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Recent charm mixing results from BABAR, Belle, and CDF (open access)

Recent charm mixing results from BABAR, Belle, and CDF

A summary of the results of several recent studies of charm mixing is presented. A number of different methods were used, including the measurement of lifetime ratios for final states of different CP, time dependence of wrong-sign hadronic decays, fits to time-dependent Dalitz plots, and searches for wrong-sign semi-leptonic decays. Taken together, they suggest mixing is of order 1%. The status of searches for indirect CP violation is also reported.
Date: February 2, 2009
Creator: Charles, M.J. & /SLAC, /Iowa U.
System: The UNT Digital Library
Vector Unparticle Contributions to Lepton g-2 (open access)

Vector Unparticle Contributions to Lepton g-2

The generic unparticle propagator may be modified in two ways. Breaking the conformal symmetry effectively adds a mass term to the propagator, while considering vacuum polarization corrections adds a width-like term. Both of these modifications result naturally from the coupling of the unparticle to standard model (SM) fields. We explore how these modifications to the propagator affect the calculation of the lepton anomalous magnetic moment using an integral approximation of the propagator that is accurate for d {approx}< 1.5, where d is the unparticle dimension. We find that for this range of d and various values of the conformal breaking scale {mu}, the value of g-2 calculated when allowing various SM fermions to run in the unparticle self-energy loops does not significantly deviate from the value of g-2 when the width term is ignored. We also investigate the limits on a characteristic mass scale for the unparticle sector as a function of {mu} and d.
Date: February 2, 2009
Creator: Conley, John A. & Gainer, James S.
System: The UNT Digital Library
Investigation of early growth of calcium hydroxide crystals in cement solution by soft x-ray transmission microscopy (open access)

Investigation of early growth of calcium hydroxide crystals in cement solution by soft x-ray transmission microscopy

Research on cement hydration was performed at the full-field soft transmission X-ray microscope XM-1 located at beamline 6.1.2 at the Advanced Light Source (ALS) in Berkeley CA which is operated by the Center for X-ray Optics, Lawrence Berkeley National Laboratory, Berkeley, California. A series of works [1-3] has been conducted using this microscope for the in situ observation and qualitative analysis of through-solution hydration products and products of topochemical reactions, which form in cementitious aqueous solutions. This paper studies the precipitation of the calcium hydroxide (CH) crystals from the cement solution. The analysis of successive images of the hydration process provides critical quantitative information about the growth rate of calcium hydroxide (CH) crystals, the supersaturation ratio, and the kinetic and diffusion coefficients of the growth process. ASTM Type II portland cement and 6% C{sub 4}A{sub 3}{bar S} admixture were mixed in aqueous solution and saturated with respect to CH and gypsum. The C{sub 4}A{sub 3}{bar S} admixture was included in the experimental program because of the general research program on expansive cements, and adding C{sub 4}A{sub 3}{bar S} to portland cement is an efficient method of generating ettringite and significant early-age expansion. The solution/solid materials ratio was 10 cm{sup 3}/g, …
Date: February 2, 2009
Creator: Harutyunyan, V. S.; Kirchheim, A. P.; Monteiro, P. J. M.; Aivazyan, A. P. & Fischer, P.
System: The UNT Digital Library
Excitation Function for the 74Se(18O,p3n) Reaction (open access)

Excitation Function for the 74Se(18O,p3n) Reaction

The 74Se(18O,p3n)88gNb excitation function was measured and a maximum cross section of 495+-5 mb was observed at and 18O energy of 74.0 MeV. Experimental cross sections were compared to theoretical calculations using the computer code ALICE-91 and the values were found to be in good agreement. The half life of 88gNb was determined to be around 14.56+-0.11 min.
Date: February 2, 2009
Creator: Gates, Jacklyn; Dragojevic, Irena; Dvorak, Jan; Ellison, Paul; Gregorich, Kenneth; Stavsetra, Liv et al.
System: The UNT Digital Library
Cerocene Revisited: The Electronic Structure of and Interconversion Between Ce2(C8H8)3 and Ce(C8H8)2 (open access)

Cerocene Revisited: The Electronic Structure of and Interconversion Between Ce2(C8H8)3 and Ce(C8H8)2

New synthetic procedures for the preparation of Ce(cot)2, cerocene, from [Li(thf)4][Ce(cot)2], and Ce2(cot)3 in high yield and purity are reported. Heating solid Ce(cot)2 yields Ce2(cot)3 and COT while heating Ce2(cot)3 with an excess of COT in C6D6 to 65oC over four months yields Ce(cot)2. The solid state magnetic susceptibility of these three organocerium compounds shows that Ce(cot)2 behaves as a TIP (temperature independent paramagnet) over the temperature range of 5-300 K, while that of Ce2(cot)3 shows that the spin carriers are antiferromagnetically coupled below 10 K; above 10 K, the individual spins are uncorrelated, and [Ce(cot)2]- behaves as an isolated f1 paramagnet. The EPR at 1.5K for Ce2(cot)3 and [Ce(cot)2]- have ground state of MJ= +- 1/2. The LIII edge XANES of Ce(cot)2 (Booth, C.H.; Walter, M.D.; Daniel, M.; Lukens, W.W., Andersen, R.A., Phys. Rev. Lett. 2005, 95, 267202) and 2Ce2(cot)3 over 30-500 K are reported; the Ce(cot)2 XANES spectra show Ce(III) and Ce(IV) signatures up to a temperature of approximately 500 K, whereupon the Ce(IV) signature disappears, consistent with the thermal behavior observed in the melting experiment. The EXAFS of Ce(cot)2 and Ce2(cot)3 are reported at 30 K; the agreement between the molecular parameters for Ce(cot)2 derived from EXAFS …
Date: February 2, 2009
Creator: Walter, Marc D.; Booth, Corwin H.; Lukens, Wayne W. & Andersen, Richard A.
System: The UNT Digital Library
Statistical mechanics of sum frequency generation spectroscopy for the liquid-vapor interface of dilute aqueous salt solutions (open access)

Statistical mechanics of sum frequency generation spectroscopy for the liquid-vapor interface of dilute aqueous salt solutions

We demonstrate a theoretical description of vibrational sum frequency generation (SFG) at the boundary of aqueous electrolyte solutions. This approach identifies and exploits a simple relationship between SFG lineshapes and the statistics of molecular orientation and electric field. Our computer simulations indicate that orientational averages governing SFG susceptibility do not manifest ion-specific shifts in local electric field, but instead, ion-induced polarization of subsurface layers. Counterbalancing effects are obtained for monovalent anions and cations at the same depth. Ions held at different depths induce an imbalanced polarization, suggesting that ion-specific effects can arise from weak, long ranged influence on solvent organization.
Date: January 2, 2009
Creator: Noah-Vanhoucke, Joyce; Smith, Jared D. & Geissler, Phillip L.
System: The UNT Digital Library
Critical Evaluation of the ISCCP Simulator Using Ground-Based Remote Sensing Data (open access)

Critical Evaluation of the ISCCP Simulator Using Ground-Based Remote Sensing Data

Given the known shortcomings in representing clouds in Global Climate Models (GCM) comparisons with observations are critical. The International Satellite Cloud Climatology Project (ISCCP) diagnostic products provide global descriptions of cloud top pressure and column optical depth that extends over multiple decades. The necessary limitations of the ISCCP retrieval algorithm require that before comparisons can be made between model output and ISCCP results the model output must be modified to simulate what ISCCP would diagnose under the simulated circumstances. We evaluate one component of the so-called ISCCP simulator in this study by comparing ISCCP and a similar algorithm with various long-term statistics derived from the Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) Climate Research Facility ground-based remote sensors. We find that were a model to simulate the cloud radiative profile with the same accuracy as can be derived from the ARM data, then the likelihood of that occurrence being placed in the same cloud top pressure and optical depth bin as ISCCP of the 9 bins that have become standard ranges from 30% to 70% depending on optical depth. While the ISCCP simulator improved the agreement of cloud-top pressure between ground-based remote sensors and satellite observations, we find minor …
Date: November 2, 2009
Creator: Mace, G. G.; Houser, S.; Benson, S.; Klein, S. A. & Min, Q.
System: The UNT Digital Library
Simulation of Electric Field in Semi Insulating Au/CdTe/Au Detector under Flux (open access)

Simulation of Electric Field in Semi Insulating Au/CdTe/Au Detector under Flux

We report our simulations on the profile of the electric field in semi insulating CdTe and CdZnTe with Au contacts under radiation flux. The type of the space charge and electric field distribution in the Au/CdTe/Au structure is at high fluxes result of a combined influence of charge formed due to band bending at the electrodes and from photo generated carriers, which are trapped at deep levels. Simultaneous solution of drift-diffusion and Poisson equations is used for the calculation. We show, that the space charge originating from trapped photo-carriers starts to dominate at fluxes 10{sup 15}-10{sup 16}cm{sup -2}s{sup -1}, when the influence of contacts starts to be negligible.
Date: August 2, 2009
Creator: Franc, J.; James, R.; Grill, R.; Kubat, J.; Belas, E.; Hoschl, P. et al.
System: The UNT Digital Library
Analytic one-loop amplitudes for a Higgs boson plus four partons (open access)

Analytic one-loop amplitudes for a Higgs boson plus four partons

We compute the one-loop QCD amplitudes for the processes H{anti q}q{anti Q}Q and H{anti q}qgg, the latter restricted to the case of opposite-helicity gluons. Analytic expressions are presented for the color- and helicity-decomposed amplitudes. The coupling of the Higgs boson to gluons is treated by an effective interaction in the limit of large top quark mass. The Higgs field is split into a complex field {phi} and its complex conjugate {phi}{sup {dagger}}. The split is useful because amplitudes involving {phi} have different analytic structure from those involving {phi}{sup {dagger}}. We compute the cut-containing pieces of the amplitudes using generalized unitarity. The remaining rational parts are obtained by on-shell recursion. Our results for H{anti q}q{anti Q}Q agree with previous semi-numerical computations. We also show how to convert existing semi-numerical results for the production of a scalar Higgs boson into analogous results for a pseudoscalar Higgs boson.
Date: June 2, 2009
Creator: Dixon, Lance J. & Sofianatos, Yorgos
System: The UNT Digital Library
Measurement of Black Carbon and Particle Number Emission Factors from Individual Heavy-Duty Trucks (open access)

Measurement of Black Carbon and Particle Number Emission Factors from Individual Heavy-Duty Trucks

Emission factors for black carbon (BC) and particle number (PN) were measured from 226 individual heavy-duty (HD) diesel-fueled trucks driving through a 1 km-long California highway tunnel in August 2006. Emission factors were based on concurrent increases in BC, PN, and CO{sub 2}B concentrations (measured at 1 Hz) that corresponded to the passage of individual HD trucks. The distributions of BC and PN emission factors from individual HD trucks are skewed, meaning that a large fraction of pollution comes from a small fraction of the in-use vehicle fleet. The highest-emitting 10% of trucks were responsible for {approx} 40% of total BC and PN emissions from all HD trucks. BC emissions were log-normally distributed with a mean emission factor of 1.7 g kg {sup -1} and maximum values of {approx} 10 g kg{sup -1}. Corresponding values for PN emission factors were 4.7 x 10{sup 15} and 4 x 10{sup 16} kg{sup -1}. There was minimal overlap among high-emitters of these two pollutants: only 1 of the 226 HD trucks measured was found to be among the highest 10% for both BC and PN. Monte Carlo resampling of the distribution of BC emission factors observed in this study revealed that uncertainties (1{sigma}) …
Date: February 2, 2009
Creator: Ban-Weiss, George A.; Lunden, Melissa M.; Kirchstetter, Thomas W. & Harley, Robert A.
System: The UNT Digital Library
SUCCESSES AND EMERGING ISSUES IN SIMULATING THE PROCESSING BEHAVIOR OF LIQUID-PARTICLE NUCLEAR WASTE SLURRIES AT THE SAVANNAH RIVER SITE - 205E (open access)

SUCCESSES AND EMERGING ISSUES IN SIMULATING THE PROCESSING BEHAVIOR OF LIQUID-PARTICLE NUCLEAR WASTE SLURRIES AT THE SAVANNAH RIVER SITE - 205E

Slurries of inorganic solids, containing both stable and radioactive elements, were produced during the cold war as by-products of the production of plutonium and enriched uranium and stored in large tanks at the Savannah River Site. Some of this high level waste is being processed into a stable glass waste form today. Waste processing involves various large scale operations such as tank mixing, inter-tank transfers, washing, gravity settling and decanting, chemical adjustment, and vitrification. The rheological properties of waste slurries are of particular interest. Methods for modeling flow curve data and predicting the properties of slurry blends are particularly important during certain operational phases. Several methods have been evaluated to predict the rheological properties of sludge slurry blends from the data on the individual slurries. These have been relatively successful.
Date: September 2, 2009
Creator: Koopman, D.; Lambert, D. & Stone, M.
System: The UNT Digital Library
Nonuniformity for rotated beam illumination in directly driven heavy-ion fusion (open access)

Nonuniformity for rotated beam illumination in directly driven heavy-ion fusion

A key issue in heavy-ion beam inertial confinement fusion is target interaction, especially implosion symmetry. In this paper the 2D beam irradiation nonuniformity on the surface of a spherical target is studied. This is a first step to studies of 3D dynamical effects on target implosion. So far non-rotated beams have been studied. Because normal incidence may increase Rayleigh-Taylor instabilities, it has been suggested to rotate beams (to increase average uniformity) and hit the target tangentially. The level of beam irradiation uniformity, beam spill and normal incidence is calculated in this paper. In Mathematica the rotated beams are modeled as an annular integrated Gaussian beam. To simplify the chamber geometry, the illumination scheme is not a 4{pi} system, but the beams are arranged on few polar rings around the target. The position of the beam spot rings is efficiently optimized using the analytical model. The number of rings and beams, rotation radii and widths are studied to optimize uniformity and spilled intensity. The results demonstrate that for a 60-beam system on four rings Peak-To-Valley nonuniformities of under 0.5% are possible.
Date: January 2, 2009
Creator: Runge, J. & Logan, B. G.
System: The UNT Digital Library
HYDROGEN TECHNOLOGY RESEARCH AT THE SAVANNAH RIVER NATIONAL LABORATORY (open access)

HYDROGEN TECHNOLOGY RESEARCH AT THE SAVANNAH RIVER NATIONAL LABORATORY

The Savannah River National Laboratory (SRNL) is a U.S. Department of Energy research and development laboratory located at the Savannah River Site (SRS) near Aiken, South Carolina. SRNL has over 50 years of experience in developing and applying hydrogen technology, both through its national defense activities as well as through its recent activities with the DOE Hydrogen Programs. The hydrogen technical staff at SRNL comprises over 90 scientists, engineers and technologists, and it is believed to be the largest such staff in the U.S. SRNL has ongoing R&D initiatives in a variety of hydrogen storage areas, including metal hydrides, complex hydrides, chemical hydrides and carbon nanotubes. SRNL has over 25 years of experience in metal hydrides and solid-state hydrogen storage research, development and demonstration. As part of its defense mission at SRS, SRNL developed, designed, demonstrated and provides ongoing technical support for the largest hydrogen processing facility in the world based on the integrated use of metal hydrides for hydrogen storage, separation, and compression. The SRNL has been active in teaming with academic and industrial partners to advance hydrogen technology. A primary focus of SRNL's R&D has been hydrogen storage using metal and complex hydrides. SRNL and its Hydrogen Technology …
Date: March 2, 2009
Creator: Danko, E
System: The UNT Digital Library
High-frequency surface acoustic wave propagation in nanaostructures characterized by coherent extreme ultraviolet beams (open access)

High-frequency surface acoustic wave propagation in nanaostructures characterized by coherent extreme ultraviolet beams

We study ultrahigh frequency surface acoustic wave propagation in nickel-on-sapphire nanostructures. The use of ultrafast, coherent, extreme ultraviolet beams allows us to extend optical measurements of propagation dynamics of surface acoustic waves to frequencies of nearly 50 GHz, corresponding to wavelengths as short as 125 nm. We repeat the measurement on a sequence of nanostructured samples to observe surface acoustic wave dispersion in a nanostructure series for the first time. These measurements are critical for accurate characterization of thin films using this technique.
Date: March 2, 2009
Creator: Siemens, M.; Li, Q.; Murnane, M.; Kapteyn, H.; Yang, R.; Anderson, E. et al.
System: The UNT Digital Library
DEEP VADOSE ZONE TREATABILITY TEST PLAN (open access)

DEEP VADOSE ZONE TREATABILITY TEST PLAN

{sm_bullet} Treatability test plan published in 2008 {sm_bullet} Outlines technology treatability activities for evaluating application of in situ technologies and surface barriers to deep vadose zone contamination (technetium and uranium) {sm_bullet} Key elements - Desiccation testing - Testing of gas-delivered reactants for in situ treatment of uranium - Evaluating surface barrier application to deep vadose zone - Evaluating in situ grouting and soil flushing
Date: July 2, 2009
Creator: CHRONISTER, GB & TRUEX, MJ
System: The UNT Digital Library
Transverse Single Bunch Instability in PEP-X (open access)

Transverse Single Bunch Instability in PEP-X

A proposed high-brightness synchrotron light source (PEP-X) is under design at SLAC. The 4.5- GeV PEP-X storage ring has four theoretical minimum emittance (TME) cells to achieve the very low emittance and two double-bend achromat (DBA) cells to provide spaces for IDs. Damping wigglers will be installed in zero-dispersion straights to reduce the emittance below 0.1nm. In this paper, we present a preliminary estimation of the threshold of the transverse mode coupling instability (TMCI). Three approaches have been used in the estimation and they agree well with each other.
Date: June 2, 2009
Creator: Wang, L. & Stupakov, G.
System: The UNT Digital Library
Effects of Beam Filling Pattern on Beam Ion Instability and Beam Loading In PEP-X (open access)

Effects of Beam Filling Pattern on Beam Ion Instability and Beam Loading In PEP-X

A proposed high-brightness synchrotron light source (PEP-X) is under design at SLAC. The 4.5-GeV PEP-X storage ring has four theoretical minimum emittance (TME) cells to achieve the very low emittance and two double-bend achromat (DBA) cells to provide spaces for IDs. Damping wigglers will be installed in zero-dispersion straights to reduce the emittance below 0.1 nm. Ion induced beam instability is one critical issue due to its ultra small emittance. Third harmonic cavity can be used to lengthen the bunch in order to improve the beam's life time. Bunch-train filling pattern is proposed to mitigate both the fast ion instability and beam loading effect. This paper investigates the fast ion instability and beam loading for different beam filling patterns.
Date: June 2, 2009
Creator: Wang, L.
System: The UNT Digital Library
Electric Field Distribution of Cadmium Zinc Telluride (CZT) (open access)

Electric Field Distribution of Cadmium Zinc Telluride (CZT)

Cadmium Zinc Telluride (CZT) is attracting increasing interest with its promise as a room-temperature nuclear-radiation-detector material. The distribution of the electric field in CZT detectors substantially affects their detection performance. At Brookhaven National Laboratory (BNL), we employed a synchrotron X-Ray mapping technique and a Pockels-effect measurement system to investigate this distribution in different detectors. Here, we report our latest experimental results with three detectors of different width/height ratios. A decrease in this ratio aggravates the non-uniform distribution of electric field, and focuses it on the central volume. Raising the bias voltage effectively can minimize such non-uniformity of the electric field distribution. The position of the maximum electric field is independent of the bias voltage; the difference between its maximum- and minimum-intensity of electric field increases with the applied bias voltage.
Date: August 2, 2009
Creator: Yang, G.; Bolotnikov, A.; Camarda, G. S.; Cui, Y.; Hossain, A.; Kim, K. et al.
System: The UNT Digital Library
A multi-threshold sampling method for TOF PET signal processing (open access)

A multi-threshold sampling method for TOF PET signal processing

As an approach to realizing all-digital data acquisition for positron emission tomography (PET), we have previously proposed and studied a multithreshold sampling method to generate samples of a PET event waveform with respect to a few user-defined amplitudes. In this sampling scheme, one can extract both the energy and timing information for an event. In this paper, we report our prototype implementation of this sampling method and the performance results obtained with this prototype. The prototype consists of two multi-threshold discriminator boards and a time-to-digital converter (TDC) board. Each of the multi-threshold discriminator boards takes one input and provides up to 8 threshold levels, which can be defined by users, for sampling the input signal. The TDC board employs the CERN HPTDC chip that determines the digitized times of the leading and falling edges of the discriminator output pulses. We connect our prototype electronics to the outputs of two Hamamatsu R9800 photomultiplier tubes (PMTs) that are individually coupled to a 6.25 x 6.25 x 25mm{sup 3} LSO crystal. By analyzing waveform samples generated by using four thresholds, we obtain a coincidence timing resolution of about 340 ps and an {approx}18% energy resolution at 511 keV. We are also able to …
Date: February 2, 2009
Creator: Kim, Heejong; Kao, Chien-Min; Xie, Q.; Chen, Chin-Tu; Zhou, L.; Tang, F. et al.
System: The UNT Digital Library
SUCCESSES AND EMERGING ISSUES IN SIMULATING THE MIXING BEHAVIOR OF LIQUID-PARTICLE NUCLEAR WASTE SLURRIES AT THE SAVANNAH RIVER SITE - 211B (open access)

SUCCESSES AND EMERGING ISSUES IN SIMULATING THE MIXING BEHAVIOR OF LIQUID-PARTICLE NUCLEAR WASTE SLURRIES AT THE SAVANNAH RIVER SITE - 211B

Aqueous radioactive high-level waste slurries are combined during processing steps that ultimately produce a stable borosilicate glass waste form. Chemically treated waste slurries are combined with each other and with glass frit-water slurries to produce the melter feed. Understanding the evolution of the rheological properties of the slurries is an important aspect of removing and treating the stored waste. To a first approximation, combinations of colloidal waste slurry with {approx}0.1-mm mean diameter glass frit or glass beads act in an analogous matter to slurries of spherical beads in Newtonian liquids. The non-Newtonian rheological properties of the waste slurries without frit, however, add complexity to the hydrodynamic analysis. The use of shear rate dependent apparent viscosities with the modified Einstein equation was used to model the rheological properties of aqueous frit-waste slurries.
Date: September 2, 2009
Creator: Koopman, D.; Pickenheim, B.; Lambert, D. & Stone, M.
System: The UNT Digital Library
Covariance Spectroscopy for Fissile Material Detection (open access)

Covariance Spectroscopy for Fissile Material Detection

Nuclear fission produces multiple prompt neutrons and gammas at each fission event. The resulting daughter nuclei continue to emit delayed radiation as neutrons boil off, beta decay occurs, etc. All of the radiations are causally connected, and therefore correlated. The correlations are generally positive, but when different decay channels compete, so that some radiations tend to exclude others, negative correlations could also be observed. A similar problem of reduced complexity is that of cascades radiation, whereby a simple radioactive decay produces two or more correlated gamma rays at each decay. Covariance is the usual means for measuring correlation, and techniques of covariance mapping may be useful to produce distinct signatures of special nuclear materials (SNM). A covariance measurement can also be used to filter data streams because uncorrelated signals are largely rejected. The technique is generally more effective than a coincidence measurement. In this poster, we concentrate on cascades and the covariance filtering problem.
Date: June 2, 2009
Creator: Rusty Trainham, Jim Tinsley, Paul Hurley, Ray Keegan
System: The UNT Digital Library
X-ray Emission Spectroscopy to Study Ligand Valence Orbitals in Mn Coordination Complexes (open access)

X-ray Emission Spectroscopy to Study Ligand Valence Orbitals in Mn Coordination Complexes

We discuss a spectroscopic method to determine the character of chemical bonding and for the identification of metal ligands in coordination and bioinorganic chemistry. It is based on the analysis of satellite lines in X-ray emission spectra that arise from transitions between valence orbitals and the metal ion 1s level (valence-to-core XES). The spectra, in connection with calculations based on density functional theory (DFT), provide information that is complementary to other spectroscopic techniques, in particular X-ray absorption (XANES and EXAFS). The spectral shape is sensitive to protonation of ligands and allows ligands, which differ only slightly in atomic number (e.g., C, N, O...), to be distinguished. A theoretical discussion of the main spectral features is presented in terms of molecular orbitals for a series of Mn model systems: [Mn(H2O)6]2+, [Mn(H2O)5OH]+, [Mn(H2O)5NH2]+, and [Mn(H2O)5NH3]2+. An application of the method, with comparison between theory and experiment, is presented for the solvated Mn2+ ion in water and three Mn coordination complexes, namely [LMn(acac)N3]BPh4, [LMn(B2O3Ph2)(ClO4)], and [LMn(acac)N]BPh4, where L represents 1,4,7-trimethyl-1,4,7-triazacyclononane, acac stands for the 2,4-pentanedionate anion, and B2O3Ph2 represents the 1,3-diphenyl-1,3-dibora-2-oxapropane-1,3-diolato dianion.
Date: March 2, 2009
Creator: Smolentsev, Grigory; Soldatov, Alexander V; Messinger, Johannes; Merz, Kathrin; Weyhermuller, Thomas; Bergmann, Uwe et al.
System: The UNT Digital Library
SNM Movement Detection/Radiation Sensors and Advanced Materials Portfolio Review, CdMnTe (CMT) Gamma Ray Detectors (open access)

SNM Movement Detection/Radiation Sensors and Advanced Materials Portfolio Review, CdMnTe (CMT) Gamma Ray Detectors

The project goals are: (1) Develop CMT radiation detectors - Demonstrate feasibility (Phase 1 is complete) and Improve material properties and device performance; (2) This project will lead to novel radiation detectors - high detection efficiency, high energy-resolution, ambient-temperature operation, and low production cost; and (3) Such detectors are needed in areas of nonproliferation and national security for detection of SNM. Research highlights are: (1) We achieved our Phase-I goal - Demonstration of CMT detector performance approaching that of CZT detectors; (2) Demonstrated that In-doped CMT is much closer to its anticipated performance as radiation detectors than other alternative materials, TlBr and HgI{sub 2} - Large crystal volumes, 10{sup 10}{Omega}{center_dot}cm, 3 x 10{sup -3}cm{sup 2}/V, and stable response; and (3) Conducted material and device characterization experiments - Detectors: I-V, {mu}{sub e}, ({mu}{tau}){sub e}, internal E fields, energy spectra, and high-resolution x-ray response mapping data and Materials - DLTS, TCT, PL, EPDs, XRD, PCD and IR transmission.
Date: June 2, 2009
Creator: Bolotnikov, A.
System: The UNT Digital Library
Search for Dimuon Decays of a Light Scalar in Radiative Transitions Y(3S) -> gamma A0 (open access)

Search for Dimuon Decays of a Light Scalar in Radiative Transitions Y(3S) -> gamma A0

The fundamental nature of mass is one of the greatest mysteries in physics. The Higgs mechanism is a theoretically appealing way to account for the different masses of elementary particles and implies the existence of a new, yet unseen particle, the Higgs boson. We search for evidence of a light scalar (e.g. a Higgs boson) in the radiative decays of the narrow {Upsilon}(3S) resonance: {Upsilon}(3S) {yields} {gamma}A{sup 0}, A{sup 0} {yields} {mu}{sup +}{mu}{sup -}. Such an object appears in extensions of the Standard Model, where a light CP-odd Higgs boson naturally couples strongly to b-quarks. We find no evidence for such processes in a sample of 122 x 10{sup 6} {Upsilon}(3S) decays collected by the BABAR collaboration at the PEP-II B-factory, and set 90% C.L. upper limits on the branching fraction product {Beta}({Upsilon}(3S) {yields} {gamma}A{sup 0}) x {Beta}(A{sup 0} {yields} {mu}{sup +}{mu}{sup -}) at (0.25 - 5.2) x 10{sup -6} in the mass range 0.212 {<=} m{sub A{sup 0}} {<=} 9.3 GeV. We also set a limit on the dimuon branching fraction of the {eta}{sub b} meson {Beta}({eta}{sub b} {yields} {mu}{sup +}{mu}{sup -}) < 0.8% at 90% C.L. The results are preliminary.
Date: June 2, 2009
Creator: Aubert, B.
System: The UNT Digital Library