Ab Initio Study of (ν_{ℓ},ℓ^{-}) and (ν[over ¯]_{ℓ},ℓ^{+}) Inclusive Scattering in ^{12}C: Confronting the MiniBooNE and T2K CCQE Data

We carry out an ab initio calculation of the neutrino flux-folded inclusive cross sections measured on ^{12}C by the MiniBooNE and T2K Collaborations in the charged-current quasielastic regime. The calculation is based on realistic two- and three-nucleon interactions, and on a realistic nuclear electroweak current with one- and two-nucleon terms that are constructed consistently with these interactions and reproduce low-energy electroweak transitions. Numerically exact quantum Monte Carlo methods are utilized to compute the nuclear weak response functions, by fully retaining many-body correlations in the initial and final states and interference effects between one- and two-body current contributions. We employ a nucleon axial form factor of the dipole form with Λ_{A}=1.0 or 1.15 GeV, the latter more in line with a very recent lattice QCD determination. The calculated cross sections are found to be in good agreement with the neutrino data of MiniBooNE and T2K, and antineutrino MiniBooNE data, yielding a consistent picture of nuclei and their electroweak properties across a wide regime of energy and momenta.