13,574 research outputs found

    The 8^8B Neutrino Spectrum

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    Knowledge of the energy spectrum of 8^8B 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 8^8Be 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 8^8B. 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 8^8B to the accessible excitation energies in 8^8Be 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

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    "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

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    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

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    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

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    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 dd of the system increases.Comment: 21 pages, 4 figure

    Found in Translation: Essays on Biblical Jewish Translation in Honor of Leonard J. Greenspoon

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    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 rph(−)r_{ph}^{(-)} in a Kerr field

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    Using the Mathisson-Papapetrou-Dixon (MPD) equations, we investigate the trajectories of a spinning particle starting near rph(−)r_{ph}^{(-)} in a Kerr field and moving with the velocity close to the velocity of light (rph(−)r_{ph}^{(-)} 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 r=rph(−)r=r_{ph}^{(-)}. 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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