226 research outputs found
Bounds on the Solar Antineutrino total Flux and Energy spectrum from the SK experiment
A search for inverse beta decay electron antineutrinos has been carried out
using the 825 days sample of solar data obtained at SK. The absence of a
significant signal, that is, contributions to the total SK background and their
angular variations has set upper bounds on a) the absolute flux of solar
antineutrinos originated from neutrinos which is equivalent to an averaged conversion
probability bound of P<3.5% (SSM-BP98 model) and b) their differential energy
spectrum, the conversion probability is smaller than 8% for all
MeV going down the 5% level above MeV. It is shown that
an antineutrino flux would have the net effect of enhancing the SK signal at
{\em hep} neutrino energies. The magnitude of this enhancement would highly
depend on the, otherwise rather uncertain, steepness of the solar neutrino
spectrum at these energies.Comment: 5 pages, 3 ps figure
Root systems from Toric Calabi-Yau Geometry. Towards new algebraic structures and symmetries in physics?
The algebraic approach to the construction of the reflexive polyhedra that
yield Calabi-Yau spaces in three or more complex dimensions with K3 fibres
reveals graphs that include and generalize the Dynkin diagrams associated with
gauge symmetries. In this work we continue to study the structure of graphs
obtained from reflexive polyhedra. We show how some particularly defined
integral matrices can be assigned to these diagrams. This family of matrices
and its associated graphs may be obtained by relaxing the restrictions on the
individual entries of the generalized Cartan matrices associated with the
Dynkin diagrams that characterize Cartan-Lie and affine Kac-Moody algebras.
These graphs keep however the affine structure, as it was in Kac-Moody Dynkin
diagrams. We presented a possible root structure for some simple cases. We
conjecture that these generalized graphs and associated link matrices may
characterize generalizations of these algebras.Comment: 24 pages, 6 figure
KamLAND Bounds on Solar Antineutrinos and neutrino transition magnetic moments
We investigate the possibility of detecting solar electron antineutrinos with
the KamLAND experiment. These electron antineutrinos are predicted by
spin-flavor oscillations at a significant rate even if this mechanism is not
the leading solution to the SNP. KamLAND is sensitive to antineutrinos
originated from solar B neutrinos. From KamLAND negative results after
145 days of data taking, we obtain model independent limits on the total flux
of solar electron antineutrinos $\Phi({}^8 B)< 1.1-3.5\times 10^4 cm^{-2}\
s^{-1}P<0.15%\mu B< 2.3\times 10^{-21}(\Delta m^2, \tan^2\theta)\mu\lsim 3.9\times 10^{-12} \mu_BB= 50\mu\lsim 9.0\times 10^{-13} \mu_BB= 200\mu\lsim 2.0\times 10^{-13} \mu_BB= 1000$ kG at the same
statistical significance.Comment: 13 pages, 2 figure
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