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Charge-current quasielastic (anti)neutrino scattering cross sections on a 12 C target are analyzed using a spectral function S(p,E) that gives a scaling function in accordance with the (e,e ) scattering data. The spectral function accounts for the nucleon-nucleon (NN) correlations, it has a realistic energy dependence, and natural orbitals (NOs) from the Jastrow correlation method are used in its construction. In all calculations the standard value of the axial mass M A = 1.032 GeV/c 2 is used. The results are compared with those when NN correlations are not included, as in the relativistic Fermi gas model, or when harmonic-oscillator single-particle wave functions are used instead of NOs. The role of the final-state interactions (FSIs) on the theoretical spectral and scaling functions, as well as on the cross sections, is accounted for. A comparison of the results for the cases with and without FSI, as well as to results from the phenomenological scaling function obtained from the superscaling analysis, is carried out. Our calculations based on the impulse approximation underpredict the MiniBooNE data but agree with the data from the NOMAD experiment. The possible missing ingredients in the considered theoretical models are discussed.

Scaling studies of inclusive quasielastic electron scattering reactions have been used in the past as a basic tool to obtain information on the nucleon momentum distribution in nuclei. However, the connection between the scaling function, extracted from the analysis of cross-section data, and the spectral function only exists assuming very restricted approximations. We revisit the basic expressions involved in scaling studies and how they can be linked to the nucleon momentum distribution. In particular, the analysis applied in the past to the so-called scaling region, that is, negative values of the scaling variable y, is extended here to positive y, as a "universal" superscaling function has been extracted from the analysis of the separated longitudinal data. This leads to results that clearly differ from those based solely on the negative-y scaling region, providing new information on how the energy and momentum are distributed in the spectral function.

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Neutral current quasielastic (anti)neutrino scattering cross sections on a 12 C target are analyzed using a realistic spectral function S(p,E) that gives a scaling function in accordance with the (e,e ) scattering data. The spectral function accounts for the nucleon-nucleon (NN) correlations by using natural orbitals from the Jastrow correlation method and has a realistic energy dependence. The standard value of the axial mass M A = 1.032 GeV is used in all calculations. The effect of the final-state interaction on the spectral and scaling functions, as well as on the cross sections, is accounted for. A comparison of the calculations with the empirical data of the MiniBooNE and BNL experiments is performed. Our results are analyzed in comparison with those when NN correlations are not included and, also, with results from other theoretical approaches, such as the relativistic Fermi gas, the relativistic mean field, and the relativistic Green's function, as well as with the SuperScaling Approach based on the analysis of quasielastic electron scattering.

Taking elastic scattering of 6,8 He on protons as an example, it is shown that the differences between density distributions coming from different models can be evaluated when scattering data of the nuclei involved are available for comparison. Microscopic elastic-scattering angular distributions have been calculated for incident energies <100A MeV by using the Tanihata and COSMA models for the density distributions of He nuclei, the M3Y-Paris effective NN interaction, and the Bray et al. imaginary part of the optical potential. The present microscopic angular distributions based on the Tanihata densities are in good agreement with the available experimental data and also similar to results of other theoretical calculations, showing the sensitivity of scattering to the density distributions of these helium isotopes.

A detailed study of charged current quasielastic neutrino and antineutrino scattering cross sections on a 12 C target with no pions in the final state is presented. The initial nucleus is described by means of a realistic spectral function S(p, E) in which nucleon-nucleon correlations are implemented by using natural orbitals through the Jastrow method. The roles played by these correlations and by final-state interactions are analyzed and discussed. The model also includes the contribution of weak two-body currents in the two-particle two-hole sector, evaluated within a fully relativistic Fermi gas. The theoretical predictions are compared with a large set of experimental data for double-differential, single-differential and total integrated cross sections measured by the Mini-BooNE, MINERνA and T2K experiments. Good agreement with experimental data is found over the whole range of neutrino energies. The results are also in global good agreement with the predictions of the superscaling approach, which is based on the analysis of electron-nucleus scattering data, with only a few differences seen at specific kinematics.