8 research outputs found
Boron abundance and solar neutrino spectrum distortion
The presence of neutrinos from Boron decay in the flux observed on Earth is
attested by the observation of their energy spectrum. Possible distortions of
the spectrum investigated in current detectors are often interpreted in terms
of evidence in favour or against various schemes of neutrino oscillations. We
stress here that a distortion of the spectrum at high energies could also
result from an increase in the ratio of neutrinos originating from (He+p)
and B reactions. While a B neutrino depletion would contribute to this
effect, an increase in the Hep contribution seems also needed to reproduce the
preliminary data.Comment: 8 pages, 2 figures; abstract and introduction rewritten to match the
conclusions bette
Probing Radiative Solar Neutrinos Decays
Motivated by a pilot experiment conducted by F.Vannucci et al. during a solar
eclipse, we work out the geometry governing the radiative decays of solar
neutrinos. Surprisingly, although a smaller proportion of the photons can be
detected, the case of strongly non-degenerate neutrinos brings better limits in
terms of the fundamental couplings. We advocate satellite-based experiments to
improve the sensitivity.Comment: 11 pages, 2 Postscript figure
Insights on neutrino lensing
We discuss the gravitational lensing of neutrinos by astrophysical objects.
Unlike photons, neutrinos can cross a stellar core; as a result, the lens
quality improves. We also estimate the depletion of the neutrino flux after
crossing a massive object and the signal amplification expected. While Uranians
alone would benefit from this effect in the Sun, similar effects could be
considered for binary systems.Comment: 15 pages, 4 figures, to be published in Phys. Lett.
Neutrino suppression and extra dimensions: a minimal model
We study flavour neutrinos confined to our 4-dimensional world coupled to one
"bulk" state, i.e. a Kaluza-Klein tower. We discuss the spatial development of
the neutrino disappearance, the possibility of resurgence and the effective
flavour transitions induced in this mechanism. We show that even a simple model
can produce an energy-independent suppression at large distances, and relate
this to experimental data.Comment: 14 pages, 8 figures; the exclusion of sterile neutrinos by
SuperKamiokande is discussed; references adde