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Old Dominion University

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Articles 421 - 440 of 440

Full-Text Articles in Nuclear

Precision Measurement Of The Spin Structure Of The Proton And The Deuteron, Frank R. Wesselmann Apr 2000

Precision Measurement Of The Spin Structure Of The Proton And The Deuteron, Frank R. Wesselmann

Physics Theses & Dissertations

Experiment E155 at the Stanford Linear Accelerator Center measured the spin structure functions g1 and g2 of the proton and deuteron using deep inelastic scattering of 50 GeV polarized electrons from dynamically polarized, solid 15NH3 and 6LiD targets. Three independent spectrometers, covering a large kinematic region, 0.014 < xBjorken < 0.9 and 1 < Q2 < 40 (GeV /c)2, detected 200 million events. A fully self-consistent and statistically sound approach to calculating radiative corrections was developed, providing well-defined statistical errors for the E155 data set. Also, a comprehensive fit to the global data set was created which simultaneously …

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Generalized Compton Amplitudes In Quantum Chromodynamics, Ignati Grigentch Apr 2000

Generalized Compton Amplitudes In Quantum Chromodynamics, Ignati Grigentch

Physics Theses & Dissertations

In this dissertation we describe results of our studies of generalized Compton amplitudes. We have calculated the one-loop corrections to the amplitude in the coordinate representation in terms of nonlocal string light-ray operators. We have also developed a consistent approach to the problem of constructing the gauge invariant Compton amplitude and obtained an expression for the explicitly gauge invariant amplitude which includes all the generalized target-mass corrections.

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Virtual Compton Scattering In The Nucleon Resonance Region, Luminita Anca Todor Jan 2000

Virtual Compton Scattering In The Nucleon Resonance Region, Luminita Anca Todor

Physics Theses & Dissertations

This thesis is a study of virtual Compton scattering reaction in which a virtual photon is elastically scattered off a proton γv p → γp. The p( e,e′p)γ reaction was measured in the nucleon resonance region for the first time in the experiment E93-050 in Hall A at Thomas Jefferson National Accelerator Facility. To lowest order in αQED, this reaction is a coherent superposition of radiation from the incident or scattered electron in elastic ep scattering (Bethe-Heitler) and exclusive production of a photon on the proton, by absorption of a virtual photon …

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Structure And Dynamics Of Few-Nucleon Systems, J. Carlson, R. Schiavilla Jan 1998

Structure And Dynamics Of Few-Nucleon Systems, J. Carlson, R. Schiavilla

Physics Faculty Publications

Few-nucleon physics is a field rich with high-quality experimental data and possibilities for accurate calculations of strongly correlated quantum systems. In this article the authors discuss the traditional model of the nucleus as a system of interacting nucleons and outline many recent experimental results and theoretical developments in the field of few-nucleon physics. The authors describe nuclear structure and spectra, clustering and correlations, elastic and inelastic electromagnetic form factors, low-energy electroweak reactions, and nuclear scattering and response in the quasi-elastic regime. Through a review of the rich body of experimental data and a variety of theoretical developments, a coherent description …

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The Use Of Operator Regularization In The Computation Of Effective Field Theories, Jeffrey M. Hersh Jul 1997

The Use Of Operator Regularization In The Computation Of Effective Field Theories, Jeffrey M. Hersh

Physics Theses & Dissertations

Current methods of computing low-energy effective field theories while being accurate are extremely cumbersome co implement. Operator regularization provides a way to calculate any desired effective field theory avoiding the tediousness of previous methods. This technique is shown to be an effective method in explicitly calculating the 1/mheavy corrections that match an original full theory to its low-energy effective counterpart. This is demonstrated up to two loop order for the case of a charged two field θ{4}{4} theory as well as up to one loop order for the Higgs sector of the Minimal Supersymmetric Model. Additionally, the renormalization …

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Pion Absorption On Polarized Lithium-7 At 165 Mev, Thomas A. Greco Apr 1996

Pion Absorption On Polarized Lithium-7 At 165 Mev, Thomas A. Greco

Physics Theses & Dissertations

Pion absorption is not well understood. Cross section data alone does not provide a complete description since the cross section tends to be sensitive only to the spin-independent terms in the transition amplitude. Polarization observables are thus necessary to complete the picture. In this experiment, analyzing powers for the reaction 7→Li(π+,pp)5He at Tπ = 165 MeV were measured at the Paul Scherrer Institut, Switzerland. The emitted protons were detected with the SUSI spectrometer at 38° in coincidence with an array of five scintillator telescopes centered around the quasi-free angle for absorption on a nucleon …

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Inclusive Electron Scattering From Nuclei At X≃1, J. Arrington, P. Anthony, R. G. Arnold, E. J. Beise, J. E. Belz, P. E. Bosted, H.- J. Bulten, M. S. Chapman, K. P. Coulter, F. Dietrich, R. Ent, M. Epstein, B. W. Filippone, H. Gao, R. A. Gearhart, D. F. Geesaman, J.- O. Hansen, R. J. Holt, H. E. Jackson, C. E. Jones, C. E. Keppel, E. R. Kinney, S. Kuhn, K. Lee, W. Lorenzon, A. Lung, N.C.R. Malkins, D. J. Margaziotis, R. D. Mckeown, R. G. Milner, B. Mueller, J. Napolitano, J. Nelson, T.G. O'Neill, V. Papavassiliou, G. G. Petratos, D. H. Potterveld, S. E. Rock, M. Spengos, Z. M. Szalata, L. H. Tao, K. Van Bibber, J.F.J. Van Den Brand, J. L. White, D. Winter, B. Zeidman Jan 1996

Inclusive Electron Scattering From Nuclei At X≃1, J. Arrington, P. Anthony, R. G. Arnold, E. J. Beise, J. E. Belz, P. E. Bosted, H.- J. Bulten, M. S. Chapman, K. P. Coulter, F. Dietrich, R. Ent, M. Epstein, B. W. Filippone, H. Gao, R. A. Gearhart, D. F. Geesaman, J.- O. Hansen, R. J. Holt, H. E. Jackson, C. E. Jones, C. E. Keppel, E. R. Kinney, S. Kuhn, K. Lee, W. Lorenzon, A. Lung, N.C.R. Malkins, D. J. Margaziotis, R. D. Mckeown, R. G. Milner, B. Mueller, J. Napolitano, J. Nelson, T.G. O'Neill, V. Papavassiliou, G. G. Petratos, D. H. Potterveld, S. E. Rock, M. Spengos, Z. M. Szalata, L. H. Tao, K. Van Bibber, J.F.J. Van Den Brand, J. L. White, D. Winter, B. Zeidman

Physics Faculty Publications

The inclusive A(e,e') cross section for x≃1 was measured on 2H, C, Fe, and Au for momentum transfers Q2 from 1 to 6.8 (GeV/c)2. The scaling behavior of the data was examined in the region of transition from y scaling to x scaling. Throughout this transitional region, the data exhibit ξ scaling, reminiscent of the Bloom-Gilman duality seen in free nucleon scattering.

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Operator Expansion For High-Energy Scattering, Ian Balitsky Jan 1996

Operator Expansion For High-Energy Scattering, Ian Balitsky

Physics Faculty Publications

I demonstrate that the leading logarithms for high-energy scattering can be obtained as a result of evolution of the non-local operators—straight-line ordered gauge factors—with respect to the slope of the straight line.

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Measurement Of Nuclear Quadrupole Interactions Using Mössbauer Spectroscopy, Desmond C. Cook Jan 1996

Measurement Of Nuclear Quadrupole Interactions Using Mössbauer Spectroscopy, Desmond C. Cook

Physics Faculty Publications

Mössbauer spectroscopy is a useful probe for investigating nuclear quadrupole interactions. It enables the magnitude, sign and asymmetry of the electric quadrupole coupling constant to be determined. It is especially important for its ability to measure these parameters for excited nuclear states. The Mössbauer effect is used to measure excited state quadrupole moments in materials whose electric field gradient (EFG) is known. More commonly however, it is used to determine the EFG from which atomic bonding and electronic structure are determined. The technique also allows temperature dependent orientation of sublattice magnetization to be measured using the direction of the electric …

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Heavy-Ion Interaction Models For Radiation Transport, Rajendra R. Dubey Oct 1995

Heavy-Ion Interaction Models For Radiation Transport, Rajendra R. Dubey

Physics Theses & Dissertations

This dissertation is concerned with finding the values for the nuclear cross sections used in the Boltzmann equation for space radiation transport and dose estimates. An extraordinary number of cross sections are required because of the large number of ion types and their extensive energy range, The Lippmann-Schwinger equation is numerically solved in momentum space for a first order optical potential (free space case) and calculations are made for the total and absorption cross sections for nudeus-nucleus scattering. Absorption cross sections are also calculated using a medium modified firstorder optical potential in the Lippmann-Schwinger equation and are compared with experimental …

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The Study Of Pion Absorption On -4he At 355 Mev/C With Lads (Large Acceptance Detector System), Thomas A. Dooling Jul 1995

The Study Of Pion Absorption On -4he At 355 Mev/C With Lads (Large Acceptance Detector System), Thomas A. Dooling

Physics Theses & Dissertations

The medium and long range part of the nucleon-nucleon interaction can be described within the framework of pion exchange. In order to understand this fundamental interaction, it is therefore important to study the interaction of pions with nucleons and nuclei, which can either be elastic or inelastic scattering or absorption. Whereas the elastic and inelastic channels can be well described by different models, our understanding of pion absorption is still rather poor. There are still a lot of open questions, for instance on the strength of three and more nucleon absorption and the role of initial and final state interactions. …

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Evidence For Virtual Compton Scattering From Proton, J.F.J. Van Den Brand, R. Ent, P. L. Anthony, R. G. Arnold, J. Arrington, E. J. Beise, J. E. Belz, P. E. Bosted, H. J. Bulten, M. S. Chapman, K. P. Coulter, F. S. Dietrich, M. Epstein, B. W. Filippone, H. Gao, R. A. Gearhart, D. F. Geesaman, J.-O. Hansen, R. J. Holt, H. E. Jackson, C. E. Jones, C. E. Keppel, E. R. Kinney, S. Kuhn, K. Lee, W. Lorenzon, A. Lung, N.C.R. Makins, D.J. Margaziotis, R.D. Mckeown, R.G. Milner, B. Mueller, J. Napolitano, J. Nelson, T. G. O'Neill, V. Pavavassiliou, G. G. Petratos, D. H. Potterveld, S. E. Rock, M. Spengos, Z. M. Szalata, L. H. Tao, K Van Bibber, D. A. Wasson, J.L. White, B. Zeidman Jan 1995

Evidence For Virtual Compton Scattering From Proton, J.F.J. Van Den Brand, R. Ent, P. L. Anthony, R. G. Arnold, J. Arrington, E. J. Beise, J. E. Belz, P. E. Bosted, H. J. Bulten, M. S. Chapman, K. P. Coulter, F. S. Dietrich, M. Epstein, B. W. Filippone, H. Gao, R. A. Gearhart, D. F. Geesaman, J.-O. Hansen, R. J. Holt, H. E. Jackson, C. E. Jones, C. E. Keppel, E. R. Kinney, S. Kuhn, K. Lee, W. Lorenzon, A. Lung, N.C.R. Makins, D.J. Margaziotis, R.D. Mckeown, R.G. Milner, B. Mueller, J. Napolitano, J. Nelson, T. G. O'Neill, V. Pavavassiliou, G. G. Petratos, D. H. Potterveld, S. E. Rock, M. Spengos, Z. M. Szalata, L. H. Tao, K Van Bibber, D. A. Wasson, J.L. White, B. Zeidman

Physics Faculty Publications

In virtual Compton scattering an electron is scattered off a nucleon such that the nucleon emits a photon. We show that these events can be selected experimentally, and present the first evidence for virtual Compton scattering from the proton in data obtained at the Stanford Linear Accelerator Center. The angular and energy dependence of the data is well described by a calculation that includes the coherent sum of electron and proton radiation.

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Accurate Nucleon-Nucleon Potential With Charge-Independence Breaking, R. B. Wiringa, V. G. J. Stoks, R. Schiavilla Jan 1995

Accurate Nucleon-Nucleon Potential With Charge-Independence Breaking, R. B. Wiringa, V. G. J. Stoks, R. Schiavilla

Physics Faculty Publications

We present a new high-quality nucleon-nucleon potential with explicit charge dependence and charge asymmetry, which we designate Argonne 𝑣18. The model has a charge-independent part with 14 operator components that is an updated version of the Argonne 𝑣14 potential. Three additional charge-dependent and one charge-asymmetric operators are added, along with a complete electromagnetic interaction. The potential has been fit directly to the Nijmegen pp and np scattering database, low-energy nn scattering parameters, and deuteron binding energy. With 40 adjustable parameters it gives a χ2 per datum of 1.09 for 4301 pp and np data in the range 0–350 …

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Dosimetry Of High-Energy Heavy-Ion Beams Using Energy-Dependent Green's Functions, Sang Yull Chun Oct 1994

Dosimetry Of High-Energy Heavy-Ion Beams Using Energy-Dependent Green's Functions, Sang Yull Chun

Physics Theses & Dissertations

A theoretical description of the transport of high-charge and high-energy (HZE) ion bombardment of biological tissue is developed. The energy-dependent Green’s functions and particle fluxes are obtained for two boundary distributions - the monoenergetic and the Gaussian. Approximate energy-dependent Green’s functions for the collision terms are obtained for computational simplicity. As an application of the energy-dependent Green’s function method, dosimetric quantities, such as dose, dose-equivalent, and average quality factor, for 600A MeV56Fe , 517A MeV 40Ar, and 625A MeV 20Ne ion beams incident on a water target are obtained and compared with the values obtained from …

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A Covariant Description Of The Deuteron, J. W. Van Orden Jan 1994

A Covariant Description Of The Deuteron, J. W. Van Orden

Physics Faculty Publications

An introduction to the use of Bethe-Salpeter and quasipotential equations in the description of electron scattering from the deuteron is provided. The basic formalism and many technical issues are introduced in the context of a simple scalar theory. Results for bound-state wave functions and scattering phases shifts for a variety of quasipotential prescriptions are presented and qualitative characteristics of these solutions are discussed. The elastic form factors for the bound state in this model are calculated using the spectator or Gross equation. The calculations are then extended to account for the complexities associated with nucleon spin and results are presented …

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Search For The Mössbauer Effect In 109ag, Shokrollah Rezaie-Serej Apr 1992

Search For The Mössbauer Effect In 109ag, Shokrollah Rezaie-Serej

Physics Theses & Dissertations

The 88-keV first-excited nuclear state in 109Ag has a mean lifetime of 57.1 sec and a corresponding natural linewidth of 1.15 x 10-17 eV which is nearly six orders of magnitude narrower than the width for the 93-keV 13.2-μsec state in 67Zn. The 93-keV transition in 67Zn has the narrowest linewidth for which the Mossbauer effect has been observed. The 88-keV transition in 109Ag is obviously a very difficult case for the observation of the Mossbauer effect and provides a stringent test for exploring the practical limits of inhomogeneous line broadening in real single …

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Nuclear Fragmentation Energy And Momentum Transfer Distributions In Relativistic Heavy-Ion Collisions, Ferdous Khan Jul 1989

Nuclear Fragmentation Energy And Momentum Transfer Distributions In Relativistic Heavy-Ion Collisions, Ferdous Khan

Physics Theses & Dissertations

An optical model description of energy and momentum transfer in relativistic heavy-ion collisions, based upon composite particle multiple scattering theory, is presented. Transverse and longitudinal momentum transfers to the projectile are shown to arise from the real and absorptive part of the optical potential, respectively. Comparisons of fragment momentum distribution observables with experiments are made and trends outlined based on our knowledge of the underlying nucleon-nucleon interaction. Corrections to the above calculations are discussed. Finally, use of the model as a tool for estimating collision impact parameters is indicated.

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Theory Of Alpha-Nucleus Collisions At High Energies, Francis A. Cucinotta Jul 1988

Theory Of Alpha-Nucleus Collisions At High Energies, Francis A. Cucinotta

Physics Theses & Dissertations

The interaction of high energy alpha particles with atomic nuclei is considered using multiple scattering theories. Semi-classical solutions to coupled-channel equations derived from Watson's form of the nucleus-nucleus multiple scattering series are shown to be equivalent to the Glauber multiple scattering series. Second-order solutions for the elastic amplitude are developed and used to study the effects of short-range correlations in nuclear scattering. The Jastrow method is used to model the two-particle density for 4He and to construct one and two particle form factors. Excellent agreement with experimental data for angular distributions, and total and reaction cross sections is found. …

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Modeling Charge Diffusion From Proton-Induced Ionization Tracks In Silicon Photodiode Arrays, Lee Cole Smith Aug 1982

Modeling Charge Diffusion From Proton-Induced Ionization Tracks In Silicon Photodiode Arrays, Lee Cole Smith

Physics Theses & Dissertations

We are modeling the combined problem of generation and collection of charge carriers created during passage of energetic protons through a silicon photodiode array. We have also experimentally obtained pulse-height distributions of noise charge collected during exposure of a Digicon-type diode array to 21 and 75 MeV protons. It is shown that the magnitude of charge collected by a diode from each proton event is determined not only by diffusion, but by statistical considerations involving the ionization process itself. Utilizing analytical solutions to the diffusion equation for transport of minority carriers, together with the Vavilov-Landau theory of energy-loss fluctuations in …

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Excitation Of Hydrogen Atoms By Fast Protons, Edward Ellis Fitchard Jan 1970

Excitation Of Hydrogen Atoms By Fast Protons, Edward Ellis Fitchard

Physics Theses & Dissertations

In this thesis a theoretical study is made of excitation of hydrogenic atom by charged particles such as protons or electrons. The approximation to the cross section for an inelastic scattering process is obtained under the following radically simplifying assumptions. The projectile is represented in its initial and final state by plane waves. All distortions are neglected whether they originate in an inelastic process or an elastic deflections of the charged particle by the nucleus. The perturbation of the atomic orbits between which the projectile induces transitions is neglected. Nonrelativistic hydrogenic wave functions are used for the electronic states. In …

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