492 research outputs found
Does the neutrino magnetic moment have an impact on solar neutrino physics?
Solar neutrino observations coupled with the recent KamLAND data suggest that
spin-flavor precession scenario does not play a major role in neutrino
propagation in the solar matter. We provide approximate analytical formulas and
numerical results to estimate the contribution of the spin-flavor precession,
if any, to the electron neutrino survival probability when the magnetic moment
and magnetic field combination is small.Comment: 7 pages, 1 figure
Search for axioelectric effect of 5.5 MeV solar axions using BGO detectors
A search for axioelectric absorption of solar axions produced in the reactions has been performed
with a BGO detector placed in a low-background setup. A model-independent limit
on an axion-nucleon and axion-electron coupling constant has been obtained: for 90% confidence level. The
constrains of the axion-electron coupling have been obtained for hadronic axion
with masses in (0.1 - 1) MeV range: .Comment: 6 pages, 4 figures, to be published in EPJ C. arXiv admin note:
substantial text overlap with arXiv:1007.338
Search for the Neutrino Magnetic Moment in the Non-Equilibrium Reactor Antineutrino Energy Spectrum
We study the time evolution of the typical nuclear reactor antineutrino
energy spectrum during reactor ON period and the decay of the residual
antineutrino spectrum after reactor is stopped. We find that relevant
variations of the soft recoil electron spectra produced via weak and magnetic
scattering process can play a signigicant role in
the current and planned searches for the neutrino magnetic moment at reactors.Comment: 4 pages LaTeX 2.09. 4 PS figures. Resume of seminar talks given at
Kurchatov Institute, March 1999
Search for solar axions produced by Compton process and bremsstrahlung using the resonant absorption and axioelectric effect
The search for resonant absorption of Compton and bremsstrahlung solar axions
by Tm nuclei have been performed. Such an absorption should lead to the
excitation of low-lying nuclear energy level: Tm Tm Tm (8.41 keV). Additionally the
axio-electric effect in silicon atoms is sought. The axions are detected using
a Si(Li) detectors placed in a low-background setup. As a result, a new model
independent restrictions on the axion-electron and the axion-nucleon coupling:
and the axion-electron
coupling constant: has been obtained. The
limits leads to the bounds 7.9 eV and 1.3 keV for the
mass of the axion in the DFSZ and KSVZ models, respectively ( C.L.).Comment: 6 pages, 3 figures, contributed to the 9th Patras Workshop on Axions,
WIMPs and WISPs, Mainz, June 24-28, 201
Constraints on the axion-electron coupling for solar axions produced by Compton process and bremsstrahlung
The search for solar axions produced by Compton () and bremsstrahlung-like () processes has
been performed. The axion flux in the both cases depends on the axion-electron
coupling constant. The resonant excitation of low-lying nuclear level of
was looked for: Tm Tm
Tm (8.41 keV). The Si(Li) detector and
Tm target installed inside the low-background setup were used to detect
8.41 keV -rays. As a result, a new model independent restriction on the
axion-electron and the axion-nucleon couplings was obtained:
. In model of hadronic
axion this restriction corresponds to the upper limit on the axion-electron
coupling and on the axion mass eV (90%
c.l.). The limits on axion mass are 105 eV and 1.3 keV for
DFSZ- and KSVZ-axion models, correspondingly (90% c.l.).Comment: 7 pages, 4 figure
Neutrino magnetic moments, flavor mixing, and the SuperKamiokande solar data
We find that magnetic neutrino-electron scattering is unaffected by
oscillations for vacuum mixing of Dirac neutrinos with only diagonal moments
and for Majorana neutrinos with two flavors. For MSW mixing, these cases again
obtain, though the effective moments can depend on the neutrino energy. Thus,
e.g., the magnetic moments measured with from a reactor and
from the Sun could be different. With minimal assumptions, we find a
new limit on using the 825-days SuperKamiokande solar neutrino
data: at 90% CL, comparable to the
existing reactor limit.Comment: 4 pages including two inline figures. New version has 825 days SK
result, some minor revisions. Accepted for Physical Review Letter
Inelastic Scattering of Tritium-Source Antineutrinos on Electrons of Germanium Atoms
Processes of the inelastic magnetic and weak scattering of
tritium-beta-source antineutrinos on the bound electrons of a germanium atom
are considered. The results obtained by calculating the spectra and cross
sections are presented for the energy-transfer range between 1 eV and 18 keV.Comment: Latex, 7 pages, 8 ps figure
On Search for New Physics in Nonequilibrium Reactor Antineutrino Energy Spectrum
The calculations of the time-dependent reactor antineutrino energy spectrum
are presented. Some problems associated with sensitive searches for neutrino
magnetic moment and neutrino oscillations in reactor antineutrino flux are
considered.Comment: 4 pages in pdf file with figures. Talk presented at International
Conference NANP-2001, Dubna, Russia, Jun-200
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