral current axial form factor using $$ \left(\overline{\nu}\right)\nu $$-nucleon scattering and lattice QCD inputs

Journal Article · 21 January 2020 · Journal of High Energy Physics (Online)

DOI: https://doi.org/10.1007/JHEP01(2020)136 · OSTI ID:1595282

Sufian, Raza Sabbir ^[1]; Liu, Keh-Fei ^[2]; Richards, David G. ^[1]

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1. Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
2. Univ. of Kentucky, Lexington, KY (United States)

We present a determination of the neutral current weak axial charge $$G$$ $$^{Z}_{A}$$(0) = –0.654(3)_stat(5)_sys using the strange quark axial charge $$G$$ $$^{s}_{A}$$(0) calculated with lattice QCD. We then perform a phenomenological analysis, where we combine the strange quark electromagnetic form factor from lattice QCD with (anti)neutrino-nucleon scattering differential cross section from MiniBooNE experiments in a momentum transfer region 0.24 ≲ Q² ≲ 0.71 GeV² to determine the neutral current weak axial form factor $$G$$ $$^{Z}_{A}$$(Q²) in the range of 0 ≲ Q² ≤ 1 GeV². This yields a phenomenological value of $$G$$ $$^{Z}_{A}$$(0) = –0.687(89)stat(40)sys. The value of $$G$$ $$^{Z}_{A}$$(0) constrained by the lattice QCD calculation of $$G$$ $$^{s}_{A}$$(0), when compared to its phenomenological determination, provides a significant improvement in precision and accuracy and can be used to provide a constraint on the fit to $$G$$ $$^{Z}_{A}$$(Q²) for Q² > 0. This constrained fit leads to an unambiguous determination of (anti)neutrino-nucleon neutral current elastic scattering differential cross section near Q² = 0 and can play an important role in numerically isolating nuclear effects in this region. We show a consistent description of $$G$$ $$^{Z}_{A}$$(Q²) obtained from the (anti)neutrino-nucleon scattering cross section data requires a nonzero contribution of the strange quark electromagnetic form factor. We demonstrate the robustness of our analysis by providing a post-diction of the BNL E734 experimental data.

• Research Organization: Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Nuclear Physics (NP) (SC-26)
• Grant/Contract Number: AC05-06OR23177; SC0013065; AC05-00OR22725
• OSTI ID: 1595282
• Report Number(s): JLAB-THY--18-2792; DOE/OR/23177--4525; arXiv:1809.03509
• Journal Information: Journal of High Energy Physics (Online), Journal Name: Journal of High Energy Physics (Online) Journal Issue: 1 Vol. 2020; ISSN 1029-8479
• Publisher: Springer BerlinCopyright Statement
• Country of Publication: United States
• Language: English