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 have measured the shift and width of the kaonic hydrogen 1s state due to the KN strong interaction. We have observed, for the first time, distinct K-series kaonic hydrogen x rays with good signal-to-noise ratio in the energy spectrum. The measured energy shift and width were determined to be DE͑1s͒ 2323 6 63͑stat͒ 6 11͑syst͒ eV (repulsive) and G͑1s͒ 407 6 208͑stat͒ 6 100͑syst͒ eV, respectively. [S0031-9007(97)02992-X] PACS numbers: 13.75. Jz, 25.80.Nv, 29.30.Kv, 36.10.Gv The determination of the strong-interaction energy level shift and width of the kaonic hydrogen x rays is one of the most important subjects for the understanding of the KN interaction. It is strongly affected by the presence of the L͑1405͒ subthreshold resonance. The study of the KN interaction is also relevant to the important question of K 2 condensation in dense matter [1,2].The observation of the shift and width of the kaonic hydrogen K a ͑2p ! 1s͒ x rays gives direct information about the KN s-wave interaction at the K 2 p threshold energy in a fairly model independent way [3]. The status of the study was quite puzzling due to the contradiction between the signs of the scattering lengths obtained by the previous x-ray measurements [4-6] and those extracted from the analyses of the low energy KN data, e.g., , as shown in Fig. 1. This contradiction is known to be almost impossible to reconcile within the conventional theoretical framework. Moreover, the x-ray signals of the previous experiments are very difficult to identify in their spectra. Therefore, a definitive experiment has been long awaited.We accumulated data for 760 hours at KEK-PS K3. A detailed description of our experimental setup is given in a separate paper [10]. Here we present a short summary.Optimization of the target density is quite important for this experiment. As a compromise between kaon stopping yield and kaon loss during the atomic cascade due to the Stark effect, we chose to operate the hydrogen FIG. 1. The energy shift and width of 1s state. One-standarddeviation region of shift and width of the previous experiments are plotted together with theoretical calculations. The present result is shown in bold.

We investigate nuclear matter on a cubic lattice. An exact thermal formalism is applied to nucleons with a Hamiltonian that accommodates on-site and next-neighbor parts of the central, spin-, and isospin-exchange interactions. We describe the nuclear matter Monte Carlo methods which contain elements from shell model Monte Carlo methods and from numerical simulations of the Hubbard model. We show that energy and basic saturation properties of nuclear matter can be reproduced. Evidence of a first-order phase transition from an uncorrelated Fermi gas to a clustered system is observed by computing mechanical and thermodynamical quantities such as compressibility, heat capacity, entropy, and grand potential. We compare symmetry energy and first sound velocities with literature and find reasonable agreement.PACS number͑s͒: 21.65.ϩf, 21.60.Ka II. THEORY OF NUCLEONIC MATTER ON A LATTICEThe general concept of the nuclear matter calculation consists of nucleons interacting via a variety of components of PHYSICAL REVIEW C, VOLUME 61, 044320