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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.

The frequencies and damping times of the non radial oscillations of neutron stars are computed for a set of recently proposed equations of state (EOS) which describe matter at supranuclear densites. These EOS are obtained within two different approaches, the nonrelativistic nuclear many-body theory and the relativistic mean field theory, that model hadronic interactions in different ways leading to different composition and dynamics. Being the non radial oscillations associated to the emission of gravitational waves, we fit the eigenfrequencies of the fundamental mode and of the first pressure and gravitational-wave mode (polar and axial) with appropriate functions of the mass and radius of the star, comparing the fits, when available, with those obtained by Andersson and Kokkotas in 1998. We show that the identification in the spectrum of a detected gravitational signal of a sharp pulse corresponding to the excitation of the fundamental mode or of the first p-mode, combined with the knowledge of the mass of the star -the only observable on which we may have reliable information -would allow to gain interesting information on the composition of the inner core. We further discuss the detectability of these signals by gravitational detectors.

The cross section for inclusive electron scattering by nuclear matter is calculated at high momentum transfers using a microscopic spectral function, and compared with that extrapolated from data on laboratory nuclei. It is found that the cross section obtained with the plane-wave impulse approximation is close to the observed data at large values of the energy loss, but too small at low values. In this regime final-state interactions are important; after including their effects theory and data are in fair agreement.It is necessary to treat nucleon-nucleon correlations consistently in estimating the final-state interactions. The effects of possible time dependence of the nucleon-nucleon cross section, giving rise to nuclear transparency, are also investigated. The y scaling of the response function is discussed to further elucidate the role of final-state interactions. the response, due to the momentum distribution in the initial state, is proportional to~q~, as it is in the case of strongly interacting quantum liquids. If the width of the folding function is finite, then it can be argued that, at large enough values of~q~, FSI can be neglected, and, as a consequence, the response will exhibit y scaling. In con-2328 1991 The American Physical Society SCATTERING OF GeV ELECTRONS BY NUCLEAR MATTER 2329 trast, in the case of the nuclear medium at high q, one has to use relativistic kinematics and therefore the width of the response due to the momentum distribution of particles in the initial state is roughly constant -k~. It then follows that FSI eA'ects can be neglected only if the folding width goes to zero at large q. The folding width is of the order of the imaginary part of the optical potential which is -60 MeV -kF/4 for several hundreds MeV nucleons. Therefore, FSI are not obviously negligible in scattering of multi-GeV electrons by nuclei.Ideally, one should start from a realistic relativistically covariant theory of nuclei; however, such a theory is not yet practicable due to difFiculties in treating pionexchange interactions.In the plane-wave impulse ap-

We construct models of rotating stars using the perturbative approach introduced by J. Hartle in 1967, and a set of equations of state proposed to model hadronic interactions in the inner core of neutron stars. We integrate the equations of stellar structure to third order in the angular velocity and show, comparing our results to those obtained with fully non linear codes, to what extent third order corrections are needed to accurately reproduce the moment of inertia of a star which rotates at rates comparable to that of the fastest isolated pulsars.

The availability of the double-differential charged-current neutrino cross section, measured by the MiniBooNE collaboration using a carbon target, allows for a systematic comparison of nuclear effects in quasi-elastic electron and neutrino scattering. The results of our study, based on the impulse approximation scheme and a state-of-the-art model of the nuclear spectral functions, suggest that the electron cross section and the flux averaged neutrino cross sections, corresponding to the same target and comparable kinematical conditions, cannot be described within the same theoretical approach using the value of the nucleon axial mass obtained from deuterium measurements. We analyze the assumptions underlying the treatment of electron scattering data, and argue that the description of neutrino data will require a new paradigm, suitable for application to processes in which the lepton kinematics is not fully determined.PACS numbers: 25.30. Pt, 13.15.+g, 24.10.Cn The data set of Charged Current Quasi Elastic (CCQE) events recently released by the MiniBooNE collaboration [1] provides an unprecedented opportunity to carry out a systematic study of the double differential cross section of the process,integrated over the neutrino flux. Comparison between the results of theoretical calculations and data may provide valuable new information on nuclear effects, whose quantitative understanding is critical to the analysis of neutrino oscillation experiments, as well as on the elementary interaction vertex. The charged current elastic neutrino-nucleon process is described in terms of three form factors. The vector form factors F 1 (Q 2 ) and F 2 (Q 2 ) (Q 2 = −q 2 , q being the four-momentum transfer) have been precisely measured, up to large values of Q 2 , in electron-proton and electrondeuteron scattering experiments (for a recent review, see, e.g., Ref.[2]). The Q 2 -dependence of the axial form factor F A (Q 2 ), whose value at Q 2 = 0 can be extracted from neutron β-decay measurements, is generally assumed to be of dipole form and parametrized in terms of the so called axial mass M A :The world average of the measured values of the axial mass, mostly obtained using deuterium targets, turns out to be M A = 1.03 ± 0. Obviously, a fully quantitative description of the electron-scattering cross section, driven by the known vector form factors, is a prerequisite for the understanding of the axial vector contribution to the CCQE neutrino-nucleus cross section.Over the past two decades, the availability of a large body of experimental data has triggered the development of advanced theoretical descriptions of the nuclear electromagnetic response. The underlying scheme, based on nuclear many-body theory and realistic nuclear hamiltonians, relies on the premises that i) the lepton kinematics is fully determined and ii) the elementary interaction vertex can be extracted from measured proton and deuteron cross sections.The above paradigm has been successfully applied to explain the electron-nucleus cross section in a variety o...