30 research outputs found
Neutrino Mass Matrices with Vanishing Determinant and
We investigate the prospects for scenarios with vanishing determinant
neutrino mass matrices and vanishing mixing angle. Normal and
inverse mass hierarchies are considered separately. For normal hierarchy it is
found that neutrinoless double beta decay cannot be observed by any of the
present or next generation experiments. For inverse hierarchy the neutrinoless
double beta decay is, on the contrary, accessible to experiments. We also
analyse for both hierarchies the case for texture zeros and equalities between
mass matrix elements. No texture zeros are found to be possible nor any such
equalities, apart from the obvious ones.Comment: 14 pages, 1 figur
KamLAND and Solar Antineutrino Spectrum
We use the recent KamLAND observations to predict the solar antineutrino
spectrum at some confidence limits. We find that a scaling of the antineutrino
probability with respect to the magnetic field profile --in the sense that the
same probability function can be reproduced by any profile with a suitable peak
field value-- can be utilised to obtain a general shape of the solar
antineutrino spectrum. This scaling and the upper bound on the solar
antineutrino event rate, that can be derived from the data, lead to: 1) an
upper bound on the solar antineutrino flux, 2) the prediction of their energy
spectrum, as the normalisation of the spectrum can be obtained from the total
number of antineutrino events recorded in the experiment. We get
or at 95% CL, assuming Gaussian or Poissonian statistics,
respectively. And for 90% CL these become and . It shows an
improvement by a factor of 3-5 with respect to existing bounds. These limits
are quite general and independent of the detailed structure of the magnetic
field in the solar interior.Comment: Based on talk given at NANP'03, JINR Dubna, Russia, June 2003. To be
published in "Physics of Atomic Nuclie