Physical Sciences and Mathematics Commons^™

Search For Higgs Bosons Produced In Association With A Vector Boson In Pp̅ Collisions At √S = 1.8 Tev, F. Abe, Kenneth A. Bloom, Collider Detector At Fermilab Collaboration

Kenneth Bloom Publications

We search for Higgs bosons produced in association with a massive vector boson in 91 ± 7 pb^-1 of pp̅ collisions at √s =1.8 TeV recorded by the Collider Detector at Fermilab. We assume the Higgs scalar H⁰ decays to a bb̅ pair with branching ratio β, and we consider the hadronic decays of the vector boson V (W or Z). Observations are consistent with background expectations. We place 95% confidence level upper limits on σ (pp̅→H⁰V) β as a function of the scalar mass (MH⁰) …

Search For The Decays BS0,BD0 → E±Μ± And Pati-Salam Leptoquarks, F. Abe, Kenneth A. Bloom, Collider Detector At Fermilab Collaboration

Kenneth Bloom Publications

We have searched for the decays B_s⁰→ e^±μ^± and B_d⁰ → e^±μ^± using a 102 pb^-1 data sample of pp̅ collisions at √s =1.8 TeV collected with the Collider Detector at Fermilab. We set upper limits on the branching fractions of Ɓ(B_s⁰ → e^±μ^±) < 6.1(8.2) X 10^-6 and Ɓ(B_d⁰ → e^±μ^±) < 3.5(4.5) X 10^-6 at 90(95)% confidence level. Using these limits, we set lower bounds on the corresponding Pati-Salam leptoquark masses and find that M_LQ(B …

Density Of Zeros On The Lee-Yang Circle Obtained From Magnetization Data Of A Two-Dimensional Ising Ferromagnet, Christian Binek

Christian Binek Publications

In order to provide experimental access to the statistical theory of Lee and Yang [Phys. Rev. 87, 410 (1952)] the density function g(θ) of zeros on the Lee-Yang circle has been determined for the first time by analyzing isothermal magnetization data m(H) of the Ising ferromagnet FeCl₂ in axial magnetic fields H at temperatures 34≤T≤99 K. The validity of our approach is demonstrated by the perfect agreement of magnetic specific heat data as calculated from g(θ) and m(H) via Maxwell's relation. Moreover, the correct in-plane exchange constant of FeCl₂ emerges from the …

Fundamental And Magnetic-Hardening Studies Of Nanocrystalline And Naaocomposite Magnets, David J. Sellmyer, George C. Hadjipanayis

David Sellmyer Publications

In this project we study new nanocrystalline and nanocomposite structures that have high potential for permanent-magnet development. These materials, which can be synthesized to have either very high or intermediate coercivities, have many applications in electric power, transportation, and information-storage industries. There is great interest in further development of understanding and application of these materials. Following are brief discussions of recent research highlights for the present grant.

Experimental Observation Of Relativistic Nonlinear Thomson Scattering, Szu-Yuan Chen, Anatoly Maksimchuk, Donald Umstadter

Donald Umstadter Publications

Classical Thomson scattering—the scattering of low-intensity light by electrons—is a linear process, in that it does not change the frequency of the radiation; moreover, the magnetic-field component of light is not involved. But if the light intensity is extremely high (~10¹⁸ Wcm^–2), the electrons oscillate during the scattering process with velocities approaching the speed of light. In this relativistic regime, the effect of the magnetic and electric fields on the electron motion should become comparable, and the effective electron mass will increase. Consequently, electrons in such high fields are predicted to quiver nonlinearly, moving in figure-eight patterns …

Relativistic Nonlinear Optics, Phillip F. Schewe, Ben Stein, Donald P. Umstadter

Donald Umstadter Publications

Laser light is a convenient way of transporting both electric and magnetic fields. When an electron encounters light, however, it is usually the electric field that does the talking; the magnetic part of light is less influential since its effect on the electron is proportional to the electron's speed as a fraction of the speed of light (c). In new experiments at the University of Michigan this is all changed since the intensity of the laser light used is so great (a terawatt of power, compared to a milliwatt for a laser in a CD player) that the electrons in …

Events With A Rapidity Gap Between Jets In P̅P Collisions At √S = 630 Gev, F. Abe, Kenneth A. Bloom, Collider Detector At Fermilab Collaboration

Kenneth Bloom Publications

We report a measurement of the fraction of dijet events with a rapidity gap between jets produced by color-singlet exchange in p̅p collisions at √s =630 GeV at the Fermilab Tevatron. In events with two jets of transverse energy E_T^jet > 8 GeV, pseudorapidity in the range 1.8 <|η^jet | < 3.5 and η₁ η₂ < 0, the color-singlet exchange fraction is found to be R=[2.7 ± 0.7(stat) ± 0.6(syst)]%. Comparisons are made with results obtained at √s =1800 GeV and with theoretical expectations.

Steps Toward Determination Of The Size And Structure Of The Broad-Line Region In Active Galactic Nuclei. Xiii. Ultraviolet Observations Of The Broad-Line Radio Galaxy 3c 390.3, Paul T. O'Brien, M. Dietrich, K. Leighly, D. Alloin, J. Clavel, D. Michael Crenshaw, K. Horne, G. A. Criss, Julian Henry Krolik, Matthew A. Malkan, Hagai Netzer, Bradley M. Peterson, G. A. Reichert, P. M. Rodriguez-Pascual, W. Wamsteker, K. S.J. Anderson, N. G. Bochkarev, F.-Z. Cheng, A. V. Filippenko, C. Martin Gaskell, I. M. George, M. R. Goad, L. C. Ho, Shai Kaspi, W. Kollatschny, Kirk T. Korista, G. Macalpine, D. Marlow, P. G. Martin, S. L. Morris, Richard William Pogge, B. C. Qian, M. C. Recondo-Gonzalez, J. M. Rodriguez Espinosa, M. Santos-Lleo, A. I. Shapovalova, J. M. Shull, G. M. Stirpe, W.-H. Sun, T. J. Turner, R. Vio, S. Wagner, I. Wanders, K. A. Wills, H. Wu, S. J. Xue, Z.-L. Zou

C. Martin Gaskell Publications

As part of an extensive multi-wavelength monitoring campaign, the International Ultraviolet Explorer satellite was used to observe the broad-line radio galaxy 3C 390.3 during the period 1994 December 31-1996 March 5. Spectra were obtained every 6È10 days. The UV continuum varied by a factor of 7 through the campaign, while the broad emission lines varied by factors of 2È5. Unlike previously monitored Seyfert 1 galaxies, in which the X-ray continuum generally varies with a larger amplitude than the UV, in 3C 390.3 the UV continuum light curve is similar in both amplitude and shape to the X-ray light curve observed …

Static-Electric-Field-Induced, High-Energy Plateau For Scattered X-Ray Photons In Laser-Assisted, X-Ray–Atom Scattering, Dejan B. Miloševic, Anthony F. Starace

Anthony F. Starace Publications

We consider scattering of x rays by H atoms in the presence of both a linearly polarized laser field and a static electric field. Results for the differential cross section as a function of the number of photons n exchanged with the laser field are presented. For x-ray–atom scattering in the presence of a 10¹⁴ W/cm² laser field the differential cross section has a plateau only for emitted photons (n<0). Adding a static electric field gives rise to an extended plateau for absorbed photons (n>0), indicating a substantial increase of the scattered x-ray energies. We present a quasiclassical explanation of these results.

The Prairie Naturalist Volume 30, No.4 December 1998

The Prairie Naturalist

FISH COMMUNITY AND WATER QUALITY CHANGES IN THE BIG SIOUX RIVER ▪ D. Dieterman, and C. R. Berry, Jr.

EFFECTS OF PARASITOIDS AND COMPETITION ON CLUTCH SIZE OF A GALLING MIDGE ▪ D. J. Kinateder and S. J. Stein

RESPONSE OF BREEDING SEASON BLUE-WINGED TEAL TO DECOY TRAPPING ▪ P. R. Garrettson

COMPARISON OF POINT-COUNT AND WADE-FLUSH METHODS FOR COUNTING DUCKS ▪ G. M. Linz, C. P McMurl, H. J. Homan, and D. L. Bergman

Reviewers 1998

Author Index - Volume 30

Subject Index - Volume 30

Announcements

Factors Affecting The Movements Of Rainbow Trout (Oncorhynchus Mykiss) In Lake Ogallala, Nebraska, Tadd M. Barrow

School of Natural Resources: Dissertations, Theses, and Student Research

No abstract provided.

Water Current, Volume 30, No. 6, December 1998

Water Current Newsletter

Additional Research Shows Promise for Buffer Strips
From the Director: Testing Your Drinking Water; Drinking Water Tabloid Suggestions; USGS RFPs
Planning Nebraska's Water Future
Where Do You Get Your Water From?
Recycling Program Collects 49 Tons of Plastic
Lingle Earns Extension Wildlife Award
Laundry Disk ClaimsDon't Hold Water
Seminars Spotlight Latest in Water Research
Nation's Water Use Down, USGS Says
Water News Briefs
Agronomy Society Lauds Website
Free Wetlands Tabloid
Franti Earns Research Award
Looking for Ideas
Ben Nelson Service Award
Great Plains Research Articles
Assessing the Impact of Waste Lagoons on Groundwater

Optimizing Amplifier Placements In A Multiwavelength Optical Lan/Man: The Unequally Powered Wavelengths Case, Byrav Ramamurthy, Jason Iness, Biswanath Mukherjee

School of Computing: Faculty Publications

Optical networks based on passive-star couplers and employing WDM have been proposed for deployment in local and metropolitan areas. These networks suffer from splitting, coupling, and attenuation losses. Since there is an upper bound on transmitter power and a lower bound on receiver sensitivity, optical amplifiers are usually required to compensate for the power losses mentioned above. Due to the high cost of amplifiers, it is desirable to minimize their total number in the network. However, an optical amplifier has constraints on the maximum gain and the maximum output power it can supply; thus, optical amplifier placement becomes a challenging …

The Probe, Issue 195 – December 1998

The Probe: Newsletter of the National Animal Damage Control Association

Rabies -- Mike Dwyer, NADCA Director, Great Lakes Region
Position Available: Wildlife Biologist, JFK Airport
NWCO Organization Forms in Calif.
Update on Idaho Wolf Damage
Wildlife Wins in UT, OH, MN, Loses in CA
Schmidt to be Appointed NADCA President
Rabies in Bats: The following article was authored by Kate Lewandowski and is reprinted with permission from "SCWDS Briefs," the quarterly newsletter of the Southeastern Cooperative Wildlife Disease Study, The University of Georgia, Athens, GA.

Bird-Strike Committee -USA Abstracts

CANADA GEESE AND SNOW GEESE – REASSESSING TRADITIONAL PARADIGMS FOR MANAGEMENT -- Robert Blohm, U.S. Fish & Wildlife Service, Migratory Bird …

Analysis Of Doubly Excited State Resonances Below The Li(5p) Threshold In Li- Photodetachment, Chien-Nan Liu, Anthony F. Starace

Anthony F. Starace Publications

Larger scale eigenchannel R-matrix calculations than those of Pan et al.  [Phys. Rev. A53, 840 (1996)] confirm the prediction of a 2-meV-wide resonance feature at a photon energy of 5.421 eV in the Li (3s) partial cross section resulting from photodetachment of Li^-. This resonance was neither clearly observed nor identified in measurements of Ljungblad et al. [Phys. Rev. Lett. 77, 3751 (1996)]. We identify this resonance as a _N{υ}_n^A=₅{1}₆^- state [having angular symmetry (K,T)^A=(2,0) ^- or (n …

Batelaan And Gay Reply, Herman Batelaan, Timothy J. Gay

Timothy J. Gay Publications

In their Comment [1] to our Letter [2], Rutherford and Grobe first disagree with our conclusion that “a tabletop Stern-Gerlach filter is feasible.” Given our estimate of the throughput for such a device, ~0.3 electrons/s, we were clearly not proposing it as an alternative to standard polarized electron sources (~10¹⁵ electrons/s). The main argument for “feasibility” is based on the relatively low currents required to establish the solenoidal magnetic field (5 A)—hence the use of the word “tabletop” in the abstract. In retrospect, a better statement would have been that “experimental demonstration of such a spin-splitting effect may be …

Laser-Plasma Harmonics With High-Contrast Pulses And Designed Prepulses, R.S. Marjoribanks, L. Zhao, F.W. Budnik, G. Kulcsar, A. Vitcu, H. Higaki, R. Wagner, Anatoly Maksimchuk, Donald P. Umstadter, S.P. Le Blanc, M.C. Downer

Donald Umstadter Publications

One aspect of the complexity of mid- and high-harmonic generation in highintensity laser-plasma interactions is that nonlinear hydrodynamics is virtually always folded together with the nonlinear optical conversion process. We have partly dissected this issue in picosecond and subpicosecond interactions with preformed plasma gradients, imaging and spectrally resolving low- and mid-order harmonics. We describe spatial breakup of the picosecond beam in preformed plasmas, concomitant broaden~ng and breakup of the harmonic spectrum. presumably through self-phase modulation, together with data on the sensitivity of harmonics production efficiency to the gradient or extent of prefomed plasma. Lastly. we show preliminary data of regular …

Sputter Deposition Of High Resistivity Boron Carbide, Ahmad A. Ahmad, Natale J. Ianno, Seong-Don Hwang, Peter A. Dowben

Peter Dowben Publications

We have succeeded in the rf magnetron sputter deposition of high resistivity boron carbide (B1−xCx). This has been accomplished by the sputter depositing the boron carbide from a methane saturated boron carbide target. We show that the composition and optical band gap of the sputter deposited material are functions of the applied rf power. Furthermore, boron carbide/silicon heterojunction diodes fabricated via sputtering compare favorably with those fabricated from borane cage molecule sources using plasma enhanced chemical vapor deposition (PECVD).

The Effect Of A Uniform Electric Field On Homogeneous Vapor–Liquid Nucleation In A Dipolar Fluid. I. Stockmayer Fluid, K.J. Oh, G.T. Gao, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

The rate of homogeneous vapor–liquid nucleation is controlled mainly by the Gibbs formation free energy of critical clusters. Within the framework of thei/υ cluster theory of Reiss and co-workers, the formation free energies of Stockmayer clusters in the presence of a uniform electric field are determined. The Helmholtz free energy of the clusters, an input required in the i/υ cluster theory, is calculated via Monte Carlo simulations. The most significant result is that as a uniform electric field is applied the formation free energy at fixed supersaturation of the vapor becomes larger than that in the absence …

The Incorporation Of Nickel And Phosphorus Dopants Into Boron-Carbon Alloy Thin Films, D.N. Mcilroy, S.-D. Hwang, K. Yang, N. Remmes, Peter A. Dowben, A.A. Ahmad, N.J. Ianno, J.Z. Li, H.X. Jiang

Peter Dowben Publications

The structural and electronic properties of nickeland phosphorus-doped boron–carbon (B₅C) alloy thin films grown by plasma-enhanced chemical vapor deposition have been examined. The Ni-doped boron–carbon alloys were grown using closo-1,2-dicarbadodecaborane (C₂B₁₀H₁₂) as the boron–carbon source compound and nickelocene (Ni(C₅H₅)₂) as the nickel source. The phosphorus-doped alloys were grown using the single-source compound: dimeric chloro-phospha(III)-carborane ([C₂B₁₀H₁₀PCl] ₂). Nickel doping increased the conductivity, relative to undoped B₅C, by six orders of magnitude from 10^-9 to 10^{-3 …}

First Search For Cp Violation In Tau Lepton Decay, S. Anderson, Kenneth A. Bloom, Cleo Collaboration

Kenneth Bloom Publications

We have performed the first search for CP violation in tau lepton decay. CP violation in lepton decay does not occur in the minimal standard model but can occur in extensions such as the multi- Higgs doublet model. It appears as a characteristic difference between the τ^- and τ⁺ decay angular distributions for the semileptonic decay modes such as τ^- → K⁰ π^-ν. We define an observable asymmetry to exploit this and find no evidence for any CP violation.

Comment On "Beach Water Table Fluctuations Due To Wave Run-Up: Capillarity Effects" By L. Li Et Al., Vitaly A. Zlotnik

Department of Earth and Atmospheric Sciences: Faculty Publications

Vitaly A. Zlotnik's comment on "Beach water table fluctuations due to wave run-up: Capillarity effects" by L. Li, D. A. Barry, J.-Y. Parlange, and C. B. Pattiaratchi, published in Water Resources Research (1997) 3(5): 935-945.

Ionization Dynamics In Fast Ion-Atom Collisions. I. Energy And Angular Distributions Of Low-Energy Electrons Emitted In Ionization Of He By Bare Carbon Ions, Lokesh C. Tribedi, P. Richard, Y. D. Wang, C. D. Lin, L. Gulyas, M. Eugene Rudd

M. Eugene Rudd Publications

We have studied the two-center effect (TCE) in ion-atom ionization by measuring the energy and angular distributions of the double-differential cross sections (DDCSs) (d²σ/dεdΩ) of the low-energy electrons emitted in a collision of He atoms with 2.5 MeV/nucleon C⁶⁺ ions. The electrons with energies between 0.1 and 300 eV were detected for 13 different emission angles between 15° and 160°. From the measured DDCSs we have deduced the single differential cross sections such as dσ/dΩ and dσ/dε and the total cross section. The data have been …

Center For Sustainable Agricultural Systems Newsletter, November/December 1998

Center for Sustainable Agricultural Systems -- Newsletters 1993-2000

Contents:

Grants to Teach Sustainable Agriculture

Spring CSAS Seminar Series: Re-Integrating Agriculture and Community in the Midwest

Highlights of Upcoming New Book: Under the Blade (Part 4)

Watershed Information Flows Along the Internet

Nordic Agroecology Program Begins August 1999

Beef Home Study Courses Begin Fifth Year

Two On-farm Assessment Tools

Analysis Of Multiphoton Ionization Of Metal Atoms In The Saturation Regime Using Subpicosecond Krf Laser Pulses, B. Witzel, Cornelis J. Uiterwaal, H. Schröder, D. Charalambidis, K.-L. Kompa

C.J.G.J. Uiterwaal Publications

Singly and multiply charged ion yield curves are reported for resonant and nonresonant two photon- ionization processes for a collection of 31 metal atoms. The atoms are created by sputtering from a solid target using an Ar-ion gun. Single and multiple ionization of these atoms is performed using linearly polarized 248.6-nm (KrF) laser pulses with a full width at half maximum duration of 500 fs, employing intensities between 10⁹ and 10¹² W cm^-2. A four-grid high-resolution reflecting time-of-flight spectrometer is used for ion detection. This advanced spectrometer has a well-defined and small source volume, enabling absolute …

Unidirectional Anisotropy In Ultrathin Transition-Metal Films , Ralph Skomski, H.-P. Oepen, J. Kirschner

Ralph Skomski Publications

Unidirectional magnetic anisotropies in low-symmetry magnetic thin films such as cobalt on vicinal copper surfaces are investigated. Possible explanations of the observed uniaxial anisotropies are competing anisotropy (CA) coefficients and Dzyaloshinskii-Moriya (DM) interactions. Unidirectional CA is an interesting mechanism occurring in low-symmetry magnets and involves neither antiferromagnetic exchange nor spin canting. It is visible in the easy-cone regime and decides, for example, whether the preferential magnetization direction points up or down a stepped surface. In the case of Co/Cu(11n) films, however, the anisotropy direction speaks in favor of DM-type interactions.

Radiative Decay Modes Of The D0 Meson, D. M. Asner, Kenneth A. Bloom, Cleo Collaboration

Kenneth Bloom Publications

In this paper we describe a search for four radiative decay modes of the D⁰ meson: D⁰ → φγ, D⁰ → ωγ, D⁰ → K^-*γ, and D⁰ → ρ⁰γ . We obtain 90% C.L. upper limits on the branching ratios of these modes of 1.9 X 10^-4, 2.4 X 10^-4, 7.6 X 10^-4, and 2.4 X 10^-4, respectively.

The Probe, Issue 194 – November 1998

The Probe: Newsletter of the National Animal Damage Control Association

Managing Wolf Predation on Livestock in Idaho Since Reintroduction: Wildlife Services Program Perspective and Summary -- Layne R. Bangerter, District Supervisor, USD A, APHIS, Wildlife Services, Boise, Idaho; George E. Graves, Assistant State Director, USD A, APHIS, Wildlife Services, Boise, Idaho, and NADC A Northern Rocky Mountains Regional Director
California Votes on Trap Ban
Book Review: "Nuisance Animals: Backyard Pests to Free-Roaming Killers" By John Trout, Jr. Midwest Publishing, 1997. 192 pages softcover ($14.95)
Record Attendance at Bird Strike Committee-USA Meeting

Bird-Strike Committee -USA Abstracts
ADVICE TO FLIGHT CREWS CONCERNING THE WILDLIFE HAZARD TO AIRCRAFT -- Paul Eschenf elder, Air …

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 …

From The Director: October 1998, Donald A. Wilhite

Drought Network News (1994-2001)

On July 16, 1998, President Clinton signed the National Drought Policy Act into law. This law creates the National Drought Policy Commission (NDPC), which will examine current laws and programs and make recommendations to the president and Congress on the needs for a national drought policy. The Farm Service Agency of the U.S. Department of Agriculture will serve as the chair for the Commission, which will comprise 16 members. In addition to the Secretary of Agriculture, other members of the Commission will include the Secretary of the Interior, Secretary of the Army, Secretary of Commerce, Director of the Federal Emergency …