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State To State He-Co Rotationally Inelastic Scattering, Stiliana Antonova, Ao Lin, Antonis P. Tsakotellis, George C. Mcbane Oct 1998

State To State He-Co Rotationally Inelastic Scattering, Stiliana Antonova, Ao Lin, Antonis P. Tsakotellis, George C. Mcbane

Peer Reviewed Articles

Relative integral cross sections for rotational excitation of CO in collisions with He were measured at energies of 72 and 89 meV. The cross sections are sensitive to anisotrophy in the repulsive wall of the He-CO interaction. The experiments were done in crossed molecular beams with resonance enhanced multiphoton ionization detection. The observed cross sections display interference structure at low Δj, despite the average over the initial CO rotational distribution. At higher Δj, the cross sections decrease smoothly. The results are compared with cross sections calculated from two high quality potential energy surfaces for the He-CO …


Factors Affecting Methane Emissions From Rice Fields, M. A. K. Khalil, R. A. Rasmussen, Martha J. Shearer, R. W. Dalluge, Lixin Ren, Chang-Lin Duan Oct 1998

Factors Affecting Methane Emissions From Rice Fields, M. A. K. Khalil, R. A. Rasmussen, Martha J. Shearer, R. W. Dalluge, Lixin Ren, Chang-Lin Duan

Physics Faculty Publications and Presentations

Methane emissions from rice fields are affected by a number of environmental and agricultural factors. We have analyzed our 7-year data set on methane emissions from rice fields in Tu Zu, China, to delineate the relationships between emissions and a number of variables that were measured at the same time. Our work was done in fields that were managed under prevailing agricultural practices of the region. Consequently, only the effect of factors that vary from year to year or during the growing season can be calculated. In our study we measured the effects of environmental variables (soil temperature, wind speed, …


Flux Measurements And Sampling Strategies: Applications To Methane Emissions From Rice Fields, M. A. K. Khalil, R. A. Rasmussen, Martha J. Shearer Oct 1998

Flux Measurements And Sampling Strategies: Applications To Methane Emissions From Rice Fields, M. A. K. Khalil, R. A. Rasmussen, Martha J. Shearer

Physics Faculty Publications and Presentations

The emissions of methane from rice fields and other sources are often measured by placing chambers on the surface and taking sequential samples. Although static chambers pose several problems that affect the accuracy of the data, there are a few parameters that, if carefully chosen, can improve the reliability of the data and reduce the uncertainties. These parameters are the length of time the chamber is kept on the rice plants, the number of samples that are drawn to estimate the flux, the basal area and height of the chamber, the frequency of measurements during the growing season, and the …


Target Dependence Of The Triply Differential Cross Section For Low Energy (E, 2e) Processes, Cheng Pan, Anthony F. Starace Oct 1998

Target Dependence Of The Triply Differential Cross Section For Low Energy (E, 2e) Processes, Cheng Pan, Anthony F. Starace

Anthony F. Starace Publications

The main purpose of this chapter is to review our calculations, whose aim is to explain the target dependence of the triply differential cross sections that has been observed in a number of recent experiments performed at relatively low energies above the ionization threshold for the two outgoing electrons leaving in opposite directions (θ12 = π). One reason for focusing on this θ12 = π geometry is that it is the most important geometry for near-threshold double-escape processes in the WPR theory. Another reason is that up to now, except for H and He targets, the triply differential …


The Electromagnetic Field Near A Dielectric Half-Space, Andrew Lang, Dr. Adam D. Helfer Oct 1998

The Electromagnetic Field Near A Dielectric Half-Space, Andrew Lang, Dr. Adam D. Helfer

College of Science and Engineering Faculty Research and Scholarship

We compute the expectations of the squares of the electric and magnetic fields in the vacuum region outside a half-space filled with a uniform non-dispersive dielectric. This gives predictions for the Casimir-Polder force on an atom in the "retarded" regime near a dielectric. We also find a positive energy density due to the electromagnetic field. This would lead, in the case of two parallel dielectric half-spaces, to a positive, separation-independent contribution to the energy density, besides the negative, separation-dependent Casimir energy. Rough estimates suggest that for a very wide range of cases, perhaps including all realizable ones, the total energy …


Ionization Of Aligned Rydberg Atoms By Ion Impact, K. R. Cornelius, J. Wang, Ronald E. Olson Oct 1998

Ionization Of Aligned Rydberg Atoms By Ion Impact, K. R. Cornelius, J. Wang, Ronald E. Olson

Physics Faculty Research & Creative Works

The classical trajectory Monte Carlo method has been used to calculate capture and ionization cross sections and final-state electron momentum distributions in H+ + H(n = 25) collisions to show how the collision mechanisms evolve over the range of intermediate projectile speeds v* = vp/ve = 1.0-5.0. A circular Rydberg target was aligned in two orientations defined by the orbital angular momentum vector of the electron being either antiparallel or perpendicular to the incident momentum vector of the projectile. Aligning the target atom in this manner helps us to single out specific collision processes otherwise obscured in a randomly oriented …


Temperature Fluctuations In Photoionized Nebulae. Ii. The Effect Of Inhomogeneous Abundances, J. B. Kingdon, Gary J. Ferland Oct 1998

Temperature Fluctuations In Photoionized Nebulae. Ii. The Effect Of Inhomogeneous Abundances, J. B. Kingdon, Gary J. Ferland

Physics and Astronomy Faculty Publications

Recent abundance determinations based on recombination lines in several emission-line nebulae yield ionic abundances several times larger than those derived from forbidden lines. These results cast uncertainty over all abundance determinations in such objects. One possible explanation for these discrepancies frequently cited in the literature is the presence of chemical inhomogeneities. We have run a series of photoionization models to examine what effect such inhomogeneities will have on the resulting temperature structure of nebulae. We then derive abundances from these models, utilizing Peimbert's t2 formalism. Our results suggest that, although chemical inhomogeneities may produce nonnegligible biases in abundance determinations …


Measurement Of Elastic Υ Photoproduction 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, N. Coppola, M. Corradi, S. De Pasquale, P. Giusti, G. Iacobucci, G. Laurenti Oct 1998

Measurement Of Elastic Υ Photoproduction 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, N. Coppola, M. Corradi, S. De Pasquale, P. Giusti, G. Iacobucci, G. Laurenti

Faculty Publications

The photoproduction reaction γp → μ+ μ-p has been studied in ep interactions using the ZEUS detector at HERA. The data sample corresponds to an integrated luminosity of 43.2pb-1. The Υ meson has been observed in photoproduction for the first time. The sum of the products of the elastic Υ(1S), Υ(2S),Υ(3S) photoproduction cross sections with their respective branching ratios is determined to be 13.3 ± 6.0(stat.)-2.3+2.7(syst.) pb at a mean photon-proton centre of mass energy of 120 GeV. The cross section is above the prediction of a perturbative QCD model. © 1998 Elsevier Science B.V. All rights reserved.


Cusp Energetic Ions: A Bow Shock Source, S. W. Chang, J. D. Scudder, S. A. Fuselier, J. F. Fennell, K. J. Trattner, J. S. Pickett, Harlan E. Spence, J. D. Menietti, W. K. Peterson, R. P. Lepping, R. Friedel Oct 1998

Cusp Energetic Ions: A Bow Shock Source, S. W. Chang, J. D. Scudder, S. A. Fuselier, J. F. Fennell, K. J. Trattner, J. S. Pickett, Harlan E. Spence, J. D. Menietti, W. K. Peterson, R. P. Lepping, R. Friedel

Physics & Astronomy

Recent interpretations of cusp energetic ions observed by the POLAR spacecraft have suggested a new energization process in the cusp [Chen et al., 1997; 1998]. Simultaneous enhancement of H+, He+2, and O>+2 fluxes indicates that they are of solar wind origin. In the present study, we examine H+ and He+2 energy spectra from 20 eV to several 100 keV measured by the Hydra, Toroidal Imaging Mass-Angle Spectrograph (TIMAS), and Charge and Mass Magnetospheric Ion Composition Experiment (CAMMICE) on POLAR. The combined spectrum for each species is shown to be continuous with a …


Evidence Of Initial-State Two-Center Effects For (E, 2e) Reactions, Sindu P. Jones, Don H. Madison Oct 1998

Evidence Of Initial-State Two-Center Effects For (E, 2e) Reactions, Sindu P. Jones, Don H. Madison

Physics Faculty Research & Creative Works

Coincidence, or (e, 2e), measurements of electron-impact ionization of atoms have established that the largest values of triply differential cross sections are obtained in collisions involving small momentum transfer to the target. Absolute measurements for these reactions are now available for hydrogen at 54.4-eV impact energy, and relative data have recently been reported at 27.2 eV. Previous theoretical works have concentrated on employing asymptotically correct two-center wave functions for the final state, leaving the initial state described by the Born approximation. Here we report results for which asymptotically correct two-center wave functions are used for both the initial and final …


Auger Resonance Decay Process In Ar 2p Shell Excitation And Ionization, Y. Lu, Wayne C. Stolte, J.A. R. Samson Oct 1998

Auger Resonance Decay Process In Ar 2p Shell Excitation And Ionization, Y. Lu, Wayne C. Stolte, J.A. R. Samson

Chemistry and Biochemistry Faculty Research

The production and subsequent autoionization of the Ar+ (1D2)6d1 satellite state that is formed either by shake-up or recapture during the Auger decay of a 2p vacancy in Ar has been studied by photoelectron spectroscopy in the energy region from 243 to 256 eV. The creation of near zero energy electrons below and immediately above the Ar 2p ionization threshold is discussed. Some ambiguous points in previous studies are clarified.


A Note On The Green Dyadic Calculation Of The Decay Rates For Admolecules At Multiple Planar Interfaces, P.T. Leung, R. L. Hartman, Scott M. Cohen Oct 1998

A Note On The Green Dyadic Calculation Of The Decay Rates For Admolecules At Multiple Planar Interfaces, P.T. Leung, R. L. Hartman, Scott M. Cohen

Physics Faculty Publications and Presentations

The Green dyadic formulation for calculating classical decay rates of admolecules at multiple planar interfaces first published by Chance, Prock and Silbey is reexamined. It is pointed out that, for the case of fluorescing molecules sandwiched between a system of super- and substrate interfaces, the original formalism requires significant modifications in order to lead to results consistent with those obtained from the Sommerfeld radiation theory.


A Zero Point And Accidental Errors For Published Values Of [Fe/H] For Cool Giants, B. J. Taylor Sep 1998

A Zero Point And Accidental Errors For Published Values Of [Fe/H] For Cool Giants, B. J. Taylor

Faculty Publications

This paper is one of a series based on published values of [Fe/H] for late-type evolved stars. Only values of [Fe/H] from high-dispersion spectroscopy or related techniques are used. The narrative in this paper begins at a point where mean values of [Fe/H] have been derived for xiVir, alphaBoo, betaGem, and the Hyades giants. By using these stars as standard stars when necessary, a zero-point data base is assembled. This data base is then expanded into its final version by correcting and adding additional data in a step-by-step process. As that process proceeds, data comparisons are used to establish rms …


Monte Carlo Renormalization Of 2d Simplicial Quantum Gravity Coupled To Gaussian Matter, Simon Catterall, Eric B. Gregory, G. Thorleifsson Sep 1998

Monte Carlo Renormalization Of 2d Simplicial Quantum Gravity Coupled To Gaussian Matter, Simon Catterall, Eric B. Gregory, G. Thorleifsson

Physics - All Scholarship

We extend a recently proposed real-space renormalization group scheme for dynamical triangulations to situations where the lattice is coupled to continuous scalar fields. Using Monte Carlo simulations in combination with a linear, stochastic blocking scheme for the scalar fields we are able to determine the leading eigenvalues of the stability matrix with good accuracy both for c = 1 and c = 10 theories.


New Analytical Results On Anisotropic Membranes, Mark Bowick, Alex Travesset Sep 1998

New Analytical Results On Anisotropic Membranes, Mark Bowick, Alex Travesset

Physics - All Scholarship

We report on recent progress in understanding the tubular phase of self-avoiding anisotropic membranes. After an introduction to the problem, we sketch the renormalization group arguments and symmetry considerations that lead us to the most plausible fixed point structure of the model. We then employ an epsilon-expansion about the upper critical dimension to extrapolate to the physical interesting 3-dimensional case. The results are $\nu=0.62$ for the Flory exponent and $\zeta=0.80$ for the roughness exponent. Finally we comment on the importance that numerical tests may have to test these predictions.


Chemical Signals From Submarine Fluid Advection Onto The Continental Shelf, W. S. Moore, Timothy J. Shaw Sep 1998

Chemical Signals From Submarine Fluid Advection Onto The Continental Shelf, W. S. Moore, Timothy J. Shaw

Faculty Publications

No abstract provided.


Dynamics Of The Conformal Mode And Simplicial Gravity, Simon Catterall, Emil Mottola, T. Bhattacharya Sep 1998

Dynamics Of The Conformal Mode And Simplicial Gravity, Simon Catterall, Emil Mottola, T. Bhattacharya

Physics - All Scholarship

We review the derivation of the Liouville action in 2DQG via the trace anomaly and emphasize how a similar approach can be used to derive an effective action describing the long wavelength dynamics of the conformal factor in 4D. In 2D we describe how to make an explicit connection between dynamical triangulations and this continuum theory, and present results which confirm the equivalance of the two approaches. By reconstructing a lattice conformal mode from DT simulations it should be possible to test this equivalence in 4D also.


Wave-Vector-Dependent Exchange Splitting In A Local Moment System, C. Waldfried, T. Mcavoy, D. Welipitiya, Takashi Komesu, Peter A. Dowben, Elio Vescovo Sep 1998

Wave-Vector-Dependent Exchange Splitting In A Local Moment System, C. Waldfried, T. Mcavoy, D. Welipitiya, Takashi Komesu, Peter A. Dowben, Elio Vescovo

Peter Dowben Publications

Wave-vector-dependent exchange splitting in a local moment system The electronic structure of strained thin films of Gd has been studied with spin- and angle-resolved photoemission and spin-polarized inverse photoemission. The spin-dependent electronic structure is dominated by a very distinct k dependence of the exchange splitting. The surface magnetic structure is observed to be different from that of the bulk, as indicated by the different electronic structure and a much higher surface Curie temperature. The 4% strain within the Gd films results in an enhanced Curie temperature.


Continuum Charged D* Spin Alignment At √S =10.5 Gev, G. Brandenburg, Kenneth A. Bloom, Cleo Collaboration Sep 1998

Continuum Charged D* Spin Alignment At √S =10.5 Gev, G. Brandenburg, Kenneth A. Bloom, Cleo Collaboration

Kenneth Bloom Publications

A measurement of the spin alignment of charged D* mesons produced in continuum e+e- → cc̅ events at √s = 10.5 GeV is presented. This study using 4.72 fb-1 of CLEO II data shows that there is little evidence of any D* spin alignment.


Track Structure Model For Radial Distributions Of Electron Spectra And Event Spectra From High-Energy Ions, F. A. Cucinotta, Robert Katz, J. W. Wilson Sep 1998

Track Structure Model For Radial Distributions Of Electron Spectra And Event Spectra From High-Energy Ions, F. A. Cucinotta, Robert Katz, J. W. Wilson

Robert Katz Publications

An analytic method is described for evaluating the average radial electron spectrum and the radial and total frequency-event spectrum for high-energy ions. For high-energy ions, indirect events make important contributions to frequency-event spectra. The method used for evaluating indirect events is to fold the radial electron spectrum with measured frequency-event spectrum for photons or electrons. The contribution from direct events is treated using a spatially restricted linear energy transfer (LET). We find that high-energy heavy ions have a significantly reduced frequency-averaged lineal energy (YF) compared to LET, while relativistic protons have a significantly increased YF and dose-averaged lineal energy (YD) …


Can Photoemission Accurately Probe The Bulk Electronic Structure Of The Complex Oxides?, Jaewu Choi, C. Waldfried, Sy_Hwang Liou, Peter A. Dowben Sep 1998

Can Photoemission Accurately Probe The Bulk Electronic Structure Of The Complex Oxides?, Jaewu Choi, C. Waldfried, Sy_Hwang Liou, Peter A. Dowben

Peter Dowben Publications

The surface of the complex oxides, in particular the manganese perovskites, is dominated by a different free enthalpy at the surface. This can be demonstrated by surface segregation after annealing the samples. By comparing relative x-ray photoelectron spectroscopy intensities of the manganese perovskite La1-xCaxMnO3 (x=0.1, 0.35) for different emission angles, the profile of elemental concentration was determined. Analysis shows evidence for pronounced surface segregation of calcium. Our results suggest that there are strong differences between surface and bulk enthalpies without segregation or surface relaxation. This is consistent with the previously observed surface resonance …


Hadronic Transitions Υ(2S)→Υ(1S), J. P. Alexander, Kenneth A. Bloom, Cleo Collaboration Sep 1998

Hadronic Transitions Υ(2S)→Υ(1S), J. P. Alexander, Kenneth A. Bloom, Cleo Collaboration

Kenneth Bloom Publications

Using a 73.6 pb-1 data sample of Υ(2S) events collected with the CLEO II detector at the Cornell Electron Storage Ring, we have investigated the hadronic transitions between the Υ(2S) and the Υ(1S). The dipion transition Υ(2S) → Υ(1S) π+π- was studied using two different analysis techniques. Selecting events in which Υ(1S) → e+e-, μ+μ- (‘‘exclusive’’ analysis), and using the Υ(1S) leptonic branching fractions world averages from the PDG review, we obtained Ɓ(Υ(2S) …


Polarization Of Astronomical Maser Radiation. Iv. Circular Polarization Profiles, Moshe Elitzur Sep 1998

Polarization Of Astronomical Maser Radiation. Iv. Circular Polarization Profiles, Moshe Elitzur

Physics and Astronomy Faculty Publications

Profile comparison of the Stokes parameters V and I is a powerful tool for maser data analysis, which provides the first direct methods for unambiguous determination of (1) the maser saturation stage, (2) the amplification optical depth and intrinsic Doppler width of unsaturated masers, and (3) the comparative magnitudes of Zeeman splitting and Doppler line width. Circular polarization recently detected in OH 1720 MHz emission from the Galactic center appears to provide the first direct evidence for maser saturation.


Can Photoemission Accurately Probe The Bulk Electronic Structure Of The Complex Oxides?, Jaewu Choi, C. Waldfried, Sy-Hwang Liou, Peter A. Dowben Sep 1998

Can Photoemission Accurately Probe The Bulk Electronic Structure Of The Complex Oxides?, Jaewu Choi, C. Waldfried, Sy-Hwang Liou, Peter A. Dowben

Peter Dowben Publications

The surface of the complex oxides, in particular the manganese perovskites, is dominated by a different free enthalpy at the surface. This can be demonstrated by surface segregation after annealing the samples. By comparing relative x-ray photoelectron spectroscopy intensities of the manganese perovskite La1-xCaxMnO3 (x=0.1, 0.35) for different emission angles, the profile of elemental concentration was determined. Analysis shows evidence for pronounced surface segregation of calcium. Our results suggest that there are strong differences between surface and bulk enthalpies without segregation or surface relaxation. This is consistent with the previously observed surface resonance in the …


Construction Of Effective Electromagnetic Currents For Two-Body Quasipotential Equations, Dmitri Krioukov Sep 1998

Construction Of Effective Electromagnetic Currents For Two-Body Quasipotential Equations, Dmitri Krioukov

Physics Theses & Dissertations

A systematic algebraic approach for the construction of effective electro-magnetic currents consistent with relativistic two-body quasipotential equations is presented. This approach generalizes the Mandelstam formalism and applies it to a generic quasipotential reduction method. The use of Ward-Takahashi identities for the effective currents guarantees conservation of current matrix elements involving any combination of bound and scattering states. This approach is shown to reproduce previous results for current matrix elements for the particular cases of the Gross and Blankenbecler-Sugar equations. A generic method of truncation of the quasipotential effective current with respect to the number of boson exchanges is introduced.


Radial Distribution Of Electron Spectra From High-Energy Ions, Francis A. Cucinotta, Robert Katz, John W. Wilson Sep 1998

Radial Distribution Of Electron Spectra From High-Energy Ions, Francis A. Cucinotta, Robert Katz, John W. Wilson

Robert Katz Publications

The average track model describes the response of physical and biological systems using radial dose distribution as the key physical descriptor. We report on an extension of this model to describe the average distribution of electron spectra as a function of radial distance from an ion. We present calculations of these spectra for ions of identical linear energy transfer (LET), but dissimilar charge and velocity to evaluate the differences in electron spectra from these ions. To illustrate the usefulness of the radial electron spectra for describing effects that are not described by electron dose, we consider the evaluation of the …


Measurement Of The Branching Ratios For The Decays Of DS+ To Ηπ+, Η′Π+, Ηρ+, And Η′Ρ+, C. P. Jessop, Kenneth A. Bloom, Cleo Collaboration Sep 1998

Measurement Of The Branching Ratios For The Decays Of DS+ To Ηπ+, Η′Π+, Ηρ+, And Η′Ρ+, C. P. Jessop, Kenneth A. Bloom, Cleo Collaboration

Kenneth Bloom Publications

Using a data sample with an integrated luminosity of 3.9 fb-1 collected in e+e- annihilation with the CLEO-II detector at the Cornell Electron Storage Ring, we have measured the branching ratios for the decay modes Ds+ → (η, η′)π+ and Ds+ → (η, η′)ρ+ relative to Ds+ → φπ+. These decay modes are among the most common hadronic decays of the Ds+, and can be related by factorization to the semileptonic decays Ds+ → (η, η′)ℓ+ν1 . …


Observation Of High Momentum Η′ Production In B Decays, T. E. Browder, Kenneth A. Bloom, Cleo Collaboration Aug 1998

Observation Of High Momentum Η′ Production In B Decays, T. E. Browder, Kenneth A. Bloom, Cleo Collaboration

Kenneth Bloom Publications

We report the first observation of B→ η′X transitions with high momentum η′ mesons. We observe 39.0 ± 11.6 B decay events with 2.0 < Pη′ < 2.7 GeV/c, the high momentum region where background from b → c processes is suppressed. We discuss the physical interpretation of the signal, including the possibility that it is due to b → sg* transitions. Given that interpretation, we find Ɓ(B →η′Xs) = [6.2 ± 1.6(stat) ± 1.3(syst) -1.5+0.0(bkg)] X 10-4 for 2.0 < Pη′ < 2.7 GeV/c.


Putative Light Scalar Nonet, Joseph Schechter, Deirdre Black, Amir H. Fariborz, Francesco Sannino Aug 1998

Putative Light Scalar Nonet, Joseph Schechter, Deirdre Black, Amir H. Fariborz, Francesco Sannino

Physics - All Scholarship

We investigate the "family" relationship of a possible scalar nonet composed of the a_0(980), the f_0(980) and the \sigma and \kappa type states found in recent treatments of \pi\pi and \pi K scattering. We work in the effective Lagrangian framework, starting from terms which yield "ideal mixing" according to Okubo's original formulation. It is noted that there is another solution corresponding to dual ideal mixing which agrees with Jaffe's picture of scalars as qq\bar q \bar q states rather than as q\bar q states. At the Lagrangian level there is no difference in the formulation of the two cases (other …


Search For Selectron And Squark Production 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, N. Coppola, M. Corradi, S. De Pasquale, P. Giusti, G. Iacobucci, G. Laurenti Aug 1998

Search For Selectron And Squark Production 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, N. Coppola, M. Corradi, S. De Pasquale, P. Giusti, G. Iacobucci, G. Laurenti

Faculty Publications

We have searched for the production of a selectron and a squark in e+p collisions at a center-of-mass energy of 300 GeV using the ZEUS detector at HERA. The selectron and squark are sought in the direct decay into the lightest neutralino in the framework of supersymmetric extensions to the Standard Model which conserve R-parity. No evidence for the production of supersymmetric particles has been found in a data sample corresponding to 46.6 pb-1 of integrated luminosity. We express upper limits on the product of the cross section times the decay branching ratios as excluded regions in the parameter space …