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in subjects: "Positron Collisions"  
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Hadron production by e/sup +/e/sup -/ annihilation at center-of-mass energies between 2. 6 and 7. 8 GeV

Description: Results are presented on multihadron production by e/sup +/e/sup -/ annihilation from the Mark I and Mark II detectors at SPEAR. Other than the narrow resonances psi (3095) and psi' (3684), the total hadronic cross section varies between 36.5 and 6.4 nb over the center-of-mass energy range 2.6 to 7.8 GeV with complicated structure near 4.1 GeV not completely resolved by these measurements. Evidence for scaling of inclusive momentum distributions of hadrons is presented.
Date: October 1, 1979
Creator: Siegrist, J.L.
Partner: UNT Libraries Government Documents Department
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Opportunities and requirements for experimentation at high energy e/sup +/e/sup /minus// collider

Description: Over the past fifteen years of high-energy physics, electron-positron annihilation has been the most productive of all reactions probing the fundamental interactions. The e/sup +/e/sup /minus// annihilation process is unique in offering at the same time copious production of novel particles, low backgrounds from more conventional physics, and the most efficient use of the energy which an accelerator provides. These features have allowed the detailed characterization of the charm and bottom quar… more
Date: May 1, 1988
Creator: Ahn, C.; Baltay, C.; Barklow, T. L.; Burchat, P. R.; Burke, D. L.; Cooper, A. R. et al.
Partner: UNT Libraries Government Documents Department
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Calculated photon spectra at several angles for 5- and 50-MeV electron beams striking solid and gas targets

Description: Coupled electron-photon transport calculations have been carried out to simulate the photon generation when a 5- or 50-MeV electron beam strikes a solid or gas target. Results indicate that a 5-MeV beam striking targets of tungsten wire, air, or air doped with Kr or Xe generates a photon spectrum sharply peaked in the forward direction and with approximately 1/E spectral intensity. At right angles to the beam the photon intensity is predominantly due to characteristic K x-rays. A 50-MeV beam st… more
Date: February 24, 1983
Creator: Slaughter, Dennis R.
Partner: UNT Libraries Government Documents Department
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Klystron switching power supplies for the Internation Linear Collider

Description: The International Linear Collider is a majestic High Energy Physics particle accelerator that will give physicists a new cosmic doorway to explore energy regimes beyond the reach of today's accelerators. ILC will complement the Large Hadron Collider (LHC), a proton-proton collider at the European Center for Nuclear Research (CERN) in Geneva, Switzerland, by producing electron-positron collisions at center of mass energy of about 500 GeV. In particular, the subject of this dissertation is the R&… more
Date: December 1, 2009
Creator: Fraioli, Andrea & /Cassino U. /INFN, Pisa
Partner: UNT Libraries Government Documents Department
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Use of Simulation for the Programs for the Modeling of the Next Linear Collider

Description: The Next Linear Collider is an electron-positron accelerator unprecedented in its size, energy, and tight tolerances. We describe the suite of simulation tools which are widely used in designing and modeling the performance of the NLC. In order to achieve a uniform beamline description and permit simulation of all facets of the collider, an extended version of the Standard Input Format (xSIF) has been developed and implemented in MAD and DIMAD. We discuss several enhancements to the MAD and DIM… more
Date: April 23, 1999
Creator: Tenenbaum, Peter G
Partner: UNT Libraries Government Documents Department
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RIKEN WINTER SCHOOL: STRUCTURE OF HADRONS - INTRODUCTION TO QCD HARD PROCESSES. PROCEEDINGS OF RIKEN BNL RESEARCH CENTER WORKSHOP, DECEMBER 9-12, 1998.

Description: In this lecture I give a pedagogical introduction to the Perturbative QCD to understand the short-distance dynamics of the strong interaction. Starting with fundamental concepts such as the color degree of freedom of QCD, non-abelian gauge field theory, renormalization group equation etc., I explain a basic idea of the perturbative QCD and apply this idea to the e{sup +}e{sup {minus}} processes and the structure functions. The notion of mass singularity and the necessity of its factorization is… more
Date: December 9, 1999
Creator: Saito, N.
Partner: UNT Libraries Government Documents Department
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Study of the Structure of e{sup +}e{sup {minus}} {r_arrow} b{bar b}g Events and Improved Limits on the Anomalous Chromomagnetic Coupling of the b-Quark

Description: The structure of e{sup +}e{sup {minus}} {r_arrow} b{bar b}g events was studied using Z{sup 0} decays recorded in the SLD experiment at SLAC. Three-jet final states were selected and the CCD-based vertex detector was used to identify two of the jets as b or {bar b}. Distributions of the gluon energy and polar angle were measured over the full kinematic range, and compared with perturbative QCD predictions. The energy distribution is potentially sensitive to an anomalous b chromomagnetic moment {… more
Date: July 9, 1999
Creator: Muller, David
Partner: UNT Libraries Government Documents Department
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High-resolution positron Q-value measurements and nuclear-structure studies far from the stability line. Progress report

Description: Extensive data analysis and theoretical analysis has been done to complete the extensive decay scheme investigation of /sup 206/ /sup 208/Fr and the level structures of /sup 206/ /sup 208/Rn. A final version of a journal article is presented in preprint form. Extensive Monte Carlo calculations have been made to correct the end point energies of positron spectra taken with intrinsic Ge detectors for annihilation radiation interferences. These calculations were tested using the decay of /sup 82/S… more
Date: February 28, 1981
Creator: Avignone, F. T. III
Partner: UNT Libraries Government Documents Department
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Production of pseudoscalar Higgs-bosons in e {gamma} collisions

Description: We investigate the production of a pseudoscalar Higgs-boson A{sup 0} using the reaction e{gamma} {yields} e A{sup 0} at an e{bar e} collider with center of mass energy of 500 GeV. Supersymmetric contributions are included and provide a substantial enhancement to the cross section for most values of the symmetry breaking parameters. We find that, despite the penalty incurred in converting one of the beams into a source of backscattered photons, the e{gamma} process is a promising channel for the… more
Date: August 21, 1995
Creator: Dicus, D.A. & Repko, W.W.
Partner: UNT Libraries Government Documents Department
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An Investigation of Positrons Interacting With Solid Argon, Krypton and Xenon

Description: With this article we intend to shed some light on all the important characteristics of the up-to-date most efficient positron moderators, the rare gas solids. We stress on the importance of the impurities in the performance of the solid rare gas moderators. The impurity factor is linked with the crystalline changes to explain the effect of annealing, and demonstrate the role of impurities in the endurance. Significant increase in the low energy positron yield is observed after repeated anneals.… more
Date: October 1, 1996
Creator: Petkov, M. P.; Roellig, L. O.; Troev, T. D. & Lynn, K. G.
Partner: UNT Libraries Government Documents Department
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NLC positron production target

Description: The NLC (Next Linear Collider, proposed) is optimized with respect to positron yield, target integrity, cooling, and shielding. Copper is proposed as a possible optimal choice.
Date: May 1, 1996
Creator: Krivosheev, O.E.; Mokhov, N.V. & Striganov, S.I.
Partner: UNT Libraries Government Documents Department
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Conformal Symmetry as a Template:Commensurate Scale Relations and Physical Renormalization Schemes

Description: Commensurate scale relations are perturbative QCD predictions which relate observable to observable at fixed relative scale, such as the ''generalized Crewther relation'', which connects the Bjorken and Gross-Llewellyn Smith deep inelastic scattering sum rules to measurements of the e{sup +}e{sup {minus}} annihilation cross section. We show how conformal symmetry provides a template for such QCD predictions, providing relations between observables which are present even in theories which are no… more
Date: June 9, 1999
Creator: Brodsky, Stanley J.
Partner: UNT Libraries Government Documents Department
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Measurement of Small Electron Beam Spots

Description: Measurements of transverse beam size are tremendously important to the performance of e{sup +}e{sup {minus}} linear colliders. In this paper we review the traditional technologies used to make such measurements, such as profile monitors and wire scanners, and the limitations on same. We then introduce a new tool for electron beam size measurement: Compton-scattered laser light, which may be used as an unbreakable ''wire'' or in the form of an interferometer beam size monitor. We describe the us… more
Date: February 3, 1999
Creator: Tenenbaum, Peter G
Partner: UNT Libraries Government Documents Department
open access

Studies of Nonlinear QED in Collisions of 46.6 Electrons with Intense LaserPulses

Description: We report on measurements of quantum electrodynamic processes in an intense electromagnetic wave, where nonlinear effects (both multiphoton and vacuum polarization) are prominent. Nonlinear Compton scattering and electron-positron pair production have been observed in collisions of 46.6 GeV and 49.1 GeV electrons of the Final Focus Test Beam at SLAC with terawatt pulses of 1053 nm and 527 nm wavelengths from a Nd:glass laser. Peak laser intensities of approximately 0.5 x 10{sup 18} W/cm{sup 2} … more
Date: February 16, 1999
Creator: McDonald, Kirk T.
Partner: UNT Libraries Government Documents Department
open access

Electroweak Precision Measurements and Collider Probes of the Standard Model with Large Extra Dimensions

Description: The elementary particles of the Standard Model may live in more than 3+1 dimensions. We study the consequences of large compactified dimensions on scattering and decay observables at high-energy colliders. Our analysis includes global fits to electroweak precision data, indirect tests at high-energy electron-positron colliders (LEP2 and NLC), and direct probes of the Kaluza-Klein resonances at hadron colliders (Tevatron and LHC). The present limits depend sensitively on the Higgs sector, both t… more
Date: June 3, 1999
Creator: Rizzo, Thomas G.
Partner: UNT Libraries Government Documents Department
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New Tests of Perturbative QCD Inspired by Hypothetical Tau Leptons

Description: Inspired by the relation between the hadronic decay of the {tau} lepton and the e{sup +}e{sup {minus}} annihilation into hadrons, we derive new tests of perturbative QCD. We design a set of commensurate scale relations to test the self-consistency of leading-twist QCD predictions for any observable which defines an effective charge. This method provides renormalization scheme and scale invariant probes of QCD which can be applied over wide data ranges.
Date: May 24, 1999
Creator: Brodsky, Stanley J.
Partner: UNT Libraries Government Documents Department
open access

Using Scalars to Probe Theories of Low Scale Quantum Gravity

Description: Arkani-Hamed, Dimopoulos and Dvali have recently suggested that gravity may become strong at energies near 1 TeV which would remove the hierarchy problem. Such a scenario can be tested at present and future colliders since the exchange of towers of Kaluza-Klein gravitons leads to a set of new dimension-8 operators that can play important phenomenological roles. In this paper we examine how the production of pairs of scalars at e{sup +}e{sup {minus}}, {gamma}{gamma} and hadron colliders can be u… more
Date: March 24, 1999
Creator: Rizzo, Thomas G.
Partner: UNT Libraries Government Documents Department
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Proceedings of RIKEN BNL Research Center Workshop: Brookhaven Summer Program on Quarkonium Production in Elementary and Heavy Ion Collisions

Description: Understanding the structure of the hadron is of fundamental importance in subatomic physics. Production of heavy quarkonia is arguably one of the most fascinating subjects in strong interaction physics. It offers unique perspectives into the formation of QCD bound states. Heavy quarkonia are among the most studied particles both theoretically and experimentally. They have been, and continue to be, the focus of measurements in all high energy colliders around the world. Because of their distinct… more
Date: August 3, 2011
Creator: Dumitru, A.; Lourenco, C.; Petreczky, P.; Qiu, Jianwei & Ruan, Lijuan
Partner: UNT Libraries Government Documents Department
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