5,985 research outputs found
Last CPT-Invariant Hope for LSND Neutrino Oscillations
It is shown that the 99% confidence limits from the analyses of the data of
cosmological and neutrino experiments imply a small marginally allowed region
in the space of the neutrino oscillation parameters of 3+1 four-neutrino mixing
schemes. This region can be confirmed or falsified by experiments in the near
future.Comment: 6 pages, added predictions for neutrinoless double beta decay and
tritium experiment
Oscillation Effects and Time Variation of the Supernova Neutrino Signal
The neutrinos detected from the next Galactic core-collapse supernova will
contain valuable information on the internal dynamics of the explosion. One
mechanism leading to a temporal evolution of the neutrino signal is the
variation of the induced neutrino flavor mixing driven by changes in the
density profile. With one and two dimensional hydrodynamical simulations we
identify the behavior and properties of prominent features of the explosion.
Using these results we demonstrate the time variation of the neutrino crossing
probabilities due to changes in the MSW neutrino transformations as the star
explodes by using the S-matrix - Monte Carlo - approach to neutrino
propagation. After adopting spectra for the neutrinos emitted from the
proto-neutron star we calculate for a Galactic supernova the evolution of the
positron spectra within a water Cerenkov detector and the ratio of charged
current to neutral current event rates for a heavy water - SNO like - detector
and find that these detector signals are feasible probes of a number of
explosion features
Sterile neutrino dark matter, CDMS-II and a light Higgs boson
We add a singlet right handed neutrino plus a charged and a neutral singlet
scalars to the standard model. This extension includes a discrete symmetry such
that we obtain a heavy sterile neutrino which couples only to the electron and
the new scalars. In this sense the singlet neutrino does not mix with ordinary
ones and thus has no effect on Big Bang Nucleosynthesis. However, such sterile
neutrino can be in equilibrium with electroweak particles in the early Universe
due to its couplings to electrons and also because the Higgs boson mixes with
the singlet scalars. We obtain that the sterile neutrino constitutes a dark
matter candidate and analyze its direct detection in the light of current
experiments. Our results show that if such a sterile neutrino is realized in
nature, and CDMS-II experiment confirms its positive signal, dark matter
demands a rather light Higgs boson with new Physics at some 500 GeV scale.Comment: 16 pages, 13 figures, uses axodraw.st
The explanation of unexpected temperature dependence of the muon catalysis in solid deuterium
It is shown that due to the smallness of the inelastic cross-section of the
-atoms scattering in the crystal lattice at sufficiently low temperatures
the -mesomolecules formation from the upper state of the hyperfine
structure starts earlier than the mesoatoms thermolization. It
explains an approximate constancy of the -mesomolecule formation rate in
solid deuterium.Comment: 6 pages, 2 jpeg-figure
Coherent pion production by neutrinos on nuclei
The main part of coherent pion production by neutrinos on nuclei is
essentially determined by PCAC, provided that the leptonic momentum transferred
square Q^2 remains sufficiently small. We give the formulas for the charged and
neutral current cross sections, including also the small non-PCAC transverse
current contributions and taking into account the effect of the \mu^- mass. Our
results are compared with the experimental ones and other theoretical
treatments.Comment: 18 pages, 4 figure
Quadrupolar contact terms and Hyperfine Structure
In the interaction of two electric quadrupoles, there is at short distances a
contact term proportional to the second derivative of a delta function. This
contact term contributes to the hyperfine splitting of bound states of two
particles with spin one or higher-for example the bound states of Omega minus
and a nucleus of spin one.The contact hyperfine splitting occurs in states with
orbital angular momentum one(p-wave), in contrast to the Fermi contact
interaction which is in s-states.We find that these contact splittings will be
observable with Omega minus atoms and help measure the quadrupole moment and
charge radius of the hyperon.Comment: 19 pages; two sentences deleted from first versio
Three-body dispersion-relation N/D equations for the coupled decay channels ppbar (J^{PC}=0^{-+}) --> pi^0 pi^0 pi^0, eta pi^0 pi^0, eta eta pi^0, K Kbar pi^0
During several years the data on different channels ppbar (J^{PC}=0^{-+}) -->
3 mesons presented by Crystal Barrel Collaboration were successfully analyzed
by extracting the leading amplitude singularities - pole singularities - with
the aim to obtain information about two-meson resonances. But these analyses do
not take into account three-body final state interactions (FSI) in an
explicitly correct way. This paper is devoted to the consideration of this
problem.Comment: 16 pages, no figure
Fermion zero modes at the boundary of superfluid 3He-B
Superfluid 3He-B belongs to the important special class of time-reversal
invariant topological superfluids. It has Majorana fermions as edge states on
the surface of bulk 3He-B. On the rough wall these fermion zero modes have
finite density of states at E=0. It is possible that Lancaster experiments with
a wire vibrating in 3He-B have already probed Majorana fermions living on the
surface of the wire.Comment: 4 pages, no Figures, JETP Letters style, version to be published in
JETP Letter
Prospects for the Bc Studies at LHCb
We discuss the motivations and perspectives for the studies of the mesons of
the (bc) family at LHCb. The description of production and decays at LHC
energies is given in details. The event yields, detection efficiencies, and
background conditions for several Bc decay modes at LHCb are estimated.Comment: 20 pages, 5 eps-figure
Graviton mass and total relative density of mass Omega_tot in Universe
It is noticed that the total relative density of mass in the Universe
Omega_tot should exceed 1, i.e. Omega_tot=1+f^2/6 according to the field
relativistic theory of gravity (RTG), which is free of the cosmological
singularity and which provides the Euclidean character for the 3-dimensional
space. Here f is the ratio of the graviton mass m_g to the contemporary value
of the ``Hubble mass'' m^0_H=\hbar H_0/c^2\simeq 3,8\cdot 10^{-66}h(g)
(h=0,71\pm0,07). Applying results of the experimental data processing presented
in [1] an upper limit for the graviton mass is established as m_g\leq 3,2\cdot
10^{-66}g at the 95% confidence level.Comment: 8 pages, latex fil
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