PT Journal
AU Yao, DL
   Alvarez-Ruso, L
   Vicente Vacas, MJ
TI Extraction of nucleon axial charge and radius from lattice QCD results using baryon chiral perturbation theory
SO Physical Review D
JI Phys. Rev. D
PY 2017
BP 116022
EP 11pp
VL 96
IS 11
DI 10.1103/PhysRevD.96.116022
LA English
AB We calculate the nucleon axial form factor up to the leading one-loop order in a covariant chiral effective field theory with the Delta(1232) resonance as an explicit degree of freedom. We fit the axial form factor to the latest lattice QCD data and pin down the relevant low-energy constants. The lattice QCD data, for various pion masses below 400 MeV, can be well described up to a momentum transfer of similar to 0.6 GeV. The Delta(1232) loops contribute significantly to this agreement. Furthermore, we extract the axial charge and radius based on the fitted values of the low-energy constants. The results are g(A) = 1.237(74) and < r(A)(2)> = 0.263(38) fm(2). The obtained coupling g(A) is consistent with the experimental value if the uncertainty is taken into account. The axial radius is below but in agreement with the recent extraction from neutrino quasielastic scattering data on deuterium, which has large error bars. Up to our current working accuracy, r(A) is predicted only at leading order, i.e., the one-loop level. A more precise determination might need terms of O(p(5)).
ER