6,123 research outputs found
Possible scenario for MaVaN's as the only neutrino flavor conversion mechanism in the Sun
Mass Varying neutrino mechanisms were proposed to link the neutrino mass
scale with dark energy, addressing the coincidence problem. In some scenarios
this mass can present a dependence on the baryonic density felt by neutrinos,
creating an effective neutrino mass that depends both on the neutrino and
baryonic densities. In this article we investigate the possibility that a
neutrino effective mass is the only flavour conversion mechanism acting in
neutrino oscillation experiments. We present a parameterization on the
environmental effects on neutrino mass that produces the right flavour
conversion probabilities for solar and terrestrial neutrinos experiments.Comment: 12 pages, 4 figure
Underinvoicing of exports, overinvoicing of imports, and the dollar premium on the black market
This paper is divided in two parts. The first is a theoretical development of the question of under or overinvoicing of exports and imports within the context of a model of choice between risky and secure assets. The second part attempts to ascertain the empirical evidence for the Brazilian economy. It is concluded that the hypothesis that the black market dollar premium plays a role in this process can not be rejected.
Solar neutrinos: the SNO salt phase results and physics of conversion
We have performed analysis of the solar neutrino data including results from
the SNO salt phase as well as the combined analysis of the solar and the
KamLAND results. The best fit values of neutrino parameters are Delta m^2 =
7.1e-5 eV^2, tan^2\theta = 0.40 with the boron flux f_B = 1.04. New SNO results
strongly disfavor maximal mixing and the h-LMA region (Delta m^2 > 1e-4 eV^2)
which is accepted now at the 3-sigma level. We find the 3-sigma upper bounds:
Delta m^2 < 1.7e-4$ eV^2 and tan^2\theta < 0.64, and the lower bound Delta m^2
> 4.8e-5 eV^2. Non-zero 13-mixing does not change these results significantly.
The present data determine quantitatively the physical picture of the solar
neutrino conversion. At high energies relevant for SNO and Super-Kamiokande the
deviation of the effective survival probability from the non-oscillatory value
is about 10 - 14%. The oscillation effect contribution to this difference about
10% and the Earth regeneration is about 3 - 4%. At low energies (E < 1 MeV) the
matter corrections to vacuum oscillation effect are below 5%. The predictions
for the forthcoming measurements are given which include the spectral
distortion and CC/NC ratio at SNO, the Day-Night asymmetry, the KamLAND
spectrum and rate.Comment: figures and some numbers corrected, discussion of coherence loss
added, number of pages slightly change
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