929 research outputs found
Comments on Neutrino Tests of Special Relativity
We point out that the assumption of Lorentz noninvariance examined recently
by Coleman and Glashow leads to neutrino flavor oscillations which are
phenomenologically equivalent to those obtained by assuming the neutrinos
violate the principle of equivalence. We then comment on the limits on Lorentz
noninvariance which can be derived from solar, atmospheric, and accelerator
neutrino experiments.Comment: 5 pages, Revte
Imprints of the nuclear symmetry energy on gravitational waves from the axial w-modes of neutron stars
The eigen-frequencies of the axial w-modes of oscillating neutron stars are
studied using the continued fraction method with an Equation of State (EOS)
partially constrained by the recent terrestrial nuclear laboratory data. It is
shown that the density dependence of the nuclear symmetry energy
affects significantly both the frequencies and the damping
times of these modes. Besides confirming the previously found universal
behavior of the mass-scaled eigen-frequencies as functions of the compactness
of neutron stars, we explored several alternative universal scaling functions.
Moreover, the -mode is found to exist only for neutron stars having a
compactness of independent of the EOS used.Comment: Version appeared in Phys. Rev. C80, 025801 (2009
Comment on ``Neutrino masses and mixing angles in a predictive theory of fermion masses''
In the extension of the Dimopoulos--Hall--Raby model of the fermion mass
matrices to the neutrino sector, there is an entry in the up-quark and neutrino
Dirac mass matrices which can be assumed to arise from the Yukawa coupling of a
{\bf 120}, instead of a {\bf 10} or a {\bf 126}, of SO(10). Although this
assumption leads to an extra undetermined complex parameter in the model, the
resulting lepton mixing matrix exhibits the remarkable feature that the does not mix with the other two neutrinos. Making a reasonable
assumption about the extra parameter, we are able to fit the large-mixing-angle
MSW solution of the solar-neutrino problem, and we obtain eV, the right mass range to close the Universe. Other possibilities for
explaining the solar-neutrino deficit are also discussed.Comment: standard LATEX, 6 pages, 2 figures available from the authors, report
No. CMU-HEP93-20 and DOE-ER/40682-4
New Constraints on Neutrino Oscillations in Vacuum as a Possible Solution of the Solar Neutrino Problem
Two-neutrino oscillations in vacuum are studied as a possible solution of the
solar neutrino problem. New constraints on the parameter sn2, characterizing
the mixing of the electron neutrino with another active or sterile neutrino, as
well as on the mass--squared difference, dm2, of their massive neutrino
components, are derived using the latest results from the four solar neutrino
experiments. Oscillations into a sterile neutrino are ruled out at 99 % C.L. by
the observed mean event rates even if one includes the uncertainties of the
standard solar model predictions in the analysis.Comment: 10 pages + 3 figures attached as postscript files, IFP-480-UNC and
Ref. SISSA 177/93/EP (Updated Version which takes into account the latest
GALLEX results from 30 runs
Constraining a possible time variation of the gravitational constant G with terrestrial nuclear laboratory data
Testing the constancy of the gravitational constant G has been a longstanding
fundamental question in natural science. As first suggested by Jofr\'{e},
Reisenegger and Fern\'{a}ndez [1], Dirac's hypothesis of a decreasing
gravitational constant with time due to the expansion of the Universe would
induce changes in the composition of neutron stars, causing dissipation and
internal heating. Eventually, neutron stars reach their quasi-stationary states
where cooling due to neutrino and photon emissions balances the internal
heating. The correlation of surface temperatures and radii of some old neutron
stars may thus carry useful information about the changing rate of G. Using the
density dependence of the nuclear symmetry energy constrained by recent
terrestrial laboratory data on isospin diffusion in heavy-ion reactions at
intermediate energies and the size of neutron skin in within the
gravitochemical heating formalism, we obtain an upper limit of the relative
changing rate of consistent with the
best available estimates in the literature.Comment: 27 pages, 11 figures, and 2 tables. Accepted version to appear in PRC
(2007
A Study of the Day - Night Effect for the Super - Kamiokande Detector: I. Time Averaged Solar Neutrino Survival Probability
This is the first of two articles aimed at providing comprehensive
predictions for the day-night (D-N) effect for the Super-Kamiokande detector in
the case of the MSW \nu_e \to \numt transition solution of the solar neutrino
problem. The one-year averaged probability of survival of the solar \nue
crossing the Earth mantle, the core, the inner 2/3 of the core, and the (core +
mantle) is calculated with high precision (better than 1%) using the elliptical
orbit approximation (EOA) to describe the Earth motion around the Sun. Results
for the survival probability in the indicated cases are obtained for a large
set of values of the MSW transition parameters and
from the ``conservative'' regions of the MSW solution,
derived by taking into account possible relatively large uncertainties in the
values of the B and Be neutrino fluxes. Our results show that the
one-year averaged D-N asymmetry in the survival probability for
neutrinos crossing the Earth core can be, in the case of , larger than the asymmetry in the probability for (only mantle
crossing + core crossing) neutrinos by a factor of up to six. The enhancement
is larger in the case of neutrinos crossing the inner 2/3 of the core. This
indicates that the Super-Kamiokande experiment might be able to test the
region of the MSW solution of the solar neutrino
problem by performing selective D-N asymmetry measurements.Comment: LaTeX2e - 18 Text Pages + 21 figures = 39 Pages. - Figures in PS +
text file sk1b14.tex requires two auxiliary files (included
How Well Do We (and Will We) Know Solar Neutrino Fluxes and Oscillation Parameters?
Assuming neutrino oscillations occur, the pp electron neutrino flux is
uncertain by at least a factor of two, the flux by a factor of
five, and the flux by a factor of forty-five. Calculations of the
expected results of future solar neutrino experiments (SuperKamiokande, SNO,
BOREXINO, ICARUS, HELLAZ, and HERON) are used to illustrate the extent to which
these experiments will restrict the range of the allowed neutrino mixing
parameters. We present an improved formulation of the ``luminosity constraint''
and show that at 95\% confidence limit this constraint establishes the best
available limits on the rate of creation of pp neutrinos in the solar interior
and provides the best upper limit to the neutrino flux.Comment: 37 pages, uuencoded Z-compressed postscript file (with figures);
Submitted to Physical Review
Pattern formation during electrodeposition of copper-antimony alloys
Aim of the present study is to establish the conditions of the electrolysis for the preparation of structured and unstressed purple-pink coatings of copper-antimony alloys, including their phase characterization. Also the task of the present investigation is, by changing drastically the metal content in the methanesulfonic electrolyte to find out the conditions of electrolysis where the self-organization of the different phases is expressed by higher-order structures - not only waves but also spirals and targets. The possibility to obtain copper-antimony alloy with up to 80 wt. % Sb from methanesulfonic acid is shown. The deposition rate, morphology and the phase composition of the obtained coatings are established. The phenomena of formation of spatio-temporal structures in this alloy are described.It is determined that the observed structures consist of Cu2Sb and Cu11Sb3 intermetallic phases
Chizhov and Petcov Reply
We have found in [1] new conditions for a total neutrino conversion in the
case of neutrino oscillations taking place in a medium, consisting of n = 2 (or
3) alternating layers with constant densities and . It is claimed in
[4] that our results are particular case of enhancement of neutrino
oscillations, which was suggested earlier by other authors and was widely
discussed in the literature. We refute these claims, confirming the novelty of
our results.Comment: 2 pages, LATEX; concise (essentially 1 page) and somewhat modified
version of Ref. SISSA 5/2000/EP (hep-ph/0003110); reply on the ``Comment on
New Conditions for a Total Neutrino Conversion in a Medium'', Phys. Rev.
Lett. 85 (2000) 3978; published as ``Chizhov and Petcov Reply'' in Phys. Rev.
Lett. 85 (2000) 397
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