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.
Object Type: Article
System: The UNT Digital Library
Longitudinal Stability Calculations (open access)

Longitudinal Stability Calculations

Coupled bunch longitudinal stability in the presence of high frequency impedances is considered. A frequency domain technique is developed and compared with simulations. The frequency domain technique allows for absolute stability tests and is applied to the problem of longitudinal stability in RHIC with the new 56 MHz RF system.
Date: January 2, 2009
Creator: Blaskiewicz, M.
Object Type: Report
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.
Object Type: Article
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.
Object Type: Article
System: The UNT Digital Library
Terascale High-Fidelity Simulations of Turbulent Combustion with Detailed Chemistry (open access)

Terascale High-Fidelity Simulations of Turbulent Combustion with Detailed Chemistry

The TSTC project is a multi-university collaborative effort to develop a high-fidelity turbulent reacting flow simulation capability utilizing terascale, massively parallel computer technology. The main paradigm of our approach is direct numerical simulation (DNS) featuring highest temporal and spatial accuracy, allowing quantitative observations of the fine-scale physics found in turbulent reacting flows as well as providing a useful tool for development of sub-models needed in device-level simulations. The code named S3D, developed and shared with Chen and coworkers at Sandia National Laboratories, has been enhanced with new numerical algorithms and physical models to provide predictive capabilities for spray dynamics, combustion, and pollutant formation processes in turbulent combustion. Major accomplishments include improved characteristic boundary conditions, fundamental studies of auto-ignition in turbulent stratified reactant mixtures, flame-wall interaction, and turbulent flame extinction by water spray. The overarching scientific issue in our recent investigations is to characterize criticality phenomena (ignition/extinction) in turbulent combustion, thereby developing unified criteria to identify ignition and extinction conditions. The computational development under TSTC has enabled the recent large-scale 3D turbulent combustion simulations conducted at Sandia National Laboratories.
Date: February 2, 2009
Creator: Im, Hong G.; Trouve, Arnaud; Rutland, Christopher J. & Chen, Jacqueline H.
Object Type: Report
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.
Object Type: Article
System: The UNT Digital Library
Sorting chromatic sextupoles for easily and effectively correcting second order chromaticity in the Relativistic Heavy Ion Collider (open access)

Sorting chromatic sextupoles for easily and effectively correcting second order chromaticity in the Relativistic Heavy Ion Collider

Based on the contributions of the chromatic sextupole families to the half-integer resonance driving terms, we discuss how to sort the chromatic sextupoles in the arcs of the Relativistic Heavy Ion Collider (RHIC) to easily and effectively correct the second order chromaticities. We propose a method with 4 knobs corresponding to 4 pairs of chromatic sextupole families to online correct the second order chromaticities. Numerical simulation justifies this method, showing that this method reduces the unbalance in the correction strengths of sextupole families and avoids the reversal of sextupole polarities. Therefore, this method yields larger dynamic apertures for the proposed RHIC 2009 100GeV polarized proton run lattices.
Date: January 2, 2009
Creator: Luo, Y.; Tepikian, S.; Fischer, W.; Robert-Demolaize, G. & Trbojevic, D.
Object Type: Report
System: The UNT Digital Library
Multipacting Simulation Study for 56 MHz Quarter Wave Resonator using 2D Code (open access)

Multipacting Simulation Study for 56 MHz Quarter Wave Resonator using 2D Code

A beam excited 56 MHz Radio Frequency (RF) Niobium Quarter Wave Resonator (QWR) has been proposed to enhance RHIC beam luminosity and bunching. Being a RF cavity, multipacting is expected; therefore an extensive study was carried out with the Multipac 2.1 2D simulation code. The study revealed that multipacting occurs in various bands up to peak surface electric field 50 kV/m and is concentrated mostly above the beam gap and on the outer conductor. To suppress multipacting, a ripple structure was introduced to the outer conductor and the phenomenon was successfully eliminated from the cavity.
Date: January 2, 2009
Creator: Naik, D. & Ben-Zvi, Ilan
Object Type: Report
System: The UNT Digital Library
Dynamic aperture evaluation of the proposed lattices for the RHIC 2009 polarized proton run (open access)

Dynamic aperture evaluation of the proposed lattices for the RHIC 2009 polarized proton run

In the article we evaluate the dynamic apertures of the proposed lattices for the coming Relativistic Heavy Ion Collider (RHIC) 2009 polarized proton (pp) 100 GeV and 250 GeV runs. One goal of this study is to find out the appropriate {beta}* for the coming 2009 pp runs. Another goal is to study the effect of second order chromaticity correction in the RHIC pp runs.
Date: January 2, 2009
Creator: Luo, Y.; Bai, M.; Beebe-Wang, J.; Fischer, W.; Montag, C.; Robert-Demolaize, G. et al.
Object Type: Report
System: The UNT Digital Library
IBS and Potential Luminosity Improvement for RHIC Operation Below Transition Energy (open access)

IBS and Potential Luminosity Improvement for RHIC Operation Below Transition Energy

There is a strong interest in low-energy RHIC operations in the single-beam total energy range of 2.5-25 GeV/nucleon [1-3]. Collisions in this energy range, much of which is below nominal RHIC injection energy, will help to answer one of the key questions in the field of QeD about the existence and location of a critical point on the QCD phase diagram [4]. There have been several short test runs during 2006-2008 RHIC operations to evaluate RHIC operational challenges at these low energies [5]. Beam lifetimes observed during the test runs were limited by machine nonlinearities. This performance limit can be improved with sufficient machine tuning. The next luminosity limitation comes from transverse and longitudinal Intra-beam Scattering (IBS), and ultimately from the space-charge limit. Detailed discussion of limiting beam dynamics effects and possible luminosity improvement with electron cooling can be found in Refs. [6-8]. For low-energy RHIC operation, particle losses from the RF bucket are of particular concern since the longitudinal beam size is comparable to the existing RF bucket at low energies. However, operation below transition energy allows us to exploit an Intra-beam Scattering (IBS) feature that drives the transverse and longitudinal beam temperatures towards equilibrium by minimizing the longitudinal …
Date: January 2, 2009
Creator: Fedotov,A.
Object Type: Report
System: The UNT Digital Library
Final Technical Report (open access)

Final Technical Report

This research consisted of a theoretical investigation of the properties of surface-based nanostructures, having as a main goal the deeper understanding of the atomic-scale mechanisms responsible for the formation and stability of such structures. This understanding will lead to the design of improved systems for applications in diverse areas such as novel electronic devices, sensors, field-effect transistors, substrates with enhanced hydro-phobic (water repelling) or hydro-philic (water absorbing) behavior for coatings of various surfaces used in bioengineering, flexible displays, organic photovoltaics, etc. The research consisted of developing new theoretical methodologies and applying them to a wide range of interesting physical systems. Highlights of the new methodologies include techniques for bridging different scales, from the quantum-mechanical electronic level to the meso-scopic level of large molecular structures such as DNA, carbon nanotubes and two-dimensional assemblies of organic molecules. These methodologies were successfully applied to investigate interactions between systems that are large on the atomic scale (reaching the scale of microns in length or milliseconds in time), but still incorporating all the essential elements of the atomic-scale structure. While the research performed here did not address applications directly, the implications of its finding are important in guiding experimental searches and in coming up with …
Date: February 2, 2009
Creator: Kaxiras, Efthimios
Object Type: Report
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.
Object Type: Article
System: The UNT Digital Library
Diffusion Simulation and Lifetime Calculation at RHIC (open access)

Diffusion Simulation and Lifetime Calculation at RHIC

The beam lifetime is an important parameter for any storage ring. For protons in RHIC it is dominated by the non-linear nature of the head-on collisions that causes the particles to diffuse outside the stable area in phase space. In this report we show results from diffusion simulation and lifetime calculation for the 2006 and 2008 polarized proton runs in RHIC.
Date: January 2, 2009
Creator: Abreu,N.P.; Fischer, W.; Luo, Y. & Robert-Demolaize, G.
Object Type: Report
System: The UNT Digital Library
56 MHZ Cavity Prototype Measurements (open access)

56 MHZ Cavity Prototype Measurements

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Date: January 2, 2009
Creator: Hahn,H. & Choi, E.
Object Type: Report
System: The UNT Digital Library
The Cost of Transmission for Wind Energy: A Review of Transmission Planning Studies (open access)

The Cost of Transmission for Wind Energy: A Review of Transmission Planning Studies

The rapid development of wind power that the United States has experienced over the last several years has been coupled with a growing concern that wind development will require substantial additions to the nation's transmission infrastructure. Transmission is particularly important for wind power due to the locational dependence of wind resources, the relatively low capacity factor of wind plants, and the mismatch between the short lead time to build a new wind project and the longer lead time often needed to plan, permit, and construct transmission. It is clear that institutional issues related to transmission planning, siting, and cost allocation will pose major obstacles to accelerated wind power deployment, but also of concern is the potential cost of this infrastructure build out. Simply put, how much extra cost will society bear to deliver wind power to load centers? Without an answer to this question, there can be no consensus on whether or not the cost of developing transmission for wind will be a major barrier to further wind deployment, or whether the institutional barriers to transmission expansion are likely to be of more immediate concern. In this report, we review a sample of 40 detailed transmission studies that have included …
Date: February 2, 2009
Creator: Mills, Andrew D.; Wiser, Ryan & Porter, Kevin
Object Type: Report
System: The UNT Digital Library
Development of dopamine receptor radiopharmaceuticals for the study of neurological and psychiatric disorders (open access)

Development of dopamine receptor radiopharmaceuticals for the study of neurological and psychiatric disorders

Our goals in this grant application are directed towards the development of radiotracers that may allow the study of the high-affinity state (functional state) of the dopamine receptors. There have been numerous reports on the presence of two inter-convertible states of these (G-protein coupled) receptors in vitro. However, there is no report that establishes the presence of these separate affinity states in vivo. We have made efforts in this direction in order to provide such direct in vivo evidence about the presence of the high affinity state. This understanding of the functional state of the receptors is of critical significance in our overall diagnosis and treatment of diseases that implicate the G-protein coupled receptors. Four specific aims have been listed in the grant application: (1). Design and syntheses of agonists (2). Radiosyntheses of agonists (3). In vitro pharmacology of agonists (4). In vivo distribution and pharmacology of labeled derivatives. We have accomplished the syntheses and radiosyntheses of three agonist radiotracers labeled with carbon-11. In vitro and in vivo pharmacological experiments have been accomplished in rats and preliminary PET studies in non-human primates have been carried out. Various accomplishments during the funded years, briefly outlined in this document, have been disseminated …
Date: January 2, 2009
Creator: Mukherjee, Dr. Jogeshwar
Object Type: Report
System: The UNT Digital Library
Effects of Booster Scraping in Polarized Proton Runs 2006 and 2008 (open access)

Effects of Booster Scraping in Polarized Proton Runs 2006 and 2008

Effects of the Booster vertical scraping on the RHIC beam polarization, the RHIC beam emittance, and on the Booster to AGS transfer efficiency and AGS transmission as well, are further studied. In [1], the strong dependence of the RHIC beam polarization and emittance on bunch intensity in proton run 2008 (pp08) is compared with the proton run 2006 (pp06), where the dependence is much weaker. The setting in the AGS Booster, mainly the vertical scraping, is suspected to having played a role in the different patterns in the two runs. In this note, we further study the effects of the Booster vertical scraping on the RHIC beam polarization, and on the RHIC beam emittance as well. With the improvement of the RHIC bunch intensity in mind, the Booster scraping effects on the Booster to AGS transfer (BtA) efficiency and the AGS transmission are also studied. For simplicity and to be more useful, only the RHIC fills after the one-week shutdown in pp06 and the fills using the AGS User 2 in pp08 are shown. For these fills, the machine settings in AGS are similar in pp06 and pp08 runs. Furthermore, this setting might be used for next polarized proton run, …
Date: January 2, 2009
Creator: Zhang, S. Y.; Ahrens, L.; Huang, H. & Zeno, K.
Object Type: Report
System: The UNT Digital Library
Cryogenic and Crysostat System for the 56 MHZ SRF Cavity (open access)

Cryogenic and Crysostat System for the 56 MHZ SRF Cavity

This report addresses the cryogenic and cryostat system for the 56 MHZ SRF Cavity
Date: January 2, 2009
Creator: Than,R.
Object Type: Report
System: The UNT Digital Library
Final Report SBIR Phase I, Improvement of Properties of Tubular Internal-Tin Nb3Sn (open access)

Final Report SBIR Phase I, Improvement of Properties of Tubular Internal-Tin Nb3Sn

Final report of SBIR to develop an economical process that can produce the best material for high field magnets to be used in the next generation of accelerators.
Date: February 2, 2009
Creator: Gregory,Eric
Object Type: Report
System: The UNT Digital Library
Energy Scaling of Spin Tune due to RHIC Snakes (open access)

Energy Scaling of Spin Tune due to RHIC Snakes

For a ring like RHIC with two full Siberian snakes on opposite sides of the ring, the spin tune for a flat orbit will be 1/2 if the snake rotation axes are perpendicular, {Delta}{phi} = {phi}{sub 9}-{phi}{sub 3} = {pi}/2. Here {phi}{sup 9} and {phi}{sub 3} are respectively the direction of the rotation axes of the 9 o'clock and 3 o'clock snakes relative to the design trajectory as shown in Figure 1. If the two snakes are slightly detuned by the same amount such that the rotation axes are no longer perpendicular, then the deviation of the closed-orbit spin tune {nu}{sub 0} from 1/2 is given by {Delta}{nu}{sub 0} {approx_equal} ({Delta}{mu}){sup 2}/4{pi} cosG{gamma}{pi} - 2{Delta}{phi}/{pi} {approx_equal} 2{Delta}{phi}/180{sup o} with G{gamma} at a half integer, and where {Delta}{mu} is the deviation of snake rotation angle from 180{sup o}. It should be noted that there is a sign ambiguity in {Delta}{mu}{sub 0} since a spin tune of 0.495 is also a spin tune of 0.505, depending on the direction taken along the stable spin axis. In order to understand the effect of energy scaling on the snake axis direction, I have integrated the trajectory and spin rotation through a model of a …
Date: January 2, 2009
Creator: MacKay, W. W.
Object Type: Report
System: The UNT Digital Library
iTOUGH2-IFC: An Integrated Flow Code in Support of Nagra's Probabilistic Safety Assessment:--User's Guide and Model Description (open access)

iTOUGH2-IFC: An Integrated Flow Code in Support of Nagra's Probabilistic Safety Assessment:--User's Guide and Model Description

This document describes the development and use of the Integrated Flow Code (IFC), a numerical code and related model to be used for the simulation of time-dependent, two-phase flow in the near field and geosphere of a gas-generating nuclear waste repository system located in an initially fully water-saturated claystone (Opalinus Clay) in Switzerland. The development of the code and model was supported by the Swiss National Cooperative for the Disposal of Radioactive Waste (Nagra), Wettingen, Switzerland. Gas generation (mainly H{sub 2}, but also CH{sub 4} and CO{sub 2}) may affect repository performance by (1) compromising the engineered barriers through excessive pressure build-up, (2) displacing potentially contaminated pore water, (3) releasing radioactive gases (e.g., those containing {sup 14}C and {sup 3}H), (4) changing hydrogeologic properties of the engineered barrier system and the host rock, and (5) altering the groundwater flow field and thus radionuclide migration paths. The IFC aims at providing water and gas flow fields as the basis for the subsequent radionuclide transport simulations, which are performed by the radionuclide transport code (RTC). The IFC, RTC and a waste-dissolution and near-field transport model (STMAN) are part of the Integrated Radionuclide Release Code (IRRC), which integrates all safety-relevant features, events, and …
Date: January 2, 2009
Creator: Finsterle, Stefan A.
Object Type: Report
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.
Object Type: Article
System: The UNT Digital Library
Superconducting Storage Cavity for RHIC (open access)

Superconducting Storage Cavity for RHIC

This document provides a top-level description of a superconducting cavity designed to store hadron beams in the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. It refers to more detailed documents covering the various issues in designing, constructing and operating this cavity. The superconducting storage cavity is designed to operate at a harmonic of the bunch frequency of RHIC at a relatively low frequency of 56 MHz. The current storage cavities of RHIC operate at 197 MHz and are normal-conducting. The use of a superconducting cavity allows for a high gap voltage, over 2 MV. The combination of a high voltage and low frequency provides various advantages stemming from the resulting large longitudinal acceptance bucket.
Date: January 2, 2009
Creator: Ben-Zvi, Ilan
Object Type: Report
System: The UNT Digital Library
Simulation of Electron Cloud Density Distributions in RHIC Dipoles at Injection and Transition and Estimates for Scrubbing Times (open access)

Simulation of Electron Cloud Density Distributions in RHIC Dipoles at Injection and Transition and Estimates for Scrubbing Times

In this report we summarize electron-cloud simulations for the RHIC dipole regions at injection and transition to estimate if scrubbing over practical time scales at injection would reduce the electron cloud density at transition to significantly lower values. The lower electron cloud density at transition will allow for an increase in the ion intensity.
Date: January 2, 2009
Creator: He, P.; Blaskiewicz, M. & Fischer, W.
Object Type: Report
System: The UNT Digital Library