976 research outputs found
Superkamiokande and solar antineutrinos
We propose to exploit the angular distribution of the positrons emitted in
the inverse beta decay to extract a possible antineutrino signal from the
Superkamiokande background. From the statistics collected in just 101.9 days
one obtains a model independent upper bound on the antineutrino flux (for
energy greater than 8.3 MeV) Phi < 9*10^4 cm^-2 s^-1 at the 95% C.L. By
assuming the same energy spectrum as for the 8B neutrinos, the 95% C.L. bound
is Phi < 6*10^4 cm^-2 s^-1. Within three years of data taking, the sensitivity
to neutrino-antineutrino transition probability will reach the 1% level, thus
providing a stringent test of hybrid oscillation models.Comment: 7 pages, 1 figure, Late
Towards the Theory of Non--Abelian Tensor Fields I
We present a triangulation--independent area--ordering prescription which
naturally generalizes the well known path ordering one. For such a prescription
it is natural that the two--form ``connection'' should carry three ``color''
indices rather than two as it is in the case of the ordinary one--form gauge
connection. To define the prescription in question we have to define how to
{\it exponentiate} a matrix with three indices. The definition uses the fusion
rule structure constants.Comment: 22 pages, 18 figure
Quantum field theoretic approach to neutrino oscillations in matter
We consider neutrino oscillations in non-uniform matter in a quantum field
theoretic (QFT) approach, in which neutrino production, propagation and
detection are considered as a single process. We find the conditions under
which the oscillation probability can be sensibly defined and demonstrate how
the properly normalized oscillation probability can be obtained in the QFT
framework. We derive the evolution equation for the oscillation amplitude and
discuss the conditions under which it reduces to the standard
Schr\"odinger-like evolution equation. It is shown that, contrary to the common
usage, the Schr\"odinger-like evolution equation is not applicable in certain
cases, such as oscillations of neutrinos produced in decays of free pions
provided that sterile neutrinos with eV exist.Comment: LaTeX, 24 pages + 16 pages of appendices, 1 figure. V2: typos
correcte
Analysis of Gamma Radiation from a Radon Source: Indications of a Solar Influence
This article presents an analysis of about 29,000 measurements of gamma
radiation associated with the decay of radon in a sealed container at the
Geological Survey of Israel (GSI) Laboratory in Jerusalem between 28 January
2007 and 10 May 2010. These measurements exhibit strong variations in time of
year and time of day, which may be due in part to environmental influences.
However, time-series analysis reveals a number of periodicities, including two
at approximately 11.2 year and 12.5 year. We have previously
found these oscillations in nuclear-decay data acquired at the Brookhaven
National Laboratory (BNL) and at the Physikalisch-Technische Bundesanstalt
(PTB), and we have suggested that these oscillations are attributable to some
form of solar radiation that has its origin in the deep solar interior. A
curious property of the GSI data is that the annual oscillation is much
stronger in daytime data than in nighttime data, but the opposite is true for
all other oscillations. This may be a systematic effect but, if it is not, this
property should help narrow the theoretical options for the mechanism
responsible for decay-rate variability.Comment: 9 pages, 21 figure
De Sitter space and perpetuum mobile
We give general arguments that any interacting non--conformal {\it classical}
field theory in de Sitter space leads to the possibility of constructing a
perpetuum mobile. The arguments are based on the observation that massive free
falling particles can radiate other massive particles on the classical level as
seen by the free falling observer. The intensity of the radiation process is
non-zero even for particles with any finite mass, i.e. with a wavelength which
is within the causal domain. Hence, we conclude that either de Sitter space can
not exist eternally or that one can build a perpetuum mobile.Comment: 11 pages revtex, no figures. Added discussion to strengthen
conclusio
Reheat temperature in supersymmetric hybrid inflation models
The allowed range of parameters for supersymmetric hybrid inflation and its
extensions are investigated. The lower bound on the reheat temperature T_r in
these models with hierarchical right handed neutrinos is found to be 3*10^7
GeV. (T_r as low as 100 GeV is possible for quasi degenerate right handed
neutrinos.) We also present revised estimates for the scalar spectral index and
the symmetry breaking scale associated with inflation.Comment: 15 pages, 8 figures, revtex4. v2: minor changes, matches published
versio
Supernova prompt neutronization neutrinos and neutrino magnetic moments
It is shown that the combined action of spin-flavor conversions of supernova
neutrinos due to the interactions of their Majorana-type transition magnetic
moments with the supernova magnetic fields and flavor conversions due to the
mass mixing can lead to the transformation of \nu_e born in the neutronization
process into their antiparticles \bar{\nu}_e. Such an effect would have a clear
experimental signature and its observation would be a smoking gun evidence for
the neutrino transition magnetic moments. It would also signify the leptonic
mixing parameter |U_{e3}| in excess of 10^{-2}.Comment: LaTex, 25 pages, 3 figures. v4: Discussion section expanded,
references added. Matches the published versio
Mass hierarchy, 2-3 mixing and CP-phase with Huge Atmospheric Neutrino Detectors
We explore the physics potential of multi-megaton scale ice or water
Cherenkov detectors with low ( GeV) threshold. Using some proposed
characteristics of the PINGU detector setup we compute the distributions of
events versus neutrino energy and zenith angle , and study
their dependence on yet unknown neutrino parameters. The
regions are identified where the distributions have the highest sensitivity to
the neutrino mass hierarchy, to the deviation of the 2-3 mixing from the
maximal one and to the CP-phase. We evaluate significance of the measurements
of the neutrino parameters and explore dependence of this significance on the
accuracy of reconstruction of the neutrino energy and direction. The effect of
degeneracy of the parameters on the sensitivities is also discussed. We
estimate the characteristics of future detectors (energy and angle resolution,
volume, etc.) required for establishing the neutrino mass hierarchy with high
confidence level. We find that the hierarchy can be identified at --
level (depending on the reconstruction accuracies) after 5 years of
PINGU operation.Comment: 39 pages, 21 figures. Description of Fig.3 correcte
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