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Full-Text Articles in Physical Sciences and Mathematics
Higher Twist Contributions To R-Hadron Phenomenology In The Light Gluino Scenario, Thomas D. Gutierrez, R. Vogt, J. F. Gunion
Higher Twist Contributions To R-Hadron Phenomenology In The Light Gluino Scenario, Thomas D. Gutierrez, R. Vogt, J. F. Gunion
Physics
The open light gluino window allows non-trivial higher-twist gluino contributions to the proton wave function. Using a two-component model originally developed for charm hadroproduction, higher-twist intrinsic gluino contributions to final-state R-hadron formation are shown to enhance leading-twist production in the forward xnF region. We calculate R-hadron production at Pnlab=800 GeV in pp, pBe, and pCu interactions with light gluino masses of 1.2, 1.5, 3.5, and 5.0 GeV.
Low-Frequency Crossover Of The Fractional Power-Law Conductivity In Srruo3, J. S. Dodge, Christopher P. Weber, J. Corson, J. Orenstein, Z. Schlesinger, J. W. Reiner, M. R. Beasley
Low-Frequency Crossover Of The Fractional Power-Law Conductivity In Srruo3, J. S. Dodge, Christopher P. Weber, J. Corson, J. Orenstein, Z. Schlesinger, J. W. Reiner, M. R. Beasley
Physics
We combine the results of terahertz time-domain spectroscopy with far-infrared transmission and reflectivity to obtain the conductivity of SrRuO 3 over an unprecedented continuous range in frequency, allowing us to characterize the approach to zero frequency as a function of temperature. We show that the conductivity follows a simple phenomenological form, with an analytic structure fundamentally different from that predicted by the standard theory of metals.
A Discotic Disguised As A Smectic: A Hybrid Columnar Bragg Glass, Karl Saunders, Leo Radzihovsky, John Toner
A Discotic Disguised As A Smectic: A Hybrid Columnar Bragg Glass, Karl Saunders, Leo Radzihovsky, John Toner
Physics
We show that discotics, lying deep in the columnar phase, can exhibit an x-ray scattering pattern which mimics that of a somewhat unusual smectic liquid crystal. This exotic, new glassy phase of columnar liquid crystals, which we call a “hybrid columnar Bragg glass,” can be achieved by confining a columnar liquid crystal in an anisotropic random environment of, e.g., strained aerogel. Long-ranged orientational order in this phase makes single-domain x-ray scattering possible, from which a wealth of information could be extracted. We give detailed quantitative predictions for the scattering pattern in addition to exponents characterizing anomalous elasticity of the system.
Two-Dimensional Pendulum Experiments Using A Spark Generator, Rand S. Worland, Matthew J. Moelter
Two-Dimensional Pendulum Experiments Using A Spark Generator, Rand S. Worland, Matthew J. Moelter
Physics
Student understanding of the superposition of perpendicular harmonic oscillators can be enhanced using a spark generator to record position-versus-time data for smallamplitude pendulum motion in two dimensions. Our students have used this arrangement to analyze the motion of a spherical pendulum and a “Y-suspended” (Blackburn) pendulum that has two effective lengths.
Occurrence And Distribution Of Diverse Populations Of Magnetic Protists In A Chemically Stratified Coastal Salt Pond, Dennis A. Bazylinski, David R. Schlezinger, Brian H. Howes, Richard B. Frankel, Slava S. Epstein
Occurrence And Distribution Of Diverse Populations Of Magnetic Protists In A Chemically Stratified Coastal Salt Pond, Dennis A. Bazylinski, David R. Schlezinger, Brian H. Howes, Richard B. Frankel, Slava S. Epstein
Physics
Chemical stratification occurs in the water columns and sediments of many aquatic habitats resulting in vertical chemical and redox gradients. Various types of microorganisms are often associated with specific depths and chemical parameters in these situations. For example, magnetite-producing magnetotactic bacteria are known to form horizontal “plates” of cells at the oxic/anoxic transition zone (OATZ) of such environments. Here, we report the presence of populations of diverse magnetic protists in a seasonally chemically stratified, coastal salt pond. The protistan types included several biflagellates, a dinoflagellate, and a ciliate that were each associated with specific depths and thus, specific chemical, microbiological …
Doomsday Fears At Rhic, Thomas D. Gutierrez
Doomsday Fears At Rhic, Thomas D. Gutierrez
Physics
This year, the Relativistic Heavy Ion Collider (RHIC) is poised to begin a program of cutting-edge nuclear science. Recently, alarmist journalism unnecessarily raised public fears about implausible doomsday scenarios associated with the machine.
Magnetite Biomineralization And Ancient Life On Mars, Richard B. Frankel, Peter R. Buseck
Magnetite Biomineralization And Ancient Life On Mars, Richard B. Frankel, Peter R. Buseck
Physics
Certain chemical and mineral features of the Martian meteorite ALH84001 were reported in 1996 to be probable evidence of ancient life on Mars. In spite of new observations and interpretations, the question of ancient life on Mars remains unresolved. Putative biogenic, nanometer magnetite has now become a leading focus in the debate.
Superconductor-Insulator Transition In Granular Pb Films Near A Superconducting Ground Plane, Richard P. Barber Jr., S. R. Khan, Eric Morre Pedersen, Ben Kain, A. J. Jordan
Superconductor-Insulator Transition In Granular Pb Films Near A Superconducting Ground Plane, Richard P. Barber Jr., S. R. Khan, Eric Morre Pedersen, Ben Kain, A. J. Jordan
Physics
We report observations of the zero-field superconductor-insulator transition in granular quench-condensed Pb for samples within 10-15 nm of relatively thick superconducting ground planes. Resistance vs temperature measurements of sufficiently thick Pb samples exhibit broadened superconductor transitions consistent with previous results on clean dielectric substrates. The lack of any measurable influence by the superconducting planes on the Pb film resistance is discussed within the context of zero-field vortex-antivortex unbinding explanations for the transition broadening.
Topologically Ordered Phases Of Smectics Confined In Anisotropic Random Media: Smectic Bragg Glasses, Karl Saunders, Brad Jacobsen, Leo Radzihovsky, John Toner
Topologically Ordered Phases Of Smectics Confined In Anisotropic Random Media: Smectic Bragg Glasses, Karl Saunders, Brad Jacobsen, Leo Radzihovsky, John Toner
Physics
We report the existence of two new topologically ordered glass phases of smectics in strained aerogel. In contrast to the case of unstrained aerogel, we find compelling theoretical arguments that a smectic in uniaxially stretched aerogel exhibits, for homeotropic nematic-aerogel alignment, a `smectic Bragg glass' in the universality class of the `XY Bragg glass'. On the other hand, a uniaxial compression, with homeotropic alignment, leads to an entirely novel type of anisotropic smectic elastic glass phase that we call the `m = 1 Bragg glass'. This latter phase exhibits anomalous elasticity, characterized by exponents that we calculate to high precision. …
Biologically-Controlled Mineralization Of Magnetic Iron Minerals By Magnetotactic Bacteria, D. A. Bazylinski, R. B. Frankel
Biologically-Controlled Mineralization Of Magnetic Iron Minerals By Magnetotactic Bacteria, D. A. Bazylinski, R. B. Frankel
Physics
No abstract provided.