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Full-Text Articles in Physics

Search For The Decays BS0,BD0 → E±Μ± And Pati-Salam Leptoquarks, F. Abe, Kenneth A. Bloom, Collider Detector At Fermilab Collaboration Dec 1998

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 Bs0→ e±μ± and Bd0 → 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(Bs0 → e±μ±) < 6.1(8.2) X 10-6 and Ɓ(Bd0 → 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 MLQ(Bs0) > 20.7(19.3) TeV/c2 and MLQ(B ...


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 Dec 1998

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 (pp̅H0V) β as a function of the scalar mass (MH0) over the range 70 < MH0 ...


Density Of Zeros On The Lee-Yang Circle Obtained From Magnetization Data Of A Two-Dimensional Ising Ferromagnet, Christian Binek Dec 1998

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 ...


Fundamental And Magnetic-Hardening Studies Of Nanocrystalline And Naaocomposite Magnets, David J. Sellmyer, George C. Hadjipanayis Dec 1998

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 Dec 1998

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 ...


Relativistic Nonlinear Optics, Phillip F. Schewe, Ben Stein, Donald P. Umstadter Dec 1998

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 ...


Events With A Rapidity Gap Between Jets In P̅P Collisions At √S = 630 Gev, F. Abe, Kenneth A. Bloom, Collider Detector At Fermilab Collaboration Dec 1998

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 ETjet > 8 GeV, pseudorapidity in the range 1.8 <|ηjet | < 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 Dec 1998

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

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 ...


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 Dec 1998

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.


Analysis Of Doubly Excited State Resonances Below The Li(5p) Threshold In Li- Photodetachment, Chien-Nan Liu, Anthony F. Starace Dec 1998

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}nA=5{1}6- state [having angular symmetry (K,T)A=(2,0) - or (n λ,nμ,m)=(1,7,0)]. This state, which ...


Batelaan And Gay Reply, Herman Batelaan, Timothy J. Gay Nov 1998

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 ...


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 Nov 1998

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 ...


Sputter Deposition Of High Resistivity Boron Carbide, Ahmad A. Ahmad, Natale J. Ianno, Seong-Don Hwang, Peter A. Dowben Nov 1998

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 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 Nov 1998

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 ...


First Search For Cp Violation In Tau Lepton Decay, S. Anderson, Kenneth A. Bloom, Cleo Collaboration Nov 1998

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.


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 Nov 1998

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 ...


Radiative Decay Modes Of The D0 Meson, D.M. Asner, Kenneth A. Bloom, Cleo Collaboration Nov 1998

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, D0K-*γ, and D0ρ0γ . 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.


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 Nov 1998

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 ...


Unidirectional Anisotropy In Ultrathin Transition-Metal Films , Ralph Skomski, H.-P. Oepen, J. Kirschner Nov 1998

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.


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 cross section ...


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.


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) → Υ(1S) π+π-) =0.189 ...


Higher-Order And Next-Nearest-Neighbor Néel Anisotropies , Y.T. Millev, Ralph Skomski, J. Kirschner Sep 1998

Higher-Order And Next-Nearest-Neighbor Néel Anisotropies , Y.T. Millev, Ralph Skomski, J. Kirschner

Ralph Skomski Publications

The problem of higher-order Néel anisotropies is solved by exploiting the addition theorem for spherical functions. A key advantage of the present approach is the orthonormal character of the expansion of the magnetic energy that simplifies the formalism and makes possible the treatment of nonideal morphologies as well. Explicit expressions for second-, fourth-, and sixth-order anisotropies are obtained for ideal bulk of fcc and bcc symmetry as well as for (001), (110), and (111) surfaces with nearest-neighbor (NN) Néel interactions. The systematic examination of the pair model involves partition by species of inequivalent sites, interaction spheres, and orders in the ...


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 ...


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 ...


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.


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′)+ν1 . The results obtained are compared with previous CLEO results and with the branching ratios measured ...


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 ...


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 ...


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 Bη′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 bc processes is suppressed. We discuss the physical interpretation of the signal, including the possibility that it is due to bsg* transitions. Given that interpretation, we find Ɓ(Bη′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.