11,357 research outputs found
Introduction to MiniBooNE and Vu charged-current quasi-elastic results
"The MiniBooNE experiment is described together with the procedures used to obtain a result for Vm - Ve oscillations. (The oscillation results are described in the companion talk of M. Sorel.) Results are given here for the charged-current quasi-elastic (CCQE) cross section, Vmn - m[?]p. It is found that the simple relativistic Fermi gas nuclear model with Fermi momentum, PF = 220 MeV/c and binding energy EB = 34 MeV is insufficient to describe the reaction for any values of the axial vector mass MA. It was found necessary to add a new empirical Pauli blocking parameter, k. With this new term, the best values found were MA = 1.23 +- 0.20 GeV and k = 1.019 +- 0.011."http://deepblue.lib.umich.edu/bitstream/2027.42/64213/1/jpconf8_110_082018.pd
Including Systematic Uncertainties in Confidence Interval Construction for Poisson Statistics
One way to incorporate systematic uncertainties into the calculation of
confidence intervals is by integrating over probability density functions
parametrizing the uncertainties. In this note we present a development of this
method which takes into account uncertainties in the prediction of background
processes, uncertainties in the signal detection efficiency and background
efficiency and allows for a correlation between the signal and background
detection efficiencies. We implement this method with the Feldman & Cousins
unified approach with and without conditioning. We present studies of coverage
for the Feldman & Cousins and Neyman ordering schemes. In particular, we
present two different types of coverage tests for the case where systematic
uncertainties are included. To illustrate the method we show the relative
effect of including systematic uncertainties the case of dark matter search as
performed by modern neutrino tel escopes.Comment: 23 pages, 10 figures, replaced to match published versio
Acoustic Identification of Liquefaction Potential
The interparticle arrangement, or fabric, of sands is a key determinant of sample rigidity. This rigidity, in large part, determines the velocity and attenuation of acoustic transmissions in a test specimen, as well as its resistance to liquefaction. Utilizing high frequency small-amplitude compressional wave transmissions, different fabric arrangements of standard triaxial samples of the same sand have been reliably identified from their acoustic response. Both the compressional wave velocity and attenuation were used to determine the acoustic signature of a sample. Cyclic triaxial testing of the same laboratory-prepared samples revealed that there is direct relationship between the acoustic response of a sample prepared by a particular method and its resistance to liquefaction. The effect of stress history, induced by pre-shaking, on the resistance to liquefaction of a test sample was also detected by changes in the acoustic signature
Raman signatures of classical and quantum phases in coupled dots: A theoretical prediction
We study electron molecules in realistic vertically coupled quantum dots in a
strong magnetic field. Computing the energy spectrum, pair correlation
functions, and dynamical form factor as a function of inter-dot coupling via
diagonalization of the many-body Hamiltonian, we identify structural
transitions between different phases, some of which do not have a classical
counterpart. The calculated Raman cross section shows how such phases can be
experimentally singled out.Comment: 9 pages, 2 postscript figures, 1 colour postscript figure, Latex 2e,
Europhysics Letters style and epsfig macros. Submitted to Europhysics Letter
Improved Probability Method for Estimating Signal in the Presence of Background
A suggestion is made for improving the Feldman Cousins method of estimating
signal counts in the presence of background. The method concentrates on finding
essential information about the signal and ignoring extraneous information
about background. An appropriate method is found which uses the condition that
the number of background events obtained does not exceed the total number of
events obtained. Several alternative approaches are explored.Comment: Modified 12/21 for singlespace to save trees, 9 pages, 1 figure.
Modified 8/11/99 to add small modifications made for the Phys. Rev. articl
Inference for bounded parameters
The estimation of signal frequency count in the presence of background noise
has had much discussion in the recent physics literature, and Mandelkern [1]
brings the central issues to the statistical community, leading in turn to
extensive discussion by statisticians. The primary focus however in [1] and the
accompanying discussion is on the construction of a confidence interval. We
argue that the likelihood function and -value function provide a
comprehensive presentation of the information available from the model and the
data. This is illustrated for Gaussian and Poisson models with lower bounds for
the mean parameter
High Order Upwind Schemes for Multidimensional Magnetohydrodynamics
A general method for constructing high order upwind schemes for
multidimensional magnetohydrodynamics (MHD), having as a main built-in
condition the divergence-free constraint \divb=0 for the magnetic field
vector \bb, is proposed. The suggested procedure is based on {\em
consistency} arguments, by taking into account the specific operator structure
of MHD equations with respect to the reference Euler equations of gas-dynamics.
This approach leads in a natural way to a staggered representation of the \bb
field numerical data where the divergence-free condition in the cell-averaged
form, corresponding to second order accurate numerical derivatives, is exactly
fulfilled. To extend this property to higher order schemes, we then give
general prescriptions to satisfy a order accurate \divb=0
relation for any numerical \bb field having a order interpolation
accuracy. Consistency arguments lead also to a proper formulation of the upwind
procedures needed to integrate the induction equations, assuring the exact
conservation in time of the divergence-free condition and the related
continuity properties for the \bb vector components. As an application, a
third order code to simulate multidimensional MHD flows of astrophysical
interest is developed using ENO-based reconstruction algorithms. Several test
problems to illustrate and validate the proposed approach are finally
presented.Comment: 34 pages, including 14 figure
An Euler Solver Based on Locally Adaptive Discrete Velocities
A new discrete-velocity model is presented to solve the three-dimensional
Euler equations. The velocities in the model are of an adaptive nature---both
the origin of the discrete-velocity space and the magnitudes of the
discrete-velocities are dependent on the local flow--- and are used in a finite
volume context. The numerical implementation of the model follows the
near-equilibrium flow method of Nadiga and Pullin [1] and results in a scheme
which is second order in space (in the smooth regions and between first and
second order at discontinuities) and second order in time. (The
three-dimensional code is included.) For one choice of the scaling between the
magnitude of the discrete-velocities and the local internal energy of the flow,
the method reduces to a flux-splitting scheme based on characteristics. As a
preliminary exercise, the result of the Sod shock-tube simulation is compared
to the exact solution.Comment: 17 pages including 2 figures and CMFortran code listing. All in one
postscript file (adv.ps) compressed and uuencoded (adv.uu). Name mail file
`adv.uu'. Edit so that `#!/bin/csh -f' is the first line of adv.uu On a unix
machine say `csh adv.uu'. On a non-unix machine: uudecode adv.uu; uncompress
adv.tar.Z; tar -xvf adv.ta
Paramaterizations of inclusive cross sections for pion production in proton-proton collisions. II. Comparison to new data
A set of new, precise data have recently been made available by the NA49
collaboration for charged pion production in proton-proton and proton-Carbon
reactions at 158 GeV. The current paper compares this new data to five
currently available arithmetic parameterizations. Although a precise fit is not
expected, two of the parameterizations do not work very well but the other
three are able to provide a moderately good, but not precise fit to the
proton-proton data. The best two of these three parameterizations are scaled to
the proton-Carbon data and again provide a moderately good, but not precise
fit.Comment: 11 pages, 13 figures, Accepted for publication in Physical Review
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