10,697 research outputs found
Super-Kamiokande data and atmospheric neutrino decay
Neutrino decay has been proposed as a possible solution to the atmospheric
neutrino anomaly, in the light of the recent data from the Super-Kamiokande
experiment. We investigate this hypothesis by means of a quantitative analysis
of the zenith angle distributions of neutrino events in Super-Kamiokande,
including the latest (45 kTy) data. We find that the neutrino decay hypothesis
fails to reproduce the observed distributions of muons.Comment: 6 pages (RevTeX) + 2 figures (Postscript
Probing finite size effects in MonteCarlo calculations
The Constrained Effective Potential (CEP) is known to be equivalent to the
usual Effective Potential (EP) in the infinite volume limit. We have carried
out MonteCarlo calculations based on the two different definitions to get
informations on finite size effects. We also compared these calculations with
those based on an Improved CEP (ICEP) which takes into account the finite size
of the lattice. It turns out that ICEP actually reduces the finite size effects
which are more visible near the vanishing of the external source.Comment: LATTICE98(Gauge, Higgs and Yukawa Models
Light Sterile Neutrinos from Large Extra Dimensions
An experimentally verifiable Higgs-triplet model of neutrino masses from
large extra dimensions was recently proposed. We extend it to accomodate a
light sterile neutrino which also mixes with the three active neutrinos. A
previously proposed phenomenological model of four neutrinos (\underline {the
only viable such model now left}, in view of the latest atmospheric and solar
neutrino-oscillation data) is specifically realized.Comment: 10 pages, no figure, remarks and references adde
Mass Determination from Constraint Effective Potential
The Constraint Effective Potential (CEP) allows a determination of the mass
and other quantities directly, without relying upon asymptotic correlator
decays. We report and discuss the results of some mass calculations in
, obtained from CEP and our improved version of CEP (ICEP).Comment: LATTICE99(Higgs, Yukawa, SUSY
Neutrino masses and mixing angles from leptoquark interactions
In this paper we show that the mixing between leptoquarks (LQ's) from
different multiplets can generate a non-trivial Majorana mass matrix
for neutrinos through one loop self energy diagrams. Such mixing can arise from
gauge invariant and renormalizable LQ-Higgs interaction terms after EW symmetry
breaking. We use the experimental indication on neutrino oscillation to find
constraints on specific combinations of LQ couplings to quark-lepton pairs and
to the SM higgs boson. These constraints are compared with the ones from
.Comment: The expressions for majorana mass matrix of neutrinos have been
corrected so that they are symmetric. Final version to be published in
Physical Review
An application of decomposable maps in proving multiplicativity of low dimensional maps
In this paper we present a class of maps for which the multiplicativity of
the maximal output p-norm holds when p is 2 and p is larger than or equal to 4.
The class includes all positive trace-preserving maps from the matrix algebra
on the three-dimensional space to that on the two-dimensional.Comment: 9 page
The Dual Meissner Effect and Magnetic Displacement Currents
The dual Meissner effect is observed without monopoles in quenched
QCD with Landau gauge-fixing. Magnetic displacement currents which are
time-dependent Abelian magnetic fields play a role of solenoidal currents
squeezing Abelian electric fields. Monopoles are not always necessary to the
dual Meissner effect. The squeezing of the electric flux means the dual London
equation and the massiveness of the Abelian electric fields as an asymptotic
field. The mass generation of the Abelian electric fields is related to a gluon
condensate of mass dimension 2.Comment: 4 pages, 5 Postscript figures, title modified, some references added,
minor changes made ; Accepted for publication in Phys.Rev.Let
Searching for Oscillations with Extragalactic Neutrinos
We propose a novel approach for studying oscillations
with extragalactic neutrinos. Active Galactic Nuclei and Gamma Ray Bursts are
believed to be sources of ultrahigh energy muon neutrinos. With distances of
100 Mpc or more, they provide an unusually long baseline for possible detection
of with mixing parameters down to
eV, many orders of magnitude below the current accelerator
experiments. By solving the coupled transport equations, we show that
high-energy 's, as they propagate through the earth, cascade down in
energy, producing the enhancement of the incoming flux in the low
energy region, in contrast to the high-energy 's, which get absorbed.
For an AGN quasar model we find the flux to be a factor of 2 to 2.5
larger than the incoming flux in the energy range between GeV and
GeV, while for a GRB fireball model, the enhancement is 10%-27% in the same
energy range and for zero nadir angle. This enhancement decreases with larger
nadir angle, thus providing a novel way to search for appearance by
measuring the angular dependence of the muons. To illustrate how the cascade
effect and the final flux depend on the steepness of the incoming
, we show the energy and angular distributions for several generic
cases of the incoming tau neutrino flux, for n=1,2 and
3.6. We show that for the incoming flux that is not too steep, the signal for
the appearance of high-energy is the enhanced production of lower
energy and their distinctive angular dependence, due to the contribution
from the decay into just below the detector.Comment: 11 pages, including 4 color figure
Control of shock wave-boundary layer interactions by bleed in supersonic mixed compression inlets
An experimental investigation was conducted to determine the effect of bleed on a shock wave-boundary layer interaction in an axisymmetric mixed-compression supersonic inlet. The inlet was designed for a free-stream Mach number of 2.50 with 60-percent supersonic internal area contraction. The experiment was conducted in the NASA Lewis Research Center 10-Foot Supersonic Wind Tunnel. The effects of bleed amount and bleed geometry on the boundary layer after a shock wave-boundary layer interaction were studied. The effect of bleed on the transformed form factor is such that the full realizable reduction is obtained by bleeding of a mass flow equal to about one-half of the incident boundary layer mass flow. More bleeding does not yield further reduction. Bleeding upstream or downstream of the shock-induced pressure rise is preferable to bleeding across the shock-induced pressure rise
Development of a Gd Loaded Liquid Scintillator for Electron Anti-Neutrino Spectroscopy
We report on the development and deployment of 11.3 tons of 0.1% Gd loaded
liquid scintillator used in the Palo Verde reactor neutrino oscillation
experiment. We discuss the chemical composition, properties, and stability of
the scintillator elaborating on the details of the scintillator preparation
crucial for obtaining a good scintillator quality and stability.Comment: 9 pages, 4 figures, submitted to NIM
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