Status of FNAL SciBooNE experiment

SciBooNE is a new experiment at FNAL which will make precision neutrino-nucleus cross section measurements in the one GeV region. These measurements are essential for the future neutrino oscillation experiments. We started data taking in the antineutrino mode on June 8, 2007, and collected 5.19 \times 10^{19} protons on target (POT) before the accelerator shutdown in August. The first data from SciBooNE are reported in this article.Comment: 3 pages, 3 figures. Proceedings of the 10th International Conference on Topics in Astroparticle and Underground Physics (TAUP) 2007, Sendai, Japan, September 11-15, 200

Bi-large neutrino mixing and the Cabibbo angle

Recent measurements of the neutrino mixing angles cast doubt on the validity of the so-far popular tri-bimaximal mixing ansatz. We propose a parametrization for the neutrino mixing matrix where the reactor angle seeds the large solar and atmospheric mixing angles, equal to each other in first approximation. We suggest such bi-large mixing pattern as a model building standard, realized when the leading order value of the reactor angle equals the Cabibbo angle.Comment: 4 pages, 2 figs. v2: matches version appearing in Phys.Rev.D, rapid communication

Resolving parameter degeneracies in long-baseline experiments by atmospheric neutrino data

In this work we show that the physics reach of a long-baseline (LBL) neutrino oscillation experiment based on a superbeam and a megaton water Cherenkov detector can be significantly increased if the LBL data are combined with data from atmospheric neutrinos (ATM) provided by the same detector. ATM data are sensitive to the octant of $\theta_{23}$ and to the type of the neutrino mass hierarchy, mainly through three-flavor effects in e-like events. This allows to resolve the so-called $\theta_{23}$- and sign($\Delta m^2_{31}$)-parameter degeneracies in LBL data. As a consequence it becomes possible to distinguish the normal from the inverted neutrino mass ordering at $2\sigma$ CL from a combined LBL+ATM analysis if $\sin^2 2\theta_{13} \gtrsim 0.02$. The potential to identify the true values of $\sin^2 2\theta_{13}$ and the CP-phase $\delta_{cp}$ is significantly increased through the lifting of the degeneracies. These claims are supported by a detailed simulation of the T2K (phase II) LBL experiment combined with a full three-flavor analysis of ATM data in the HyperKamiokande detector.Comment: 25 pages, 10 figure

νμ\nu_\mu disappearance at the SPL, T2K-I and the Neutrino Factory

We study the $\nu_\mu$ disappearance channel at T2K-phase I and the SPL and analyse the achievable reduction of present uncertainties in $\theta_{23}$ and $\Delta m^2_{23}$. We analyse the impact of discrete ambiguities in sign($\Delta m^2{23}$) and sign($2 \tan \theta_{23}$). We show how the disappearance channel at the Neutrino Factory is complementary to the ``golden'' and ``silver'' appearance channels and can be used to reduce the eightfold-ambiguity problem in ($\theta_{13}-\delta$).Comment: 2 pages, 3 epsfig; NUFACT'05, 21-26 June 2005, Frascat

From Double Chooz to Triple Chooz - Neutrino Physics at the Chooz Reactor Complex

We discuss the potential of the proposed Double Chooz reactor experiment to measure the neutrino mixing angle $\sin^2 2\theta_{13}$. We especially consider systematical uncertainties and their partial cancellation in a near and far detector operation, and we discuss implications of a delayed near detector startup. Furthermore, we introduce Triple Chooz, which is a possible upgrade scenario assuming a second, larger far detector, which could start data taking in an existing cavern five years after the first far detector. We review the role of the Chooz reactor experiments in the global context of future neutrino beam experiments. We find that both Double Chooz and Triple Chooz can play a leading role in the search for a finite value of $\sin^2 2\theta_{13}$. Double Chooz could achieve a sensitivity limit of $\sim 2 \cdot 10^{-2}$ at the 90%~confidence level after 5~years while the Triple Chooz setup could give a sensitivity below $10^{-2}$.Comment: 18 pages, 6 figure

Physics Potential of the SPL Super Beam

Performances of a neutrino beam generated by the CERN SPL proton driver are computed considering a 440 kton water Cerenkov detector at 130 km from the target. $\theta_{13}$ sensitivity down to $1.2^\circ$ and a $\delta$ sensitivity comparable to a Neutrino Factory, for $\theta_{13} \geq 3^\circ$, are within the reach of such a project.Comment: Invited talk at the Nufact02 Workshop, Imperial College of Science, Technology and Medicine, London, July 200

Diagnostic Potential of Cosmic-Neutrino Absorption Spectroscopy

Annihilation of extremely energetic cosmic neutrinos on the relic-neutrino background can give rise to absorption lines at energies corresponding to formation of the electroweak gauge boson $Z^{0}$. The positions of the absorption dips are set by the masses of the relic neutrinos. Suitably intense sources of extremely energetic ($10^{21}$ -- $10^{25}$-eV) cosmic neutrinos might therefore enable the determination of the absolute neutrino masses and the flavor composition of the mass eigenstates. Several factors--other than neutrino mass and composition--distort the absorption lines, however. We analyze the influence of the time-evolution of the relic-neutrino density and the consequences of neutrino decay. We consider the sensitivity of the lineshape to the age and character of extremely energetic neutrino sources, and to the thermal history of the Universe, reflected in the expansion rate. We take into account Fermi motion arising from the thermal distribution of the relic-neutrino gas. We also note the implications of Dirac vs. Majorana relics, and briefly consider unconventional neutrino histories. We ask what kinds of external information would enhance the potential of cosmic-neutrino absorption spectroscopy, and estimate the sensitivity required to make the technique a reality.Comment: 25 pages, 26 figures (in 46 files), uses RevTe

太平洋地域における大陸と島嶼の森林の種多様性

Alpha diversity, or species richness, of East Asian mainland evergreen broadleaved forests, expressed by indices of Fisher\u27s alpha (agr) and S(100), a new index showing species number in a 100-individual sample, is significantly correlated with the climatic favorableness, expressed by Kira\u27s warmth index. On the contrary, diversity values of insular forests studied on Kyushu satellites of Japan, the Bonins, the Eastern Carolines of Micronesia, and the Galapagos in the eastern Pacific, are below those expected from the climate of respective oceanic islands. Species-individual curves, comparing mainland-and insular communities, also support clearly the above conclusion of species poverty in the insular communities studied.The original publication is available at www.springerlink.co