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Articles 301 - 330 of 340
Full-Text Articles in Physics
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
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.
Surface Reflection Hyperthermal Neutral Stream Source, Christopher A. Nichols
Surface Reflection Hyperthermal Neutral Stream Source, Christopher A. Nichols
Dissertations, Theses, and Masters Projects
A novel source of hyperthermal (1-30 eV) reactive neutrals based on the surface-reflection-neutralization technique is described. This source is potentially capable of minimizing the charge-induced damage associated with plasma based semiconductor processing steps. The goal of this thesis is to investigate the issues involved in scale-up of this technology for processing of 8{dollar}\sp{lcub}\prime\prime{rcub}{dollar} diameter wafers used today in the semiconductor industry. This includes modeling the plasma ion source and trajectory simulations of the reflected neutral flux. A prototype source was constructed for experimental verification of the plasma model.;An inductively coupled plasma (ICP) source is used to provide a source of …
Selective Inversion In Solid-State Deuteron Nmr, Marco J. Brown
Selective Inversion In Solid-State Deuteron Nmr, Marco J. Brown
Dissertations, Theses, and Masters Projects
Deuteron NMR selective inversion (SI) is developed to study slow molecular motions in solids. Theoretical and practical aspects of selective inversion of spin-1 nuclei in solids are presented. Differences between powdered solids and liquids are considered. Double sideband modulated (DSBM) shaped pulses are shown to improve the performance of SI pulses. DSBM and DANTE selective pulses are compared for off-resonance SI applications. Common spin-{dollar}{lcub}1{rcub}\over{lcub}2{rcub}{dollar} shaped pulses are tested for suitability to solid state deuteron NMR. Simple, short pulses are shown to be most effective due to fast spin-spin relaxation and large underlying homogeneous linewidths in solids.;The power and utility of …
Quantum Version Of A Spherical Model: Crossover From Quantum To Classical Critical Behavior, Thomas Vojta
Quantum Version Of A Spherical Model: Crossover From Quantum To Classical Critical Behavior, Thomas Vojta
Physics Faculty Research & Creative Works
We investigate a quantum version of the spherical model which is obtained from the classical Berlin-Kac spherical model by a simple canonical quantization scheme. We find a complete solution of the model for short-range as well as for long-range interactions. At finite temperatures the critical behavior is the same as in the classical spherical model whereas at zero temperature we find a quantum phase transition characterized by new critical exponents. Based on a functional-integral representation of the partition function the free energy of the model is shown to be equivalent to that of the nonlinear σ model in the limit …
Final State Interactions In The Decay Of Heavy Quarks, John Donoghue
Final State Interactions In The Decay Of Heavy Quarks, John Donoghue
Physics Department Faculty Publication Series
I discuss some recent results on the systematic behavior of final state rescattering which makes use of the limit of a heavy B meson. The results suggest that soft final state interactions do not disappear in the large $m_B$ limit. Soft and hard final state phases can both contribute to CP violating asymmetries in B decay. The way that the soft phases occur is interesting theoretically and suggests the violation of local quark-hadron duality.
Model Equations From Gyrokinetic Theory For A Non-Neutral Plasma To Include Temperature Effects And Applications To A Plasma Of Infinite Length, S. Neil Rasband
Model Equations From Gyrokinetic Theory For A Non-Neutral Plasma To Include Temperature Effects And Applications To A Plasma Of Infinite Length, S. Neil Rasband
Faculty Publications
Gyrokinetic equations are derived for applications to non-neutral plasmas in constant, straight magnetic fields wherein E X B drift velocities are of the same order as thermal velocities. The ratio of the E X B rotation frequency to the cyclotron frequency and the ratio of the gyroradius to a plasma scale length are assumed to be of order epsilon and terms are retained in the gyrokinetic expansion to second order to include finite-Larmor-radius (FLR) effects. A mode equation is obtained for a non-neutral plasma in the infinite-length approximation. The singularities of this equation are compared and contrasted with the familiar …
Nonperturbative Methods In Kaon Physics (Aside From The Lattice), John Donoghue
Nonperturbative Methods In Kaon Physics (Aside From The Lattice), John Donoghue
Physics Department Faculty Publication Series
I discuss the progress in the use of analytic techniques for low energy QCD, in particular as applied to kaon physics. These methods are becoming increasingly powerful and we have gained a good deal of control over the difficult hadronic interactions. There are continuing developments, and I speculate on the ways that these techniques may become yet more sophisticated in the future.
Is B→Xsγ Equal To B→Sγ? Spectator Contributions To Rare Inclusive B Decays, John Donoghue, Alexey A. Petrov
Is B→Xsγ Equal To B→Sγ? Spectator Contributions To Rare Inclusive B Decays, John Donoghue, Alexey A. Petrov
Physics Department Faculty Publication Series
In B→Xsγ, there are perturbative QCD corrections at order αs not only to the single quark line process b→sγ but also coming from a set of diagrams where the weak interaction vertex involves a gluon which interacts with the spectator quark in the B hadron. We discuss the impact of the full set of these diagrams. These can influence the decay rate and also the line shape of the photon spectrum as they favor a softer photon energy than does the pure spectator decay b→sγ. A subset of these diagrams generates differences in the decay rates for charged and neutral …
A Simple Model For Nonequilibrium Fluctuations In A Fluid, Alejandro Garcia, F. Baras, M. Malek Mansour
A Simple Model For Nonequilibrium Fluctuations In A Fluid, Alejandro Garcia, F. Baras, M. Malek Mansour
Alejandro Garcia
Presents a train model that shows the long-range spatial correlations of fluctuations in nonequilibrium fluid systems. Illustration of model through analysis of flat-car trains running on parallel tracks; Simulation of train model in computers; Theoretical analysis for fluctuations in the train model; Relationship between train model and the fluctuating hydrodynamic theory of fluids.
Imaging Of Saddle Point Electron Emission In Slow, R. Dörner, H. Khemliche, M. H. Prior, C. L. Cocke, J. A. Gary, Ronald E. Olson, V. Mergel, J. Ullrich, H. Schmidt-Böcking
Imaging Of Saddle Point Electron Emission In Slow, R. Dörner, H. Khemliche, M. H. Prior, C. L. Cocke, J. A. Gary, Ronald E. Olson, V. Mergel, J. Ullrich, H. Schmidt-Böcking
Physics Faculty Research & Creative Works
The two-dimensional velocity distribution of electrons emitted in 5-15 keV p - He collisions has been measured for completely determined motion of the nuclei, that is, as a function of the impact parameter and in a well defined scattering plane. The electrons are emitted preferentially in the scattering plane and in the forward direction. The velocity distributions show sharp structures that vary strongly with impact parameter and projectile velocity. The results are compared to classical trajectory calculations. © 1996 The American Physical Society.
High-Temperature Thermopower Of And Related Systems, D. Marsh, Paul Ernest Parris
High-Temperature Thermopower Of And Related Systems, D. Marsh, Paul Ernest Parris
Physics Faculty Research & Creative Works
We investigate theoretically the high-temperature Seebeck coefficient in LaMnO3 and related transition-metal-oxide perovskites. Our analysis employs a model for small polaron conduction that takes into account the electronic structure of the 3d orbitals of B-site transition-metal cations, yielding expressions for systems in which conduction occurs through the eg transition-metal manifold. Limiting forms for the Seebeck coefficient as a function of carrier concentration and site degeneracy are identified for strong and weak Coulomb interactions between electrons on the same and neighboring sites. Results are applied to an analysis of experimental data for LaMnO3, the La1-xCa …
Single Ionization Of He By Low-Velocity Protons And [Formula Presented]: Ejected Electron Momentum Distributions, S. D. Kravis, M. Abdallah, C. L. Cocke, C. D. Lin, M. Stockli, B. Walch, Y. D. Wang, Ronald E. Olson, V. D. Rodríguez, W. Wu, M. Pieksma, N. Watanabe
Single Ionization Of He By Low-Velocity Protons And [Formula Presented]: Ejected Electron Momentum Distributions, S. D. Kravis, M. Abdallah, C. L. Cocke, C. D. Lin, M. Stockli, B. Walch, Y. D. Wang, Ronald E. Olson, V. D. Rodríguez, W. Wu, M. Pieksma, N. Watanabe
Physics Faculty Research & Creative Works
A technique for electron spectroscopy which yields full two-dimensional momentum distributions for continuum electrons has been used to study ejected electrons from single ionization of He by [Formula Presented] and proton projectiles at low velocities. Projectile velocities of 1.63, 1.38, and 1.16 a.u. for [Formula Presented] and 2.39, 1.71, 1.15,. 85, and 0.63 a.u. for protons were used. All spectra show much broader distributions along the beam than transverse to the beam. For the case of proton bombardment, the spectra are strongly influenced by both target and projectile potentials, maximizing near the velocity of the saddle in the potential between …
An Inline Optical Electron Polarimeter, K. W. Trantham, Timothy J. Gay, R. J. Vandiver
An Inline Optical Electron Polarimeter, K. W. Trantham, Timothy J. Gay, R. J. Vandiver
Physics Faculty Research & Creative Works
The design and operation of a simple inline optical electron polarimeter is presented. It is based on exchange excitation of ground state neon atoms. The electron polarization is determined from the degree of circular polarization of the subsequent 2p53p 3D3→2p53s 3P2 (6402 Å) fluorescence. This device can characterize both longitudinally and transversely polarized electron beams in a nondestructive fashion, and is inexpensive and easily constructed. © 1996 American Institute of Physics.
Doubly Differential Final-State Momentum Distributions Of The Ionization Products In Collision Of Bare Ions With Hydrogen, Lokesh C. Tribedi, P. Richard, Y. D. Wang, C. D. Lin, Ronald E. Olson
Doubly Differential Final-State Momentum Distributions Of The Ionization Products In Collision Of Bare Ions With Hydrogen, Lokesh C. Tribedi, P. Richard, Y. D. Wang, C. D. Lin, Ronald E. Olson
Physics Faculty Research & Creative Works
In this paper recoil-ion production cross sections are presented differential in recoil-ion longitudinal momentum and electron emission angle in ionization of atomic and molecular hydrogen by bare ion projectiles. A new formulation for constructing these double differential distributions from the measured electron double differential cross sections is used. A novel feature is the separation of two different branches of the recoil-ion longitudinal momentum distribution corresponding to soft and hard collision mechanisms of ionization. The single differential distributions have also been derived. © 1996 The American Physical Society.
Collective Behavior Of Electrons Emitted In Multiply Ionizing Collisions Of 5.9 Mev/U U⁶⁵⁺ With Ne, M. Unverzagt, R. Moshammer, W. Schmitt, Ronald E. Olson, P. Jardin, V. Mergel, J. Ullrich, H. Schmidt-Böcking
Collective Behavior Of Electrons Emitted In Multiply Ionizing Collisions Of 5.9 Mev/U U⁶⁵⁺ With Ne, M. Unverzagt, R. Moshammer, W. Schmitt, Ronald E. Olson, P. Jardin, V. Mergel, J. Ullrich, H. Schmidt-Böcking
Physics Faculty Research & Creative Works
The collective behavior of up to six target electrons emitted in a single collision of 5.9 MeV/u U65+ with Ne was investigated using high-resolution recoil-ion momentum spectroscopy. With an increasing number of ejected electrons the recoil ions are increasingly scattered into the backward direction, providing evidence that the electrons are emitted into the forward hemisphere. Their mean longitudinal sum energy varies from about 5 eV for single ionization up to 1.1 keV for Ne6+. Experimental recoil-ion momentum distributions are in excellent agreement with results of classical many-particle calculations. © 1996 The American Physical Society.
Optical Electron Polarimetry With Heavy Noble Gases, Timothy James Gay, J. E. Furst, K. W. Trantham, W. M.K.P. Wijayaratna
Optical Electron Polarimetry With Heavy Noble Gases, Timothy James Gay, J. E. Furst, K. W. Trantham, W. M.K.P. Wijayaratna
Physics Faculty Research & Creative Works
We have measured the polarization of fluorescence emitted by the noble gases He, Ne, Ar, Kr, and Xe following impact excitation by polarized electrons. In He, the [Formula Presented]P→[Formula Presented]S transition was studied; in the heavy noble gases the [Formula Presented](n+1)p[Formula Presented]→[Formula Presented](n+1)s[Formula Presented] transitions were analyzed. We investigated these transitions as candidates for efficient optical electron polarimetry and found that, because of their larger excitation cross sections and analyzing power, the heavy noble gases are superior to He, which had been used previously as a polarimetric target. Several issues with regard to the implementation and accuracy of optical electron …
Double Ionization Of Helium And Neon For Fast Heavy-Ion Impact: Correlated Motion Of Electrons From Bound To Continuum States, R. Moshammer, J. Ullrich, H. Kollmus, W. Schmitt, M. Unverzagt, O. Jagutzki, V. Mergel, H. Schmidt-Böcking, R. Mann, C. J. Woods, Ronald E. Olson
Double Ionization Of Helium And Neon For Fast Heavy-Ion Impact: Correlated Motion Of Electrons From Bound To Continuum States, R. Moshammer, J. Ullrich, H. Kollmus, W. Schmitt, M. Unverzagt, O. Jagutzki, V. Mergel, H. Schmidt-Böcking, R. Mann, C. J. Woods, Ronald E. Olson
Physics Faculty Research & Creative Works
Double ionization of He and Ne by charged particle impact was explored in kinematically complete experiments measuring the final momenta of the two emerging electrons(Pfe1, Pfe2) and of the recoiling target ion PRf. The momentum transfer from the 3.6 MeV/u Se28+projectile to the electrons is found to be negligibly small. Thus distinct patterns observed in the Pfe1- versus - Pfe2spectra sensitively reflect the details of the electrons' correlated motion. Classical calculations reasonably describe the data only when the (e-e)interaction during the ionization reaction is included. © 1996 The American Physical Society.
Measurements Of Recoil And Projectile Momentum Distributions For 19-Mev [Formula Presented] + Ne Collisions, V. Frohne, S. Cheng, R. M. Ali, M. L.A. Raphaelian, C. L. Cocke, Ronald E. Olson
Measurements Of Recoil And Projectile Momentum Distributions For 19-Mev [Formula Presented] + Ne Collisions, V. Frohne, S. Cheng, R. M. Ali, M. L.A. Raphaelian, C. L. Cocke, Ronald E. Olson
Physics Faculty Research & Creative Works
The collision system of 19-MeV [Formula Presented] on Ne has been studied using recoil and projectile momentum spectroscopy. For each event, identified by final recoil and projectile charge state, the three-dimensional momentum vector of the recoil ion and the transverse momentum vector of the projectile ion were measured. The transverse momenta of the recoil and projectile ions were found to be equal in magnitude and opposite in direction, indicating that the transverse momentum exchange is dominated by interactions between the two ion cores. The transverse momentum distributions are well described by nCTMC calculations. The longitudinal momentum distributions of the recoil …
The Stability Of Compressible Mixing Layers In Binary Gases, F. Kozusko, D. G. Lasseigne, C. E. Grosch, T. L. Jackson
The Stability Of Compressible Mixing Layers In Binary Gases, F. Kozusko, D. G. Lasseigne, C. E. Grosch, T. L. Jackson
Mathematics & Statistics Faculty Publications
We present the results of a study of the inviscid two-dimensional spatial stability of a parallel compressible mixing layer in a binary gas. The parameters of this study are the Mach number of the fast stream, the ratio of the velocity of the slow stream to that of the fast stream, the ratio of the temperatures, the composition of the gas in the slow stream and in the fast stream, and the frequency of the disturbance wave. The ratio of the molecular weight of the slow stream to that of the fast stream is found to be an important quantity …
Simple Approximation For Thermal Diffusion In Ionized Gas Mixtures, John D. Ramshaw
Simple Approximation For Thermal Diffusion In Ionized Gas Mixtures, John D. Ramshaw
Physics Faculty Publications and Presentations
A simple approximation for thermal diffusion in gas mixtures was recently proposed [1]. This approximation was based upon relations valid for rigid spheres. It is therefore appropriate for molecules with steep repulsive potentials, but not for ionized species interacting via the Coulomb potential. Here we formulate an analogous approximation for ionized species and free electrons. The resulting thermal diffusion coefficients differ in sign from those for hard molecules.
Translation Of 'Profiles In Faith', Monish Ranjan Chatterjee
Translation Of 'Profiles In Faith', Monish Ranjan Chatterjee
Electrical and Computer Engineering Faculty Publications
Sarat Chandra Chatterjee (1876-1938) may be considered one of the three most significant figures of the literary component of the Bengal Renaissance, the other two being Bankim Chandra Chatterjee (1838-1894) and Rabindranath Tagore (1861-1941). As much as Bankim Chandra is identified with the new age in the Bengali novel, and the development of serious vernacular journalism, and Rabindranath with modern/classical movements in Bengali poetry and music, along with novel ideas in methods of education and teaching, Sarat Chandra, as a novelist and storyteller, perfected the art of narration and critical analyses of a variety of contemporaneous social and political issues, …
Surface Debye Temperature Measurement With Reflection High-Energy Electron Diffraction, H. E. Elsayed-Ali
Surface Debye Temperature Measurement With Reflection High-Energy Electron Diffraction, H. E. Elsayed-Ali
Electrical & Computer Engineering Faculty Publications
Measurement of the surface mean-square atomic vibrational amplitude, or equivalently the surface Debye temperature, with reflection high-energy electron diffraction is discussed. Low-index surfaces of lead are used as examples. Particular details are given about the temperature-dependent diffraction pattern of Pb(100) in the Debye-Waller region. The use of reflection high-energy electron diffraction for measurement of the substrate surface temperature in thin-film deposition chambers is suggested. © 1996 American Institute of Physics.
Transport In Chaotic Systems, Xian Zhu Tang
Transport In Chaotic Systems, Xian Zhu Tang
Dissertations, Theses, and Masters Projects
This dissertation addresses the general problem of transport in chaotic systems. Typical fluid problem of the kind is the advection and diffusion of a passive scalar. The magnetic field evolution in a chaotic conducting media is an example of the chaotic transport of a vector field. In kinetic theory, the collisional relaxation of a distribution function in phase space is also an advection-diffusion problem, but in a higher dimensional space.;In a chaotic flow neighboring points tend to separate exponentially in time, exp({dollar}\omega t{dollar}) with {dollar}\omega{dollar} the Liapunov exponent. The characteristic parameter for the transport of a scalar in a chaotic …
The Projector Basis Method For Electronic Band Structure Calculations, Christopher Haas
The Projector Basis Method For Electronic Band Structure Calculations, Christopher Haas
Dissertations, Theses, and Masters Projects
Over the last several decades, two methods have emerged as the standard tools for the calculation of electronic band structures. These methods, the Car-Parinello plane wave method and the linear augmented plane wave method (LAPW), each have strengths and weaknesses in different regimes of physical problems. The Car-Parinello algorithm is ideal for calculations with soft pseudopotentials and large numbers of atoms. The LAPW method, on the other hand, easily handles all-electron and hard-core pseudopotential calculations with a small number of atoms. The projector basis method, presented here, is a hybrid mixed basis method which allows the calculation of moderately large …
Relationship Of Theoretical Patch Climatology To Polar Cap Patch Observations, M. D. Bowline, Jan Josef Sojka, Robert W. Schunk
Relationship Of Theoretical Patch Climatology To Polar Cap Patch Observations, M. D. Bowline, Jan Josef Sojka, Robert W. Schunk
All Physics Faculty Publications
During a southward orientation of the interplanetary magnetic field (IMF), patches are often observed moving antisunward across the polar cap. In saying “patches” we refer to structures in which the F region electron densities are enhanced relative to lower background levels; we do not in this paper consider patches which are observed optically (see J. J. Sojka et al., Ambiguity in identificiation of polar cap F region patches, submitted to the Journal of Atmospheric and Terrestrial Physics, 1995). The patches can be modeled by a process which involves the “chopping up” of the tongue of ionization (TOI) [Sojka …
Multiple Polar Cap Arcs: Akebono (Exos D) Observations, T. Obara, T. Mukai, H. Hayakawa, K. Tsurda, A. Matsuoka, A. Nishida, H. Fukunishi, L. Zhu, Jan Josef Sojka, D. J. Crain
Multiple Polar Cap Arcs: Akebono (Exos D) Observations, T. Obara, T. Mukai, H. Hayakawa, K. Tsurda, A. Matsuoka, A. Nishida, H. Fukunishi, L. Zhu, Jan Josef Sojka, D. J. Crain
All Physics Faculty Publications
Akebono (Exos D) observations demonstrate that polar cap arcs sometimes have a fine structure, that is, multiple (double or triple) arcs with spacing of a few tens of kilometers. The multiple polar cap arcs are dominantly observed in the nightside polar cap region, suggesting that low background conductance favors the appearance of the structured arcs. A relationship between the spacing and the average energy of the precipitating electrons is investigated. Results show that a higher energy leads to a wider spacing. Akebono observations also show the existence of a downward current region embedded between upward current regions (arcs). Comparison of …
Scale-Invariant Phase Space And The Conformal Group, James Thomas Wheeler
Scale-Invariant Phase Space And The Conformal Group, James Thomas Wheeler
All Physics Faculty Publications
The gauge bundle of the 4-dim conformal group over an 8-dim base space, called biconformal space, is shown have a consistent interpretation as a scale-invariant phase space. Specifically, we show that a classical Hamiltonian system generates a differential geometry which is necessarily biconformal, and that the classical Hamiltonian dynamics of a point particle is equivalent to the specification of a 7-dim hypersurface in flat biconformal space together with the consequent necessary existence of a set of preferred curves. The result is centrally important for establishing the physical interpretation of conformal gauging.
Measurement Of The F2 Structure Function In Deep Inelastic E+P Scattering Using 1994 Data From The Zeus Detector At Hera, M. Derrick, D. Krakauer, S. Magill, D. Mikunas, B. Musgrave, J. R. Okrasinski, J. Repond, R. Stanek, R. L. Talaga, H. Zhang, Margarita C. K. Mattingly, F. Anselmo, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, P. Bruni, G. Cara Romeo, G. Castellini, L. Cifarelli, F. Cindolo, A. Contin, M. Corradi, I. Gialas, P. Giusti, G. Iacobucci, G. Laurenti, G. Levi
Measurement Of The F2 Structure Function In Deep Inelastic E+P Scattering Using 1994 Data From The Zeus Detector At Hera, M. Derrick, D. Krakauer, S. Magill, D. Mikunas, B. Musgrave, J. R. Okrasinski, J. Repond, R. Stanek, R. L. Talaga, H. Zhang, Margarita C. K. Mattingly, F. Anselmo, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, P. Bruni, G. Cara Romeo, G. Castellini, L. Cifarelli, F. Cindolo, A. Contin, M. Corradi, I. Gialas, P. Giusti, G. Iacobucci, G. Laurenti, G. Levi
Faculty Publications
We present measurements of the structure function F2 in e+p scattering at HERA in the range 3.5 GeV2 < Q2 < 5000 GeV2. A new reconstruction method has allowed a significant improvement in the resolution of the kinematic variables and an extension of the kinematic region covered by the experiment. At Q2 < 35 GeV2 the range in x now spans 6.3 · 10-5 < x < 0.08 providing overlap with measurements from fixed target experiments. At values of Q2 above 1000 GeV2 the x range extends to 0.5. Systematic errors below 5% have been achieved for most of the kinematic region. The structure function rises as x decreases; the rise becomes more pronounced as Q2 increases. The behaviour of the structure function data is well described by next-to-leading order perturbative QCD as implemented in the DGLAP evolution equations. © Springer-Verlag 1996.
Measurement Of The Diffractive Cross Section In Deep Inelastic Scattering, M. Derrick, D. Krakauer, S. Magill, D. Mikunas, B. Musgrave, J. R. Okrasinski, J. Repond, R. Stanek, R. L. Talaga, H. Zhang, Margarita C. K. Mattingly, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, P. Bruni, G. Cara Romeo, G. Castellini, L. Cifarelli, F. Cindolo, A. Contin, M. Corradi, I. Gialas, P. Giusti, G. Iacobucci, G. Laurenti, G. Levi, A. Margotti, T. Massam
Measurement Of The Diffractive Cross Section In Deep Inelastic Scattering, M. Derrick, D. Krakauer, S. Magill, D. Mikunas, B. Musgrave, J. R. Okrasinski, J. Repond, R. Stanek, R. L. Talaga, H. Zhang, Margarita C. K. Mattingly, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, P. Bruni, G. Cara Romeo, G. Castellini, L. Cifarelli, F. Cindolo, A. Contin, M. Corradi, I. Gialas, P. Giusti, G. Iacobucci, G. Laurenti, G. Levi, A. Margotti, T. Massam
Faculty Publications
© Springer-Verlag 1996. Diffractive scattering of γ∗p → X + N, where N is either a proton or a nucleonic system with MN < 4 GeV has been measured in deep inelastic scattering (DIS) at HERA. The cross section was determined by a novel method as a function of the γ∗p c.m. energy W between 60 and 245 GeV and of the mass MX of the system X up to 15 GeV at average Q2 values of 14 and 31 GeV2. The diffractive cross section dσdi f f /dMX is, within errors, found to rise linearly with W. Parameterizing the W dependence by the form dσdi f f /dMX ∞ (W2)(2αIP - 2) the DIS data yield for the pomeron trajectory αIP = 1.23±0.02(stat)±0.04(syst) averaged over t in the measured kinematic range assuming the longitudinal photon contribution to be zero. This value for the pomeron trajectory is substantially larger than αIP extracted from soft interactions. The value of αIP measured in this analysis suggests that a substantial part of the diffractive DIS cross section originates from processes which can be described by perturbative QCD. From the measured diffractive cross sections the diffractive structure function of the proton F2D(3) (β,Q2, xIP) has been determined, where β is the momentum fraction of the struck quark in the pomeron. The form F2D(3) = constant·(1/xIP)a gives a good fit to the data in all β and Q2 intervals with a = 1.46 ± 0.04(stat) ± 0.08(syst).
Modelling An Optical Fiber Bragg Grating, Claudio Oliveira Egalon
Modelling An Optical Fiber Bragg Grating, Claudio Oliveira Egalon
Electrical & Computer Engineering Theses & Dissertations
A theoretical investigation of a single mode optical fiber with one and two superimposed Bragg grating is presented. The formulation relies in the determination of an approximate solution in the asymptotic region of one of the fiber parameters. A correction is then applied to the asymptotic solution using the Method of the Successive Approximations also known as the Piccard Method. The approximation was then compared to the numerical solution using the Runge-Kutta method. Assuming that each Bragg grating has modulation frequencies given by Ω1 and Ω2, it has been found that the second Bragg grating shifts the …