Bulletin of the American Physical Society
2006 Texas Section APS/AAPT/SPS Joint Spring Meeting
Thursday–Saturday, March 23–25, 2006; San Angelo, Texas
Session APS2: APS2: Contributed Oral Presentations |
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Chair: Christian Aars, Angelo State University Room: UC 203 |
Saturday, March 25, 2006 10:30AM - 10:42AM |
APS2.00001: High- resolution VLBA Observations of Low- Luminosity Radio Galaxies David Hough, Tait Ecklund, William Lester, Christian Aars There is a well-known dichotomy of radio galaxies: low- luminosity ``FR I'' objects have edge-darkened structures with twin kiloparsec-scale jets, while high-luminosity ``FR II'' sources have edge-brightened structures with one-sided kiloparsec-scale jets. The ``magnetic switch'' model of Meier et al. (1997, Nature, 388, 350) predicts that parsec-scale jet speeds will be slower (0.6c) in ``FR I'' objects and faster ($>$0.98c) in ``FR II'' sources. To test this model, we made high-resolution 8.4-GHz VLBA observations of the ``FR I'' radio galaxies 3C31, 3C76.1, 3C296, and 3C449 on 2003 August 13. All four objects have compact cores. 3C31 and 3C296 show well- resolved jet structures on the scale of about 1 pc, with possible counterjet features. Analyses of the current images suggest that the jets lie at large angles (75-80 degrees) to our line of sight, but do not provide strong constraints on jet speeds. Future observations are planned for direct measurements of jet speeds. [Preview Abstract] |
Saturday, March 25, 2006 10:42AM - 10:54AM |
APS2.00002: Correcting the Hubble constant, 41.6. Russell Collins The Hubble constant, obtained from a plot of measured distance vs. red shift Z, is seriously flawed. Distance must be extrapolated to present time. Only the Doppler portion of the red shift should be used. And the gravitational changes of the metric, through which the light passes, invalidates the inverse square law and leads to curvature of the Hubble plot. The big bang is modeled as a sphere of radius R=cT, with uniform mass density. The separation of Doppler shift $\beta$ from Z is accomplished by recognizing that the event time T* connects the gravitational and Doppler components. The gravitational potential decreases as the big bang expands, and this increases the measured optical distance. Extrapolation is had by multiplying distance by 1+$\beta$. Mass-metric relativity fully accounts for the curvature in high Z plots. Using a data set to Z=1.2 by Riess, one finds T=23.5 billion years (Ho=41.6). This is larger than present consensus values, T=14 billion years (Ho=71). Plotted as present distance vs. Doppler velocity, a linear Hubble plot is obtained. There is no need to invent “dark energy” to explain curved Hubble plots. Details at arxiv physics/0601013. [Preview Abstract] |
Saturday, March 25, 2006 10:54AM - 11:06AM |
APS2.00003: Is Quantum Mechanics Nonlocal? James Espinosa It has been accepted generally that as a result of experiment confirming the breaking of Bell's inequality that the world as described by quantum mechanics is nonlocal. We show that this is not the case. Bell's inequality is based on the introduction of hidden variables. We believe that it must be a requirement that only a probabilistic method can be used to decide whether or not quantum mechanics is local or nonlocal. We supply necessary and sufficient conditions for locality. [Preview Abstract] |
Saturday, March 25, 2006 11:06AM - 11:18AM |
APS2.00004: Lagrangian Densities and Principle of Least Action in Quantum Mechanics Donald H. Kobe A Lagrangian density in terms of the wave function and its first derivatives can be used to derive the Schroedinger equation. From this Lagrangian density, we derive an equivalent one involving the Hamiltonian with second derivatives of the wave function that is commonly used in quantum mechanics. Using Hamilton's Principle of Least Action, we obtain the time-dependent Schroedinger equation by varying with respect to the wave function. For a time-independent Hamiltonian and a stationary-state trial wave function, the Principle of Least Action gives the usual Rayleigh-Ritz energy variational principle. Using a Hartree product trial wave function for a many-boson system, we apply the Principle of Least Action to obtain the time-dependent Gross-Pitaevski equation, a nonlinear Schroedinger equation that describes a Bose condensate. [Preview Abstract] |
Saturday, March 25, 2006 11:18AM - 11:30AM |
APS2.00005: What is baryon spectroscopy and what should we do about it? Michael Sadler Existing determinations of the masses, widths and decay modes of low-lying excited states of the nucleon, as compiled in the Review of Particle Physics, are determined from energy-independent partial wave analyses of pion-nucleon scattering data. For the N*(1440) and most other resonances under 2 GeV, the analyses cited are the Karlsruhe-Helsinki, Carnegie Mellon-Berkeley and Kent State analyses, the latter of which used the elastic amplitudes from the other two. The data included in these analyses were published before 1980. Other analyses, notably the recent ones from George Washington University and the Pittsburgh-Argonne group, are ``not used for averages, fits, limits, etc.'' Complete sets of measurements (differential cross sections, analyzing powers and spin rotation parameters) have been measured in the N*(1440) resonance region since 1980, culminating in the Crystal Ball program at BNL to measure all-neutral final states (charge exchange, multiple $\pi ^{0}$ final states, $\eta $ production near threshold and inverse photoproduction). An overview of these data will be presented, the need for a revitalized partial wave analysis effort will be described, and plans for future experiments at ITEP in Moscow and J-PARC in Japan will be discussed. [Preview Abstract] |
Saturday, March 25, 2006 11:30AM - 11:42AM |
APS2.00006: Measuring the Spin of the Proton with an Upgraded PHENIX Muon Trigger Rusty Towell While significant progress has been made in understanding the structure of the nucleon, many important questions remain including the origin of the proton spin. Plans have been made to develop a new state-of-the-art trigger system for the PHENIX muon arms. With this new system a precise measurement of the flavor structure of the quark polarizations in the proton can be made via the observations of W-bosons in polarized proton-proton collisions. W-bosons can be detected in PHENIX through the appearance of a high-energy muon in one of the two existing muon spectrometers. The trigger upgrade is based on fast resistive plate counter stations. This talk will describe the proposed upgrade and some of the physics results that can be expected. [Preview Abstract] |
Saturday, March 25, 2006 11:42AM - 11:54AM |
APS2.00007: Supersymmetry from a Fundamental Statistical Theory Roland E. Allen, Seiichirou Yokoo This abstract was not submitted electronically. [Preview Abstract] |
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