Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons™

Open Access. Powered by Scholars. Published by Universities.®

1997

Physics

Institution
Keyword
Publication
Publication Type
File Type

Articles 1 - 30 of 371

Full-Text Articles in Physical Sciences and Mathematics

Observation Of The Plasma Channel Dynamics And Coulomb Explosion In The Interaction Of A High-Intensity Laser Pulse With A He Gas Jet, G.S. Sarkisov, V. Yu. Bychenkov, V.T. Tikhonchuk, Anatoly Maksimchuk, Shouyuan Chen, R. Wagner, G. Mourou, Donald P. Umstadter Dec 1997

Observation Of The Plasma Channel Dynamics And Coulomb Explosion In The Interaction Of A High-Intensity Laser Pulse With A He Gas Jet, G.S. Sarkisov, V. Yu. Bychenkov, V.T. Tikhonchuk, Anatoly Maksimchuk, Shouyuan Chen, R. Wagner, G. Mourou, Donald P. Umstadter

Donald Umstadter Publications

We report the first interferometric observations of the dynamics of electron–ion cavitation of relativistically self-focused intense 4 TW, 400 fs laser pulse in a He gas jet. The electron density in a channel 1 mm long and 30 mm in diameter drops by a factor of approximately 10 from the maximum value of ~8x1019 cm23. A high radial velocity of the plasma expansion, ~3.8x108 cm/s, corresponding to an ion energy of about 300 keV, is observed. The total energy of fast ions is estimated to be 6% of the laser pulse energy. The high-velocity radial plasma …

Go to article

Global Energetic Neutral Atom (Ena) Measurements And Their Association With The Dst Index, A. M. Jorgensen, Harlan E. Spence, M. G. Henderson, G. D. Reeves, M. Sugiura, T. Kamei Dec 1997

Global Energetic Neutral Atom (Ena) Measurements And Their Association With The Dst Index, A. M. Jorgensen, Harlan E. Spence, M. G. Henderson, G. D. Reeves, M. Sugiura, T. Kamei

Physics & Astronomy

We present a new global magnetospheric index that measures the intensity of the Earth's ring current through energetic neutral atoms (ENAs). We have named it the Global Energetic Neutral Index (GENI), and it is derived from ENA measurements obtained by the Imaging Proton Spectrometer (IPS), part of the Comprehensive Energetic Particle and Pitch Angle Distribution (CEPPAD) experiment on the POLAR satellite. GENI provides a simple orbit-independent global sum of ENAs measured with IPS. Actual ENA measurements for the same magnetospheric state look different when seen from different points in the POLAR orbit. In addition, the instrument is sensitive …

Go to article

Nanoscale Imaging Of Domain Dynamics And Retention In Ferroelectric Thin Films, Alexei Gruverman, H. Tokumoto, A. S. Prakash, S. Aggarwal, B. Yang, M. Wuttig, R. Ramesh, O. Auciello, T. Venkatesan Dec 1997

Nanoscale Imaging Of Domain Dynamics And Retention In Ferroelectric Thin Films, Alexei Gruverman, H. Tokumoto, A. S. Prakash, S. Aggarwal, B. Yang, M. Wuttig, R. Ramesh, O. Auciello, T. Venkatesan

Alexei Gruverman Publications

We report results on the direct observation of the microscopic origins of backswitching in ferroelectric thin films. The piezoelectric response generated in the film by a biased atomic force microscope tip was used to obtain static and dynamic piezoelectric images of individual grains in a polycrystalline material. We demonstrate that polarization reversal occurs under no external field (i.e., loss of remanent polarization) via a dispersive continuous-time random walk process, identified by a stretched exponential decay of the remanent polarization.

Go to article

Hyperfine Splitting Of Low-Lying Heavy Baryons, Joseph Schechter, Masayasu Harada, Asif Qamar, Francesco Sannino, Herbert Weigel Dec 1997

Hyperfine Splitting Of Low-Lying Heavy Baryons, Joseph Schechter, Masayasu Harada, Asif Qamar, Francesco Sannino, Herbert Weigel

Physics - All Scholarship

We calculate the next-to-leading order contribution to the masses of the heavy baryons in the bound state approach for baryons containing a heavy quark. These 1/N_C corrections arise when states of good spin and isospin are generated from the background soliton of the light meson fields. Our study is motivated by the previously established result that light vector meson fields are required for this soliton in order to reasonably describe the spectrum of both the light and the heavy baryons. We note that the inclusion of light vector mesons significantly improves the agreement of the predicted hyperfine splitting with experiment. …

Go to article

Phase Structure Of Dynamical Triangulation Models In Three Dimensions, Simon Catterall, Ray L. Renken, John B. Kogut Dec 1997

Phase Structure Of Dynamical Triangulation Models In Three Dimensions, Simon Catterall, Ray L. Renken, John B. Kogut

Physics - All Scholarship

The dynamical triangulation model of three-dimensional quantum gravity is shown to have a line of transitions in an expanded phase diagram which includes a coupling mu to the order of the vertices. Monte Carlo renormalization group and finite size scaling techniques are used to locate and characterize this line. Our results indicate that for mu < mu1 ~ -1.0 the model is always in a crumpled phase independent of the value of the curvature coupling. For mu < 0 the results are in agreement with an approximate mean field treatment. We find evidence that this line corresponds to first order transitions extending to positive mu. However, the behavior appears to change for mu > mu2 ~ 2-4. The simplest scenario that is consistent with the data is the existence of a critical end point.

Go to article

Remark On The Potential Function Of The Linear Sigma Model, Joseph Schechter, David Delphenich Dec 1997

Remark On The Potential Function Of The Linear Sigma Model, Joseph Schechter, David Delphenich

Physics - All Scholarship

It is shown that the potential functions for the ordinary linear sigma model can be divided into two topographically different types depending on whether the quantity R\equiv (m_\sigma /m_\pi)^2 is greater than or less than nine. Since the Wigner-Weyl mode (R=1) and the Nambu-Goldstone mode (R=\infty belong to different regions, we speculate that this classification may provide a generalization to the broken symmetry situation, which could be convenient for roughly characterizing different possible applications of the model. It is noted that a more complicated potential does not so much change this picture as add different new regions.

Go to article

Measurement Of The Decay Amplitudes And Branching Fractions Of B → J/Ψ K* And B → J/Ψ K Decays, C. P. Jessop, Kenneth A. Bloom, Cleo Collaboration Dec 1997

Measurement Of The Decay Amplitudes And Branching Fractions Of B → J/Ψ K* And B → J/Ψ K Decays, C. P. Jessop, Kenneth A. Bloom, Cleo Collaboration

Kenneth Bloom Publications

Using data taken with the CLEO II detector at the Cornell Electron Storage Ring, we present the first full angular analysis in the color-suppressed modes B0 → J/Ψ K *0and B0 → J/Ψ K*+. This leads to a complete determination of the decay amplitudes of these modes including the longitudinal polarization ΓL/Γ= 0.52 ± 0.07 ± 0.04 and the P wave component │P│2= 0.16 ± 0.08 ± 0.04. In addition, we update the branching fractions for B → J/Ψ K and B → J/Ψ K …

Go to article

Stern-Gerlach Effect For Electron Beams, Herman Batelaan, Timothy J. Gay, J. J. Schwendiman Dec 1997

Stern-Gerlach Effect For Electron Beams, Herman Batelaan, Timothy J. Gay, J. J. Schwendiman

Timothy J. Gay Publications

The conflict between Bohr’s assertion that the magnetic moment of the electron cannot be measured with experiments based on the concept of classical trajectories, and the measurement of the magnetic moment of electrons in a modified Penning trap by Dehmelt et al. has led us to reevaluate other implications of Bohr’s assertion. We show that, contrary to the analysis of Bohr and Pauli, the assumption of classical trajectories in a Stern-Gerlach–like device can result in a high degree of spin separation for an electron beam. This effect may persist within a fully quantum-mechanical analysis. The magnetic fields considered are such …

Go to article

"Hands-On" Epicycles And Retrograde Motion, Matthew J. Moelter, Bernard A. Bates Dec 1997

"Hands-On" Epicycles And Retrograde Motion, Matthew J. Moelter, Bernard A. Bates

Physics

No abstract provided.

Go to article

Electron-Impact Total Ionization Cross Sections Of Ch And C2H2, Yong-Ki Kim, M. Asgar Ali, M. Eugene Rudd Dec 1997

Electron-Impact Total Ionization Cross Sections Of Ch And C2H2, Yong-Ki Kim, M. Asgar Ali, M. Eugene Rudd

M. Eugene Rudd Publications

Electron-impact total ionization cross sections for the CH radical and C2H2 (acetylene) have been calculated using the Binary-Encounter-Bethe (BEB) model. The BEB model combines the Mott cross section and the asymptotic form of the Bethe theory, and has been shown to generate reliable ionization cross sections for a large variety of molecules. The BEB cross sections for CH and C2H2 are in good agreement with the available experimental data from ionization thresholds to hundreds of eV in incident energies.

Go to article

Shielding Strategies For Human Space Exploration Chapter 9: Hze Interactions In Biological Materials, M. Eugene Rudd Dec 1997

Shielding Strategies For Human Space Exploration Chapter 9: Hze Interactions In Biological Materials, M. Eugene Rudd

M. Eugene Rudd Publications

It is shown that most of the energy deposited by fast charged particles traversing matter occurs through ionization, i.e., the ejection of electrons during the atomic collision. The important mechanisms of ionization are identified and several methods of calculating the relevant differential and total cross sections are described. These include both classical and quantum theoretical methods and two semi-empirical models. The calculational methods were intended only for light, bare-ion projectiles, and care must be exercised in extending them to heavy, dressed projectiles.

Go to article

Joint Map Registration And High Resolution Image Estimation Using A Sequence Of Undersampled Images, Russell C. Hardie, Kenneth J. Barnard, Ernest E. Armstrong Dec 1997

Joint Map Registration And High Resolution Image Estimation Using A Sequence Of Undersampled Images, Russell C. Hardie, Kenneth J. Barnard, Ernest E. Armstrong

Electrical and Computer Engineering Faculty Publications

n many imaging systems, the detector array is not sufficiently dense to adequately sample the scene with the desired field of view. This is particularly true for many infrared focal plane arrays. Thus, the resulting images may be severely aliased. This paper examines a technique for estimating a high-resolution image, with reduced aliasing, from a sequence of undersampled frames. Several approaches to this problem have been investigated previously. However, in this paper a maximum a posteriori (MAP) framework for jointly estimating image registration parameters and the high-resolution image is presented. Several previous approaches have relied on knowing the registration parameters …

Go to article

Spin Splitting Of Donor-Bound Excitons In Zno Due To Combined Stress And Spin Exchange, D. C. Reynolds, David C. Look, B. Jogai, T. C. Collins Dec 1997

Spin Splitting Of Donor-Bound Excitons In Zno Due To Combined Stress And Spin Exchange, D. C. Reynolds, David C. Look, B. Jogai, T. C. Collins

Physics Faculty Publications

No abstract provided.

Go to article

Exotic Mesons In Quenched Lattice Qcd, James E. Hetrick, C. Bernard Dec 1997

Exotic Mesons In Quenched Lattice Qcd, James E. Hetrick, C. Bernard

All Faculty Articles - School of Engineering and Computer Science

Since gluons in QCD are interacting fundamental constituents just as quarks are, we expect that in addition to mesons made from a quark and an antiquark, there should also be glueballs and hybrids (bound states of quarks, antiquarks and gluons). In general, these states would mix strongly with the conventional q-bar-q mesons. However, they can also have exotic quantum numbers inaccessible to q-bar-q mesons. Confirmation of such states would give information on the role of "dynamical" color in low energy QCD. In the quenched approximation we present a lattice calculation of the masses of mesons with exotic quantum numbers. These …

Go to article

Bound Μ⁺Μˉ System, Ulrich D. Jentschura, Gerhard Soff, Vladimir G. Ivanov, Savely Karshenboim Dec 1997

Bound Μ⁺Μˉ System, Ulrich D. Jentschura, Gerhard Soff, Vladimir G. Ivanov, Savely Karshenboim

Physics Faculty Research & Creative Works

We consider the hyperfine structure, the atomic spectrum, and the decay channels of the bound μ+μ- system (dimuonium). The annihilation lifetimes of low-lying atomic states of the system lie in the 10-12 s range. The decay rates could be measured by detection of the decay products (high-energy photons or electron-positron pairs). The hyperfine-structure splitting of the dimuonic system and its decay rate are influenced by electronic vacuum polarization effects in the far timelike asymptotic region. This constitutes a previously unexplored kinematic regime. We evaluate next-to-leading-order radiative corrections to the decay rate of low-lying atomic states. We …

Go to article

Reactive Quantum Scattering In Two Dimensions, Roy S. Calfas Dec 1997

Reactive Quantum Scattering In Two Dimensions, Roy S. Calfas

Theses and Dissertations

In an effort to develop a more efficient time dependent approach for calculating scattering matrix elements, absorbing boundary conditions are combined together with the channel packet method. As an introduction to scattering, scattering matrix elements are presented for a one-dimensional square well and a one-dimensional potential consisting of a Gaussian well with symmetric Gaussian barriers. Next, the combination of the channel packet method together with absorbing boundary conditions yields an order of magnitude savings in the time necessary to compute the correlation function for the collinear H+H

Go to article

A Large Scintillation Detector For Nuclear Physics Experiments At Indiana University Cyclotron Facility, Apurva Pathak Dec 1997

A Large Scintillation Detector For Nuclear Physics Experiments At Indiana University Cyclotron Facility, Apurva Pathak

Masters Theses

A new, large, scintillation detector, called the "K" detector has been designed and built for use in a series of nuclear physics experiments being performed at the Indiana University Cyclotron Facility (IUCF). This project describes the design, construction and testing of this scintillation detector. The K detector was designed to augment an existing detector stack at IUCF, and will serve to increase the energy range of previous studies of neutral pion production in proton-proton collisions near threshold. The test data for the current project came from a proton-proton scattering experiment, during which several runs were carried out between the bombarding …

Go to article

Displacement Of The Earth's Bow Shock And Magnetopause Due To An Impinging Interplanetary Shock Wave, William A. Olson Dec 1997

Displacement Of The Earth's Bow Shock And Magnetopause Due To An Impinging Interplanetary Shock Wave, William A. Olson

Theses and Dissertations

Interplanetary shock waves (ISWs) propagating through the solar wind can collide with the earth's bow shock, resulting in a series of new shocks, contact discontinuities, and rarefaction waves which interact to effectively move the bow shock and magnetopause toward the earth. A one dimensional MacCormack predictor corrector algorithm with Flux Corrected Transport (FCT) was developed to model the ISW bow shock and magnetopause interactions, and to numerically predict their propagation speeds after collision. Analytic relationships for the Mach numbers and propagation speeds of the generated shock waves and contact discontinuities were used to validate the model and to compare numerical …

Go to article

Three-Dimensional Camera Calibration Technique For Stereo Imaging Velocimetry Experiments, Mark D. Bethea, James A. Lock, Frank Merat, Paul Crouser Dec 1997

Three-Dimensional Camera Calibration Technique For Stereo Imaging Velocimetry Experiments, Mark D. Bethea, James A. Lock, Frank Merat, Paul Crouser

Physics Faculty Publications

A three-dimensional camera calibration technique is developed by combining two, 2-D camera calibrations for an orthogonal stereo viewing geometry. The left camera view (YZ view) and the right camera view (XZ view) are calibrated separately and then combined to produce an XYZ (3-D) calibration routine, Our technique employs three parallel calibration planes. One is placed along the main diagonal of the cubic experimental chamber, and the other two planes are placed known distances in front of it and behind it within the chamber. Both cameras view the calibration points on the planes simultaneously. Given the coordinates of a number of …

Go to article

Spontaneous Emission In Microcavity Lasers, Dustin Philip Ziegler Dec 1997

Spontaneous Emission In Microcavity Lasers, Dustin Philip Ziegler

Theses and Dissertations

An understanding of spontaneous emission processes within microcavities is crucial in addressing the need to make tomorrow's microlasers more efficient. One approach to improving the device efficiency is to reduce the threshold input energy at which lasing begins to occur. It has been suggested that the threshold in a microcavity laser can be decreased by increasing the fraction of spontaneous emission into the lasing mode, this can be accomplished by preferentially coupling the gain medium of the laser to the electromagnetic cavity mode of interest. It therefore becomes necessary to understand the mechanism by which this coupling takes place. This …

Go to article

Photoluminescence Study Of Gan Implanted With Erbium And Erbium-Oxygen, Lori R. Everitt Dec 1997

Photoluminescence Study Of Gan Implanted With Erbium And Erbium-Oxygen, Lori R. Everitt

Theses and Dissertations

Erbium emits at 1540 nm, which propagates well through fiber optic cables. This work studies the photoluminescence (PL) from GaN, GaN implanted with Er alone, and GaN implanted with both Er and O as functions of excitation laser energy and sample temperature. When the exciton bound to a neutral donor recombined, a photon was emitted at 3.47 eV. A photon emitted at 3.457 eV may have been evidence of the recombination of an exciton bound to a neutral acceptor. Second, the Er-ion transitions were observed in two groups around 0.805 and 1.25 eV. The PL intensity was measured at four …

Go to article

Time Resolved Photoluminescence Spectra Of A Mid-Infrared Multiple Quantum Well Semiconductor Laser, Anthony L. Franz Dec 1997

Time Resolved Photoluminescence Spectra Of A Mid-Infrared Multiple Quantum Well Semiconductor Laser, Anthony L. Franz

Theses and Dissertations

Recombination mechanisms in mid-IR semiconductor lasers are strongly dependent on the carrier density of the active region. The objective of this research is to improve previous carrier density estimates through the incorporation of spectral information. One hundred photoluminescence (PL) spectra were calculated for a variety of carrier densities. Calculations were made for an InAsSb/InAlAsSb multiple quantum well laser sample assuming parabolic bands. The widths of the calculated spectral profiles were tabulated as a function of carrier density. Actual spectra were measured using the Ultrafast Mid-Infrared Photoluminescence System, which uses upconversion to measure the PL intensity in time steps smaller than …

Go to article

Microelectromechanical Optical Beam Steering Systems, David M. Burns Dec 1997

Microelectromechanical Optical Beam Steering Systems, David M. Burns

Theses and Dissertations

The development of microelectromechanical systems (MEMS) has matured to the point where the fabrication of micron sized devices is feasible. State of the art MEMS construction processes now support the fabrication of novel optical devices that could not previously be built. This dissertation reports on the development of innovative micro optical devices such as Variable Blaze Gratings (VBGs) using state of the art MEMS construction processes. The principle application of the micro optical devices described in this dissertation is steering optical beams; however other applications such as spectral analysis are identified. Specific optical beam steering systems developed and characterized in …

Go to article

Reduced Computational Cost, Totally Symmetric Angular Quadrature Sets For Discrete Ordinates Radiation Transport, Joseph M. Oder Dec 1997

Reduced Computational Cost, Totally Symmetric Angular Quadrature Sets For Discrete Ordinates Radiation Transport, Joseph M. Oder

Theses and Dissertations

Several new quadrature sets for use in the discrete ordinates method of solving the Boltzmann neutral particle transport equation are derived. These symmetric quadratures extend the traditional symmetric quadratures by allowing ordinates perpendicular to one or two of the coordinate axes. Comparable accuracy with fewer required ordinates is obtained. Quadratures up to seventh order are presented. The validity and efficiency of the quadratures is then tested and compared with the Sn level symmetric quadratures relative to a Monte Carlo benchmark solution. The criteria for comparison include current through the surface, scalar flux at the surface, volume average scalar flux, and …

Go to article

Collisional Broadening Of Spectral Lines In The X → B System Of O2 And The First Vibrational Band Of No By The Noble Gases, John J. Cornicelli Dec 1997

Collisional Broadening Of Spectral Lines In The X → B System Of O2 And The First Vibrational Band Of No By The Noble Gases, John J. Cornicelli

Theses and Dissertations

Collisional broadening of the rotational spectral lines of the X to b system of O2 and the first vibrational band of NO by the noble gases is examined by Fourier transform spectroscopy. Peaks of the individual rotational lines are modeled with a Voigt function, from which Lorentzian half widths are extracted. Lorentzian widths are plotted vs. pressure of foreign gas, from which the pressure broadening coefficients and pressure broadening cross sections are calculated. The pressure broadening coefficients are compared to theoretical values determined by past research for O2. NO coefficients are compared to similar research using N …

Go to article

An Analytical Method To Calculate Activity From Measurements Affected By Coincidence Summing, Anthony P. Popovich Dec 1997

An Analytical Method To Calculate Activity From Measurements Affected By Coincidence Summing, Anthony P. Popovich

Theses and Dissertations

An analytical method is developed and applied to find the activities of two radioisotopes based on measurements influenced by true coincidence summing. The method incorporates the solid angle subtended by the detector, the macroscopic cross sections of the materials present, the absolute peak and total efficiencies of the detector, and the modes and probabilities of decay of the radioisotope. With this information, the method corrects for both summing-in and summing-out events. Summing events affect peak counts and cause the calculated activity to differ from the true activity. Thin disk sources of Mo-99 and Cs-136 on the face of a closed-end, …

Go to article

Unfolding Of The Period-Two Bifurcation In A Fiber Laser Pumped With Two Modulation Tones, Scott Glasgow, T. C. Newell, A. Gavrielides, V. Kovanis, D. Sukow, T. Erneux Dec 1997

Unfolding Of The Period-Two Bifurcation In A Fiber Laser Pumped With Two Modulation Tones, Scott Glasgow, T. C. Newell, A. Gavrielides, V. Kovanis, D. Sukow, T. Erneux

Faculty Publications

The effect of a small second frequency component on a pump modulated neodymium fiber laser is investigated experimentally and theoretically. This term, whose frequency is exactly half the primary driver, incites an unfolding of the attractor. It breaks the period two pitchfork bifurcation and splits the period one orbit. The modification of the bifurcation diagram is studied analytically by employing a map derived from the class B laser rate equations. We determine specific conditions and scaling laws for this phenomenon. Our analytical predictions are in good agreement with recorded experimental data.

Go to article

Near-Field Measurements On Contrail Properties From Fuels With Different Sulfur Content, Andreas Petzold, Reinhold Busen, Franz Peter Schroder, Robert Baumann, Markus Kuhn, Johan Strom, Donald E. Hagen, Philip D. Whitefield, Darrel G. Baumgardner, Frank Arnold, Stephan Borrmann, Ulrich Schumann Dec 1997

Near-Field Measurements On Contrail Properties From Fuels With Different Sulfur Content, Andreas Petzold, Reinhold Busen, Franz Peter Schroder, Robert Baumann, Markus Kuhn, Johan Strom, Donald E. Hagen, Philip D. Whitefield, Darrel G. Baumgardner, Frank Arnold, Stephan Borrmann, Ulrich Schumann

Physics Faculty Research & Creative Works

Microphysical properties of jet exhaust aerosol and contrails were studied in the near field of the emitting aircraft for different fuel sulfur contents. Measurements were performed behind two different aircraft (ATTAS test aircraft of type VFW 614 and Airbus A310-300) using fuels with sulfur contents of 6 ppm and 2700 ppm, respectively. At closest approach (plume age < 1 s), the total number concentrations exceeded the measuring range of the condensation particle counter, i.e., N > 105 cm-3. The concentration of the dry accumulation mode aerosol, i.e., predominantly soot particles, was not affected by the fuel sulfur content. At a plume age of 10 s, an increase in total number concentration (Dp > 0.01 μm) by a …

Go to article

A New Dynamic Mechanism Of Topological Charge Creation In A Commensurate One-Dimensional Charge Density Wave Near The Contact With A Normal Metal, A. S. Rozhavsky, Yuriy V. Pershin Dr, A. S. Kovalev Dec 1997

A New Dynamic Mechanism Of Topological Charge Creation In A Commensurate One-Dimensional Charge Density Wave Near The Contact With A Normal Metal, A. S. Rozhavsky, Yuriy V. Pershin Dr, A. S. Kovalev

Faculty Publications

The dynamics of conversion of conduction electrons into topological solitons of a charge density wave (CDW) commensurability in an external electric field is investigated. A novel mechanism of initiation of a nonlinear CDW current in the vicinity of the interface between a CDW and a normal metal is revealed and explained. The nonlinear current is produced by the conduction solitons created by the moving profile of the order parameter, formed during the conversion of electrons into collective phase excitations of a CDW. The field dependence of the current is of threshold nature and has no analogs in the bulk mechanisms …

Go to article

A Search For Excited Fermions In E+P Collisions At Hera, J. Breitweg, M. Derrick, D. Krakauer, S. Magill, D. Mikunas, B. Musgrave, J. Repond, R. Stanek, R. L. Talaga, R. Yoshida, H. Zhang, Margarita C. K. Mattingly, F. Anselmo, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, G. Cara Romeo, G. Castellini, L. Cifarelli, F. Cindolo, A. Contin, M. Corradi, S. De Pasquale, I. Gialas, P. Giusti, G. Iacobucci, G. Laurenti Dec 1997

A Search For Excited Fermions In E+P Collisions At Hera, J. Breitweg, M. Derrick, D. Krakauer, S. Magill, D. Mikunas, B. Musgrave, J. Repond, R. Stanek, R. L. Talaga, R. Yoshida, H. Zhang, Margarita C. K. Mattingly, F. Anselmo, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, G. Cara Romeo, G. Castellini, L. Cifarelli, F. Cindolo, A. Contin, M. Corradi, S. De Pasquale, I. Gialas, P. Giusti, G. Iacobucci, G. Laurenti

Faculty Publications

Using the ZEUS detector at HERA, we have searched for heavy excited states of electrons, neutrinos, and quarks in e+p collisions at a center-of-mass energy of 300 GeV. With an integrated luminosity of 9.4 pb-1, no evidence was found for electroweak production and decay of such states. Limits on the production cross section times branching ratio and on the characteristic couplings, f/Λ, are derived for masses up to 250 GeV. For the particular choice f/Λ = 1/Mf*, we exclude at the 95% confidence level excited electrons with mass between 30 and 200 GeV, excited electron neutrinos with mass between 40 …

Go to article

Next Last