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Observation Of Events At Very High Q^2 In E^+P Collisions At Hera, A. Wagner Jan 1998

Observation Of Events At Very High Q^2 In E^+P Collisions At Hera, A. Wagner

Turkish Journal of Physics

Data collected at the $e^+p$ collider HERA at DESY by the experiments H1 and ZEUS have allowed to probe a previously inaccessible domain of very large $Q^2$ in deep-inelastic $ep$ scattering. For $Q^2 > 15000 GeV^2$ both experiments see more events than expected assuming the Standard Model of deep-inelastic scattering. In this report the observed events, the theoretical expectations and their comparison are discussed.

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Electroweak Gauge Boson Production At \Gamma\Gamma Collider, G. Jikia Jan 1998

Electroweak Gauge Boson Production At \Gamma\Gamma Collider, G. Jikia

Turkish Journal of Physics

No abstract provided.

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Ordinary And Coherent Bremsstrahlung At Linac-Ring Ep Colliders, V.G. Serbo, D.V. Serebryakova Jan 1998

Ordinary And Coherent Bremsstrahlung At Linac-Ring Ep Colliders, V.G. Serbo, D.V. Serebryakova

Turkish Journal of Physics

The ordinary bremsstrahlung $ep \rightarrow ep\gamma$ can be used at the linac-ring $ep$ colliders for luminosity measurement. It is known that at high energies this process has a large correction due to beam-size effect. We have calculated this effect for $ep$ colliders of the linac-ring type. For the LHC+CLIC collider the correction exceeds 10\% for $E_{\gamma} < 0.95\;E_e$. As a rule, the bremsstrahlung of protons in the $ep$ scattering is not considered due to its small cross section. However, if the photon energy $E_{\gamma}$ becomes small enough, the number of produced photons become large because in this case the radiation is determined by the interaction of a proton with the collective electromagnetic field of the electron bunch. It is coherent bremsstrahlung (CBS). We present the main characteristics of CBS calculated for linac-ring $ep$ colliders. At the LHC+CLIC collider it should be about $1700 \; dE_\gamma /E_\gamma$ photons for a single collision of bunches at $E_\gamma \stackrel{

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The Heavy Higgs Effects In The Framework Of Sm, V. Borodulin, G. Jikia Jan 1998

The Heavy Higgs Effects In The Framework Of Sm, V. Borodulin, G. Jikia

Turkish Journal of Physics

No abstract provided.

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Observed Coupling Of The Mesosphere Inversion Layer To The Thermal Tidal Structure, J W. Meriwether, X Gao, Vincent B. Wickwar, T D. Wilkerson, K C. Beissner, S C. Collins, M E. Hagan Jan 1998

Observed Coupling Of The Mesosphere Inversion Layer To The Thermal Tidal Structure, J W. Meriwether, X Gao, Vincent B. Wickwar, T D. Wilkerson, K C. Beissner, S C. Collins, M E. Hagan

All Physics Faculty Publications

Rayleigh lidar observations of mesosphere temperature profiles obtained from 40 to ∼100 km from Logan, Utah (41.7, 111.8 W, altitude, 1.9 km) over 10 nights in late February, 1995, revealed an interesting development between 60 to 75 km of a winter mesosphere inversion layer with an amplitude of ∼20–30 K and a downward phase progression of ∼1 km/hr. The data also showed two altitude regions exhibiting significant cooling of 10–30 K in extent. These were located below and above the peak of the inversion layer, respectively, at altitudes of ∼50–55 km and ∼70–80 km. When these results were compared with …

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New Conformal Gauging And The Electromagnetic Theory Of Weyl, James Thomas Wheeler Jan 1998

New Conformal Gauging And The Electromagnetic Theory Of Weyl, James Thomas Wheeler

All Physics Faculty Publications

A new eight-dimensional conformal gauging solves the auxiliary field problem and eliminates unphysical size change from Weyl’s electromagnetic theory. We derive the Maurer–Cartan structure equations and find the zero curvature solutions for the conformal connection. By showing that every one-particle Hamiltonian generates the structure equations we establish a correspondence between phase space and the eight-dimensional base space, and between the action and the integral of the Weyl vector. Applying the correspondence to generic flat solutions yields the Lorentz force law, the form and gauge dependence of the electromagnetic vector potential and minimal coupling. The dynamics found for these flat solutions …

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Ionospheric Storm Simulations Driven By Magnetospheric Mhd And Empirical Models With Data Comparisons, Jan Josef Sojka, Robert W. Schunk, M. D. Bowline, J. Chen, S. Slinker, J. Fedder, P. J. Sultan Jan 1998

Ionospheric Storm Simulations Driven By Magnetospheric Mhd And Empirical Models With Data Comparisons, Jan Josef Sojka, Robert W. Schunk, M. D. Bowline, J. Chen, S. Slinker, J. Fedder, P. J. Sultan

All Physics Faculty Publications

The results of two ionospheric simulations are compared with each other and with ionospheric observations of the southern hemisphere for the magnetic cloud passage event of January 14, 1988. For most of the event one simulation agrees with observations, while the other does not. Electric fields and electron precipitation patterns generated by a magnetospheric MHD model are used as inputs to a physical model of the ionosphere in the successful simulation, while empirical electric fields and electron precipitation are used as the inputs for the second simulation. In spite of ionospheric summer conditions a large and deep polar hole is …

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Superfluorescence From Optically Trapped Calcium Atoms, Xianming Han Jan 1998

Superfluorescence From Optically Trapped Calcium Atoms, Xianming Han

Scholarship and Professional Work - LAS

We have studied superfluorescence (SF) under highly unfavorable conditions of rapid collisional and radiative distribution in a Doppler-broadened medium. Nanosecond SF pulses at 5.5 μm were generated on the Ca 4s4p1P1–3d4s1D2 transition from a column of calcium vapor buffered with Ar by optically pumping the 4s21S0–4s4p1P1 transition. The Rabi frequency associated with the intense pump pulse prevents the occurrence of SF while the pump laser is on. As a result, the predicted scaling laws that describe the properties of SF in a transversely excited system, such as peak heights, pulse widths, and delay times, are shown to apply in our …

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Intercomparison Of Physical Models And Observations Of The Ionosphere, D. N. Anderson, M. J. Buonsanto, M. Codrescu, D. Decker, C. G. Fesen, T. J. Fuller-Rowell, B. W. Reinisch, P. G. Richards, R. G. Roble, Robert W. Schunk, Jan Josef Sojka Jan 1998

Intercomparison Of Physical Models And Observations Of The Ionosphere, D. N. Anderson, M. J. Buonsanto, M. Codrescu, D. Decker, C. G. Fesen, T. J. Fuller-Rowell, B. W. Reinisch, P. G. Richards, R. G. Roble, Robert W. Schunk, Jan Josef Sojka

All Physics Faculty Publications

Five physical models of the ionosphere were compared with each other and with data obtained at the Millstone Hill Observatory. Two of the models were self-consistent ionosphere-thermosphere models, while for the other ionospheric models the thermospheric parameters were provided by empirical inputs. The comparisons were restricted to midlatitudes and low geomagnetic activity, but four geophysical cases were considered that covered both the summer and winter solstices at solar maximum and minimum. The original motivation of the study was to determine why several physical models consistently underestimated the F region peak electron density, by up to a factor of 2, in …

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Rayleigh Lidar Measurements Of The Temporal Frequency And Vertical Wavenumber Spectra In The Mesosphere Over The Rocky Mountain Region, X Gao, J W. Meriwether, Vincent B. Wickwar, T D. Wilkerson, S C. Collins Jan 1998

Rayleigh Lidar Measurements Of The Temporal Frequency And Vertical Wavenumber Spectra In The Mesosphere Over The Rocky Mountain Region, X Gao, J W. Meriwether, Vincent B. Wickwar, T D. Wilkerson, S C. Collins

All Physics Faculty Publications

Temporal and spatial spectral analysis techniques were applied to lidar data collected over a period of 18 months above the Rocky Mountain region at an altitude range from 45 to 70 km by a Rayleigh lidar system located in Logan, Utah (41.7°N, 111.8°W). Examination of the averaged temporal frequency F(ω) and vertical wavenumber F(m) spectra showed spectral slope values of −1.49 ± 0.03 and −2.3 ± 0.1, respectively. The observed slope for the overall averaged F(m) spectrum is considerably more positive than the value of −3 predicted by the linear instability theory but close to the …

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Transfer Of Photometric Quantities At Arbitrary Distribution Temperatures, İzmir Mamedbeyli̇, Zafer Ürey, A. Kamuran Türkoğlu Jan 1998

Transfer Of Photometric Quantities At Arbitrary Distribution Temperatures, İzmir Mamedbeyli̇, Zafer Ürey, A. Kamuran Türkoğlu

Turkish Journal of Physics

Characteristics of a photometric setup used for the measurement of photometric quantities at the National Institute of Metrology (UME) in Turkey are reported. A high accuracy method is developed to adjust the filaments of incandescent lamps with respect to the optical axis. The method also provides the basis for low uncertainty distance measurements between lamp filaments and photometers. Transfer of photometric quantities at arbitrary distribution temperatures is examined both theoretically and experimentally, and the results are compared to the calibration values of the Bureau International Des Poids Et Measures (BIPM), Paris, France.

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Physisorbed Co On Ionic Crystals: An Extended Beg Spin-Lattice Model Of Adsorbed Dipolar Molecules, T. E. Burns, Jr Dennison Jan 1998

Physisorbed Co On Ionic Crystals: An Extended Beg Spin-Lattice Model Of Adsorbed Dipolar Molecules, T. E. Burns, Jr Dennison

Journal Articles

The 2D dielectric phases and phase transitions of adsorbed dipolar molecules are studied using a dilute spin-one Ising model. The spin-one formulation assigns a spin Si = ±1 to a (up/down) dipole occupying a lattice site i adsorbed perpendicular to the substrate surface and Si = 0 to unoccupied sites. We relate the mean field expression for the spin-model interaction energy to a more detailed microscopic model involving dipolar, quadrupolar and dispersive interactions beyond nearest neighbor. Analytic solutions in the mean field approximation are discussed for dipole-orientation order-disorder transitions and ferroelectric-to-antiferroelectric transitions as a function of temperature and …

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Cell Size Dependence Of Transport Coefficients In Stochastic Particle Algorithms, Alejandro Garcia, F. Alexander, B. Alder Jan 1998

Cell Size Dependence Of Transport Coefficients In Stochastic Particle Algorithms, Alejandro Garcia, F. Alexander, B. Alder

Faculty Publications

Using the Green–Kubo theory, the dependence of the viscosity and thermal conductivity on cell size is obtained explicitly for stochastic particle methods such as direct simulation Monte Carlo (DSMC) and its generalization, the consistent Boltzmann algorithm (CBA). These analytical results confirm empirical observations that significant errors occur when the cell dimensions are larger than a mean free path.

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Physical Dependence Of The Sensitivity And Room-Temperature Stability Of Auxge1-X Thin Film Resistive Thermometers On Annealing Conditions, Nathanael A. Fortune, Michael J. Graf, Keizo Murata Jan 1998

Physical Dependence Of The Sensitivity And Room-Temperature Stability Of Auxge1-X Thin Film Resistive Thermometers On Annealing Conditions, Nathanael A. Fortune, Michael J. Graf, Keizo Murata

Physics: Faculty Publications

The reported nearly constant temperature sensitivity of appropriately annealed polycrystalline AuxGe1-x thin films at cryogenic temperatures would appear to make them promising materials for low mass, rapid thermal response resistive thermometers, but their adoption has been limited by difficulties in fabrication and uncertainties in annealing. In this work, we present a method of fabrication and annealing which allows control of the two most important parameters for these films: the room-temperature resistivity ρRT and the temperature sensitivity η(T), where η ≡ -d In R/d In T. We find that the dependence of ρRT on total anneal duration t for x≈0.18 is …

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Applying Binomial Statistics To Weighted Monte Carlo, Sue Ellen Mccloskey, William C. Hall, Wilfred J. Braithwaite Jan 1998

Applying Binomial Statistics To Weighted Monte Carlo, Sue Ellen Mccloskey, William C. Hall, Wilfred J. Braithwaite

Journal of the Arkansas Academy of Science

Weighted Monte Carlo calculations requiring a uniform sampling of the problem-space can suffer from diminished statistical significance because many, if not most, of the randomly-chosen sampling points contribute only slightly to the desired result. Their contribution is reduced in size due the variable-size of the weighting terms. In contrast, none of the randomly-chosen points which are favored by variable size weighting terms will have their statistical significance enhanced beyond that of just one random point in the Monte Carlo sampling. A Monte Carlo analysis was used in earlier work to verify both Gauss' Law and Newton's Shell Theorem. Both examples …

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Microscale And Nanoscale Testing Of Materials Using Scanning Probe Technologies, Mark Phelan Jan 1998

Microscale And Nanoscale Testing Of Materials Using Scanning Probe Technologies, Mark Phelan

Theses

Understanding solid surfaces and their properties is of crucial importance for many sectors of industry. This interest stems from the fact that solid surfaces are the working interface between a solid material and its environment and in many cases it is this interface which determines both the suitability and life span of a mechanical component. Furthermore the modification of surface properties using coatings and multi-layered materials has grown significantly, particularly in the case of data storage, optics and microelectronics. The demands of these and other sectors have provided the impetus for the development of material testing techniques applicable to coatings …

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Solar Cycle Variability Of Hot Oxygen Atoms At Mars, Jhoon Kim, Andrew F. Nagy, Jane L. Fox, Thomas E. Cravens Jan 1998

Solar Cycle Variability Of Hot Oxygen Atoms At Mars, Jhoon Kim, Andrew F. Nagy, Jane L. Fox, Thomas E. Cravens

Physics Faculty Publications

The population of hot oxygen atoms in the Martian exosphere is reexamined using newly calculated hot O production rates for both low and high solar cycle conditions. The hot oxygen production rates are assumed to result from the dissociative recombination of O2+ ions. These calculations take into account the calculated vibrational distribution of O2+ and the new measured branching ratios. Furthermore, these calculations also consider the variation of the dissociative recombination cross section with the relative speed of the participating ions and electrons, the rotational energy of the O2+ ions, and the spread of …

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Attitude Measurement, Mark A. Stedham, Partha P. Banerjee, Seiji Nishifuji, Shogo Tanaka Jan 1998

Attitude Measurement, Mark A. Stedham, Partha P. Banerjee, Seiji Nishifuji, Shogo Tanaka

Electrical and Computer Engineering Faculty Publications

In many practical situations, it is important to determine and measure the attitude of a particular vehicle, such as a ship, an airplane, a piece of mechanical equipment such as a, crane lifter, or a spacecraft. For this reason, many attitude sensors have been developed with advanced computer and semiconductor technologies. This section first introduces the various attitude sensors with an explanation of their operating principles and then presents several methodologies for attitude measurement and determination, including ships and crane lifters, aircraft, and spacecraft applications.

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Correlation Function Formulation For The State Selected Total Reaction Probability, Sophya V. Garashchuk, D. J. Tannor Jan 1998

Correlation Function Formulation For The State Selected Total Reaction Probability, Sophya V. Garashchuk, D. J. Tannor

Faculty Publications

A correlation function formulation for the state-selected total reaction probability, Nα(E), is suggested. A wave packet, correlating with a specific set of internal reactant quantum numbers, α, is propagated forward in time until bifurcation is complete at which time the nonreactive portion of the amplitude is discarded. The autocorrelation function of the remaining amplitude is then computed and Fourier transformed to obtain a reactivity spectrum. Dividing by the corresponding spectrum of the original, unfiltered, wave packet normalizes the reactivity spectrum, yielding the total reaction probability from the internal state, α. The procedure requires negligible storage and just one time-energy Fourier …

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Theoretical Treatment Of Quasibound Resonances In Two-Color Resonant Four-Wave Mixing Spectroscopy, F. Di Teodoro, Elizabeth Mccormack Jan 1998

Theoretical Treatment Of Quasibound Resonances In Two-Color Resonant Four-Wave Mixing Spectroscopy, F. Di Teodoro, Elizabeth Mccormack

Physics Faculty Research and Scholarship

A treatment of continuum states in the application of diagrammatic perturbation theory to calculate the signal produced in two-color resonant four-wave mixing (TC-RFWM) spectroscopy is developed. The third-order susceptibility is significantly modified from that obtained when considering only discrete states. To illustrate the contribution of continuum states, the line profile of a quasibound resonance arising from the configuration interaction of bound and continuum states is derived. Analytic expressions for line profiles are presented for two specific experimental implementations of TC-RFWM used in gas-phase spectroscopic studies. While the TC-RFWM line profiles are found to be very distinct from the line profiles …

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Measurement Of The Compton And Coherent Scattering Differential Cross-Sections, Yakup Kurucu, Salih Erzeneoğlu, Rıdvan Durak, Yusuf Şahi̇n Jan 1998

Measurement Of The Compton And Coherent Scattering Differential Cross-Sections, Yakup Kurucu, Salih Erzeneoğlu, Rıdvan Durak, Yusuf Şahi̇n

Turkish Journal of Physics

The total atomic Compton and coherent scattering differential cross section of Al, Sn and Ta for 59.5 keV gamma rays of Am-241 point source have been measured for scattering angles $\theta=81^{\circ}$, $85.5^{\circ}$, $90^{\circ}$ and $94.5^{\circ}$ by a direct method with an energy dispersive x-ray spectrometer. The background correction and detection efficiency are also included the study. The experimental results are comparatively given with some available theoretical data obtained with some approximation methods.

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Bulk Modulus Calculations Of Liquid Alkali Metal Alloys, Mehmet Yilmaz, Seyfeddin Karagözoğlu, İris Gümüş Jan 1998

Bulk Modulus Calculations Of Liquid Alkali Metal Alloys, Mehmet Yilmaz, Seyfeddin Karagözoğlu, İris Gümüş

Turkish Journal of Physics

In this work, the bulk modulus values for liquid alkali metal alloys near melting point are studied in the framework of the Gibbs-Bogoliubov method. We use the local Heine-Abarenkov pseudopotential and Ichimaru-Utsumi screening function in these alloys. The results are compared with experimental and theoretical results.

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Electron Attachment Energies Of The Dna Bases, Kayvan Aflatooni, Gordon A. Gallup, Paul Burrow Jan 1998

Electron Attachment Energies Of The Dna Bases, Kayvan Aflatooni, Gordon A. Gallup, Paul Burrow

Paul Burrow Publications

Injection of electrons into the empty π* molecular orbitals of uracil and the DNA bases creates short-lived anion states whose energies have been determined by electron scattering. A common range of attachment energies into the lowest orbitals is observed in all the bases. Evidence for nuclear motion during the lifetimes of the anions is found in all the compounds except adenine. These properties of the bases as bridge sites along the π-stack of DNA, namely, the effective degeneracy of the anion energies and the strong excitation of vibration, are key parameters for theories of electron-transfer rate, some of …

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Letter To The Editor, John C. Wheeler Jan 1998

Letter To The Editor, John C. Wheeler

Journal of the Minnesota Academy of Science

No abstract provided.

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Complete Single-Ionization Momentum Spectra For Strong Perturbation Collisions, Ronald E. Olson, C. J. Wood, H. Schmidt-Böcking, R. Moshammer, J. Ullrich Jan 1998

Complete Single-Ionization Momentum Spectra For Strong Perturbation Collisions, Ronald E. Olson, C. J. Wood, H. Schmidt-Böcking, R. Moshammer, J. Ullrich

Physics Faculty Research & Creative Works

The combination of recoil ion and ionized electron momentum spectroscopy provides an unparalleled method to investigate the details of ion-atom collision dynamics in kinematically complete experiments. To predict single ionization scattering behavior at the level now realized by experiment, the classical trajectory three-body Monte Carlo method has been used to obtain complete momenta information for the ionized electron, recoil ion, and projectile in the collision plane defined by the incident projectile and outgoing recoil ion. Strongly coupled systems were considered where the charge state of the projectile divided by the speed of the collision [Formula Presented] is greater than unity. …

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A Longitudinal Study Of Engineering Student Performance And Retention. V. Comparisons With Traditionally-Taught Students, Richard M. Felder, Gary Felder, E. Jacquelin Dietz Jan 1998

A Longitudinal Study Of Engineering Student Performance And Retention. V. Comparisons With Traditionally-Taught Students, Richard M. Felder, Gary Felder, E. Jacquelin Dietz

Physics: Faculty Publications

In a longitudinal study at North Carolina State University, a cohort of students took five chemical engineering courses taught by the same instructor in five consecutive semesters. The courses made extensive use of active and cooperative learning and a variety of other techniques designed to address a broad spectrum of learning styles. Previous reports on the study summarized the instructional methods used in the experimental course sequence, described the performance of the cohort in the introductory chemical engineering course, and examined performance and attitude differences between students from rural and urban backgrounds and between male and female students.1–4 This paper …

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Ab Initio Study Of Formazan And 3-Nitroformazan, G. Buemi, F. Zuccarello, P. Venuvanalingam, M. Ramalingam, Salai Cheettu Ammal Jan 1998

Ab Initio Study Of Formazan And 3-Nitroformazan, G. Buemi, F. Zuccarello, P. Venuvanalingam, M. Ramalingam, Salai Cheettu Ammal

Faculty Publications

Formazan and 3-nitroformazan have been investigated at abinitio level (MP2/6-31G** and B3LYP/6-31G**) in all their possible conformations, for studying the various possibilities of intramolecular hydrogen bonding formation. The trans-syn-s-cis (TSSC), known also asyellowform, has been found to be the most stable conformer (at least in the gas phase) in both compounds. This particular structure is strongly stabilized by a N–H···N hydrogen bridge, which gives rise to a hexatomic chelate ring, with the possibility of a proton transfer process.This closely resembles that of malondialdehyde, previously studied, in the evolution of the …

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Determination Of Temperature Dependent Frequency Factor Constant From Tl Glow Curves, A. Necmeddin Yazici Jan 1998

Determination Of Temperature Dependent Frequency Factor Constant From Tl Glow Curves, A. Necmeddin Yazici

Turkish Journal of Physics

A new method solely based on the theoretical and experimental analysis of thermoluminescence glow curves is proposed for the determination of the temperature dependent frequency factor constant.

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Analysis Of Atmospheric Concentrations Of Radon And Thoron Using Beta Counting Technique, G. S. Islam, S. M. Basunia Jan 1998

Analysis Of Atmospheric Concentrations Of Radon And Thoron Using Beta Counting Technique, G. S. Islam, S. M. Basunia

Turkish Journal of Physics

This paper presents a detailed theory and experimental procedure for measurement and analysis of mixed radon and thoron in the environment. The technique has been successfully applied to the study of seasonal variations of radon and thoron in the atmosphere around Rajshahi, Banladesh, during the years 1989-1991. The maximum radon concentration in outdoor air was observed in the winter from December to January while the indoor radon concentration was found to be maximum during the monsoon months of July and August. The implication of the results is briefly discussed in the paper.

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Quantum Integrable Systems Of The Group Su(1, 1), Mehmet Sezgi̇n, Yılmaz Asad Verdi̇yev Jan 1998

Quantum Integrable Systems Of The Group Su(1, 1), Mehmet Sezgi̇n, Yılmaz Asad Verdi̇yev

Turkish Journal of Physics

Quantum integrable systems related with SU(1, 1) group manifold or hyperboloid [x, x] = x^2_1 + x^2_2 - x^2_3 - x^2_4 = 1 in spherical, hyperbolic and parabolic coordinates systems are considered. The explicit expressions for waves functions, spectra and S-matrices are given.

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