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Articles 30871 - 30900 of 35520

Full-Text Articles in Physical Sciences and Mathematics

Energy And Angular Distributions Of Electrons From Ion Impact On Atomic And Molecular Hydrogen. Iii. 28–114-Kev He+ + H2, Y.-Y. Hsu, M. W. Gealy, G. W. Kerby Iii, M. Eugene Rudd Jan 1996

Energy And Angular Distributions Of Electrons From Ion Impact On Atomic And Molecular Hydrogen. Iii. 28–114-Kev He+ + H2, Y.-Y. Hsu, M. W. Gealy, G. W. Kerby Iii, M. Eugene Rudd

M. Eugene Rudd Publications

Absolute cross sections, differential in energy and angle of ejection of the secondary electrons, were determined for electron emission from He+ +H2 collisions at 28–114 keV by measuring electron energy spectra from 1.5 to 300 eV at several angles from 15° to 160°. A rotatable electrostatic analyzer was used with an energy resolution of 5% and an angular acceptance of 4.6° full width at half maximum. The double-differential cross sections were integrated over angle, energy, or both to obtain single-differential and total ionization cross sections. The latter are in excellent agreement with previous experimental results. Agreement of the …

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Using Symbolic Manipulation To Evaluate Feynman's Path Integral For An Interaction Of The Form F(T) X R, Min-Qi Bao, Anthony F. Starace Jan 1996

Using Symbolic Manipulation To Evaluate Feynman's Path Integral For An Interaction Of The Form F(T) X R, Min-Qi Bao, Anthony F. Starace

Anthony F. Starace Publications

Obtaining Feynman's path integral, which is a representation for the system's Green's function, is essential for many physical problems. In this paper, a symbolic algebra program is presented to evaluate analytically Feynman's path integral for an interaction of the form F(t) x r. Such an interaction governs the motion of an electron in the field of one or more lasers as well as in a static electric field.

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Novel Doubly Excited States Produced In Negative Ion Photodetachment, Anthony F. Starace Jan 1996

Novel Doubly Excited States Produced In Negative Ion Photodetachment, Anthony F. Starace

Anthony F. Starace Publications

Eigenchannel R-matrix calculations (including effects of long-range multipole interactions beyond the reaction volume) for Li– photodetachment partial cross sections from the vicinity of the Li 3s threshold to the Li 6s threshold (3.8 eV ≤ ħω ≤ 5.65 eV) are presented. Excellent agreement with recent relative total cross section measurements of U. Berzinsh et al. [Phys. Rev. Lett. 74, 4795 (1995)] in the vicinity of the Li 3s and Li 3p thresholds is found. The calculated resonance structures are analyzed in detail and compared with similar calculations for H– photodetachment above the H(n = …

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Internal Time Formalism For Spacetimes With Two Killing Vectors, Joseph D. Romano, Charles G. Torre Jan 1996

Internal Time Formalism For Spacetimes With Two Killing Vectors, Joseph D. Romano, Charles G. Torre

All Physics Faculty Publications

The Hamiltonian structure of spacetimes with two commuting Killing vector fields is analyzed for the purpose of addressing the various problems of time that arise in canonical gravity. Two specific models are considered: (i) cylindrically symmetric spacetimes, and (ii) toroidally symmetric spacetimes, which respectively involve open and closed universe boundary conditions. For each model canonical variables which can be used to identify points of space and instants of time, {\it i.e.}, internally defined spacetime coordinates, are identified. To do this it is necessary to extend the usual ADM phase space by a finite number of degrees of freedom. Canonical transformations …

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Relationship Of Theoretical Patch Climatology To Polar Cap Patch Observations, M. D. Bowline, Jan Josef Sojka, Robert W. Schunk Jan 1996

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 …

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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 Jan 1996

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 …

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Model-Observation Comparison Study Of Multiple Polar Cap Arcs, Lie Zhu, Cesar E. Valladares, Jan Josef Sojka, Robert W. Schunk, D. J. Crain Jan 1996

Model-Observation Comparison Study Of Multiple Polar Cap Arcs, Lie Zhu, Cesar E. Valladares, Jan Josef Sojka, Robert W. Schunk, D. J. Crain

All Physics Faculty Publications

A quantitative model-observation comparison of multiple polar cap arcs has been conducted by using a time-dependent theoretical model of polar cap arcs. In particular, the electrodynamical features of multiple polar cap arcs with various spacings are simulated and the results are compared with the images obtained from the All-Sky Intensified Photometer at Qaanaaq. The results show that the observed and simulated arcs are quite similar, both spatially and temporally. The results support the theory proposed by Zhu et al. [1993a, 1994b] that the structure of polar cap arcs is mainly determined by the magnetosphere-ionosphere (M-I) coupling processes and that …

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Resonance Lidar To Study Temperatures, Winds, And Metal Densities In The Upper Mesosphere And Lower Thermosphere, Vincent B. Wickwar, T D. Wilkerson, D Rees, S C. Collins Jan 1996

Resonance Lidar To Study Temperatures, Winds, And Metal Densities In The Upper Mesosphere And Lower Thermosphere, Vincent B. Wickwar, T D. Wilkerson, D Rees, S C. Collins

All Physics Faculty Publications

None available.

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Scale-Invariant Phase Space And The Conformal Group, James Thomas Wheeler Jan 1996

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.

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Friction-Weighted Self-Consistent Effective Binary Diffusion Approximation, John D. Ramshaw, C. H. Chang Jan 1996

Friction-Weighted Self-Consistent Effective Binary Diffusion Approximation, John D. Ramshaw, C. H. Chang

Physics Faculty Publications and Presentations

The self-consistent effective binary diffusion (SCEBD) approximation for multicomponent diffusion in gas mixtures is reconsidered and reformulated. The new formulation is based on the fact that a suitable rearrangement of the Stefan-Maxwell equations provides an exact expression for the complementary mean velocity ai for species i as a weighted average of the velocities of all the other species. The coefficients in ai are normalized friction coefficients which are simply related to the true binary diffusion coefficients. A simple factorized bilinear approximation to the friction coefficients then yields approximate species diffusion fluxes identical in form to those of a …

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Simple Approximation For Thermal Diffusion In Ionized Gas Mixtures, John D. Ramshaw Jan 1996

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.

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Synthesis And Characterization Of Boron-Containing Polymeric Materials For Neutron Shielding Applications, Michael B. Glasgow Jan 1996

Synthesis And Characterization Of Boron-Containing Polymeric Materials For Neutron Shielding Applications, Michael B. Glasgow

Dissertations, Theses, and Masters Projects

The development of boron-containing polymeric materials for neutron shielding applications was undertaken. Three types of materials were characterized for physical and thermal properties: boron powder-filled epoxy composites, carborane polyamides having boron chemically bonded into the polymer, and boron-loaded polyimide thin films. Addition of amorphous submicron boron powder did not affect significantly the thermal performance of the epoxy. The 17% boron loading produced a 26% increase in compressive failure strength and a 68% increase in the compressive modulus. 0.125 inch thick specimens containing 17% boron absorbed 92% of incident neutrons from a 5-Curie Pu/Be source compared with {dollar}<{dollar}1% for the neat epoxy. Dispersion of the boron in the epoxy was improved with the addition of larger size crystalline boron powders. Carborane polyamides containing up to 35% boron were thermally stable up to 400{dollar}\sp\circ{dollar}C in air. The polymers had hydrogen/boron ratios from 2.0 to 3.8 and were soluble in several organic solvents. Polymer solutions were processed into clear, colored thin films. Boron-filled polyamic acid solutions of a PMDA-ODA polyimide containing up to 10% boron were processed into thin films. Neutron absorption of the opaque films measured in a 5-Curie Pu/Be neutron source was linear with boron concentration and film thickness. The fraction of neutrons absorbed varied linearly with boron concentration and film thickness. The applicability of boron-containing materials to the aerospace, nuclear power and accelerator industries was investigated.

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The Strong Force: Two Calculations Of Strong Interaction Phenomena, Richard L. Kahler Jan 1996

The Strong Force: Two Calculations Of Strong Interaction Phenomena, Richard L. Kahler

Dissertations, Theses, and Masters Projects

Because the theory of strong interactions is mathematically intractable, it is necessary to make approximations which preserve phenomenological features of the theory in order to get answers to practical questions. This thesis explores two such techniques: (1) the chiral bag model is used to investigate the nucleon-nucleon potential and (2) perturbative QCD is used to investigate the pion form factor. An extensive introduction is presented to make the thesis more understandable to a wider audience of people otherwise unfamiliar with particle physics.

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Wave Profile For Proforce Current Bearing Waves, Mostafa Hemmati, Steven Young Jan 1996

Wave Profile For Proforce Current Bearing Waves, Mostafa Hemmati, Steven Young

Journal of the Arkansas Academy of Science

A complete wave profile for proforce style of breakdown waves with a current behind the shock front is discussed. The solution of the electron fluid dynamical equations in the sheath region for proforce current bearing waves conforms with the expected conditins for the values of the dynamical variables at the trailing edge of the wave. The wave profile for electric field and electron velocity, temperature, and number density are presented.

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Measuring Strangeness Production From Relativisitic Collisions Between Pairs Of Nuclei Using A Vertex Time Projection Chamber, Christine A. Byrd, Wilfred J. Braithwaite Jan 1996

Measuring Strangeness Production From Relativisitic Collisions Between Pairs Of Nuclei Using A Vertex Time Projection Chamber, Christine A. Byrd, Wilfred J. Braithwaite

Journal of the Arkansas Academy of Science

At collider energies of 200A-GeV, tracking of charged particle pairs originating from neutrals is dominated by singlystrange KJ.' decays. Counting the number ofsecondary vertex pairs is a method of measuring the strangeness production. The VTX is a four-layer micro-strip gas time projection chamber being designed for use with the STAR instrument in an experiment using the Relativistic Heavy Ion Collider under construction at Brookhaven National Laboratory. Simulated pixel data generated from CERN's Monte Carlo detector-modeling program Geant were put into tables using the TAS sorting structures available from the STAR Collaboration. The response of VTX was mapped for charged pion …

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Quantum Version Of A Spherical Model: Crossover From Quantum To Classical Critical Behavior, Thomas Vojta Jan 1996

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 …

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Selective Inversion In Solid-State Deuteron Nmr, Marco J. Brown Jan 1996

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 …

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Transport In Chaotic Systems, Xian Zhu Tang Jan 1996

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 …

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The Projector Basis Method For Electronic Band Structure Calculations, Christopher Haas Jan 1996

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 …

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Surface Reflection Hyperthermal Neutral Stream Source, Christopher A. Nichols Jan 1996

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 …

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Q² Evolution Of Chiral-Odd Twist-3 Distributions HL(𝓍, Q²) And E(𝓍, Q²) In Large- NC Qcd, I.I. Balitsky, V. M. Braun, K. Koike, K. Tanaka Jan 1996

Q² Evolution Of Chiral-Odd Twist-3 Distributions HL(𝓍, Q²) And E(𝓍, Q²) In Large- NC Qcd, I.I. Balitsky, V. M. Braun, K. Koike, K. Tanaka

Physics Faculty Publications

We prove that the twist-3 chiral-odd parton distributions obey simple Gribov-Lipatov-Altarelli-Parisi evolution equations in the limit Nc → ∞ and give analytic results for the corresponding anomalous dimensions. To this end we introduce an evolution equation for the corresponding three-particle twist-3 parton correlation functions and find an exact analytic solution. For large values of n (operator dimension) we are further able to collect all corrections subleading in Nc, so our final results are valid to O((1/N2c)ln(n)/n) accuracy

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Final State Interactions In The Decay Of Heavy Quarks, John Donoghue Jan 1996

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.

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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 Jan 1996

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 …

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Nonperturbative Methods In Kaon Physics (Aside From The Lattice), John Donoghue Jan 1996

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.

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Is B→Xsγ Equal To B→Sγ? Spectator Contributions To Rare Inclusive B Decays, John Donoghue, Alexey A. Petrov Jan 1996

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 …

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Polymers Interacting With Spherical And Rodlike Particles, E. Eisenriegler, Andreas Hanke, S. Dietrich Jan 1996

Polymers Interacting With Spherical And Rodlike Particles, E. Eisenriegler, Andreas Hanke, S. Dietrich

Physics and Astronomy Faculty Publications and Presentations

The interaction of a long flexible polymer chain with mesoscopic particles of spherical or elongated cylindrical shape is investigated by field-theoretic methods using the polymer-magnet analogy. In the case that these particles are immersed in a dilute polymer solution and exhibit purely repulsive surfaces we study density profiles for monomers and chain ends near such a particle, the change of configurational entropy by immersing a particle into the solution, and the depletion interaction between a particle and a distant planar wall. Both ideal chains and chains with an excluded-volume interaction are considered. We also analyze particle surfaces with a short-ranged …

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Hierarchical Search Strategy For The Detection Of Gravitational Waves From Coalescing Binaries, Soumya Mohanty, S. Dhurandhar Jan 1996

Hierarchical Search Strategy For The Detection Of Gravitational Waves From Coalescing Binaries, Soumya Mohanty, S. Dhurandhar

Physics and Astronomy Faculty Publications and Presentations

The detection of gravitational waves from coalescing compact binaries would be a computationally intensive process if a single bank of template wave forms (i.e., a one-step search) is used. We present, in this paper, a method which leads to a large reduction in the computational power required as compared to a one-step search. This method is a hierarchical search strategy involving two template banks. We show that the computational power required by such a two-step search, for an on-line detection of the one-parameter family of Newtonian signals, is 18 of that required when an on-line one-step search is used. This …

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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 Jan 1996

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.

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Measurement Of Elastic Ω Photoproduction At Hera, M. Derrick, D. Krakauer, S. Magill, D. Mikunas, B. Musgrave, J. R. Okrasiński, 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 Jan 1996

Measurement Of Elastic Ω Photoproduction At Hera, M. Derrick, D. Krakauer, S. Magill, D. Mikunas, B. Musgrave, J. R. Okrasiński, 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

No abstract provided.

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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 Jan 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

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).

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