97 research outputs found
Astrophysical tau neutrino detection in kilometer-scale Cherenkov detectors via muonic tau decay
Kilometer-scale deep under-ice or -water Cherenkov neutrino detectors may
detect muon and electron neutrinos from astrophysical sources at energies of a
TeV and above. Tau neutrinos are also expected from these sources due to
neutrino flavor oscillations in vacuum, and tau neutrinos are free of
atmospheric background at a much lower energy than muon and electron neutrinos.
Identification of tau neutrinos is expected to be possible above the PeV energy
range through the "double bang" and "lollipop" signatures. We discuss another
signature of tau in the PeV-EeV range, arising from the decay of tau leptons
inside the detector to much brighter muons.Comment: 6 pages, 3 figure
Tritium Beta Decay, Neutrino Mass Matrices and Interactions Beyond the Standard Model
The interference of charge-changing interactions, weaker than the V-A
Standard Model (SM) interaction and having a different Lorentz structure, with
that SM interaction, can, in principle, produce effects near the end point of
the Tritium beta decay spectrum which are of a different character from those
produced by the purely kinematic effect of neutrino mass expected in the
simplest extension of the SM. We show that the existence of more than one mass
eigenstate can lead to interference effects at the end point that are stronger
than those occurring over the entire spectrum. We discuss these effects both
for the special case of Dirac neutrinos and the more general case of Majorana
neutrinos and show that, for the present precision of the experiments, one
formula should suffice to express the interference effects in all cases.
Implications for "sterile" neutrinos are noted.Comment: 32 pages, LaTeX, 6 figures, PostScript; full discussion and changes
in notation from Phys. Lett. B440 (1998) 89, nucl-th/9807057; submitted to
Phys. Rev.
Detecting a stochastic gravitational wave background with the Laser Interferometer Space Antenna
The random superposition of many weak sources will produce a stochastic
background of gravitational waves that may dominate the response of the LISA
(Laser Interferometer Space Antenna) gravitational wave observatory. Unless
something can be done to distinguish between a stochastic background and
detector noise, the two will combine to form an effective noise floor for the
detector. Two methods have been proposed to solve this problem. The first is to
cross-correlate the output of two independent interferometers. The second is an
ingenious scheme for monitoring the instrument noise by operating LISA as a
Sagnac interferometer. Here we derive the optimal orbital alignment for
cross-correlating a pair of LISA detectors, and provide the first analytic
derivation of the Sagnac sensitivity curve.Comment: 9 pages, 11 figures. Significant changes to the noise estimate
A Search for the Dark Matter Annual Modulation in South Pole Ice
Astrophysical observations and cosmological data have led to the conclusion
that nearly one quarter of the Universe consists of dark matter. Under certain
assumptions, an observable signature of dark matter is the annual modulation of
the rate of dark matter-nucleon interactions taking place in an Earth-bound
experiment. To search for this effect, we introduce the concept for a new dark
matter experiment using NaI scintillation detectors deployed deep in the South
Pole ice. This experiment complements dark matter search efforts in the
Northern Hemisphere and will investigate the observed annual modulation in the
DAMA/LIBRA and DAMA/NaI experiments. The unique location will permit the study
of background effects correlated with seasonal variations and the surrounding
environment. This paper describes the experimental concept and explores the
sensitivity of a 250 kg NaI experiment at the South Pole.Comment: FERMILAB-PUB-11-251-A
IceCube - the next generation neutrino telescope at the South Pole
IceCube is a large neutrino telescope of the next generation to be
constructed in the Antarctic Ice Sheet near the South Pole. We present the
conceptual design and the sensitivity of the IceCube detector to predicted
fluxes of neutrinos, both atmospheric and extra-terrestrial. A complete
simulation of the detector design has been used to study the detector's
capability to search for neutrinos from sources such as active galaxies, and
gamma-ray bursts.Comment: 8 pages, to be published with the proceedings of the XXth
International Conference on Neutrino Physics and Astrophysics, Munich 200
Muon Track Reconstruction and Data Selection Techniques in AMANDA
The Antarctic Muon And Neutrino Detector Array (AMANDA) is a high-energy
neutrino telescope operating at the geographic South Pole. It is a lattice of
photo-multiplier tubes buried deep in the polar ice between 1500m and 2000m.
The primary goal of this detector is to discover astrophysical sources of high
energy neutrinos. A high-energy muon neutrino coming through the earth from the
Northern Hemisphere can be identified by the secondary muon moving upward
through the detector. The muon tracks are reconstructed with a maximum
likelihood method. It models the arrival times and amplitudes of Cherenkov
photons registered by the photo-multipliers. This paper describes the different
methods of reconstruction, which have been successfully implemented within
AMANDA. Strategies for optimizing the reconstruction performance and rejecting
background are presented. For a typical analysis procedure the direction of
tracks are reconstructed with about 2 degree accuracy.Comment: 40 pages, 16 Postscript figures, uses elsart.st
Results from the Antarctic Muon and Neutrino Detector Array (AMANDA)
We show new results from both the older and newer incarnations of AMANDA
(AMANDA-B10 and AMANDA-II, respectively). These results demonstrate that AMANDA
is a functioning, multipurpose detector with significant physics and
astrophysics reach. They include a new higher-statistics measurement of the
atmospheric muon neutrino flux and preliminary results from searches for a
variety of sources of ultrahigh energy neutrinos: generic point sources,
gamma-ray bursters and diffuse sources producing muons in the detector, and
diffuse sources producing electromagnetic or hadronic showers in or near the
detector.Comment: Invited talk at the XXth International Conference on Neutrino Physics
and Astrophysics (Neutrino 2002), Munich, Germany, May 25-30, 200
Sensitivity of the IceCube Detector to Astrophysical Sources of High Energy Muon Neutrinos
We present the results of a Monte-Carlo study of the sensitivity of the
planned IceCube detector to predicted fluxes of muon neutrinos at TeV to PeV
energies. A complete simulation of the detector and data analysis is used to
study the detector's capability to search for muon neutrinos from sources such
as active galaxies and gamma-ray bursts. We study the effective area and the
angular resolution of the detector as a function of muon energy and angle of
incidence. We present detailed calculations of the sensitivity of the detector
to both diffuse and pointlike neutrino emissions, including an assessment of
the sensitivity to neutrinos detected in coincidence with gamma-ray burst
observations. After three years of datataking, IceCube will have been able to
detect a point source flux of E^2*dN/dE = 7*10^-9 cm^-2s^-1GeV at a 5-sigma
significance, or, in the absence of a signal, place a 90% c.l. limit at a level
E^2*dN/dE = 2*10^-9 cm^-2s^-1GeV. A diffuse E-2 flux would be detectable at a
minimum strength of E^2*dN/dE = 1*10^-8 cm^-2s^-1sr^-1GeV. A gamma-ray burst
model following the formulation of Waxman and Bahcall would result in a 5-sigma
effect after the observation of 200 bursts in coincidence with satellite
observations of the gamma-rays.Comment: 33 pages, 13 figures, 6 table
Production and Decay of D_1(2420)^0 and D_2^*(2460)^0
We have investigated and final states and
observed the two established charmed mesons, the with mass
MeV/c and width MeV/c and
the with mass MeV/c and width
MeV/c. Properties of these final states, including
their decay angular distributions and spin-parity assignments, have been
studied. We identify these two mesons as the doublet predicted
by HQET. We also obtain constraints on {\footnotesize } as a function of the cosine of the relative phase of the two
amplitudes in the decay.Comment: 15 pages in REVTEX format. hardcopies with figures can be obtained by
sending mail to: [email protected]
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