84 research outputs found
Neutrino mass spectrum and lepton mixing
The program of reconstruction of the neutrino mass and flavor spectrum is
outlined and the present status of research is summarized. We describe the role
of future solar and atmospheric neutrino experiments, detection of the Galactic
supernovae and double beta decay searches in accomplishing this program. The
LSND result and four neutrino mass spectra are considered in connection with
recent searches for the sterile components in the solar and atmospheric
neutrino fluxes.Comment: 8 pages, latex, 4 figures. Talk given at the XIX International
Conference on Neutrino Physics and Astrophysics, Neutrino-2000, Sudbury,
Canada, 16 - 21 June 200
Axino-Neutrino Mixing in Gauge-Mediated Supersymmetry Breaking Models
When the strong CP problem is solved by spontaneous breaking of an anomalous
global symmetry in theories with gauge-mediated supersymmetry breaking, the
pseudo Goldstone fermion (the axino) is a good candidate of a light sterile
neutrino. Its mixing with neutrinos relevant for current neutrino experiments
can arise in the presence of R-parity violation. The realistic four neutrino
mass matrix is obtained when the see-saw mechanism is brought in, and an ansatz
for the right-handed neutrino mass is constructed.Comment: Revtex, 7 pp. Version to appear in Phys. Lett.
Non-Oscillation Searches of Neutrino Mass in the Age of Oscillations
We focus on the implications of the oscillations for the shape of nuclear
beta-spectrum (=direct search for nu mass). This is of interest because of the
existing bound, m_(nu_e)<2.2 eV, that could improve by one order of magnitude
with future experiments. We stress important connections with the results of
Liquid Scintillator Neutrino Detector, nu_e disappearance experiments,
supernova neutrinos and neutrinoless double beta decay.Comment: 3 pages, 1 figure. Matches the version to appear in the Proceedings
of NOW 2000 Worksho
Neutrinoless double beta decay, solar neutrinos and mass scales
We obtain bounds for the neutrino masses by combining atmospheric and solar
neutrino data with the phenomenology of neutrinoless double beta decay where
hypothetical values of || are envisaged from future
0\nu\beta\beta-experiments. Different solutions for the solar neutrino data are
considered. For the Large-Mixing-Angle solution, a bound || \leq 0.01 eV
would strongly disfavour an inverted hierarchy of the neutrino masses.Comment: 14 pages, including 6 figures; v2: some polishing, additional
references, version to appear in Phys. Lett.
Search for decay at Super factory
A Monte Carlo study of possible background processes in a search for decay has been performed for conditions of the Super
factory (CTF) (at a center-of-mass energy 3.686 GeV, 3.77 GeV and 4.17 GeV).
The background from events has been analysed. Selection
criteria for background suppression are suggested and necessary requirements on
the detector characteristics have been found. The CTF can successfully compete
with the Super B-factory in a search for decay.Comment: 3 pages, 1 figures; contribution to the Proceedings of the PHIPSI11
Workshop (Novosibirsk, Russia, 19-22 September 2011
Unknowns after the SNO Charged-Current Measurement
We perform a model-independent analysis of solar neutrino flux rates
including the recent charged-current measurement at the Sudbury Neutrino
Observatory (SNO). We derive a universal sum rule involving SNO and
SuperKamiokande rates, and show that the SNO neutral-current measurement can
not fix the fraction of solar oscillating to sterile neutrinos. The
large uncertainty in the SSM B flux impedes a determination of the sterile
neutrino fraction.Comment: Version to appear in PRL; includes analysis with anticipated SNO NC
measuremen
Systematic Approach to Gauge-Invariant Relations between Lepton Flavor Violating Processes
We analyze four-lepton contact interactions that lead to lepton flavor
violating processes, with violation of individual family lepton number but
total lepton number conserved. In an effective Lagrangian framework, the
assumption of gauge invariance leads to relations among branching ratios and
cross sections of lepton flavor violating processes. In this paper, we work out
how to use these relations systematically. We also study the consequences of
loop-induced processes.Comment: 17 pages, 1 figure, 5 table
Anomalous diffusion modifies solar neutrino fluxes
Density and temperature conditions in the solar core suggest that the
microscopic diffusion of electrons and ions could be nonstandard:
Diffusion and friction coefficients are energy dependent, collisions are not
two-body processes and retain memory beyond the single scattering event.
A direct consequence of nonstandard diffusion is that the equilibrium energy
distribution of particles departs from the Maxwellian one (tails goes to zero
more slowly or faster than exponentially) modifying the reaction rates.
This effect is qualitatively different from temperature and/or composition
modification: Small changes in the number of particles in the distribution
tails can strongly modify the rates without affecting bulk properties, such as
the sound speed or hydrostatic equilibrium, which depend on the mean values
from the distribution.
This mechanism can considerably increase the range of predictions for the
neutrino fluxes allowed by the current experimental values (cross sections and
solar properties) and can be used to reduce the discrepancy between these
predictions and the solar neutrino experiments.Comment: 16 pages, ReVTeX, no figures. Text partially revised (24 april 1998
Resolving the Solar Neutrino Problem with KamLAND
We study how well KamLAND, the first terrestrial neutrino experiment capable
of addressing the solar neutrino problem, will perform in ascertaining whether
or not the large mixing angle MSW solution (with and oscillation amplitude ) is correct.
We find that in a year of operation KamLAND will provide unequivocal evidence
for or against this solution. Furthermore, its sensitivity to the
three-neutrino oscillation parameters in this region is sufficiently acute as
to determine to approximately % (for ) and to fix to within (at the
level) with three years of accumulated data, independent of the value
of .Comment: A typographical error is corrected. "3\sigma" is replaced by
"2\sigma" everywher
Currents and charges for mixed fields
We present an analysis of currents and charges for a system of two mixed
fields, both for spinless bosons and for Dirac fermions. This allows us to
obtain in a straightforward way the exact field theoretical oscillation
formulas exhibiting corrections with respect to the usual ones derived in
quantum mechanics.Comment: 4 pages, RevTe
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