The likelihood for supernova neutrino analyses

We derive the event-by-event likelihood that allows to extract the complete information contained in the energy, time and direction of supernova neutrinos, and specify it in the case of SN1987A data. We resolve discrepancies in the previous literature, numerically relevant already in the concrete case of SN1987A data.Comment: 7 pages, 2 figures. Accepted for publication in PR

A Critical Appraisal of Some Concepts Used in Neutrino Physics

We examine the value of certain concepts highly regarded in the past decade, that concern neutrino propagation, models for the leptonic mixing, interpretations of neutrinoless double beta dec\ ay and of SN1987A observations. We argue that it would useful to strengthen the role of the discussions among experts of neutrino physics, regarding the hypotheses underlying the theoretical investigations.Comment: 5 pages, 4 figures. Presented at IFAE 201

Neutrino mass bound in the standard scenario for supernova electronic antineutrino emission

Based on recent improvements of the supernova electron antineutrino emission model, we update the limit on neutrino mass from the SN1987A data collected by Kamiokande-II, IMB and Baksan. We derive the limit of 5.8 eV at 95 % CL, that we show to be remarkably insensitive to the astrophysical uncertainties. Also we evaluate the ultimate mass sensitivity of this method for a detector like Super-Kamiokande. We find that the bound lies in the sub-eV region, 0.8 eV at 95 % CL being a typical outcome, competitive with the values that are presently probed in laboratory. However, this bound is subject to strong statistical fluctuations, correlated to the characteristics of the first few events detected. We briefly comment on the prospects offered by future detectors.Comment: 16 pages, 3 figures. Accepted for publication in Astroparticle Physic

Counting muons to probe the neutrino mass spectrum

The experimental evidence that \theta_{13} is large opens new opportunities to identify the neutrino mass spectrum. We outline a possibility to investigate this issue by means of conventional technology. The ideal setup turns out to be long baseline experiment: the muon neutrino beam, with 10^{20} protons on target, has an average energy of 6 (8) GeV; the neutrinos, after propagating 6000 (8000) km, are observed by a muon detector of 1 Mton and with a muon energy threshold of 2 GeV. The expected number of muon events is about 1000, and the difference between the two neutrino spectra is sizeable, about 30%. This allows the identification of the mass spectrum just counting muon tracks. The signal events are well characterized experimentally by their time and direction of arrival, and 2/3 of them are in a region with little atmospheric neutrino background, namely, between 4 GeV and 10 GeV. The distances from CERN to Baikal Lake and from Fermilab to KM3NET, or ANTARES, fit in the ideal range.Comment: 14 pages, 5 figures. Version accepted for publication on EPJ

The use of FLAC for the seismic evaluation of a concrete gravity dam including dam-water-sediments-foundation rock interaction

Seismic safety of 65m-high Licodia Eubea gravity dam located in Southeastern Sicily (Italy) has been assessed by means of advanced dynamic analyses of the tallest cross-section of the dam. The analyses were performed with two-dimensional, plane strain, finite difference FLAC code, taking into consideration simultaneously the dam-water-sediments-foundation interaction. The analyses have been carried out for an earthquake scenario corresponding to the Collapse Limit State (CLS), using a set of seven natural accelerograms for the simulations (both vertical and horizontal components). The physical and mechanical parameters of the concrete and foundation rock were obtained from in situ and laboratory tests campaigns. A validation of the dynamic model in terms of fundamental mode vibration periods of the dam was carried out first. Then, linear analyses allowed to understand whether nonlinear analyses were necessary. From nonlinear analyses results, Licodia Eubea dam has been found to have an acceptable margin of safety for CLS. The implementation of nonlinearity at the dam-foundation interface reduced the tensile stress within the structure. The dam might experience limited sliding along its base, but its structural integrity would be preserved