Damping of supernova neutrino transitions in stochastic shock-wave density profiles

Supernova neutrino flavor transitions during the shock wave propagation are known to encode relevant information not only about the matter density profile but also about unknown neutrino properties, such as the mass hierarchy (normal or inverted) and the mixing angle theta_13. While previous studies have focussed on "deterministic" density profiles, we investigate the effect of possible stochastic matter density fluctuations in the wake of supernova shock waves. In particular, we study the impact of small-scale fluctuations on the electron (anti)neutrino survival probability, and on the observable spectra of inverse-beta-decay events in future water-Cherenkov detectors. We find that such fluctuations, even with relatively small amplitudes, can have significant damping effects on the flavor transition pattern, and can partly erase the shock-wave imprint on the observable time spectra, especially for sin^2(theta_13) > O(10^-3).Comment: v2 (23 pages, including 6 eps figures). Typos removed, references updated, matches the published versio

CP violation effect in long-baseline neutrino oscillation in the four-neutrino model

We investigate CP-violation effect in the long-baseline neutrino oscillation in the four-neutrino model with mass scheme of the two nearly degenerate pairs separated with the order of 1 eV, by using the data from the solar neutrino deficit, the atmospheric neutrino anomaly and the LSND experiments along with the other accelerator and reactor experiments. By use of the most general parametrization of the mixing matrix with six angles and six phases, we show that the genuine CP-violation effect could attain as large as 0.3 for $\Delta P(\nu_\mu\to\nu_\tau) \equiv P(\nu_\mu\to\nu_\tau) - P(\bar{\nu_\mu}\to\bar{\nu_\tau})$ and that the matter effect is negligibly small such as at most 0.01 for $\Delta P(\nu_\mu\to\nu_\tau)$ for $\Delta m^2 = (1-5)\times 10^{-3} {\rm eV}^2$, which is the mass-squared difference relevant to the long-baseline oscillation.Comment: 21 pages in LaTeX, 9 ps figures. Some changes in the Introduction and Reference

Physics at a future neutrino factory and super-beam facility

The conclusions of the Physics Working Group of the International Scoping Study of a future Neutrino Factory and super-beam facility (the ISS) are presented. The ISS was carried out by the international community between NuFact05, (the 7th International Workshop on Neutrino Factories and Super-beams, Laboratori Nazionali di Frascati, Rome, 21-26 June 2005) and NuFact06 (Ivine, CA, 24-30 August 2006). The physics case for an extensive experimental programme to understand the properties of the neutrino is presented and the role of high-precision measurements of neutrino oscillations within this programme is discussed in detail. The performance of second-generation super-beam experiments, beta-beam facilities and the Neutrino Factory are evaluated and a quantitative comparison of the discovery potential of the three classes of facility is presented. High-precision studies of the properties of the muon are complementary to the study of neutrino oscillations. The Neutrino Factory has the potential to provide extremely intense muon beams and the physics potential of such beams is discussed in the final section of the report