Bulletin of the American Physical Society
APS April Meeting 2010
Volume 55, Number 1
Saturday–Tuesday, February 13–16, 2010; Washington, DC
Session M1: Welcome Reception and Poster Session II: (7:00-9:00 PM) |
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Room: Exhibit Hall A-B-C |
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M1.00001: FEW-BODY SYSTEMS AND NUCLEAR PHYSICS |
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M1.00002: Is there evidence of simple relationship among measured yrast energies in even-even nuclei? Dongwoo Cha, Jin-Hee Yoon, Dooyoung Kim We benefit often by studying particular nuclear properties in terms of simple variables over the wide span of the chart of nuclides. A well-known such example for the ground state is the semi-classical mass formula. But, there have seldom appeared similar studies on observables concerning the excited states of nuclei. In this work, we collect measured yrast energies in even-even nuclei and test whether there exists any simple relationship among them. [Preview Abstract] |
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M1.00003: Precision Measurement of $d_2^n$: Probing the Lorentz Color Force David Flay In order to gain a better understanding of the spin structure of the neutron, the experiment to measure the quantity $d_2^n$ was carried out from February to March of 2009 at Jefferson Lab. The experiment consisted of measuring the asymmetries $A_{\vert \vert}$ and $A_\perp$, and the total cross section $\sigma_0$ by scattering a longitudinally polarized electron beam off of a longitudinally and transversely polarized $^3$He target. The experiment covered excitation energies in the deep inelastic valence quark and resonance regions. From the asymmetries and total cross section, the spin dependent structure functions $g_1$ and $g_2$ will be extracted. Using these, the quantity $d_2^n$ is determined as the second moment of a linear combination of $g_1$ and $g_2$. $d_2^n$ is a measure of the Lorentz color force between quarks averaged over the volume of the neutron. The measurement will provide a benchmark test of Lattice QCD calculations of $d_2^n$ by lowering the uncertainty in the present value by a factor of approximately four. This measurement will also provide for further understanding of quark-gluon correlations in connection to the nucleon spin structure. [Preview Abstract] |
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M1.00004: Maximum Entropy Analysis of Lattice QCD Data for Hadron Mass Spectrum Tom Harsono, Frank X. Lee The application of the Maximum Entropy Method (MEM) to the analysis of lattice QCD data is presented. We obtain information on the mass spectrum of hadrons by extracting spectral functions from correlation functions. Tests, results, and limitations of the MEM algorithm are discussed. The data sets are on $20^3\times 32$ quenched lattices using the overlap fermion action, with pion mass as low as 180 MeV. A variety of mesons and baryons are considered, with focus on the extraction of the 1st excited states of the hadrons. [Preview Abstract] |
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M1.00005: Eta-Nucleon Coupling Constant with SU(3) Breaking Contributions in QCD Sum Rules Janardan P. Singh, Frank X. Lee We study the $\eta$NN coupling constant using the method of QCD Sum Rules starting from the vacuum-to-eta correlation function of the interpolating fields of two nucleons. The matrix element of this correlation has been taken with respect to nucleon spinors to avoid unwanted excited states. The SU(3) breaking effects have been accounted in the form of ?-mass, s-quark mass and eta decay constant. The results obtained have been compared with phenomenologically determined values of the coupling constant from literature. [Preview Abstract] |
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M1.00006: Deconfinement of Quarks with TeV Attosecond Photon Beams V. Alexander Stefan Recently, I have proposed a novel heuristic method for the deconfinement of quarks.\footnote{M. Gell-Mann. \textbf{The Quark and the Jaguar: Adventures in the Simple and the Complex }(New York, NY: W.H. Freeman and Co., 1994) [cf. M. Gell-Mann, \textit{The Garden of Live Flowers} in: V. Stefan (Editor), \textbf{Physics and Society. Essays Honoring Victor Frederick Weisskopf }(Springer, 1998), pp. 109-121].} It proceeds in two phases.\footnote{V. Alexander Stefan, \textbf{On a Heuristic Point of View About Inertial Deconfinement of Quarks}, American Physical Society, 2009 APS April Meeting, May 2-5, 2009, abstract {\#}E1.038.} Firstly, a frozen hydrogen pellet is inertially confined by the ultra-intense lasers up to a solid state density. Secondly, a solid state nano-pellet is ``punched'' by the photon beam created in the beat wave driven free electron laser (BW-FEL), leading to the ``rapture'' (in a ``karate chop'' model) of the ``MIT Bag''\footnote{J. I. Friedman and H. Kendall, \textit{Viki}, in: V. Stefan (Editor), \textbf{Physics and Society. }(Springer, 1998), pp. 103-108].\par } before the asymptotically free quarks move apart. Hereby, I propose TeV, a few 100s attosecond, photon beams in interaction with the nano-pellet. The threshold ``rapture force'' of the TeV attosecond photon is 10$^{7 }$N. [Preview Abstract] |
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M1.00007: Neutron Detection Efficiency in the Crystal Ball and TAPS at MAMI Zoe Marinides The aim of the research project is to determine the neutron detection efficiency of the Crystal Ball and Two Armed Photon Spectrometer (TAPS) detector system used in the A2 collaboration at MAMI, at the University of Johannes Guttenberg in Mainz, Germany. A photon beam of energies up to 1.5 GeV is used to investigate photodisintegration and photo-production processes from a deuterium target. By looking at both the breakup of the deuteron into the proton and neutron, as well as coherent $\pi ^{0 }$production, the efficiency of neutron detection can be determined at a range of energies. The results of the efficiency measurements are essential in determining cross sections for future experiments as well as in testing the accuracy of simulations for channels such as double $\pi ^{0}$ and $\pi ^{0}\eta $ production on the neutron. [Preview Abstract] |
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M1.00008: Gas Chromatography Patrick Hansen, C. Steven Whisnant To prepare frozen-spin HD targets for photonuclear physics at JLab, high purity HD is required. Commercially available gas is only $\sim$98\% HD. To reach the purity required to make nuclear targets, the gas is distilled at low temperature to remove the H$_2$ and D$_2$ impurities. To monitor the distillation process and correlate the gas purity with the spin relaxation times, a low temperature gas chromatograph system has been developed that produces good separation of H$_2$, HD and D$_2$. The system uses a PLOT 5A column in a mixture of LN$_2$ and i-pentane at temperatures between 110K and 135K. With this system, the relative concentrations can be determined with uncertainties of $\sim$10\%. The chromatography process and the resulting chromatograms will be discussed. [Preview Abstract] |
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M1.00009: Tagging Efficiency Measurements at the A2 Glasgow Photon Tagging Facility at MAMI Brendan Freehart We present the analysis of experiment-specific measurements of the efficiency of the Glasgow Photon Tagging Spectrometer in the A2 Hall at the Mainz Microtron (MAMI C). The photon tagger is being used for Crystal Ball and TAPS experiments. MAMI C is a particle accelerator capable of producing energies of up to 1.604 GeV. Photons are produced from the MAMI electron beam via bremsstrahlung on a thin radiator. Electrons that have radiated photons are analyzed by the tagger spectrometer. The photons are collimated, and thus only a fraction of the ``tagged'' photons get to the target. Special runs measure the ratio of analyzed electrons to tagged photons at the target position. This ratio is used to normalize the experimental cross section. We present tagging efficiencies for experiments eta production on Helium-3, threshold pion production, and meson production on the proton and deuterium. [Preview Abstract] |
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M1.00010: Tagging Efficiency Measurements at the Nuclear Physics Beam Line at MAX-lab Matty Litwack A comprehensive series of near-threshold pion photoproduction measurements have been approved for the Tagged-Photon Facility at MAX-lab, the Swedish National Electron Accelerator Facility located at Lund University in Lund, Sweden. The photon beam is produced via bremsstrahlung radiation when a 200 MeV pulse-stretched electron beam strikes a 300 $\mu $m aluminum foil. To determine the absolute probability for producing pions, the exact number of photons striking the target must be known. This information is determined using the photon-tagging technique, where the momenta of the post-bremsstrahlung electrons are determined together with the number of radiated photons, their energies and their relative timings. An important quantity in the photon-tagging process is the tagging efficiency. The tagging efficiency is the ratio of the number of photons striking the target to the total number of photons produced at the radiator. In this poster, the principles of photon tagging and tagging efficiency are illustrated. A detailed analysis of the daily tagging efficiencies determined during a recent four-week run period at MAX-lab is presented, and conclusions based on these results are discussed. [Preview Abstract] |
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M1.00011: Proton Identification using Plastic Scintillator Counters at MAX-lab Jason Lemrise One of the most important questions in nuclear science is describing the properties of the nucleon in terms of the framework provided by QCD. The QCD calculations in the low-energy nuclear region are impossible to do using standard techniques, making it necessary to use alternate approaches to solve these calculations. Two processes for which these techniques are both valid and useful are pion photoproduction and nuclear Compton scattering below the $\Delta$ resonance. The newly upgraded tagging facility at MAX-lab in Lund, Sweden is capable of tagging photons at energies up to 200 MeV, and is ideally suited to make measurements of these fundamental processes in the low-energy region. High-quality measurements are needed to test the predictions of the various quark-based models. To achieve the required precision, it is necessary to understand the detectors used for the measurements. For the pion photoproduction experiments, it is necessary to understand both the detection efficiency for different particle types and the energy determination from the plastic scintillator counters. Since the $^{12}C(\gamma, p)$ cross-section is well known, its determination using the proton yield from the counters and the photon flux from the tagger serves as a good test of the systematics of the new MAX-lab facility. An overview of the particle identification and energy determination for protons from $^{12}$C$(\gamma, p)$ will be shown. [Preview Abstract] |
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M1.00012: Pion Identification in Photonuclear Measurements at MAX-lab Colleen Allen One of the important questions in nuclear science is to describe the properties of the nucleon in terms of a QCD-based framework. In the low-energy nuclear region, the QCD calculations are impossible to do using standard techniques, so it is necessary to use alternate approaches. A process where these other techniques are both valid and useful is near-threshold pion photoproduction. This process involves a rearrangement of the quarks in the nucleon and thus is directly accessing the underlying quark structure. The newly upgraded tagging facility at MAX-lab in Lund, Sweden is capable of tagging photons at energies up to 200 MeV and is ideally suited for performing measurements of pion photoproduction in the energy range from threshold to the $\Delta$-resonance. Standard $\Delta$E vs.\ E particle identification methods are insufficient to separate the pions from the very large proton and electron background. By searching for the 4.12~MeV muon from pion decay in the E~counter, it is possible to identify candidate pion events. A final cross-check of the pion identification is made by examining the decay curve for these candidate pion events. In order to determine accurate cross sections, it is necessary to correct the final pion yield for events lost through the particle identification cuts, as well as for the misidentification of background events as pions. The particle identification techniques and analysis will be shown. [Preview Abstract] |
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M1.00013: CUORE: Cryogenic Maintenance Alison Goodsell, Robin Reil CUORE (Cryogenic Underground Observatory for Rare Events) will be the largest detector used to investigate neutrinoless double beta decay in $^{130}$Te. Neutrinoless double beta decay has never been observed in nature. If detected, it would be a major scientific discovery indicating that the neutrino is its own antiparticle; this breakthrough would signal a fundamental revision to the Standard Model of physics. Located in Assergi, Italy at the Gran Sasso National Laboratory (LNGS), CUORE will be a cryogenic bolometer composed of 988 TeO$_2$ crystals with a total mass of 750 kg. Over the summer of 2009, we traveled to the LNGS to assist the CUORE Collaboration by performing standard shifts for the Three Towers Test, a diagnostic experiment used to determine optimal hardware cleaning methods. Shifts involved refilling the cryogenics system with liquid helium coolant to keep the crystal bolometers at an operating temperature of approximately 10 mK, and other routine tasks. [Preview Abstract] |
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M1.00014: GEM Detectors for Muon Tomography of Nuclear Contraband Amilkar Quintero, Kondo Gnanvo, Leonard Grasso, Judson Locke, Debasis Mitra, Marcus Hohlmann The construction of a Muon Tomography station is presented. Muon Tomography (MT), based on scattering of cosmic ray muons, is an improvement to actual portal monitors at borders, since the current techniques use regular radiation detection that are not very sensitive to nuclear contraband (U, Pu), if these materials are well shielded to absorb emanating radiation. We use a low mass, high spatial resolution ($\sim $50 $\mu $m) Gas Electron Multiplier (GEM) detectors for MT to overcome the intrinsic limitations. The prototype MT station employs 6 tracking stations based on 33cm x 33cm triple-GEM detectors with 2D readout. The detectors are arranged into tracking superlayers at the top and bottom of the probed volume. Due to the excellent spatial resolution of GEM, it is sufficient to use few cm gap between tracking stations. We present details of the production and assembly of the GEM-based tracking stations in collaboration with CERN-GDD lab and RD51 experiment as well as the design of the corresponding front-end electronics and readout system. Discussion about GEM detectors in two sides of the probed volume for a complete muon tracking, and large-area (1m x 1m) GEM-based MT station prototype to be tested under realistic conditions, are made. [Preview Abstract] |
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M1.00015: PARTICLES AND FIELDS |
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M1.00016: A New Derivation of Biquaternion Schr\"{o}dinger Equation and Plausible Implications Vic Christianto, Florentin Smarandache In the preceding article we argue that biquaternionic extension of Klein-Gordon equation has solution containing imaginary part, which differs appreciably from known solution of KGE. In the present article we discuss some possible interpretation of this imaginary part of the solution of biquaternionic KGE (BQKGE); thereafter we offer a new derivation of biquaternion Schr\"{o}dinger equation using this method. Further observation is of course recommended in order to refute or verify this proposition. [Preview Abstract] |
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M1.00017: Double Chooz Slow Monitoring System Pi-Jung Chang, Glenn Horton-Smith, David McKee, Deepak Shrestha, Lindley Winslow, Janet Conrad The Double Chooz experiment aims to measure neutrino flux from two nearly identical detectors with an uncertainty less than 0.6{\%}. The Double Chooz slow monitoring system records conditions of the experiment's environment which can impact the experiment's goals. The slow monitoring system includes temperatures and voltages in electronics, experimental hall environmental conditions, line voltages, liquid temperatures, PMT's magnetic field, radon concentrations, and photo-tube high voltages. This system scans all channels automatically, stores data in a common database, and warns of changes in the two detectors' physical environments. Most functions in this system can be accomplished by 1-Wire{\textregistered} products from Dallas Semiconductor. We can use a single master for several functions' controls and operations and the power is derived from a signal bus. Every device has a unique unalterable ID. The sensors monitoring the liquid system, such as liquid thermal meters, are covered by epoxy in order to isolate in the liquid. Their radioactivity can be ignored and will not affect the uncertainty in the system. [Preview Abstract] |
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M1.00018: Simulation of Scalar Potential Model of photon diffraction John Hodge A model of the single slit experiment with particle-like light was proposed (SESAPS log. No. SES09-2009-000064). The model combined the Bohm interpretation with the Scalar Potential Model (SPM) of photons. A toy model computer simulation was developed. The pattern on the screen showed a pulse pattern rather than a diffraction wave pattern. Although showing promise, the model needs more work. The papers may be viewed at \underline {http://web.citcom.net/$\sim $scjh/} . [Preview Abstract] |
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M1.00019: The Effective Kahler Potential, Metastable Vacua and R-Symmetry Breaking in O'Raifeartaigh Models Ben Kain, Shermane Benjamin, Christopher Freund Much has been learned about metastable vacua and R-symmetry breaking in O'Raifeartaigh models. Such work has largely been done from the perspective of the superpotential and by including Coleman-Weinberg corrections to the scalar potential. Instead, we consider these ideas from the perspective of the one loop effective K\"ahler potential. We translate known ideas to this framework and then construct convenient formulas for computing individual terms in the expanded effective K\"ahler potential. We do so for arbitrary R-charge assignments and allow for small R-symmetry violating terms so that both spontaneous an explicit R-symmetry breaking is included in our analysis. [Preview Abstract] |
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M1.00020: Search for the Standard Model Higgs boson produced in Vector Boson Fusion and decaying into a tau pair in CMS Anthony Moeller The Standard Model Higgs boson produced in vector boson fusion and decaying to a pair of tau leptons is an important channel in the search of the Higgs boson in the mass range between 115 and 145 GeV. A selection strategy for the tau tau-$>$ lepton+neutrinos+jet final state is presented. [Preview Abstract] |
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M1.00021: PARTICLE THEORY |
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M1.00022: The Fine-Structure Constant \& Quantization are prescribed by Einstein's Equations Bill Webb The string theory closed-loop hydrogen electron is assumed to be stretched to its full circumferential length. This distinctive shape, developed by the Quarkeosynthesis Model, supports a natural standing wave with frequency equal to that of the photon it will emit. The energy of the electron's wave is given by the Einstein Photon equation. The ratio of the electron's wave energy to its total mass-energy correctly prescribes both the quantization requirement and the fine-structure constant. [Preview Abstract] |
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M1.00023: A Simple Model and Unified Theory of Elementary Particles and Interactions (UTOEPI) Ashok Sinha This paper introduces a new paradigm involving the concept of a three-dimensional time which, together with the usual three-dimensional space, forms a six-dimensional spacetime, as an extension of Einstein's 4-D spacetime continuum, for explaining elementary particle and cosmological phenomena. A simple unified theory of elementary particles and the four basic interactions is developed, including a parametric representation of the elementary particle masses in terms of the basic parameters of the interactions. The questions of supersymmetry and the Higgs field are briefly discussed. Development of a statistical theory (Maxwell-Boltzmann Equation) of a relativistic quark-gluon plasma in the manifestly 4-covariant and 6-covariant forms is indicated, illustrating the interrelations among the four interactions. [Preview Abstract] |
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M1.00024: The 5th Generation model of Particle Physics Theodore Lach Recent discoveries of the excited states of the B meson along with the discovery of the omega-b-minus have brought into popular acceptance the concept of orbiting quarks predicted by the Checker Board Model (CBM) 14 years ago. Back then the concept of orbiting quarks was not fashionable, the bag model was the dominate theory. Recent estimates of velocities of these quarks inside the proton and neutron are in excess of 90{\%} the speed of light also in agreement with the CBM prediction. Still a 2D structure of the nucleus has not been accepted. The CBM predicts masses of the up and dn quarks (which make up the proton and neutron) of 237.31 MeV and 42.392 MeV respectively and suggests that a lighter generation of quarks u and d make up a different generation of quarks that make up light mesons. The CBM also predicts that the T' and B' quarks do exist and are not as massive as might be expected. [Preview Abstract] |
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M1.00025: Every Elementary Particle Will Exhibit No Motion, Linear, Rotational and or Vibratory Motion, Singly or in Some Combination a Natural Law and Therefore, The Mass Energy Conservation Law Regarding Particle Creation Must Include Those Factors Stewart Brekke Every mass has no motion, linear, rotational and or vibratory motion singly or in some combination. Therefore, every elementary particle will exhibit these characteristics. Therefore, mass-energy equivalence for particle conservation law of elementary particle interaction is $m_1c^2 +1/2m_1v_1v^2 + 1/2I\omega_1^2 + 1/2k_1x_1^2 + m_2c^2 + 1/2m_2v_2^2 +1/2I_2\omega_2^2 + 1/2k_2x_2^2+...= m_3c^2 +1/2m_3v_3^2 +1/2I_3\omega_3^2 + 1/2k_3x_3^2 + m_4c^2 + 1/2m_4v_4^2 + 1/2I_4\omega_4^2 + 1/2k_4x_4^2 +...$ [Preview Abstract] |
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M1.00026: Vector Pion Model and the Pion-Muon Decay Asymmetry Walton Perkins From the pion-muon asymmetry experiments of the 1950's and 1960's, there is significant evidence that pions can carry a direction. There is also solid evidence that the spin of the pion is zero. These two sets of evidence are not necessarily mutually exclusive. Along the lines of Yukawa's original ideas, we consider a pion-photon model with both being composite particles formed from the same fermions and antifermions. In this model the pion is an helicity-0 vector particle with longitudinal polarization. If such pions are created by protons impinging on a low-Z target, theory predicts that they will be almost completely polarized along the direction of the proton beam. Indeed, the pion-muon asymmetry experiments showed a longitudinal polarization along the direction of the proton beam. Since an helicity-0 vector pion has no magnetic moment, the direction of the its polarization relative to its momentum can be changed by bending it in a magnetic field, leading to an experiment that can prove that the pion is not a pseudoscalar particle. See W. A. Perkins, ``Pion-Muon Asymmetry Revisited,' http://arXiv.org hep-ph/0807.3182v1 (2008). [Preview Abstract] |
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M1.00027: Unification of Einstein's Gravity with Quantum Chromodynamics Jack Sarfatti The four tetrad and six spin-connection Cartan 1-forms of Einstein's GeoMetroDynamic (GMD) field emerge from the eight virtual gluon macro-quantum coherent QCD post-inflation vacuum condensates that form in the inflationary phase transition. This joint emergence of gravity and the strong force is similar to the emergence of irrotational superflow with vortex defects in liquid helium below the Lambda Point. Repulsive dark energy is from the residual random virtual bosons that did not cohere in the moment of inflation. Similarly, attractive dark matter is from the residual random virtual fermion-antifermion pairs. Therefore, I predict that the LHC will not detect any on-mass-shell real particles that can explain $\Omega _{DM} \sim 0.23$. As first suggested by Abdus Salam (f-gravity) the low energy tail of the nuclear force can be explained as strong short-range Yukawa gravity. QCD's IR confinement and UV asymptotic freedom are elementary consequences in this simple model. [Preview Abstract] |
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M1.00028: Signatures of Fourth Generation Quarks in Mesons Martin McHugh, Erin De Pree It is possible that we will see fourth generation particles produced at the Large Hadron Collider. We extend the standard model to include a sequential fourth generation of quarks, the most straight-forward approach. If the mass difference between the two heavy quarks is less than the mass of the $W^{\pm}$-boson, then the heavier quark cannot decay directly into one the lighter fourth generation quark. Unitarity requires the $V_{34}$ mixing angle remain small. This surpresses the heavy quark decay rates and may allow both heavy quarks to live long enough to hadronize. We consider signatures of the fourth generation quark (or anti-quark) forming a meson with a Standard Model anti-quark (quark). [Preview Abstract] |
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M1.00029: UNDERGRADUATE RESEARCH (Including Society of Physics Students) |
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M1.00030: Crater Ages, Hydrogen Deposition and LRO Neutron Mapping of the Lunar Surface Daniel McNeel, Larry Evens, Timothy McClanahan, Boris Kiefer The knowledge of the abundance and distribution of natural resources on the moon has been a challenge for many decades. Neutron observation from the Lunar Prospector mission suggests the presence of water/ice mainly in the permanent shadows of craters close to the lunar north- and south-pole. In contrast to previous mission, LRO has a much smaller field of view and it will be possible to use these improved neutron count rates to locate water/ice much more accurately. According to current theory hydrogen particles in the solar wind are deposited on the surface of the moon over time. The neutron detectors on both the 1998 Lunar Prospector and the current LRO missions detect the presence of hydrogen by the decrease of the epithermal count. This research compares the neutron maps made by Lunar Prospector to the ages of craters from the Lunar Impact Crater Database to determine if there is a relationship between neutron flux and age of the crater. This method incorporates many more craters for a survey of the neutron count over all of the lunar history. Using this method, it is possible to determine how much the LRO sensitivity can increase our knowledge of crater age. [Preview Abstract] |
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M1.00031: NIR PCA of Mars Peter Harrison The possibility of upcoming human exploration of Mars and the refining of climate and weather models make understanding Mars' water cycle and budget an important undertaking. The research in this project, the study of Martian clouds, is a step in the overall scheme to this understanding. In order to measure the water content of clouds it is necessary to be able to remove the effect of the Martian surface on the data. I am using Principle Components Analysis (PCA) to look for baseline spectra which are consistent throughout all the data. These can then be used to search for surface spectral endmembers, as it is assumed that these should be unchanging. This research is comparing the PCA of some of our best observations of Mars to research previously done in order to provide a more comprehensive characterization of these surface endmembers. Over five successive oppositions, near-infrared images of Mars were taken at the NASA Infrared Telescope Facility. The data were then reduced, calibrated, and remapped. Using the stellar photometry from each night the most consistent nights for data collection were found. Finally, PCA was applied to these best data. I present the results from that PCA and compare it to previous results. [Preview Abstract] |
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M1.00032: Searching for Superconducting Cosmic Strings Calvin Woo The cusp (or kink) of a superconducting cosmic string is expected to produce gravitational waves (GW) and electromagnetic radiation. Both the GW and the electromagnetic emissions are beamed along the direction of motion of the cusp, leading to an enhancement in the observed signal if the Earth lies within the beam. The electromagnetic luminosity may be substantially larger than the gravitational luminosity. It has been argued that searches in the radio spectrum would be optimal for the detection of these bursts. Such cosmic strings would be part of networks created during phase transitions in the early universe. These networks could even be composed of cosmic superstrings. We will present details of an ongoing search for such events by the Eight-meter-wavelength Transient Array (ETA). [Preview Abstract] |
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M1.00033: Sparks from Superconducting Cosmic Strings Kevin Chen Cosmic strings would be part of networks created during phase transitions in the early universe. These networks could even be composed of cosmic superstrings. The cusp or kink of a superconducting cosmic string is expected to produce a burst of electromagnetic radiation. Such a burst or ``spark'' would be relativistically beamed as a low frequency electromagnetic pulse. Results of a numerical simulation estimating the event rate of such ``sparks'' detectable with current radio telescopes will be presented. [Preview Abstract] |
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M1.00034: Designing Electronics and PMT Housing for a Liquid Scintillation Detector to be Used for Measuring Muon-Induced Processes at Homestake Brian Woltman, Patrick Davis, Dongming Mei, Chao Zhang Understanding the backgrounds produced by muon-induced processes is important to the success of experiments searching for rare event physics such as neutrinoless double-beta decay, dark matter, or neutrino oscillations, which require extremely low backgrounds. Measuring these muon-induced processes is vital for the low background experiments planned for the Sanford Lab. We have designed a detector to measure the muon-induced backgrounds produced underground. Our detector consists of a 10.8 liter scintillator joined with two PMT's. We will present our design for housing the PMT's, including their attachment to the scintillator and necessary magnetic shielding. We will also present our design for a voltage divider that was constructed and tested for use on the PMT's. [Preview Abstract] |
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M1.00035: Magnetic enhancement of neutrino oscillations in matter William Porter, Todd Tinsley Neutrinos produced in supernovae and other astrophysical phenomena are subject to matter-induced flavor oscillations, or the MSW effect. A common characteristic among such events is the intense magnetic field that often is produced. We consider what effects the magnetic field has on matter-induced oscillations. We begin by deriving the correction to the phase difference between two neutrino mass eigenstates to first order in the magnetic field strength. This result is compared to the free field case. [Preview Abstract] |
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M1.00036: Ground Motion Sensing Using a Triangular Laser Lauren Kendall Seismologists have known for decades that seismic waves can create rotational ground motion. There are documented cases in Japan where tombstones have been rotated during strong earthquakes. The effect of ground rotation on buildings, bridges, overpasses, hydroelectric dams, pipelines, and levee systems has been hard to determine because of the difficulties in measuring ground rotation. By capitalizing on the extreme sensitivity of large ring lasers to rotation, high resolution ground rotation measurements are now possible. This presentation will include a discussion of the ring laser's operation and the ground rotation results. [Preview Abstract] |
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M1.00037: Optical tweezers position measurement - comparing position sensitive detectors and high-speed cameras Laura Sparks, John Sharpe The design and construction of a low-cost optical trapping system is described. Trapping is performed on 1 micron diameter silica beads using 785 nm light from a diode laser. The particle position is measured using visible 633 nm light imaged onto a position sensitive lateral effect photodiode. We simultaneously acquire images of the trapped particle with a high-speed CCD camera and compare the accuracy of the camera to that obtained with the position sensitive detector. [Preview Abstract] |
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M1.00038: Examination of Brownian vortex dynamics of an aerosol droplet trapped in a horizontal optical tweezers Aaron Lemmer, Luke Titus The use of optical tweezers in aerosol research greatly facilitates the characterization of the physical properties and dynamics of individual droplets. Using a modified single-beam optical trap to determine the position of a droplet in three-dimensional space, trends in the dynamics of single saline droplets trapped in air have been examined. We consider the possibility that non-conservative optical forces bias the average motion of a given droplet such that it circulates in a toroidal manner. [Preview Abstract] |
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M1.00039: ABSTRACT WITHDRAWN |
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M1.00040: Growth and Characterization of GdGaO3 Multilayer Structures Kunal Bhatnagar, Toni Sauncy, Ravi Droopad Molecular Beam Epitaxy (MBE) is an advanced atomic precision epitaxial deposition technique that utilizes Ultra High Vacuum conditions for optimal crystal growth. Recently, new MBE facilities have been installed at Texas State University. The facility includes growth chambers for III-V compound semiconductor, Si, II-VI semiconductors and analysis chambers for STM, XPS, LEED and other characterization techniques. Several novel structures have been produced and analyzed using characterization facilities at Angelo State University, namely Spectroscopic Ellipsometry(SE). SE is a non-destructive thin film characterization technique used for determining film thickness, interfacial roughness and optical properties of multilayered structures. Gadolinium Gallium Oxide(GdGaO3) is one material that is important as a high-k dielectric in compound semiconductor MOSFET application and has not been characterized very well using ellipsometry. Ellipsometric data will be presented for GaGdO3 on GaAs and optical properties will be discussed. [Preview Abstract] |
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M1.00041: Electrodeposition and Characterization of Thin Films Created for Giant Magnetoresistance Alyssa Frey, Nicholas Wozniak, Jennifer Hampton Giant magnetoresistance occurs when a non-magnetic thin film is sandwiched between two magnetic films. In the presence of an external magnetic field, the magnetic films align, allowing increased current flow. Electrodeposition was used to deposit nickel-iron and copper films from sulfate solutions containing 100 mM nickel, 10 mM iron, and 1 mM copper onto gold-plated silicon wafers. Particle induced x-ray emission (PIXE) and atomic force microscopy (AFM) were used to study how the deposition time and deposition potential affect the composition and surface roughness of the deposits. PIXE analysis showed that at less negative potentials, the deposit is dominated by copper, and at more negative potentials, the deposit has a greater nickel and iron concentration. The ratio of iron to total magnetic material changes with varying potential and reaches a maximum value at -900 mV. Analysis of RMS roughness from the AFM data for varying length scales reveals the fractal nature of the deposits below a characteristic length. [Preview Abstract] |
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M1.00042: Automated data acquisition of switching events of current-biased Josephson Junctions Pubudu Galwaduge, Zechariah Thrailkill, Joseph Lambert, Steven Carabello, Roberto Ramos A data acquisition and visualization system was developed by combining LabView, C++ and batch scripts. The system automates the collection of large amounts of data at high sampling rates and was used to observe the resonant activation of current-biased Josephson junctions operating near the classical-quantum crossover. Above the characteristic crossover temperature, the junction behaves classically. Below the crossover temperature, it shows quantum features. [Preview Abstract] |
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M1.00043: Theory of the Anisotropic Magnetoresistance in Copper Yoichi Takato, Nebi Demez, Shigeji Fujita, Salvador Godoy The motion of the guiding center of magnetic circulation generates a charge transport. The application of kinetic theory to the motion gives a formula for the magnetoconductivity: $\sigma = e^2 n_{\mathrm{c}} \tau /M^*$, where $M^*$ is the magnetotransport mass distinct from the cyclotron mass, $n_{\mathrm{c}}$ the density of the conduction electrons, and $\tau$ the relaxation time. The density $n_{\mathrm{c}}$ depends on the applied magnetic field direction relative to copper's face-centered-cubic lattice, when the Fermi surface of copper is nonspherical with \emph{necks}. The anisotropic magnetoresistance of copper is calculated. A good fit with experiments is obtained. [Preview Abstract] |
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M1.00044: Patterns in Vertically Oscillated Granular Layers: Experiment and Simulation Dustin Kimble, Jon Bougie Vertically oscillated layers of grains provide an important testbed for studying the physics of granular materials. I will present an ongoing undergraduate experimental research project investigating the self-organization of granular media. When shaken vertically and sinusoidally, grains self-organize into patterns such as squares, stripes, and hexagons. Using a modified subwoofer I have built an apparatus to fluidize grains so that granular phenomena can be examined. This experimental project is designed to complement an ongoing computational study of hydrodynamic models of granular media, and can be extended beyond pattern formation to study other granular phenomena. Finally, this experimental component was initiated by an undergraduate student, illustrating the importance of student initiative in establishing research opportunities. [Preview Abstract] |
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M1.00045: Exploiting the Properties of Aquaporin to Calculate Free Energy Hugo Espejel, Liao Chen Aquaporins' (AQPs) main purpose is to facilitate the transfer of water molecules through a molecular membrane. We can calculate the free energy of the AQP system when water permeates through it. This is performed using the Visual Molecular Dynamics (VMD) and the Nanoscale Molecular Dynamics (NAMD) programs. In our first set of experiments, AQP is submerged in a body of water, in which case a water molecule near AQP is pulled through the protein. The data is then used to calculate the free energy using two different equations: the Jarzynski equality and the fluctuation-dissipation theorem. The values from both equations are then compared to examine their accuracy. The second set of experiments has the same set up, but now AQP is embedded in a lipid bilayer. We found that both equations give values that are much smaller than kT. This verifies that AQP is a channel for water molecules because the pulling of water gives constant values of free energy. We also found that the water molecules' negative poles were all pointing towards the center of the AQP channel. This means that the process of proton transport in AQP is overwhelmingly difficult. [Preview Abstract] |
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