9,621 research outputs found
One pion events by atmospheric neutrinos: A three flavor analysis
We study the one-pion events produced via neutral current (NC) and charged
current (CC) interactions by the atmospheric neutrinos. We analyze the ratios
of these events in the framework of oscillations between three neutrino
flavors. The ratios of the CC events induced by to that of the NC
events and a similar ratio defined with help us in distinguishing the
different regions of the neutrino parameter space.Comment: 14 pages, 4 figures (separate postscript files
Heat conduction in the \alpha-\beta -Fermi-Pasta-Ulam chain
Recent simulation results on heat conduction in a one-dimensional chain with
an asymmetric inter-particle interaction potential and no onsite potential
found non-anomalous heat transport in accordance to Fourier's law. This is a
surprising result since it was long believed that heat conduction in
one-dimensional systems is in general anomalous in the sense that the thermal
conductivity diverges as the system size goes to infinity. In this paper we
report on detailed numerical simulations of this problem to investigate the
possibility of a finite temperature phase transition in this system. Our
results indicate that the unexpected results for asymmetric potentials is a
result of insufficient chain length, and does not represent the asymptotic
behavior.Comment: 14 pages, 6 figure
Suboptimality of Nonlocal Means for Images with Sharp Edges
We conduct an asymptotic risk analysis of the nonlocal means image denoising
algorithm for the Horizon class of images that are piecewise constant with a
sharp edge discontinuity. We prove that the mean square risk of an optimally
tuned nonlocal means algorithm decays according to , for an -pixel image with . This decay rate is an improvement
over some of the predecessors of this algorithm, including the linear
convolution filter, median filter, and the SUSAN filter, each of which provides
a rate of only . It is also within a logarithmic factor from
optimally tuned wavelet thresholding. However, it is still substantially lower
than the the optimal minimax rate of .Comment: 33 pages, 3 figure
Testing LSND at long-baseline neutrino experiments
Recently it was suggested that two very different mass-squared differences
play a role in atmospheric neutrino oscillations. The larger of these also
accounts for the LSND result and the smaller of these also drives the solar
neutrino oscillations. We consider the predictions of this scheme for
long-baseline experiments. We find that high statistics experiments, such as
MINOS, can observe a clean signal for this scheme, which is clearly
distinguishable from the usual scheme of atmospheric neutrino oscillations
driven by a single mass-squared difference.Comment: 13 pages, 3 figure
Self similar Barkhausen noise in magnetic domain wall motion
A model for domain wall motion in ferromagnets is analyzed. Long-range
magnetic dipolar interactions are shown to give rise to self-similar dynamics
when the external magnetic field is increased adiabatically. The power spectrum
of the resultant Barkhausen noise is of the form , where
can be estimated from the critical exponents for interface
depinning in random media.Comment: 7 pages, RevTex. To appear in Phys. Rev. Let
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