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Selected Works

2001

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Articles 1 - 30 of 47

Full-Text Articles in Physics

The Minimal Model Of Nonbaryonic Dark Matter: A Singlet Scalar, C Burgess, M Pospelov, Tonnis Ter Veldhuis Dec 2001

The Minimal Model Of Nonbaryonic Dark Matter: A Singlet Scalar, C Burgess, M Pospelov, Tonnis Ter Veldhuis

Tonnis ter Veldhuis

No abstract provided.


The Evidence Of The Mode Selectivity Of The Infrared Predissociation Reaction Of The Hydrogen Bonds In The Aniline–Water–Pyrrole Cluster Cation, Taisuke Nakanaga, Naveed Piracha, Fumiyuki Ito Oct 2001

The Evidence Of The Mode Selectivity Of The Infrared Predissociation Reaction Of The Hydrogen Bonds In The Aniline–Water–Pyrrole Cluster Cation, Taisuke Nakanaga, Naveed Piracha, Fumiyuki Ito

Naveed K. Piracha

The infrared spectrum of aniline–water–pyrrole cluster cation has been measured in the 3 μm region. Four strong vibrational bands were observed at 3313, 3515, 3637, and 3721cm−1, and the cluster dissociated into fragments in two reaction paths, AWP+→AW++P and AWP+→AP++W (A: aniline, W: water, P: pyrrole) when it absorbed an infrared photon. The branching ratio (AW+/AP+) has been determined to be 0.20±0.02 for the NH stretching vibration of aniline (3313cm−1, hydrogen-bonded to pyrrole) and 0.14±0.03 for the other three bands. This vibrational mode dependence should ...


Relativistic Effects And Two-Body Currents In 2h(E⃗,E′P)N Using Out-Of-Plane Detection, Z L. Zhou, X Jiang, R Hicks, A Hotta, R Miskimen, Gerald Alvin Peterson, J Shaw Oct 2001

Relativistic Effects And Two-Body Currents In 2h(E⃗,E′P)N Using Out-Of-Plane Detection, Z L. Zhou, X Jiang, R Hicks, A Hotta, R Miskimen, Gerald Alvin Peterson, J Shaw

Gerald Alvin Peterson

Measurements of the 2H(e⃗,e′p)n reaction were performed with the out-of-plane magnetic spectrometers (OOPS) at the MIT-Bates Linear Accelerator. The longitudinal-transverse, fLT and fLT′, and the transverse-transverse, fTT, interference responses at a missing momentum of 210MeV/c were simultaneously extracted in the dip region at Q2 = 0.15 (GeV/c)2. In comparison to models of deuteron electrodisintegration, the data clearly reveal strong effects of relativity and final-state interactions and the importance of two-body meson-exchange currents and isobar configurations. We demonstrate that such effects can be disentangled by extracting these responses using the novel out-of-plane technique.


Transport Properties Of Bi2−Xinxse3 Single Crystals., J. Navrátil, T. Plecháček, J. Horák, S. Karamazov, P. LošŤÁK, Jeffrey Dyck, W. Chen, C. Uher Aug 2001

Transport Properties Of Bi2−Xinxse3 Single Crystals., J. Navrátil, T. Plecháček, J. Horák, S. Karamazov, P. LošŤÁK, Jeffrey Dyck, W. Chen, C. Uher

Jeffrey Dyck

The paper reports on the temperature dependence of the electrical and thermal conductivity, Hall constant, and Seebeck coefficient of Bi2−xInxSe3 (x=0, 0.2, 0.4) single crystals measured over the temperature range from 2 to 300 K. One single-valley conduction band model is used to interpret relations among transport coefficients. The data analysis relies on the use of a mixed carrier scattering mechanism consisting of acoustic scattering and scattering on ionized impurities. The effect of In incorporation into the Bi2Se3 crystal lattice on the individual components of thermal conductivity is evaluated and discussed. Copyright 2001 Academic Press.


Electroproduction Of The Λ(1520) Hyperon, S P. Barrow, L Dennis, S B. Mcaleer, B Asavapibhop, R S. Hicks, D Lawrence, R Miskimen, Gerald Alvin Peterson, J Shaw Aug 2001

Electroproduction Of The Λ(1520) Hyperon, S P. Barrow, L Dennis, S B. Mcaleer, B Asavapibhop, R S. Hicks, D Lawrence, R Miskimen, Gerald Alvin Peterson, J Shaw

Gerald Alvin Peterson

The reaction ep⃗e′K+Λ(1520) with Λ(1520)→p′K- was studied at electron beam energies of 4.05, 4.25, and 4.46 GeV, using the CLAS detector at the Thomas Jefferson National Accelerator Facility. The cosθK+, φK+, Q2, and W dependencies of Λ(1520) electroproduction are presented for the kinematic region 0.9


Towards String Predictions, G Cleaver, A Faraggi, D Nanopoulos, Tonnis Ter Veldhuis Aug 2001

Towards String Predictions, G Cleaver, A Faraggi, D Nanopoulos, Tonnis Ter Veldhuis

Tonnis ter Veldhuis

No abstract provided.


Anomalous Barium Filling Fraction And N-Type Thermoelectric Performance Of Ba[Sub Y]Co[Sub 4]Sb[Sub 12]., L. Chen, T. Kawahara, X. Tang, T. Goto, T. Hirai, Jeffrey Dyck, W. Chen, C. Uher Aug 2001

Anomalous Barium Filling Fraction And N-Type Thermoelectric Performance Of Ba[Sub Y]Co[Sub 4]Sb[Sub 12]., L. Chen, T. Kawahara, X. Tang, T. Goto, T. Hirai, Jeffrey Dyck, W. Chen, C. Uher

Jeffrey Dyck

Barium-filled skutterudites BaCoSb with an anomalously large filling fraction of up to y=0.44 have been synthesized. The lattice parameters increase linearly with Ba content. Magnetic susceptibility data show that BaCoSb is paramagnetic, which implies that some of the Co atoms in BaCoSb have acquired a magnetic moment. The presence of the two different valence states of Co (Co3+ and Co2+) leads to the anomalously large barium filling fraction even without extra charge compensation. All samples show n-type conduction. The electrical conductivity increases with increasing the Ba filling fraction. The lattice thermal conductivity of BaCoSb is significantly depressed as ...


Terahertz Emission From Gaas And Inas In A Magnetic Field, James Heyman, P Neocleous, D Hebert, P.A. Crowell, T Muller, K Unterrainer Aug 2001

Terahertz Emission From Gaas And Inas In A Magnetic Field, James Heyman, P Neocleous, D Hebert, P.A. Crowell, T Muller, K Unterrainer

James Heyman

No abstract provided.


Exact Topological Density In The Lattice Skyrme Model, Alec Schramm, Benjamin Svetitsky Jun 2001

Exact Topological Density In The Lattice Skyrme Model, Alec Schramm, Benjamin Svetitsky

Alec J Schramm

We propose using the Skyrme model on a lattice as an effective field theory of meson–baryon interactions. To this end we construct a local topological density that involves the volumes of tetrahedra in the target space S3 and we make use of Coxeter’s formula for the Schla¨fli function to implement it. We calculate the mean-square radius of a skyrmion in the three-dimensional Skyrme model, and find some surprises.


Third Generation Seesaw Mixing With New Vector-Like Weak-Doublet Quarks, Marko Popovic Jun 2001

Third Generation Seesaw Mixing With New Vector-Like Weak-Doublet Quarks, Marko Popovic

Marko B. Popovic

We present a class of models with a third generation seesaw mixing with new vectorlike weak-doublet quarks. We analyze a low-energy phenomenology and present several strong dynamics, high-energy realizations of these models. In the top-color-type scenario, named top-bottom color, we obtain an effective, composite two Higgs doublet model where the third generation isospin splitting is introduced via tilting interactions related to the broken non-Abelian gauge groups @i.e., without strong, triviality-sensitive U~1! groups#. In addition, we discuss t t ¯ production at the Next Linear Collider and suggest how one can experimentally observe and distinguish between the weak-doublet and the ...


Russian Summary Of Phd Dissertation, Serge Y. Kalmykov Jun 2001

Russian Summary Of Phd Dissertation, Serge Y. Kalmykov

Serge Youri Kalmykov

Author's Summary of Dissertation submitted in partial fulfillment of the requirements for the academic degree of Candidate of Sciences (Ph.D.) in physics and mathematics (original in Russian)


Notarized English Translation Of The Author's Summary Of Phd Dissertation, Serge Y. Kalmykov Jun 2001

Notarized English Translation Of The Author's Summary Of Phd Dissertation, Serge Y. Kalmykov

Serge Youri Kalmykov

Qualification code 01.04.08 - Plasma Physics
Author's Summary of Dissertation submitted in partial fulfillment of the requirements for the academic degree of
Candidate of Sciences (Ph.D.) in physics and mathematics (author's translation)
The work is completed in the Institute for High Energy Densities of Joint Institute for High Temperatures of Russian Academy of Sciences
Supervised by: Doctor of Science (Dr. Habil.) in physics and mathematics, Professor Nikolai E. Andreev
© Serge Kalmykov


Stimulated Raman Scattering Of Short Intense Laser Pulses In Plasmas, Serge Y. Kalmykov Jun 2001

Stimulated Raman Scattering Of Short Intense Laser Pulses In Plasmas, Serge Y. Kalmykov

Serge Youri Kalmykov

Qualification code 01.04.08 - Plasma Physics
Dissertation submitted in partial fulfillment of the requirements for the academic degree of Candidate of Sciences (Ph.D.) in physics and mathematics
The work is completed in the Institute for High Energy Densities of Joint Institute for High Temperatures of Russian Academy of Sciences
© Serge Kalmykov, 2001


Measurement Of The Elastic Magnetic Form Factor Of 3he At High Momentum Transfer, I Nakagawa, J Shaw, S Churchwell, X Jiang, B Asavapibhop, M C. Berisso, P E. Bosted, K Burchesky, R S. Hicks, A Hotta, R A. Miskimen, Gerald Alvin Peterson, S E. Rock Jun 2001

Measurement Of The Elastic Magnetic Form Factor Of 3he At High Momentum Transfer, I Nakagawa, J Shaw, S Churchwell, X Jiang, B Asavapibhop, M C. Berisso, P E. Bosted, K Burchesky, R S. Hicks, A Hotta, R A. Miskimen, Gerald Alvin Peterson, S E. Rock

Gerald Alvin Peterson

New electron scattering measurements have been made that extend data on the 3He elastic magnetic form factor up to Q2 = 42.6fm-2. These new data test theoretical conjectures regarding non-nucleonic effects in the three-body system. The very small cross sections, as low as 10-40cm2/sr, required the use of a high-pressure cryogenic gas target and a detector system with excellent background rejection capability. No existing theoretical calculation satisfactorily accounts for all the available data.


Excitation Of Ion-Acoustic-Like Waves By Subcritical Currents In A Plasma Having Equal Electron And Ion Temperatures, Erick Agrimson, Nicola D'Angelo, Robert L. Merlino Jun 2001

Excitation Of Ion-Acoustic-Like Waves By Subcritical Currents In A Plasma Having Equal Electron And Ion Temperatures, Erick Agrimson, Nicola D'Angelo, Robert L. Merlino

Erick Agrimson

No abstract provided.


On The Effect Of Electron Plasma Waves With Relativistic Phase Velocity On Large-Angle Stimulated Raman Scattering Of Modulated Short Laser Pulse In Plasmas, Nikolai E. Andreev, Serguei Y. Kalmykov May 2001

On The Effect Of Electron Plasma Waves With Relativistic Phase Velocity On Large-Angle Stimulated Raman Scattering Of Modulated Short Laser Pulse In Plasmas, Nikolai E. Andreev, Serguei Y. Kalmykov

Serge Youri Kalmykov

Suppression of a large-angle stimulated Raman scattering (LA-SRS) of a short modulated (two-frequency) laser pulse in a transparent plasma in the presence of a linear long-wavelength electron plasma wave (LW EPW) having relativistic phase velocity is considered under the conditions of weak and strong coupling. The laser spectrum includes two components with a frequency shift equal to the frequency of the LW EPW. The mutual influence of different spectral components of a laser on the SRS under a given angle in the presence of the LW EPW is examined.


Exclusive Electroproduction Of Φ Mesons At 4.2 Gev, K Lukashin, E S. Smith, B Asavapibhop, R A. Hicks, D Lawrence, R Miskimen, Gerald Alvin Peterson, J Shaw May 2001

Exclusive Electroproduction Of Φ Mesons At 4.2 Gev, K Lukashin, E S. Smith, B Asavapibhop, R A. Hicks, D Lawrence, R Miskimen, Gerald Alvin Peterson, J Shaw

Gerald Alvin Peterson

We studied the exclusive reaction ep⃗e′p′φ using the φ⃗K+K- decay mode. The data were collected using a 4.2 GeV incident electron beam and the CEBAF Large Acceptance Spectrometer (CLAS) at the Thomas Jefferson National Accelerator Facility. Our experiment covers the range in Q2 from 0.7 to 2.2 GeV2, and W from 2.0 to 2.6 GeV. Taken together with all previous data, we find a consistent picture of φ production on the proton. Our measurement shows the expected decrease of the t slope with the vector-meson formation time cΔτ below 2 ...


Entropy Bounds, Monotonicity Properties And Scaling In Cfts, D. Klemm, A.C. Petkou, George Siopsis May 2001

Entropy Bounds, Monotonicity Properties And Scaling In Cfts, D. Klemm, A.C. Petkou, George Siopsis

George Siopsis

We study the ratio of the entropy to the total energy in conformal field theories at finite temperature. For the free field realizations of N=4 source super Yang–Mills theory in D=4 and the (2,0) tensor multiplet in D=6, the ratio is bounded from above. The corresponding bounds are less stringent than the recently proposed Verlinde bound. We show that entropy bounds arise generically in CFTs in connection to monotonicity properties with respect to temperature changes of a generalized C-function. For strongly coupled CFTs with AdS duals, we show that the ratio obeys the Verlinde ...


Investigation Of The Structure Of T He Ternary Cluster Of Aniline−Water−Tetrahydrofuran And Its Cation By Infrared Depletion Spectroscopy, Taisuke Nakanaga, Naveed Piracha, Fumiyuki Ito May 2001

Investigation Of The Structure Of T He Ternary Cluster Of Aniline−Water−Tetrahydrofuran And Its Cation By Infrared Depletion Spectroscopy, Taisuke Nakanaga, Naveed Piracha, Fumiyuki Ito

Naveed K. Piracha

No abstract provided.


Simulation Of Inviscid Multi-Species Plasma Flow, Alexandre Martin, Marcelo Reggio, Jean-Yves Trépanier Apr 2001

Simulation Of Inviscid Multi-Species Plasma Flow, Alexandre Martin, Marcelo Reggio, Jean-Yves Trépanier

Alexandre Martin

A multi-species solver for plasma at thermodynamical equilibrium is developed. A numerical scheme, based on Roe's, is implemented with some modification regarding the average quantities. A perfect gas treatment is carried out for validations, and a quasi-real gas treatment is also presented. The latter takes into account the changes in the composition of the gas caused by fluctuations in temperature and density.


Temperature Of D3-Branes Off Extremality, Suphot Musiri, George Siopsis Apr 2001

Temperature Of D3-Branes Off Extremality, Suphot Musiri, George Siopsis

George Siopsis

We discuss non-extremal rotating D3-branes. We solve the wave equation for scalars in the supergravity background of certain distributions of branes and compute the absorption coefficients. The form of these coefficients is similar to the gray-body factors associated with black-hole scattering. They are given in terms of two different temperature parameters, indicating that fields (open string modes) do not remain in thermal equilibrium as we move off extremality. This should shed some light on the origin of the disagreement between the supergravity and conformal field theory results on the free energy of a system of non-coincident D-branes.


Domain Walls In Supersymmetric Qcd: The Taming Of The Zoo, D Binosi, Tonnis Ter Veldhuis Apr 2001

Domain Walls In Supersymmetric Qcd: The Taming Of The Zoo, D Binosi, Tonnis Ter Veldhuis

Tonnis ter Veldhuis

No abstract provided.


A2bi8se1 3 (A = Rb, Cs), Csbi3.67se6, And Babi2< /Inf>Se4: New Ternary Semiconducting Bismuth Selenides, Lykourgis Iordanidis, Paul Brazis, Theodora Kyratsi, John Irel, Melissa Lane, Carl Kannewurf, Wei Chen, Jeffrey Dyck, Ctirad Uher, Nishant Ghelani, Tim Hogan, Mercouri Kanatzidis Jan 2001

A2bi8se1 3 (A = Rb, Cs), Csbi3.67se6, And Babi2Se4: New Ternary Semiconducting Bismuth Selenides, Lykourgis Iordanidis, Paul Brazis, Theodora Kyratsi, John Irel, Melissa Lane, Carl Kannewurf, Wei Chen, Jeffrey Dyck, Ctirad Uher, Nishant Ghelani, Tim Hogan, Mercouri Kanatzidis

Jeffrey Dyck

No abstract provided.


Bps Saturated Domain Walls Along A Compact Dimension, R Hofmann, Tonnis Ter Veldhuis Jan 2001

Bps Saturated Domain Walls Along A Compact Dimension, R Hofmann, Tonnis Ter Veldhuis

Tonnis ter Veldhuis

No abstract provided.


Leaving The Bps Bound: Tunneling Of Classically Saturated Solitons, D Binosi, M Shifman, Tonnis Ter Veldhuis Jan 2001

Leaving The Bps Bound: Tunneling Of Classically Saturated Solitons, D Binosi, M Shifman, Tonnis Ter Veldhuis

Tonnis ter Veldhuis

No abstract provided.


Simple Relationships For The Estimation Of Melting Temperatures Of Homologous Series, James S. Chickos, Gary Nichols Jan 2001

Simple Relationships For The Estimation Of Melting Temperatures Of Homologous Series, James S. Chickos, Gary Nichols

James Chickos

No abstract provided.


The Influence Of Ni On The Transport Properties Of Cosb3, C. Uher, Jeffrey Dyck, W. Chen, G. Meisner, J. Yang Dec 2000

The Influence Of Ni On The Transport Properties Of Cosb3, C. Uher, Jeffrey Dyck, W. Chen, G. Meisner, J. Yang

Jeffrey Dyck

The effect of Ni doping on the Co site of the binary skutterudite CoSb3 is investigated. We measured resistivity, Hall effect, magnetoresistance, thermopower, thermal conductivity, and magnetization of a series of samples of the form Co1-xNixSb3 with x in the range x=0 to x=0.01. We find that Ni takes the tetravalent state Ni4+, assumes the d6 electronic configuration for the lower energy non-bonding orbitals, and gives an electron to the conduction band. Ni doping dramatically suppresses the thermal conductivity, changes the temperature dependence of the thermopower, and increases the carrier concentration. Low temperature anomalies in thermopower, Hall ...


Low Temperature Thermoelectric Properties Of Ni Doped N-Type Filled Skutterudites Ba0.3co4sb12 ., W. Chen, Jeffrey Dyck, C. Uher, L. Chen, X. Tang, T. Hirai Dec 2000

Low Temperature Thermoelectric Properties Of Ni Doped N-Type Filled Skutterudites Ba0.3co4sb12 ., W. Chen, Jeffrey Dyck, C. Uher, L. Chen, X. Tang, T. Hirai

Jeffrey Dyck

n-type Ba filled skutterudites doped with Ni, Ba0.3Ni xCo4-xSb12 with 0⩽x⩽0.2, have been synthesized and the Seebeck coefficient, thermal conductivity, electrical resistivity and Hall coefficient have been measured. ZT of 1.2 has been achieved at 800 K with x=0.05. The thermal conductivity data are fitted and the rattling effect of the Ba atoms is identified through a resonance scattering term. The Hall mobility is studied and a mixed scattering mechanism of acoustic phonons and ionized impurities based on a single, rigid band picture is presented. The role of Ni atoms in enhancing the ...


Multi-Filling Approach For The Improvement Of Thermoelectric Properties Of Skutterudites., L. Chen, X. Tang, T. Kawahara, Jeffrey Dyck Dec 2000

Multi-Filling Approach For The Improvement Of Thermoelectric Properties Of Skutterudites., L. Chen, X. Tang, T. Kawahara, Jeffrey Dyck

Jeffrey Dyck

Several skutterudite antimonides filled with atoms of different kinds, (Ba, M)yCo4Sb12 (M=Ce, La, Sr), have been synthesized by the combination of solid state reaction and melting methods. Thermal conductivity of (Ba,Sr)yCo4 Sb12 samples shows a behavior similar to that of BayCo4Sb12. Adding a small amount of Ce or La to the BayCo4Sb12 system is effective in further reducing the lattice thermal conductivity. The difference in the ionic radii of the two co-filler atoms is the most sensitive factor for scattering of phonons. The multi-filled (Ba, M)yCo4Sb12 (M=Sr, Ce, La) show lower Seebeck coefficients as ...


High-Temperature Thermoelectric Properties Of N-Type Baynixco4-Xsb12., X. Tang, L. Zhang, R. Yuan, L. Chen, T. Goto, T. Hirai, Jeffrey Dyck, W. Chen, C. Uher Dec 2000

High-Temperature Thermoelectric Properties Of N-Type Baynixco4-Xsb12., X. Tang, L. Zhang, R. Yuan, L. Chen, T. Goto, T. Hirai, Jeffrey Dyck, W. Chen, C. Uher

Jeffrey Dyck

Effects of Ba filling fraction and Ni content on the thermoelectric properties of n-type BayNixCo4-xSb12 (x = 0-0.1, y = 0.-0.4) were investigated at temperature range of 300 to 900 K. Thermal conductivity decreased with increasing Ba filling fraction and temperature. When y was fixed at 0.3, thermal conductivity decreased with increasing Ni content and reached a minimum value at about x = 0.05. Lattice thermal conductivity decreased with increasing Ni content, monotonously (y ≤ 0.1). Electron concentration and electrical conductivity increased with increasing Ba filling fraction and Ni content. Seebeck coefficient increased with increasing temperature and ...