415 research outputs found
Limits on the high-energy gamma and neutrino fluxes from the SGR 1806-20 giant flare of December 27th, 2004 with the AMANDA-II detector
On December 27th 2004, a giant gamma flare from the Soft Gamma-ray Repeater
1806-20 saturated many satellite gamma-ray detectors. This event was by more
than two orders of magnitude the brightest cosmic transient ever observed. If
the gamma emission extends up to TeV energies with a hard power law energy
spectrum, photo-produced muons could be observed in surface and underground
arrays. Moreover, high-energy neutrinos could have been produced during the SGR
giant flare if there were substantial baryonic outflow from the magnetar. These
high-energy neutrinos would have also produced muons in an underground array.
AMANDA-II was used to search for downgoing muons indicative of high-energy
gammas and/or neutrinos. The data revealed no significant signal. The upper
limit on the gamma flux at 90% CL is dN/dE < 0.05 (0.5) TeV^-1 m^-2 s^-1 for
gamma=-1.47 (-2). Similarly, we set limits on the normalization constant of the
high-energy neutrino emission of 0.4 (6.1) TeV^-1 m^-2 s^-1 for gamma=-1.47
(-2).Comment: 14 pages, 3 figure
Solar 8B and hep Neutrino Measurements from 1258 Days of Super-Kamiokande Data
Solar neutrino measurements from 1258 days of data from the Super-Kamiokande
detector are presented. The measurements are based on recoil electrons in the
energy range 5.0-20.0MeV. The measured solar neutrino flux is 2.32 +-
0.03(stat.) +0.08-0.07(sys.)*10^6cm^{-2}s^{-1}, which is
45.1+-0.5(stat.)+1.6-1.4(sys.)% of that predicted by the BP2000 SSM. The day vs
night flux asymmetry is 0.033+-0.022(stat.)+0.013-0.012(sys.). The recoil
electron energy spectrum is consistent with no spectral distortion
(\chi^2/d.o.f. = 19.0/18). The seasonal variation of the flux is consistent
with that expected from the eccentricity of the Earth's orbit (\chi^2/d.o.f. =
3.7/7). For the hep neutrino flux, we set a 90% C.L. upper limit of 40
*10^3cm^{-2}s^{-1}, which is 4.3 times the BP2000 SSM prediction.Comment: 7 pages, 5 figures, submitted to PRL (part of this paper
Three flavor neutrino oscillation analysis of atmospheric neutrinos in Super-Kamiokande
We report on the results of a three-flavor oscillation analysis using
Super-Kamiokande~I atmospheric neutrino data, with the assumption of one mass
scale dominance (0). No significant flux change due to
matter effect, which occurs when neutrinos propagate inside the Earth for
0, has been seen either in a multi-GeV -rich sample
or in a -rich sample. Both normal and inverted mass hierarchy
hypotheses are tested and both are consistent with observation. Using
Super-Kamiokande data only, 2-dimensional 90 % confidence allowed regions are
obtained: mixing angles are constrained to and for the normal mass hierarchy. Weaker constraints,
and , are obtained
for the inverted mass hierarchy case.Comment: 7 figures, 3 table
Evidence for an oscillatory signature in atmospheric neutrino oscillation
Muon neutrino disappearance probability as a function of neutrino flight
length L over neutrino energy E was studied. A dip in the L/E distribution was
observed in the data, as predicted from the sinusoidal flavor transition
probability of neutrino oscillation. The observed L/E distribution constrained
nu_mu nu_tau neutrino oscillation parameters; 1.9x10^-3 < Delta m^2 <
3.0x10^-3 eV^2 and \sin^2(2theta) > 0.90 at 90% confidence level.Comment: 5 pages, 5 figures, submitted to PR
Constraints on Neutrino Oscillations Using 1258 Days of Super-Kamiokande Solar Neutrino Data
We report the result of a search for neutrino oscillations using precise
measurements of the recoil electron energy spectrum and zenith angle variations
of the solar neutrino flux from 1258 days of neutrino-electron scattering data
in Super-Kamiokande. The absence of significant zenith angle variation and
spectrum distortion places strong constraints on neutrino mixing and mass
difference in a flux-independent way. Using the Super-Kamiokande flux
measurement in addition, two allowed regions at large mixing are found.Comment: 6 pages, 4 figures, submitted to PR
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Review of experience of family medicine in Europe and Central Asia : Executive summary
This report summarizes the findings of four case studies that review the experience of family medicine in Europe and Central Asia (ECA) Region. It is part of a study comprising five volumes that review the experience of family medicine in four countries in ECA--Armenia, Bosnia and Herzegovina, Kyrgyz Republic and Moldova. The report reviews the experience, draws lessons, and establishes an evidence base for detailed analysis. The study presents best practices for policy dialogue and future investments by the World Bank and other financial institutions. The detailed case studies compare these countries and draw common themes and issues. Comparisons are made with best-developed or existing models in the OECD and other countries in the Europe and Central Asia Region that have already undertaken family medicine reform
Search for Dark Matter WIMPs using Upward Through-going Muons in Super-Kamiokande
We present the results of indirect searches for Weakly Interacting Massive
Particles (WIMPs) with 1679.6 live days of data from the Super-Kamiokande
detector using neutrino-induced upward through-going muons. The search is
performed by looking for an excess of high energy muon neutrinos from WIMP
annihilations in the Sun, the core of the Earth, and the Galactic Center, as
compared to the number expected from the atmospheric neutrino background. No
statistically significant excess was seen. We calculate flux limits in various
angular cones around each of the above celestial objects. We obtain
conservative model-independent upper limits on WIMP-nucleon cross-section as a
function of WIMP mass and compare these results with the corresponding results
from direct dark matter detection experiments.Comment: 10 pages, 14 figures, Submitted to Phys. Rev.
Solar neutrino measurements in Super-Kamiokande-I
The details of Super--Kamiokande--I's solar neutrino analysis are given.
Solar neutrino measurement in Super--Kamiokande is a high statistics collection
of B solar neutrinos via neutrino-electron scattering. The analysis method
and results of the 1496 day data sample are presented. The final oscillation
results for the data are also presented.Comment: 32pages, 57figures, submitted to Physical Review
A search for periodic modulations of the solar neutrino flux in Super-Kamiokande-I
A search for periodic modulations of the solar neutrino flux was performed
using the Super-Kamiokande-I data taken from May 31st, 1996 to July 15th, 2001.
The detector's capability of measuring the exact time of events, combined with
a relatively high yield of solar neutrino events, allows a search for
short-time variations in the observed flux. We employed the Lomb test to look
for periodic modulations of the observed solar neutrino flux. The obtained
periodogram is consistent with statistical fluctuation and no significant
periodicity was found
Search for nucleon decay via modes favored by supersymmetric grand unification models in Super-Kamiokande-I
We report the results for nucleon decay searches via modes favored by
supersymmetric grand unified models in Super-Kamiokande. Using 1489 days of
full Super-Kamiokande-I data, we searched for , , and modes. We found no
evidence for nucleon decay in any of these modes. We set lower limits of
partial nucleon lifetime 2.3, 1.3,
1.3 and 1.0 years at 90% confidence level for , , and modes, respectively. These results give a strong constraint on
supersymmetric grand unification models.Comment: 14 pages, 13 figure
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