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in publisher: "Stanford Linear Accelerator Center"  
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Radiation monitoring with CVD Diamonds and PIN Diodes at BaBar

Description: The BaBar experiment at the Stanford Linear Accelerator Center has been using two polycrystalline chemical vapor deposition (pCVD) diamonds and 12 silicon PIN diodes for radiation monitoring and protection of the Silicon Vertex Tracker (SVT). We have used the pCVD diamonds for more than 3 years, and the PIN diodes for 7 years. We will describe the SVT and SVT radiation monitoring system as well as the operational difficulties and radiation damage effects on the PIN diodes and pCVD diamonds in a… more
Date: February 13, 2008
Creator: Bruinsma, M.; Burchat, P.; Curry, S.; Edwards, A.J.; Kagan, H.; Kass, R. et al.
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Partner: UNT Libraries Government Documents Department
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Charmless Two-Body and Quasi-Two-Body B-decays at BABAR

Description: The authors present improved measurements of the branching fractions and CP asymmetries in the two-body decays B{sup 0} {yields} {pi}{sup 0}{pi}{sup 0}, B{sup 0} {yields} K{sup 0}{pi}{sup 0} and B{sup 0} {yields} K{sup +}{pi}{sup -} as well as the quasi two-body B{sup 0} {yields} K{sub 1}(1270){sup +} {pi}{sup -} and B{sup 0} {yields} K{sub 1}(1400){sup +} {pi}{sup -} decays. These updated measurements are made using the complete set of BABAR data taken at the Y(4S) resonance, collected between… more
Date: October 13, 2008
Creator: Ofte, Ingrid
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Partner: UNT Libraries Government Documents Department
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Machine-Detector Interface Issues for the ILCPolarimeters

Description: This note examines several Machine-Detector Interface (MDI) issues for the Compton polarimeters in the Beam Delivery System of the International Linear Collider (ILC), including (1) alignment tolerances, (2) impact of crossing angle and IR magnets on spin alignment, (3) Z-pole operation, and (4) costs and conventional facilities.
Date: June 13, 2008
Creator: Woods, Mike
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Partner: UNT Libraries Government Documents Department
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The AdS/CFT Correspondence and Light-Front QCD

Description: We identify an invariant light-front coordinate {zeta} which allows the separation of the dynamics of quark and gluon binding from the kinematics of constituent spin and internal orbital angular momentum. The result is a single-variable light-front Schroedinger equation for QCD which determines the eigenspectrum and the light-front wavefunctions of hadrons for general spin and orbital angular momentum. This frame-independent light-front wave equation is equivalent to the equations of motion whi… more
Date: October 13, 2008
Creator: Brodsky, Stanley J. & de Teramond, Guy F.
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Partner: UNT Libraries Government Documents Department
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Unexpected Cancellations in Gravity Theories

Description: Recent computations of scattering amplitudes show that N = 8 supergravity is surprisingly well behaved in the ultraviolet and may even be ultraviolet finite in perturbation theory. The novel cancellations necessary for ultraviolet finiteness first appear at one loop in the guise of the ''no-triangle hypothesis''. We study one-loop amplitudes in pure Einstein gravity and point out the existence of cancellations similar to those found previously in N = 8 supergravity. These cancellations go beyon… more
Date: July 13, 2007
Creator: Bern, Z.; Carrasco, J.J.; /UCLA; Forde, D.; /SLAC, /UCLA; Ita, H. et al.
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Partner: UNT Libraries Government Documents Department
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Faint Radio Sources in the NOAO Bootes Field. VLBA Imaging And Optical Identifications

Description: As a step toward investigating the parsec-scale properties of faint extragalactic radio sources, the Very Long Baseline Array (VLBA) was used at 5.0 GHz to obtain phase-referenced images of 76 sources in the NOAO Booetes field. These 76 sources were selected from the FIRST catalog to have peak flux densities above 10 mJy at 5'' resolution and deconvolved major diameters of less than 3'' at 1.4 GHz. Fifty-five of these faint radio sources were identified with accretion-powered radio galaxies and… more
Date: June 13, 2005
Creator: Wrobel, J. M.; /NRAO, Socorro; Taylor, Greg B.; /NRAO, Socorro /KIPAC, Menlo Park; Rector, T. A.; /NRAO, Socorro /Alaska U. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Mechanical Design of the LSST Camera

Description: The LSST camera is a tightly packaged, hermetically-sealed system that is cantilevered into the main beam of the LSST telescope. It is comprised of three refractive lenses, on-board storage for five large filters, a high-precision shutter, and a cryostat that houses the 3.2 giga-pixel CCD focal plane along with its support electronics. The physically large optics and focal plane demand large structural elements to support them, but the overall size of the camera and its components must be minim… more
Date: June 13, 2008
Creator: Nordby, Martin; Bowden, Gordon; Foss, Mike; Guiffre, Gary; Ku, John & Schindler, Rafe
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Lattice and Collective Effects for PEP-X

Description: This is a more comprehensive report of the accelerator physics in the white paper 'PEP-X Light Source at SLAC'. A new light source called 'PEP-X' would reside in the 2.2-km PEP-II tunnel. It has a hybrid lattice where two of its six arcs contain DBA cells that provide a total of 30 straight sections for insertion device beam lines and the remaining arcs contain TME cells for an extremely low emittance. Using 90 meter damping wigglers the horizontal emittance at 4.5 GeV is further reduced to 0.1… more
Date: May 13, 2008
Creator: Bane, Karl; Cai, Yunhai; Chao, Alex; Hettel, Robert; Huang, Zhirong; Nosochkov, Yuri et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Chandra Reveals Twin X-ray Jets in the Powerful FR-II Radio Galaxy 3C353

Description: We report X-ray imaging of the powerful FR II radio galaxy 3C 353 using the Chandra X-ray Observatory. 3C 353's two 4-inch wide and 2-feet long jets allow us to study in detail the internal structure of the large-scale relativistic outflows at both radio and X-ray photon energies with the sub-arcsecond spatial resolution provided by the VLA and Chandra instruments. In a 90 ks Chandra observation, we have detected X-ray emission from most radio structures in 3C 353, including the nucleus, the je… more
Date: June 13, 2008
Creator: Kataoka, J.; Stawarz, L.; Harris, D.E.; Siemiginowska, A.; Ostrowski, M.; Swain, M.R. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Recent Developments in Impact and Application to Future Light Sources

Description: This paper discusses two recently added capabilities of the IMPACT suite that are relevant to modeling electron linacs, namely the new 1D coherent synchrotron radiation (CSR) modeling capability and the integrated Green's function (IFG) algorithm for modeling high aspect ratio beams. In addition, we present initial results of application of the enhanced version of IMPACT-Z to high-fidelity modeling of the microbunching instability in a realistic light source lattice.
Date: February 13, 2008
Creator: Pogorelov, I.; Qiang, J.; Ryne, R.; Venturini, M.; Zholents, A. & Warnock, R.
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Partner: UNT Libraries Government Documents Department
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MAXI and GLAST Studies of Jets in Active Galaxies

Description: The recent launch of GLAST--coinciding with the MAXI workshop--opens a new era for studies of jet-dominated active galaxies, known as blazars. While the emission processes operating in various spectral bands in blazars are reasonably well understood, the knowledge of the details of the structure of the jet, location of the dissipation region with respect to the accreting black hole, and coupling of the jet to the accretion process are known only at a rudimentary level. Blazars are variable, and… more
Date: October 13, 2008
Creator: Madejski, Greg; Kataoka, Jun & Sikora, Marek
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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The work function of sub-monolayer cesium-covered gold: A photoelectronspectroscopy study

Description: Using visible and X-ray photoelectron spectroscopy we measured the work function of a Au(111) surface at a well-defined sub-monolayer coverage of Cs. For a Cs coverage producing a photoemission maximum with a He-Ne laser, the work function is 1.61 {+-} 0.08 eV consistent with previous assumptions used to analyze vibrationally promoted electron emission. A discussion of possible Cs layer structures is also presented.
Date: June 13, 2008
Creator: LaRue, J. L.; White, J. D.; Nahler, N. H.; Liu, Z.; Sun, Y.; Pianetta, P. A. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Measurement of \mathcal{B}(\tau^{-}\-->\bar{K^{0}}\pi^{-}\nu_{\tau}) Using the \babar Detector

Description: A preliminary measurement of the branching fraction {Beta}({tau}{sup -} {yields} K{sub S}{sup 0}{pi}{sup -}{nu}{sub {tau}}) is made using 384.6 fb{sup -1} of e{sup +}e{sup -} collision data provided by the PEP-II collider, operating primarily at {radical}s = 10.58 GeV, and recorded using the BABAR detector. From this they measure: {Beta}({tau}{sup -} {yields} {bar K}{sup 0}{pi}{sup -}{nu}{sub {tau}}) = (0.840 {+-} 0.004(stat) {+-} 0.023(syst))%. This result is the most precise measurement to da… more
Date: August 13, 2008
Creator: Wren, A
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Identification of the Origin of Monojet Signatures at the LHC

Description: Several new physics scenarios can lead to monojet signatures at the LHC. If such events are observed above the Standard Model background it will be important to identify their origin. In this paper we compare and contrast these signatures as produced in two very different pictures: vector or scalar unparticle production in the scale-invariant/conformal regime and graviton emission in the Arkani-Hamed, Dimopoulos and Dvali extra-dimensional model. We demonstrate that these two scenarios can be d… more
Date: May 13, 2008
Creator: Rizzo, Thomas G.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Constraining Cosmic Evolution of Type Ia Supernovae

Description: We present the first large-scale effort of creating composite spectra of high-redshift type Ia supernovae (SNe Ia) and comparing them to low-redshift counterparts. Through the ESSENCE project, we have obtained 107 spectra of 88 high-redshift SNe Ia with excellent light-curve information. In addition, we have obtained 397 spectra of low-redshift SNe through a multiple-decade effort at Lick and Keck Observatories, and we have used 45 ultraviolet spectra obtained by HST/IUE. The low-redshift spect… more
Date: February 13, 2008
Creator: Foley, Ryan J.; Filippenko, Alexei V.; Aguilera, C.; Becker, A. C.; Blondin, S.; Challis, P. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Observation of B0 -> chi_c0 K*0 and Evidence of B+ -> chi_c0 K*+

Description: The authors present the observation of the decay B{sup 0} {yields} {chi}{sub c0}K*{sup 0} as well as evidence of B{sup +} {yields} {chi}{sub c0}K*{sup +}, with an 8.9 and a 3.6 standard deviation significance, respectively, using a data sample of 454 million {Upsilon}(4S) {yields} B{bar B} decays collected with the BABAR detector at the PEP-II B meson factory located at the Standard Linear Accelerator Center (SLAC). The measured branching fractions are: {Beta}(B{sup 0} {yields} {chi}{sub c0}K*{… more
Date: August 13, 2008
Creator: Aubert, B.
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Partner: UNT Libraries Government Documents Department
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Hosing Instability in the Blow-Out Regime for Plasma-Wakefield Acceleration

Description: The electron hosing instability in the blow-out regime of plasma-wakefield acceleration is investigated using a linear perturbation theory about the electron blow-out trajectory in Lu et al. [in Phys. Rev. Lett. 96, 165002 (2006)]. The growth of the instability is found to be affected by the beam parameters unlike in the standard theory Whittum et al. [Phys. Rev. Lett. 67, 991 (1991)] which is strictly valid for preformed channels. Particle-in-cell simulations agree with this new theory, which … more
Date: February 13, 2008
Creator: Huang, C.; Lu, W.; Zhou, M.; Clayton, C. E.; Joshi, C.; Mori, W.B. et al.
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Partner: UNT Libraries Government Documents Department
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Beam Dynamics Challenges for the ILC

Description: The International Linear Collider (ILC) is a proposal for 500 GeV center-of-mass electron-positron collider, with a possible upgrade to {approx}1 TeV center-of-mass. At the heart of the ILC are the two {approx}12 km 1.3 GHz superconducting RF (SCRF) linacs which will accelerate the electron and positron beams to an initial maximum energy of 250 GeV each. The Global Design Effort (GDE)--responsible for the world-wide coordination of this uniquely international project--published the ILC Referenc… more
Date: February 13, 2008
Creator: Kubo, Kiyoshi; /KEK, Tsukuba; Seryi, Andrei; /SLAC; Walker, Nicholas; /DESY et al.
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Partner: UNT Libraries Government Documents Department
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On Projecting Discretized Electromagnetic Fields with Unstructured Grids

Description: A new method for projecting discretized electromagnetic fields on one unstructured grid to another grid is presented in this paper. Two examples are used for studying the errors of different projection methods. The analysis shows that the new method is very effective on balancing both the error of the electric field and that of the magnetic field (or curl of the electric field).
Date: August 13, 2008
Creator: Lee, Lie-Quan; Candel, Arno; Kabel, Andrea & Li, Zenghai
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Search for b\to u Transitions in \Bz \to \Dz \Kstarz Decays

Description: We present a study of the decays B{sup 0} {yields} D{sup 0} K*{sup 0} and B{sup 0} {yields} {bar D}{sup 0} K*{sup 0} with K*{sup 0} {yields} K{sup +}{pi}{sup -}. The D{sup 0} and the {bar D}{sup 0} mesons are reconstructed in the final states f = K{sup +} {pi}{sup -}, K{sup +}{pi}{sup -}{pi}{sup 0}, K{sup +}{pi}{sup -}{pi}{sup +}{pi}{sup -} and their charge conjugates. Using a sample of 465 million B{bar B} pairs collected with the BABAR detector at PEP-II asymmetric-energy e{sup +}e{sup -} col… more
Date: April 13, 2009
Creator: Aubert, B.; Bona, M.; Karyotakis, Y.; Lees, J. P.; Poireau, V.; Prencipe, E. et al.
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Partner: UNT Libraries Government Documents Department
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Evidence for Nodal Superconductivity in LaFePO from Scanning SQUID Susceptometry

Description: We measure changes in the penetration depth {lambda} of the T{sub c} {approx} 6 K superconductor LaFePO. In the process scanning SQUID susceptometry is demonstrated as a technique for accurately measuring local temperature-dependent changes in {lambda}, making it ideal for studying early or difficult-to-grow materials. {lambda} of LaFePO is found to vary linearly with temperature from 0.36 to {approx} 2 K, with a slope of 143 {+-} 15 {angstrom}/K, suggesting line nodes in the superconducting or… more
Date: April 13, 2009
Creator: Hicks, Clifford W.; Lippman, Thomas M.; /Stanford U., Geballe Lab. /SLAC; Huber, Martin E.; /Colorado U., Denver; Analytis, James G. et al.
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Partner: UNT Libraries Government Documents Department
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Calculation of Photoneutrons from Varian Clinac Accelerators and Their Transmissions in Materials

Description: Monte Carlo calculations of the giant-dipole-resonance photoneutrons (GRN) around the Varian Clinac 2100C/2300C medical accelerator heads (10-20 MV modes) were made using the coupled EGS4-MORSE code. The actual head materials and geometries were simulated in great detail using the Combinatorial Geometry facility of MORSE. The neutron production (i.e., sites and yields) was calculated with EGS4 and, then, the neutron transport in the accelerator head was done with MORSE. Both the evaporation and… more
Date: November 13, 2006
Creator: Liu, J. C.; Kase, K. R.; Mao, X. S.; Nelson, W. R.; Kleck, J. H. & Johnson, S.
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Partner: UNT Libraries Government Documents Department
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