Speaker
Description
In recent years, there has been substantial development in accelerator-based neutrino-oscillation experiments. The quest for more precise measurements of the neutrino mass-squared differences and mixing angles in these experiments, faces a number of challenges. These are related to the large systematic uncertainties associated with the basic underlying neutrino-nucleus signal in the detector. Major issues arise from the fact that the neutrino energy-flux in experiments is distributed over a wide range of energies from very low to a few GeV. Hence a number of nuclear effects over a broad kinematical range (from low-energy nuclear excitations to multinucleon emission) simultaneously come into play. The simulation codes used in the analysis of the experimental results are predominantly based on relativistic Fermi gas (RFG) models. RFG can describe the quasielastic (QE) cross section sufficiently accurate for medium momentum (q ≈ 500 MeV/c) transfer reactions, but its description becomes poor for low momentum (q < 300 MeV/c) transfer processes, where nuclear effects are prominent. For the broad neutrino energy-flux used in the experiments, more realistic nuclear models are required.
We present a self-consistent continuum random phase approximation (CRPA) approach to inclusive quasielastic neutrino-nucleus scattering. The description of the nucleus starts from a mean field (MF) potential, where long-range correlations are added by means of a continuum random phase approximation (CRPA) based on a Green's function approach using an effective Skyrme interaction as residual interaction. We validate our formalism by confronting our cross-section predictions with high-precision inclusive electron-scattering data for a variety of nuclear targets (12C, 16O, 40Ca), in the kinematic region where quasielastic scattering is expected to be the dominant process. We examine the separate longitudinal and transverse contributions to 12C (e,e′) and compare them with the available data. We report on cross sections calculations for charged-current quasielastic (anti)neutrino scattering off 12C in the energy range of interest for the MiniBooNE and T2K experiments. We compare our results with the MiniBooNE (neutrino and antineutrino) and T2K (neutrino) cross-section measurements. The CRPA predictions reproduce the gross features of the measured cross sections. We pay special attention to the low-energy excitations which appear to account for the non-negligible contributions in the signal of MiniBooNE, T2K and other similar experiments, and require a microscopic nuclear investigation beyond the Fermi gas model.
