13,574 research outputs found
The B Neutrino Spectrum
Knowledge of the energy spectrum of B neutrinos is an important
ingredient for interpreting experiments that detect energetic neutrinos from
the Sun. The neutrino spectrum deviates from the allowed approximation because
of the broad alpha-unstable Be final state and recoil order corrections to
the beta decay. We have measured the total energy of the alpha particles
emitted following the beta decay of B. The measured spectrum is
inconsistent with some previous measurements, in particular with a recent
experiment of comparable precision. The beta decay strength function for the
transition from B to the accessible excitation energies in Be is fit to
the alpha energy spectrum using the R-matrix approach. Both the positron and
neutrino energy spectra, corrected for recoil order effects, are constructed
from the strength function. The positron spectrum is in good agreement with a
previous direct measurement. The neutrino spectrum disagrees with previous
experiments, particularly for neutrino energies above 12 MeV.Comment: 15 pages, 13 figures, 4 tables, submitted to Phys. Rev. C, typos
correcte
Obsidian Procurement at Pecica S ?an ?tul Mare, Romania
"Since its founding the Museum of Art and Archaeology has actively pursued archaeological field research projects and reported the results in Muse. Here we present the initial results of characterization studies on obsidian recovered during the course of the 2008 field campaign at Pecica S?ant?ul Mare, a major Middle Bronze Age tell settlement in western Romania, sponsored by the Museum of Art and Archaeology as an international collaborative project. This research reflects collaborations both in the field (among multiple museums in Romania and the United States) and in the laboratory (between the Museum of Art and Archaeology and the University of Missouri Research Reactor [MURR] Archaeometry Laboratory)."--First paragraph.Includes bibliographical reference
New broad 8Be nuclear resonances
Energies, total and partial widths, and reduced width amplitudes of 8Be
resonances up to an excitation energy of 26 MeV are extracted from a coupled
channel analysis of experimental data. The presence of an extremely broad J^pi
= 2^+ ``intruder'' resonance is confirmed, while a new 1^+ and very broad 4^+
resonance are discovered. A previously known 22 MeV 2^+ resonance is likely
resolved into two resonances. The experimental J^pi T = 3^(+)? resonance at 22
MeV is determined to be 3^-0, and the experimental 1^-? (at 19 MeV) and 4^-?
resonances to be isospin 0.Comment: 16 pages, LaTe
Covariant Calculation of General Relativistic Effects in an Orbiting Gyroscope Experiment
We carry out a covariant calculation of the measurable relativistic effects
in an orbiting gyroscope experiment. The experiment, currently known as Gravity
Probe B, compares the spin directions of an array of spinning gyroscopes with
the optical axis of a telescope, all housed in a spacecraft that rolls about
the optical axis. The spacecraft is steered so that the telescope always points
toward a known guide star. We calculate the variation in the spin directions
relative to readout loops rigidly fixed in the spacecraft, and express the
variations in terms of quantities that can be measured, to sufficient accuracy,
using an Earth-centered coordinate system. The measurable effects include the
aberration of starlight, the geodetic precession caused by space curvature, the
frame-dragging effect caused by the rotation of the Earth and the deflection of
light by the Sun.Comment: 7 pages, 1 figure, to be submitted to Phys. Rev.
Properties of finite Gaussians and the discrete-continuous transition
Weyl's formulation of quantum mechanics opened the possibility of studying
the dynamics of quantum systems both in infinite-dimensional and
finite-dimensional systems. Based on Weyl's approach, generalized by Schwinger,
a self-consistent theoretical framework describing physical systems
characterised by a finite-dimensional space of states has been created. The
used mathematical formalism is further developed by adding finite-dimensional
versions of some notions and results from the continuous case. Discrete
versions of the continuous Gaussian functions have been defined by using the
Jacobi theta functions. We continue the investigation of the properties of
these finite Gaussians by following the analogy with the continuous case. We
study the uncertainty relation of finite Gaussian states, the form of the
associated Wigner quasi-distribution and the evolution under free-particle and
quantum harmonic oscillator Hamiltonians. In all cases, a particular emphasis
is put on the recovery of the known continuous-limit results when the dimension
of the system increases.Comment: 21 pages, 4 figure
Found in Translation: Essays on Biblical Jewish Translation in Honor of Leonard J. Greenspoon
Found in Translation is at once a themed volume on the translation of ancient Jewish texts and a Festschrift for Leonard J. Greenspoon, the Philip M. and Ethel Klutznick Professor in Jewish Civilization and professor of classical and near Eastern studies and of theology at Creighton University in Omaha, Nebraska. Greenspoon has made significant contributions to the study of Jewish biblical translations, particularly the ancient translation of the Hebrew Bible into Greek, known as the Septuagint. This volume comprises an internationally renowned group of scholars presenting a wide range of original essays on Bible translation, the influence of culture on biblical translation, Bible translations’ reciprocal influence on culture, and the translation of various Jewish texts and collections, especially the Septuagint. Volume editors have painstakingly planned Found in Translation to have the broadest scope of any current work on Jewish biblical translation to reflect Greenspoon’s broad impact on the field throughout an august career.https://docs.lib.purdue.edu/purduepress_previews/1009/thumbnail.jp
Highly relativistic spinning particle starting near in a Kerr field
Using the Mathisson-Papapetrou-Dixon (MPD) equations, we investigate the
trajectories of a spinning particle starting near in a Kerr
field and moving with the velocity close to the velocity of light
( is the Boyer-Lindquist radial coordinate of the
counter-rotation circular photon orbits). First, as a partial case of these
trajectories, we consider the equatorial circular orbit with .
This orbit is described by the solution that is common for the rigorous MPD
equations and their linear spin approximation. Then different cases of the
nonequatorial motions are computed and illustrated by the typical figures. All
these orbits exhibit the effects of the significant gravitational repulsion
that are caused by the spin-gravity interaction. Possible applications in
astrophysics are discussed.Comment: 10 pages, 12 figure
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