Physics Commons^™

The Rotundity Of Large Planetary Objects, Adesanwo Moradeyo

Graduate Student Papers (Physics)

The most obvious structural feature of planetary bodies is their roundness. This arises because of the dominate roles of the two effects of gravity and case of the deformation of matter, whether gas, liquid or solid. This project is about proving and solving out the time scale (τ ) of flow restoring the body to spherical shape when we consider a slightly deformed self-gravitating sphere and also checking for spherical of different planetary objects.

Measurement Of D*± Production In Deep Inelastic E±P Scattering At Desy Hera, S. Chekanov, M. Derrick, D. Krakauer, J. H. Loizides, S. Magill, B. Musgrave, J. Repond, R. Yoshida, Margarita C. K. Mattingly, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, G. Cara Romeo, L. Cifarelli, F. Cindolo, A. Contin, M. Corradi, S. De Pasquale, P. Giusti, G. Iacobucci, A. Margotti, A. Montanari, R. Nania, F. Palmonari, A. Pesci, G. Sartorelli, A. Zichichi

Faculty Publications

Inclusive production of D*± (2010) mesons in deep inelastic scattering has been measured with the ZEUS detector at DESY HERA using an integrated luminosity of 81.9 pb-1. The decay channel D*+ →D0π+ with D 0→K-π+ and corresponding antiparticle decay were used to identify D* mesons. Differential D* cross sections with 1.5

Search For A Narrow Charmed Baryonic State Decaying To D*±P∓ In Ep Collisions At Hera, S. Chekanov, M. Derrick, J. H. Loizides, S. Magill, S. Miglioranzi, B. Musgrave, J. Repond, R. Yoshida, Margarita C. K. Mattingly, N. Pavel, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, G. Cara Romeo, L. Cifarelli, F. Cindolo, A. Contin, M. Corradi, S. De Pasquale, P. Giusti, G. Iacobucci, A. Margotti, A. Montanari, R. Nania, F. Palmonari, A. Pesci, A. Polini

Faculty Publications

A resonance search has been made in the D*±p∓ invariant-mass spectrum with the ZEUS detector at HERA using an integrated luminosity of 126 pb-1. The decay channels D*+ -→ D0πs+ → (K -π+)πs+ and D*+ → D0πs+ → (K-π+π+π-) πs+ (and the corresponding antiparticle decays) were used to identify D*± mesons. No resonance structure was observed in the D*± p∓ mass spectrum from more than 60 000 reconstructed D*± mesons. The results are not compatible with a report of the H1 Collaboration of a charmed pentaquark, Θc0. © Springer-Verlag / Società Italiana di Fisica 2004.

Dissociation Of Virtual Photons In Events With A Leading Proton At Hera, S. Chekanov, M. Derrick, J. H. Loizides, S. Magill, S. Miglioranzi, B. Musgrave, J. Repond, R. Yoshida, Margarita C. K. Mattingly, N. Pavel, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, G. Cara Romeo, L. Cifarelli, F. Cindolo, A. Contin, M. Corradi, S. De Pasquale, P. Giusti, G. Iacobucci, A. Margotti, T. Massam, A. Montanari, R. Nania, F. Palmonari, A. Pesci

Faculty Publications

The ZEUS detector has been used to study dissociation of virtual photons in events with a leading proton, γ*p → Xp, in e+p collisions at HERA. The data cover photon virtualities in two ranges, 0.03 < Q2 < 0.60 GeV2 and 2 < Q2 < 100 GeV2, with MX > 1.5 GeV, where MX is the mass of the hadronic final state, X. Events were required to have a leading proton, detected in the ZEUS leading proton spectrometer, carrying at least 90% of the incoming proton energy. The cross section is presented as a function of t, the squared four-momentum transfer at the proton vertex, Φ, the azimuthal angle between the positron scattering plane and …

Coordinate Conditions For A Uniformly Accelerated Or Static Plane Symmetric Metric, Preston Jones, Lucas Wanex

Publications

The coordinate conditions for three exact solutions for the metric components of a coordinate system with constant acceleration or of a static plane symmetric gravitational field are presented. First, the coordinate condition that the acceleration of light is constant is applied to the field equations to derive the metric of a coordinate system of constant acceleration. Second, the coordinate conditions required to produce the metrics of Rindler and Lass are applied to the field equations to calculate the components of these two metrics and the coordinate velocities and coordinate accelerations for light of these two metrics are compared to the …

Teacher In The Spotlight, Aaron Beaumont

Lake Union Herald

No abstract provided.

Neutron Multiplicity Measurements For The Afci Program Quarterly Progress Report September-December 2004, Denis Beller

Transmutation Sciences Physics (TRP)

The U.S. Advanced Fuel Cycle Initiative (AFCI) is a program to develop economic and environmental methods to reduce the impact of waste from commercial nuclear fuel cycles. One concept for near-complete destruction of waste isotopes from used nuclear fuel is accelerator driven transmutation. High-power accelerators would be used to produce high-energy charged particles, which then collide with heavy metal targets to create a cascade of neutrons. These neutrons then cause a nuclear chain reaction in subcritical systems. Fission neutrons then transmute fissile waste isotopes as well as other problematic isotopes such as technetium-99 and iodine-129. To design these systems, complex …

The Kinetics Following Photolysis Of Nitrosyl Bromide, Lori A. Mahoney

Theses and Dissertations

One candidate for the development of a tunable laser in the mid-infrared for use as a defensive countermeasure against passive sensors exploits the nitric oxide (NO) transition at 5.4 μm. However, the difficulty with this mechanism is that when bromine (Br₂) and NO are present in a mixture, nitrosyl bromide (BrNO) is also created. The absorption bands present in BrNO complicate the design of such a laser. This thesis determines the forward and reverse rate constants of the reaction of Br₂ and NO to form BrNO following the photolysis of BrNO using Fourier Transform Infrared absorption spectroscopy. …

The Meyer-Neldel Rule For Diodes In Forward Bias, Ralf Widenhorn, Michael Fitzgibbons, Erik Bodegom

Physics Faculty Publications and Presentations

We analyzed the temperature dependence of the forward current of a silicon diode. Instead of representing the data in the ordinarily used current versus voltage graph, the currents are plotted for different voltages as a function of the inverse temperature. The constant voltage curves can be fitted linearly and the extrapolations of the fits seem to merge to one common focal point. Hence, we demonstrate that a real diode follows the Meyer-Neldel rule (MNR). It is shown that the MNR is due to a shift of the current from ideal-diode to high-injection-diode behavior. We will argue that the merging of …

Afci Quarterly Input – Unlv October Through December, 2004, Harry Reid Center For Environmental Studies. Nuclear Science And Technology Division

Transmutation Research Program Reports (TRP)

Quarterly report highlighting research projects, activities and objectives of the Transmutation Research Program at the Nuclear Science & Technology Division, Harry Reid Research Center.

The University of Nevada, Las Vegas supports the AFCI through research and development of technologies for economic and environmentally sound refinement of spent nuclear fuel. The UNLV program has four components: infrastructure, international collaboration, student-based research, and management and program support. Management and program support highlights are the following: the UNLV TRP hosted the Eighth Annual IAEA Actinide and Fission Product Partitioning & Transmutation Information Exchange Meeting (Nov. 9 – 11). 120 people from 22 countries …

Reactor Physics Studies For The Afci Race Project: Reactor-Accelerator Coupling Experiments Project: Quarterly Progress Report September-December 2004, Denis Beller

Transmutation Sciences Physics (TRP)

In the RACE Project of the U.S. Advanced Fuel Cycle Initiative (AFCI), a series of accelerator driven subcritical systems (ADSS) experiments will be conducted at the Idaho State University’s Idaho Accelerator Center (ISU-IAC), at the University of Texas (UT) at Austin, and at the Texas A&M University. In these experiments we will use electron accelerators to induce bremsstrahlung photon-neutron reactions in heavy-metal targets; this source of about 10¹² to 10¹³ n/s will then initiate fission reactions in the subcritical systems. These systems will include a compact, transportable assembly at ISU and TRIGA reactors at UT-Austin and Texas A&M. …

The Electrochemical Separation Of Curium And Americium: Quaterly Report August-December 2004, David W. Hatchett, Kenneth Czerwinski

Separations Campaign (TRP)

This research report outlines the current status and progress associated with the electrochemical separation of Curium and Americium. The following pages outline the progress on our project to date. We have been actively performing research on this project for three months and are currently on schedule in terms of the proposed timelines.

The initial focus of the project involved setting up the laboratories for the studies outlined in the grant proposal. The instrumentation needed included an electrochemical work station that will perform the bulk of the electrochemical studies. This instrument will complement the electrochemical instrumentation in Dr. Hatchett’s laboratory and …

Dissolution, Reactor, And Environmental Behavior Of Zro2-Mgo Inert Fuel Matrix: Quarterly Report, October 2004 To December 2004, Earl Wolfram, Thomas Hartmann, Kenneth Czerwinski

Fuels Campaign (TRP)

This project will examine inert matrix fuels containing ZrO₂ and MgO as the inert matrix, with the relative amount of MgO varied from 30% to 70% in ZrO₂. Reactor physics calculations will be used to examine suitable quantities of burnable poisons from the candidate elements Gd, Er, or Hf with reactor grade Pu providing the fissile component, with up to 10% of ²³⁹Pu. Ceramics will be synthesized and characterized based on the reactor physics results. The solubility the fuel ceramics, in reactor conditions, reprocessing conditions, and repository conditions, will be investigated in a manner to provide …

Self‐Consistent Diffusive Lifetimes Of Weibel Magnetic Fields In Gamma‐Ray Bursts, C. H. Jaroschek, H. Lesch, R. A. Treumann

Dartmouth Scholarship

Weibel filamentation in relativistic plasma shell collisions has been demonstrated as an efficient and fast mechanism for the generation of near-equipartition magnetic fields in self-consistent particle-in-cell (PIC) simulations. In generic γ-ray burst (GRB) models with kinetically dominated plasma outflow, sufficient strength and lifetime of magnetic fields are essential to validate synchrotron emission as the source of radiative outbursts. In this article we report on self-consistent PIC simulations of pair-plasma shell collisions in the highly relativistic regime with particle ensembles up to 5 × 10⁸. Energy dependence of magnetic field generation in the Weibel process is discussed, and for …

Phase Coherent Effects In The Speckle Correlation Of Light Scattered From Volume Disordered Media And Randomly Rough Surfaces, Bogdan Danila

Dissertations

We present a study of the statistics of the intensity patterns produced when coherent light is scattered by random media (volume disorder) or randomly rough surfaces. Such a random, granular interference pattern is called speckle. Particular emphasis is on the statistical correlations arising between thefluctuations of the intensities corresponding to distinct scattering paths; which are quantified by the speckle correlation function. In the first part, we present results for the correlation function computed for volume-disordered media by means of numerical simulation. Our focus is on the sensitivity of the correlationfunction to statistical parameters characterizing the volume distribution of the refraction …

Design And Model Verification Of An Infrared Chromotomographic Imaging System, Daniel A. Lemaster

Theses and Dissertations

A prism chromotomographic hyperspectral imaging sensor is being developed to aid in the study of bomb phenomenology. Reliable chromotomographic reconstruction depends on accurate knowledge of the sensor specific point spread function over all wavelengths of interest. The purpose of this research is to generate the required point spread functions using wave optics techniques and a phase screen model of system aberrations. Phase screens are generated using the Richardson-Lucy algorithm for extracting point spread functions and Gerchberg-Saxton algorithm for phase retrieval. These phase screens are verified by comparing the modeled results of a blackbody source with measurements made using a chromotomographic …

The Dependence Of Dijet Production On Photon Virtuality In Ep Collisions At Hera, S. Chekanov, M. Derrick, J. H. Loizides, S. Magill, S. Miglioranzi, B. Musgrave, J. Repond, R. Yoshida, Margarita C. K. Mattingly, N. Pavel, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, G. Cara Romeo, L. Cifarelli, F. Cindolo, A. Contin, M. Corradi, S. De Pasquale, P. Giusti, G. Iacobucci, A. Margotti, A. Montanari, R. Nania, F. Palmonari, A. Pesci, L. Rinaldi

Faculty Publications

The dependence of dijet production on the virtuality of the exchanged photon, Q2, has been studied by measuring dijet cross sections in the range 0 ≲ Q2 < 2000 GeV2 with the ZEUS detector at HERA using an integrated luminosity of 38.6 pb-1. Dijet cross sections were measured for jets with transverse energy ETjet > 7.5 and 6.5 GeV and pseudorapidities in the photon-proton centre-of-mass frame in the range -3 < jet < 0. The variable xγobs, a measure of the photon momentum entering the hard process, was used to enhance the sensitivity of the measurement to the photon structure. The Q2 dependence of the ratio of low- to high-xγobs events was measured. Next-to-leading-order QCD predictions were found to generally underestimate the low-xγobs contribution relative to that at high xγobs. Monte Carlo models based on leading-logarithmic parton-showers, using a partonic structure for the photon which falls smoothly with increasing Q2, provide a qualitative description of the data. © Springer-Verlag / Società Italiana di Fisica 2004.

Interferences In Electron Emission Spectra For H+ Impact On H2, Sabbir Hossain

Dissertations

No abstract provided.

Concurrent Oh Imager And Sodiumtemperature/Wind Lidar Observation Of A Mesopause Region Undular Bore Event Over Fort Collins/Platteville, Co, C. Y. She, T. Li, B. P. Williams, Tao Yuan, R. H. Picard

All Physics Faculty Publications

We reported the observation of a mesospheric front with the properties of an undular bore by an OH imager, over the Fort Collins/Platteville area on 6/7 October 2002. Unlike the earlier bore observations, a Na lidar capable of measuring mesopause region temperature, zonal, and meridional winds was in operation concurrently. The lidar data confirm, for the first time, the existence of a collocated temperature inversion layer to serve as the ducting region for bore propagation, as required by the simple theory proposed by Dewan and Picard 6 years ago. In addition, the lidar data in principle provide sufficient information for …

Search For Doubly Charged Higgs Bosons Decaying To Dileptons In Pp̅ Collisions At √S =1:96 Tev, Darin Acosta, Kenneth A. Bloom, Collider Detector At Fermilab Collaboration

Kenneth Bloom Publications

We present the results of a search for doubly charged Higgs bosons (H^±±) decaying to dileptons (ll′ ) using ≈240 pb^-1 of pp̅ collision data collected by the CDF II experiment at the Fermilab Tevatron. In our search region, given by same-sign ll′ mass m_ll′ >80 GeV/c² (100 GeV/c² for ee channel), we observe no evidence for H^±± production. We set limits on σ (pp̅→ H⁺⁺H^--→l⁺l⁺l^-l^-) as a function of the mass of the H^{±± …}

Measurements Of Transverse Energy Distributions In Au+Au Collisions At √SNn=200 Gev, Star Collaboration, T.D. Gutierrez

Physics

Transverse energy (E_T) distributions have been measured for Au+Au collisions at √s_NN=200GeV by the STAR Collaboration at RHIC. E_T is constructed from its hadronic and electromagnetic components, which have been measured separately. E_T production for the most central collisions is well described by several theoretical models whose common feature is large energy density achieved early in the fireball evolution. The magnitude and centrality dependence of E_T per charged particle agrees well with measurements at lower collision energy, indicating that the growth in E_T for larger collision energy results from the growth in …

Simulation Of Ultrashort Electron Pulse Generation From Optical Injection Into Wake-Field Plasma Waves, D.S. Dodd, J.K. Kim, Donald P. Umstadter

Donald Umstadter Publications

A laser-plasma-based source of relativistic electrons is described in detail, and analyzed in two dimensions using theoretical and numeric techniques. Two laser beams are focused in a plasma, one exciting a wake-field electron plasma wave while another locally alters some electron trajectories in such a way that they can be trapped and accelerated by the wave. Previous analyses dealt only with one-dimensional models. In this paper two-dimensional particle-in-cell simulations and analysis of single particle trajectories show that the radial wake field plays an important role. The simulation results are interpreted to evaluate the accelerated electron beam's properties and compared with …

Local Optical Properties, Electron Densities, And London Dispersion Energies Of Atomically Structured Grain Boundaries, Roger H. French

Faculty Scholarship

Quantitative analysis of spatially resolved valence electron energy-loss spectra shows strong physical property contrasts for Σ5 and near Σ13 grain boundaries in Fe-doped SrTiO3, resulting in London dispersion interaction energies of 14 to 50mJ/m2 between the adjacent grains. The determination of local physical properties of grain boundary cores and the appreciable contribution of long-range London dispersion to interface energies provides new information on formation and control of interfaces in materials.

The Structures Of C-C4F8 And C-C4F8¯ And The Adiabatic Electron Affinity Of C-C4F8, Gordon A. Gallup

Gordon Gallup Publications

Calculations at the 6311G(dps) level have been used to elucidate the structures of octafluorocyclobutane c-C₄F₈ and its negative ion c-C₄F₈^¯. With no empirical adjustments, we obtain 0.640 eV for the adiabatic electron affi nity of c-C₄F₈. This may be compared with an experimental value of 0.63 ± 0.05 eV from the FALP method. c-C₄F₈ has unusual features in that there is an increase in symmetry, D_2d to D_4h, in going from the neutral molecule to the negative ion, and …

The Nuclear Reddening Curve For Active Galactic Nuclei And The Shape Of The Infrared To X-Ray Spectral Energy Distribution, C. Martin Gaskell, René W. Goosmann, Robert R. J. Antonucci, David H. Whysong

Department of Physics and Astronomy: Faculty Publications

We present extinction curves derived from the broad emission lines and continua of samples of 72 radio-loud and 1018 radio-quiet active galactic nuclei (AGNs). The curves are significantly flatter in the UV than curves for the local interstellar medium. The reddening curves for the radio-quiet Large Bright Quasar Survey quasars are slightly steeper than those of the radio-loud quasars in the UV, probably because of additional reddening by dust farther out in the host galaxies of the former. The UV extinction curves for the radio-loud AGNs are very flat. This is explicable with slight modifications to standard Mathis-Rumpl-Nordsieck dust models: …

Mechanism And Control Of High-Intensity-Laser-Driven Proton Acceleration, T. Lin, K. Flippo, M. Rever, Anatoly Maksimchuk, Donald P. Umstadter

Donald Umstadter Publications

We discuss the optimization and control of laser-driven proton beams. Specifically, we report on the dependence of high-intensity laser accelerated proton beams on the material properties of various thin-film targets. Evidence of star-like filaments and beam hollowing (predicted from the electrothermal instability theory) is observed on Radiochromic Film (RCF) and CR-39 nuclear track detectors. The proton beam spatial profile is found to depend on initial target conductivity and target thickness. For resistive target materials, these structured profiles are explained by the inhibition of current, due to the lack of a return current. The conductors, however, can support large propagating currents …

Bell’S Inequalities For Particles Of Arbitrary Spin In Fixed Analyzers, Ronen Mukamel, John C. Howell

Mathematics, Physics, and Computer Science Faculty Articles and Research

We propose a new set of observables for experiments on entangled particles of arbitrarily large spin that produce significant Clauser-Horne-Shimony-Holt inequality violations for fixed analyzer settings over a wider range of spins than was previously possible. These observables are better suited for experiments where analyzer orientations must be chosen before the spin of the entangled particles is known, such as experiments using polarization entangled downconverted photons.

Combination Of Cdf And D0 Results On The W Boson Mass And Width, Darin Acosta, Kenneth A. Bloom, Collider Detector At Fermilab Collaboration

Kenneth Bloom Publications

The results based on 1992–95 data (Run 1) from the CDF and D0 experiments on the measurements of the W boson mass and width are presented, along with the combined results. We report a Tevatron collider average M_W =80.456±0.059 GeV. We also report the Tevatron collider average of the directly measured W boson width Γ_W=2.115±0.105 GeV. We describe a new joint analysis of the direct W mass and width measurements. Assuming the validity of the standard model, we combine the directly measured W boson width with the width extracted from the ratio of W and Z boson …

Substructure Dependence Of Jet Cross Sections At Hera And Determination Of ΑS, S. Chekanov, M. Derrick, J. H. Loizides, S. Magill, S. Miglioranzi, B. Musgrave, J. Repond, R. Yoshida, Margarita C. K. Mattingly, N. Pavel, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, G. Cara Romeo, L. Cifarelli, F. Cindolo, A. Contin, M. Corradi, S. De Pasquale, P. Giusti, G. Iacobucci, A. Margotti, A. Montanari, R. Nania, F. Palmonari, A. Pesci, L. Rinaldi

Faculty Publications

No abstract provided.

What Are The Building Blocks Of Our Universe?, Kameshwar C. Wali

Physics - All Scholarship

We are told that we are living in a Golden Age of Astronomy. Cosmological Parameters are found with un precedented accuracy. Yet, the known form of matter forms only a small fraction of the total energy density of the universe. Also, a mysterious dark energy dominates the universe and causes acceleration in the rate of expansion.