Physical Sciences and Mathematics Commons^™

Bottom Photoproduction Measured Using Decays Into Muons In Dijet Events In Ep Collisions At √S=318 Gev, S. Chekanov, M. Derrick, D. Krakauer, J. H. Loizides, S. Magill, S. Miglioranzi, 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

Faculty Publications

The photoproduction of bottom quarks in events with two jets and a muon has been measured with the ZEUS detector at HERA using an integrated luminosity of 110 pb-1. The fraction of jets containing b quarks was extracted from the transverse momentum distribution of the muon relative to the closest jet. Differential cross sections for bottom production as a function of the transverse momentum and pseudorapidity of the muon, of the associated jet and of xγjets, the fraction of the photon's momentum participating in the hard process, are compared with MC models and QCD predictions made at next-to-leading order. The …

Search For Contact Interactions, Large Extra Dimensions And Finite Quark Radius In Ep Collisions At Hera, S. Chekanov, M. Derrick, D. Krakauer, J. H. Loizides, S. Magill, S. Miglioranzi, 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

Faculty Publications

A search for physics beyond the Standard Model has been performed with high-Q2 neutral current deep inelastic scattering events recorded with the ZEUS detector at HERA. Two data sets, e+p→e +X and e-p→e-X, with respective integrated luminosities of 112 pb-1 and 16 pb-1, were analyzed. The data reach Q2 values as high as 40000 GeV2. No significant deviations from Standard Model predictions were observed. Limits were derived on the effective mass scale in eeqq contact interactions, the ratio of leptoquark mass to the Yukawa coupling for heavy leptoquark models and the mass scale parameter in models with large extra dimensions. …

Dynamical Studies Of Model Membrane And Cellular Response To Nanosecond, High-Intensity Pulsed Electric Fields, Qin Hu

Electrical & Computer Engineering Theses & Dissertations

The dynamics of electroporation of biological cells subjected to nanosecond, high intensity pulses are studied based on a coupled scheme involving the current continuity and Smoluchowski equations. The improved pore formation energy model includes a dependence on pore population and density. It also allows for variable surface tension and incorporates the effects of finite conductivity on the electrostatic correction term, which was not considered by the simple energy models in the literature. It is shown that E(r) becomes self-adjusting with variations in its magnitude and profile. The whole scheme is self-consistent and dynamic.

An electromechanical analysis based on thin-shell theory …

Azimuthally Sensitive Hanbury Brown–Twiss Interferometry In Au+Au Collisions At √SNn=200 Gev, Star Collaboration, T.D. Gutierrez

Physics

We present the results of a systematic study of the shape of the pion distribution in coordinate space at freeze-out in Au+Au collisions at BNL RHIC using two-pion Hanbury Brown–Twiss (HBT) interferometry. Oscillations of the extracted HBT radii versus emission angle indicate sources elongated perpendicular to the reaction plane. The results indicate that the pressure and expansion time of the collision system are not sufficient to completely quench its initial shape.

Design And Analysis Of A Process For Melt Casting Metallic Fuel Pins Incorporating Volatile Actinides, Yitung Chen, Randy Clarksean, Darrell Pepper

Fuels Campaign (TRP)

After considering the heating mechanisms, casting issues, crucible design and issues related to the mass transport of americium, an ISM system was selected for melting the feedstock and casting fuel pins containing high vapor pressure actinides (americium). The finite element commercial software (FIDAP) was used to simulate the induction melting process and the casting process. Phase change is considered both in the heating and in the solidification process. Various factors and properties are studied, such as boundary conditions and initial conditions, output current, frequency of the current, main dimensions of the system, mold preheating temperature, heat transfer coefficient and mold …

Ester Type Banana-Shaped Liquid Crystalline Monomers: Synthesis And Physical Properties, Katalin Fodor-Csorba, Aniko Vajda, Antal Jakli, Christian Slugovc, Gregor Trimmel, Dietrich Demus, Eszter Gacz-Baitz, Sandor Holly, Giancarlo Galli

Antal Jakli

New ester-type banana (bent-shaped) monomers, 1,3-phenylene bis[4'-(alken-1-yloxy)-biphenyl-4-carboxylate] s Ia - Vb, with different substituent(s) on the central phenyl ring (H, CH3, Cl or NO2) and alkenyl tails in the side arms ( decenyl or undecenyl) were prepared. The analogues IIIa - IVb with 4-chloro- or 4,6-dichloro-substituents exhibited a nematic phase, while Va, Vb with 2-nitro-substituent showed a B-7 phase at relatively low temperature. All the compounds were stable, no degradation or polymerization was observed under applied electric fields or heat treatments. Electro-hydrodynamic instabilities were observed in the nematic phase of each sample. In the B-7 phase of Vb there was …

Mesospheric Mid-Latitude Density Climatology Above Utah State University, Eric M. Lundell, Vincent B. Wickwar

Posters

Lidars have been used extensively to derive temperatures, but not absolute densities, in the mesospheric region of the atmosphere. We used observations since 1993 with the Rayleigh- scatter lidar at the Atmospheric Lidar Observatory (ALO) at Utah State University (41.7oN, 111.8oW) to create an absolute density climatology between 45 and ~95 km. The observations provide profiles of relative density to which an absolute scale is attached by normalizing the profiles at 45 km to the densities in the MSISe00 empirical model. We examine the density variations on several time scales—during the climatological year, from year to year, and over several …

Atmospheric Lidar Observatory (Alo) Ten-Year Mesospheric Temperature Climatology, Joshua P. Herron, Vincent B. Wickwar

Posters

The Rayleigh-scatter lidar at the Atmospheric Lidar Observatory (ALO) on the Utah State University (USU) (41.7°N, 111.8°W) campus has been in operation since 1993. The temperature database now contains over ten years of Rayleigh-scatter temperatures. A multi-year temperature climatology has been calculated from these observations along with the RMS and interannual variability. These temperatures and the climatology are currently being used in a number of mesospheric studies, including mesospheric inversion layers, tides, planetary waves, cyclical variations, trends, longitudinal comparisons, and validation studies.

Another Noctilucent Cloud At 41.7ºn, Joshua P. Herron, Vincent B. Wickwar

Posters

On June 23, 1995, a noctilucent cloud (NLC) was detected with the Rayleigh-scatter lidar at the Atmospheric Lidar Observatory (ALO) on the campus of Utah State University (USU) located in Logan, UT (41.7° N 111.8° W). This observation preceded, by four years, the one from 1999 that was previously reported [Wickwar et al., 2002]. These are both important because of their occurrence significantly equatorward of 50° latitude. The NLC was observed for 45 minutes shortly after local midnight. This was well past the twilight period when NLCs are visible to the naked eye. Several parameters of the NLC were …

Reliable First-Principles Alloy Thermodynamics Via Truncated Cluster Expansions, Nikolai A. Zarkevich, Duane D. Johnson

Nikolai A. Zarkevich

In alloys cluster expansions (CE) are increasingly used to combine first-principles electronicstructure calculations and Monte Carlo methods to predict thermodynamic properties. As a basis-set expansion in terms of lattice geometrical clusters and effective cluster interactions, the CE is exact if infinite, but is tractable only if truncated. Yet until now a truncation procedure was not well defined and did not guarantee a reliable truncated CE. We present an optimal truncation procedure for CE basis sets that provides reliable thermodynamics. We then exemplify its importance in Ni3V, where the CE has failed unpredictably, and now show agreement to a range of …

Photoproduction Of D*± Mesons Associated With A Leading Neutron, S. Chekanov, M. Derrick, D. Krakauer, J. H. Loizides, S. Magill, S. Miglioranzi, 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

Faculty Publications

The photoproduction of D*±(2010) mesons associated with a leading neutron has been observed with the ZEUS detector in ep collisions at HERA using an integrated luminosity of 80 pb-1. The neutron carries a large fraction, xL>0.2, of the incoming proton beam energy and is detected at very small production angles, θn< 0.8 mrad, an indication of peripheral scattering. The D* meson is centrally produced with pseudorapidity η1.9 GeV, which is large compared to the average transverse momentum of the neutron of 0.22 GeV. The ratio of neutron-tagged to inclusive D* production is 8.85±0.93(stat.) +0.48-0.61(syst.)% in the photon-proton center-of-mass energy range 130

Study Of Leptonic Cp Violation, Joseph Schechter, Salah Nasri, Sherif Moussa

Physics - All Scholarship

The "complementary" Ansatz, Tr(M_\nu)=0, where M_\nu is the prediagonal neutrino mass matrix, seems a plausible approximation for capturing in a self-contained way some of the content of Grand Unification. We study its consequences in the form of relations between the neutrino masses and CP violation phases.

Intensity Interferometry With Anyons, Thomas D. Gutierrez

Physics

A pairwise correlation function in relative momentum space is discussed as a tool to characterize the properties of an incoherent source of noninteracting Abelian anyons. This is analogous to the Hanbury-Brown Twiss effect for particles with fractional statistics in two dimensions. In particular, using a flux tube model for anyons, the effects of source shape and quantum statistics on a two-particle correlation function are examined. Such a tool may prove useful in the context of quantum computing and other experimental applications where studying anyon sources are of interest.

An Experimental Study Of Micron-Scale Droplet Aerosols Produced Via Ultrasonic Atomization, Thomas D. Donnelly, J. Hogan '03, A. Mugler '04, N. Schommer '04, M. Schubmehl '02, Andrew J. Bernoff, B. Forrest '02

All HMC Faculty Publications and Research

In the last 10 years, laser-driven fusion experiments performed on atomic clusters of deuterium have shown a surprisingly high neutron yield per joule of input laser energy. Results indicate that the optimal cluster size for maximizing fusion events should be in the 0.01–μm diameter range, but an appropriate source of droplets of this size does not exist. In an attempt to meet this need, we use ultrasonic atomization to generate micron-scale droplet aerosols of high average density, and we have developed and refined a reliable droplet sizing technique based on Mie scattering. Harmonic excitation of the fluid in …

Examples Of Alo Results, Vincent B. Wickwar, Joshua P. Herron, Karen M. Nelson, Troy A. Wynn, Kristina Thomas, Eric M. Lundell

Presentations

No abstract provided.

Investigation Of Pb(Zr,Ti)O3 /Gan Heterostructures By Scanning Probe Microscopy, Alexei Gruverman, W. Cao, S. Bhaskar, S. K. Dey

Alexei Gruverman Publications

Piezoresponse force microscopy (PFM) technique has been utilized to study the evolution of domain structure with varying Pb(Zr,Ti)O₃(PZT) thickness on GaN substrate. Sol-gel PZT films were deposited on the GaN/ sapphire substrate with PZT thickness of 100, 200, and 300 nm. The films exhibit ferroelectric properties that vary as a function of the film thickness. This is explained by the mechanical stress at the PZT/GaN interface. The thicker film (300 nm) is characterized by the presence of a number of oppositely polarized domains and a relatively high value of the effective piezoelectric constant. The laminar domain structure, consisting …

Simulations Of Ferroelectric Polymer Film Polarization: The Role Of Dipole Interactions, Chun-Gang Duan, Wai-Ning Mei, Wei-Guo Yin, Jianjun Liu, J. R. Hardy, Stephen Ducharme, Peter A. Dowben

Department of Physics and Astronomy: Faculty Publications

We present a systematic study of the dipole alignment in the polyvinylidene fluoride (PVDF) films using first-principles total energy calculations. The ground state of a single layer film is a state with all the dipoles lying parallel to the film plane. This can also be explained by a dipole-dipole interaction model. The induced mirror charges on conducting substrates or substrates with a non-negligible dielectric response play an important role in aligning the polarization perpendicular to the film. From fitting the ab initio calculations, we obtain an effective monomer dipole moment of 4.7×10^–30 C m. This corresponds to a spontaneous …

Extended Tidal Structure In Two Lyalpha-Emitting Starburst Galaxies, John M. Cannon, E D. Skillman, D Kunth, C Leitherer, M Mas-Hesse, G Östlin, A Petrosian

John Cannon

No abstract provided.

Driven Diffusive Systems: How Steady States Depend On Dynamics, D. P. Landau, Wooseop Kwak, Beate Schmittmann

Beate Schmittmann

In contrast to equilibrium systems, nonequilibrium steady states depend explicitly on the underlying dynamics. Using Monte Carlo simulations with Metropolis, Glauber, and heat bath rates, we illustrate this expectation for an Ising lattice gas, driven far from equilibrium by an “electric” field. While heat bath and Glauber rates generate essentially identical data for structure factors and two-point correlations, Metropolis rates give noticeably weaker correlations, as if the “effective” temperature were higher in the latter case. We also measure energy histograms and define a simple ratio which is exactly known and closely related to the Boltzmann factor for the equilibrium case. …

Bridging The Microscopic And The Hydrodynamic In Active Filament Solutions, Tanniemola B. Liverpool, M. Cristina Marchetti

Physics - All Scholarship

Hydrodynamic equations for an isotropic solution of active polar filaments are derived from a microscopic mean-field model of the forces exchanged between motors and filaments. We find that a spatial dependence of the motor stepping rate along the filament is essential to drive bundle formation. A number of differences arise as compared to hydrodynamics derived (earlier) from a mesoscopic model where relative filament velocities were obtained on the basis of symmetry considerations. Due to the anisotropy of filament diffusion, motors are capable of generating net filament motion relative to the solvent. The effect of this new term on the stability …

Approximate Thermodynamic State Relations In Partially Ionized Gas Mixtures, John D. Ramshaw

Physics Faculty Publications and Presentations

Thermodynamic state relations for mixtures of partially ionized nonideal gases are often approximated by artificially partitioning the mixture into compartments or subvolumes occupied by the pure partially ionized constituent gases, and requiring these subvolumes to be in temperature and pressure equilibrium. This intuitively reasonable procedure is easily shown to reproduce the correct thermal and caloric state equations for a mixture of neutral nonionized ideal gases. The purpose of this paper is to point out that (a) this procedure leads to incorrect state equations for a mixture of partially ionized ideal gases, whereas (b) the alternative procedure of requiring that the …

Geometry And Electronic Structure Of Vn(Bz)M Complexes, Anil K. Kandalam, B. K. Rao, Puru Jena, Michigan Technological University

Physics & Engineering Faculty Publications

No abstract provided.

Search For Narrow Tt̅ Resonances In Pp̅ Collisions At √S = 1.8 Tev, V. M. Abazov, Gregory R. Snow, D0 Collaboration

Gregory Snow Publications

A search for narrow resonances that decay into tt̅ pairs has been performed using 130 pb^-1 of data in the lepton + jets channel collected by the DØ detector in pp̅ collisions at √s = 1.8 TeV. There is no significant deviation observed from the standard-model predictions at a top-quark mass of 175 GeV/c². We therefore present upper limits at the 95% confidence level on the product of the production cross section and branching fraction to tt̅ for narrow resonances as a function of the resonance mass M_x. These limits are used to …

Using Time-Resolved Photoluminescence To Measure The Excitation And Temperature Dependence Of Carrier Relaxation In Mid-Wave Infrared Semiconductors, Kevin Cumblidge

Theses and Dissertations

Research in the field of mid-wave infrared (MWIR) semiconductor photonic devices has led to applications in a variety of disciplines including atmospheric monitoring, optical communications, non-invasive glucose testing for diabetics, and infrared (IR) countermeasures. One of the limiting factors for improving the modulation rates of MWIR devices is the carrier relaxation time. This is the time required for energetic carriers to cool to the edge of their respective bands in a bulk semiconductor material, or to the bottom of a well through inter- and intra-sub-band scattering in a quantum well (QW) structure. From these lower energy states, they can then …

Comparison Of Hyperspherical Versus Common-Reaction-Coordinate Close-Coupling Methods For Ion-Atom Collisions At Low Energies, Anh-Thu Le, C. D. Lin, L. F. Errea, L. Mendez, A. Riera, B. Pons

Physics Faculty Research & Creative Works

We present detailed comparisons between the two quantal approaches--hyperspherical close-coupling and common-reaction-coordinate close-coupling methods--on an exemplary case of He²⁺ + H(1s) collisions at center-of-mass energy from 20eV up to 1.6keV. It is shown that the partial-wave charge-transfer cross sections from the two approaches agree very well at low energy below 200eV down to 30eV. This good agreement is a strong indication of the validity of both methods. The small difference at very low energies and the convergence with respect to the number of channels in both approaches at higher energies are also discussed.

Beam Conditions For Radiation Generated By An Electromagnetic Gaussian Schell-Model Source, Olga Korotkova, Mohamed Salem, Emil Wolf

Physics Articles and Papers

It was shown recently that the basic properties of a fluctuating electromagnetic beam can be derived from knowledge of a 2×2 cross-spectral density matrix of the electric field in the source plane. However, not every such matrix represents a source that will generate a beamlike field. We derive conditions that the matrix must satisfy for the source to generate an electromagnetic Gaussian Schell-model beam.

Growth And Magnetism Of Fept:C Composites In Nanoscale Channels, Yucheng Sui, J. Zhou, Xingzhong Li, Ralph Skomski, David J. Sellmyer

David Sellmyer Publications

Nanochannels of porous alumina films were used as nanoreactors for the reaction of hydrogen gas with a mixture of Fe nitrate and Pt chloride. This results in the formation of of FePt clusters within the nanochannels. Both the sizes of the clusters and the coercivity the cluster assembly increase with the increase of annealing temperature. In order to reduce excessive agglomeration at high temperature, carbon was introduced by chemical vapor deposition and FePt:C composites in nanoscale channels were created. When FePt clusters were synthesized with carbon and heat treated at high temperatures, cluster sizes were much smaller than those without …

Multidomain And Incoherent Effects In Magnetic Nanodots, Ralph Skomski, Arti Kashyap, Kory D. Sorge, David J. Sellmyer

David Sellmyer Publications

The magnetic ground state and the magnetization reversal of aspherical nanoparticles are investigated by model calculations and micromagnetic simulations. Essential deviations from Kittel's domain theory occur for very flat and very elongated particles, for particles whose size is comparable to the domain-wall width, and when the particle shape is strongly nonellipsoidal. For example, the single-domain state of square rod is much less stable than that of comparable elongated ellipsoids, because most of the surface charge of long ellipsoids is located on the sides. Another specific feature of flat particles is suppression of the curling mode.

Finite-Difference Time-Domain Calculations Of A Liquid-Crystal-Based Switchable Bragg Grating, Bin Wang, Xinghua Wang, Philip Bos

Philip J. Bos

A polymer-wall-confined transmissive switchable liquid crystal grating is proposed and investigated by two-dimensional finite-difference time-domain optical calculation and liquid-crystal-director calculation, to our knowledge for the first time. The results show how to obtain optimized conditions for high diffraction efficiency by adjusting the liquid crystal parameters, grating geometric structure, and applied voltages. The light propagation direction and efficiency can be accurately calculated and visualized concurrently.

Interferometric And Holographic Imaging Of Surface-Breaking Cracks, James Lawrence Blackshire, Bradley D. Duncan

Electro-Optics and Photonics Faculty Publications

Two advanced nondestructive evaluation systems are developed for imaging surface-breaking cracks in aerospace materials. The systems use scanning heterodyne interferometry and frequency-translated holography principles to image ultrasonic displacement fields on material surfaces with high resolution and sensitivity. Surface-breaking cracks are detected and characterized by visualizing near-field ultrasonic scattering processes, which in turn results in local intensification of ultrasonic displacement fields in the immediate vicinity of a crack. The local intensification permits cracks to be easily distinguished from background levels, and creates unique displacement field images that follow the contours and morphology of the cracks with microscopic precision. The interferometric and …