A quantitative understanding of the weak nuclear response is a prerequisite for the analyses of neutrino experiments such as K2K and MiniBOONE, which measure energy and angle of the muons produced in neutrino-nucleus interactions in the energy range 0:5-3 GeV and reconstruct the incident neutrino energy to determine neutrino oscillations. In this paper we discuss theoretical calculations of electron-and neutrino-nucleus scattering, carried out within the impulse approximation scheme using realistic nuclear spectral functions. Comparison between electron scattering data and the calculated inclusive cross section of oxygen, at beam energies ranging between 700 and 1200 MeV, show that the Fermi gas model, widely used in the analysis of neutrino oscillation experiments, fails to provide a satisfactory description of the measured cross sections, and inclusion of nuclear dynamics is needed.

We discuss the observed disagreement between the Q 2 distributions of neutrino-nucleus quasielastic events, measured by a number of recent experiments, and the predictions of Monte Carlo simulations based on the relativistic Fermi gas model. The results of our analysis suggest that these discrepancies are likely to be ascribable to both the breakdown of the impulse approximation and the limitations of the Fermi gas description. Several issues related to the extraction of the Q 2 distributions from the experimental data are also discussed, and new kinematical variables, which would allow for an improved analysis, are proposed.

The consistent description of the nuclear response at low and high momentum transfer requires a unified dynamical model, suitable to account for both short- and long-range correlation effects. We report the results of a study of the charged current weak response of symmetric nuclear matter, carried out using an effective interaction obtained from a realistic model of the nucleon-nucleon force within the formalism of correlated basis functions. Our approach allows for a clear identification of the kinematical regions in which different interaction effects dominate

Correlated basis function perturbation theory and the formalism of cluster expansions have been recently employed to obtain an effective interaction from a state-of-the-art nucleon nucleon potential model. The approach based on the effective interaction allows for a consistent description of the nuclear matter ground state and nucleon-nucleon scattering in the nuclear medium. This paper reports the the results of numerical calculations of different properties of nuclear and neutron matter, including the equation of state and the shear viscosity and thermal conductivity transport coefficients, carried out using the effective interaction.