The Left-hand Forward-backward Asymmetry of Heavy Quarks Measured with Jet Charge and with Leptons at the SLD.

The Left-hand Forward-backward Asymmetry of Heavy Quarks Measured with Jet Charge and with Leptons at the SLD. PDF Author:
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Category :
Languages : en
Pages :

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The Left-right Forward-backward Asymmetry of Heavy Quarks Measured with Jet Charge and with Leptons at the SLD.

The Left-right Forward-backward Asymmetry of Heavy Quarks Measured with Jet Charge and with Leptons at the SLD. PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 7

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The authors present direct measurements of the left-right asymmetry of b- and c-quarks from the decay of Z° bosons produced in the annihilation of longitudinally polarized electrons and unpolarized positrons. Two complementary techniques are presented: (1) Z° --> b{bar b} decays are tagged using track impact parameters with b{bar b} discrimination provided by momentum-weighted track charge; (2) semileptonic b-decays are tagged using high p and p{sub T} muons and electrons. The preliminary results from their 1993 data sample are: A{sub b} = 0.93 " 0.13 " 0.13 for the jet charge and A{sub b} = 0.93 " 0.14 " 0.09, and A{sub c} = 0.40 " 0.23 " 0.20 for the leptons, where the first error is statistical and the second systematic.

Lepton-photon Interactions, Lp'97 - Proceedings Of The Xviii International Symposium

Lepton-photon Interactions, Lp'97 - Proceedings Of The Xviii International Symposium PDF Author: Albert De Roeck
Publisher: World Scientific
ISBN: 9814545120
Category :
Languages : en
Pages : 778

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This book constitutes the proceedings of the XVIII International Symposium on Lepton-Photon Interactions. It contains 30 review papers on the latest developments by experts in the field. The subjects cover the structure of photons and hadrons, progress in QCD and diffraction, heavy quark (c, b, t) physics, electroweak precision measurements and tests, CP violation, neutrino physics, searches for new particles and phenomena, cosmology, progress in theory and physics at future colliders.

Measurement of the Polarized Forward-backward Asymmetry of B Quarks Using Momentum-weighted Track Charge at SLD.

Measurement of the Polarized Forward-backward Asymmetry of B Quarks Using Momentum-weighted Track Charge at SLD. PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 132

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This thesis presents a direct measurement of the parity-violating parameter A{sub b} by analyzing the polarized forward-backward asymmetry of b quarks in ee− --> Z° --> b{bar b}. Data were taken at the Stanford Linear Accelerator Center (SLAC), with the Stanford Large Detector (SLD), which records the products of ee− interactions at a center of mass energy (square root)s = 91.2 GeV/c2 at the SLAC Linear Collider (SLC). The SLC/SLD experimental apparatus provides a unique and ideal environment for measuring electroweak asymmetries. Heavy flavor decays of the Z° were identified inclusively by taking advantage of the long lifetime of B hadrons, the small, stable SLC beam spot, and SLD's precise tracking detectors. Two analysis techniques for measuring A{sub b} are presented: a binned fit to the left-right forward-backwards asymmetry of tagged events signed with momentum-weighted track charge, and a self-calibrating maximum-likelihood technique using momentum-weighted charge from the two hemispheres in each tagged event. From our 1994-1995 sample of 3.6 pb−1, having a luminosity-weighted average e− polarization of 77.3%, and our 1993 sample of 1.8 pb−1, having a luminosity-weighted polarization of 63.1%, we obtain A{sub b} = 0.848 " 0.046(stat.) " 0.050(syst.).

Measurement of the Polarized Forward-backward Asymmetry of B Quarks at SLD.

Measurement of the Polarized Forward-backward Asymmetry of B Quarks at SLD. PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 134

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This thesis presents a direct measurement of the parity-violating parameter A{sub b} using the Left-Right Forward-Backward asymmetry of b{anti b} pair production at the Z° pole. The measurement was done at the Stanford Linear Accelerator Center (SLAC) using data from the SLAC Large Detector (SLD). The authors take advantage of the high polarization of the SLAC Linear Collider (SLC) electron beam. To identify heavy flavor decays of the Z°, they use a b-tag based on the topological reconstruction of the mass of the B vertex. Discrimination between the b and {anti b} quark directions is provided by a self-calibrating jet-charge technique. This technique allows calibration of the analyzing power from data and gives a much reduced model dependence. Based on the 1994--95 (1993) sample of 100,000 (50,000) Z° decays recorded with an electron beam polarization of P{sub e} = 77% (63%), they have obtained A{sub b} = 0.911 " 0.045(stat) " 0.045(syst). This value is in goo d agreement with the Standard Model.

The Left-right Forward-backward Asymmetry for B Quarks at the SLD.

The Left-right Forward-backward Asymmetry for B Quarks at the SLD. PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 199

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Book Description
The left-right asymmetry for b quarks, A{sub b}, is precisely predicted by the Weinberg-Salam-Glashow model of particle interactions, now the standard model for high-energy particle physics. As a test of this model, A{sub b} is directly measured at the SLC Large Detector (SLD) by taking advantage of the unique polarized electron beam at the Stanford Linear Collider (SLC) and measuring the left-right forward-backward asymmetry of b quarks. To measure the asymmetry, b quarks are identified using muons of high total and transverse momenta. The result for the 1993 data sample of 37,843 hadronic Z's is A{sub b} = 0.91 " 0.19 " 0.06, where the first error is statistical and the second systematic. This result is in agreement with the standard model prediction of A{sub b} = 0.935.

The Standard Theory of Particle Physics

The Standard Theory of Particle Physics PDF Author: Luciano Maiani
Publisher: World Scientific Publishing Company
ISBN: 9814733512
Category : Science
Languages : en
Pages : 483

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Book Description
The book gives a quite complete and up-to-date picture of the Standard Theory with an historical perspective, with a collection of articles written by some of the protagonists of present particle physics. The theoretical developments are described together with the most up-to-date experimental tests, including the discovery of the Higgs Boson and the measurement of its mass as well as the most precise measurements of the top mass, giving the reader a complete description of our present understanding of particle physics.

Standard Theory Of Particle Physics, The: Essays To Celebrate Cern's 60th Anniversary

Standard Theory Of Particle Physics, The: Essays To Celebrate Cern's 60th Anniversary PDF Author: Luciano Maiani
Publisher: World Scientific
ISBN: 9814733520
Category : Science
Languages : en
Pages : 484

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Book Description
'The editors make a good point in claiming the time has come to upgrade the Standard Model into the ‘Standard Theory’ of particle physics, and I think this book deserves a place in the bookshelves of a broad community, from the scientists and engineers who contributed to the progress of high-energy physics to younger physicists, eager to learn and enjoy the corresponding inside stories.'Carlos LourençoCERN CourierThe book gives a quite complete and up-to-date picture of the Standard Theory with an historical perspective, with a collection of articles written by some of the protagonists of present particle physics. The theoretical developments are described together with the most up-to-date experimental tests, including the discovery of the Higgs Boson and the measurement of its mass as well as the most precise measurements of the top mass, giving the reader a complete description of our present understanding of particle physics.

The Left-right Forward-backward Asymmetry for B Quarks at the SLD

The Left-right Forward-backward Asymmetry for B Quarks at the SLD PDF Author: David Charles Williams
Publisher:
ISBN:
Category :
Languages : en
Pages : 178

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Measurement of the Polarized Forward-backward Asymmetry of B Quarks at SLD

Measurement of the Polarized Forward-backward Asymmetry of B Quarks at SLD PDF Author: Victor V. Serbo
Publisher:
ISBN:
Category :
Languages : en
Pages : 284

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