High-energy neutrino-nucleus interactions

High-energy neutrino-nucleus interactions are discussed by considering neutrino-oscillation experiments and ultra-high-energy cosmic neutrino interactions. The largest systematic error for the current neutrino oscillation measurements comes from the neutrino-nucleus interaction part, and its accurate understanding is essential for high-precision neutrino physics, namely for studying CP violation in the lepton sector. Depending on neutrino beam energies, quasi-elastic, resonance, Regge, or/and deep inelastic scattering (DIS) processes contribute to the neutrino cross section. It is desirable to have a code to calculate the neutrino-nucleus cross section in any kinematical range by combining various theoretical descriptions. On the other hand, the IceCube collaboration started obtaining cross section data up to the $10^{15}$ eV range, so that it became necessary to understand ultra-high-energy neutrino interactions beyond the artificial lepton-accelerator energy range. For future precise neutrino physics including the CP measurement, it is also necessary to understand accurate nuclear corrections. The current status is explained for nuclear corrections in DIS structure functions. The possibility is also discussed to find gravitational sources within nucleons and nuclei, namely matrix elements of quark-gluon energy-momentum tensor. They could be probed by neutrino interactions without replying on direct ultra-weak "gravitational interactions" with high-intensity neutrino beams, possibly at a future neutrino factory, by using techniques of hadron tomography.Comment: 6 pages, LaTeX, 1 style file, 11 figure files, Invited talk, 20th International Symposium on Very High Energy Cosmic Ray Interactions, May 21-25, 2018, Nagoya University, Nagoya, Japa

Neutrino Scattering Physics at Superbeams and Neutrino Factories

Neutrino scattering physics is discussed for investigating internal structure of the nucleon and nuclei at future neutrino facilities. We explain structure functions in neutrino scattering. In particular, there are new polarized functions g_3, g_4, and g_5, and they should provide us important information for determining internal nucleon spin structure. Next, nuclear structure functions are discussed. From F_3 structure function measurements, valence-quark shadowing should be clarified. Nuclear effects on the NuTeV sin^2\theta_W anomaly are explained. We also comment on low-energy neutrino scattering, which is relevant to current long-baseline neutrino oscillation experiments.Comment: 1+8 pages, LaTeX2e, 6 figures. Plenary talk at the 5th International Workshop on Neutrino Factories and Superbeams, Columbia University, New York, USA, June 5-11, 2003. To be published in AIP proceedings. Group web page at http://hs.phys.saga-u.ac.j