Download or read book Parity Violation in Decays of Z Bosons Into Heavy Quarks at SLD written by Thomas R. Wright and published by . This book was released on 2001 with total page 172 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Parity Violation in Decays of Z Bosons Into Heavy Quarks at SLD written by and published by . This book was released on 2002 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work presents measurements of the parity-violation parameters A{sub c} and A{sub b} made at the Z pole. These measurements include the data taken with the SLD detector at the SLAC Linear Collider (SLC) during the period 1996-98. Heavy flavor events are selected with high efficiency and purity by searching for displaced vertices, identified with the SLD precision CCD vertex detector. Two methods are used for quark/antiquark discrimination: the net charge of the displaced vertex, and tracks in the displaced vertex identified as kaons by the SLD Cherenkov Ring Imaging Detector (CRID). The signal purities and analyzing powers are calibrated from the data to reduce the systematic errors and avoid experimental bias. The results are A{sub c} = 0.673 " 0.029 " 0.023 and A{sub b} = 0.919 " 0.018 " 0.017, where the first error is statistical and the second systematic. Fits to the electroweak data performed by the LEP Electroweak Working Group are used to study the consistency of the Standard Model, and to constrain the mass of the Standard Model Higgs boson.

Download or read book A Preliminary Direct Measurement of the Parity Violating Coupling of the Z to Strange Quarks A sub S written by and published by . This book was released on 1999 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present an updated direct measurement of the parity-violating coupling of the Z° to strange quarks, A{sub s}, derived from the full SLD data sample of approximately 550,000 hadronic decays of Z° bosons produced with a polarized electron beam and recorded by the SLD experiment at SLAC between 1993 and 1998. Z° → s{bar s} events are tagged by the presence in each event hemisphere of a high-momentum K{sup ±}, K{sub s} or [Lambda]°/{bar {Lambda}}° identified using the Cherenkov Ring Imaging Detector and/or a mass tag. The CCD vertex detector is used to suppress the background from heavy-flavor events. The strangeness of the tagged particle is used to sign the event thrust axis in the direction of the initial s quark. The coupling A{sub s} is obtained directly from a measurement of the left-right-forward-backward production asymmetry in polar angle of the tagged s quark. The background from u{bar u} and d{bar d} events is measured from the data, as is the analyzing power of the method for s{bar s} events. We measure: A{sub s} = 0.85 ± 0.06(stat.) {+-} 0.07(syst.)(preliminary).

Download or read book A Preliminary Direct Measurement of the Parity violating Coupling of the Z sup 0 to Strange Quarks A sub S written by and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The authors present a preliminary direct measurement of the parity violating coupling of the Z[sup 0] to strange quarks, A[sub s], derived from a sample of approximately 300,000 hadronic decays of Z[sup 0] bosons produced with a polarized electron beam and recorded by the SLD experiment at SLAC between 1993 and 1997. Z[sup 0][yields] s[bar s] events are tagged by the presence in each event hemisphere of a high-momentum K[sup[+-]], K[sub s][sup 0] or[Lambda][sup 0]/[bar[Lambda]][sup 0] identified using the Cherenkov Ring Imaging Detector and/or a mass tag. The CCD vertex detector is used to suppress the background from heavy flavor events. The strangeness of the tagged particle is used to sign the event thrust axis in the direction of the initial s quark. The coupling A[sub s] is obtained directly from a measurement of the left-right-forward-backward production asymmetry in polar angle of the tagged s quark. To reduce the model dependence of the measurement, the background from u[bar u] and d[bar d] events is measured from the data, as is the analyzing power o the method for s[bar s] events. The authors measure A[sub s]= 0.82[+-] 0.10(stat.)[+-] 0.07(syst.)(preliminary).

Download or read book Searches for New Quarks and Leptons in Z Boson Decays written by Richard James Van Kooten and published by Ann Arbor, Mich. : University Microfilms International. This book was released on 1990 with total page 380 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Heavy Quark Production in Z0 Decays written by and published by . This book was released on 1998 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We present studies of 3-jet final states from hadronic Z0 decays recorded by the SLD experiment. A comparison of the strong couplings of light, c, and b quarks is made using 3-jet rates. We have performed a detailed study of e+e---> b anti-bg final states, in which the quark, antiquark, and gluon jets are identified. The gluon energy spectrum, measured over the full kinematic range, is consistent with the predictions of QCD, and we derive a limit on an anomalous chromomagnetic bbg coupling. We measure the parity violation in Z0 decays into b anti-bg to be consistent with the predictions of electroweak theory and QCD, and perform new tests of T- and CP-conservation at the bbg vertex.

Download or read book Energy Research Abstracts written by and published by . This book was released on 1995 with total page 782 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 704 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Searches for New Quarks and Leptons in Z Boson Decays written by and published by . This book was released on 1990 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Left right Forward backward Asymmetry of Heavy Quarks Measured with Jet Charge and with Leptons at the SLD written by and published by . This book was released on 1994 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Measurement of the Z Boson Branching Fraction Into Hadrons Containing Bottom Quarks written by J. Frederic Kral and published by . This book was released on 1990 with total page 286 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Measurement of Bottom Quark Production in Z Boson Hadronic Decays written by J. Coller and published by . This book was released on 2003 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: A precise measurement of R{sub b}, the fraction of hadronic decays of the Z{sup 0} boson into bottom quark pairs, will test the Standard Model of particle physics. By measuring R{sub b}, the coupling between the Z{sup 0} boson and bottom quarks can be investigated. The strength of this coupling is sensitive to the top quark mass and to physics which lies outside the Standard Model. This thesis presents a measurement of R{sub b} made at the Stanford Linear Accelerator Center with the SLD experiment. Approximately 196,000 hadronic events are used in the measurement. The data set was obtained during the 1997-98 SLD physics run. The selection of B hadrons for identifying Z{sup 0} {yields} b{bar b} events is based on the invariant mass of topologically reconstructed vertices separated from the primary vertex for the event. This reconstruction method identifies B hadrons with a high efficiency (49.9%) and high purity (98.0%). Each candidate Z{sup 0} {yields} b{bar b} event is split into two separate hemispheres which are analyzed independently. The efficiency for tagging B hadrons is extracted from the data, reducing the dependence on the Monte Carlo simulation for B hadron and b quark systematic errors. A measured result of R{sub b} = 0.2185 {+-} 0.0013{sub (stat)} {+-} 0.0022{sub (syst.)} is reported. This value is consistent within measurement errors with the Standard Model prediction of 0.2158. The significant of this measurement is discussed.

Download or read book Search for the Production of ZW and ZZ Boson Pairs Decaying Into Charged Leptons and Jets in Proton antiproton Collisions at Sqrt s written by and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We present a measurement of the production cross section for ZW and ZZ boson pairs in final states with a pair of charged leptons, from the decay of a Z boson, and at least two jets, from the decay of a W or Z boson, using the full sample of proton-antiproton collisions recorded with the CDF II detector at the Tevatron, corresponding to 8.9 fb(̂-1) of integrated luminosity. We increase the sensitivity to vector boson decays into pairs of quarks using a neural network discriminant that exploits the differences between the spatial spread of energy depositions and charged-particle momenta contained within the jet of particles originating from quarks and gluons. Additionally, we employ new jet energy corrections to Monte Carlo simulations that account for differences in the observed energy scales for quark and gluon jets. The number of signal events is extracted through a simultaneous fit to the dijet mass spectrum in three classes of events: events likely to contain jets with a heavy-quark decay, events likely to contain jets originating from light quarks, and events that fail these identification criteria. We determine the production cross section to be 2.5 +2.0 -1.0 pb (

Download or read book Physics of Heavy Quark Decays and CP Violation written by and published by . This book was released on 1985 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The phenomena of quark mixing in weak interaction are described. The current experimental status of the mixing matrix, charm and beauty particle decays, and CP violations are reported. Future interesting experiments are pointed out, especially in the event that higher generations of quarks exist. 78 refs., 5 figs.

Download or read book Cbt Workshop written by F. Caruso and published by Atlantica Séguier Frontières. This book was released on 1995 with total page 558 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book High Energy Physics written by Hesheng Chen and published by World Scientific. This book was released on 2005-05-03 with total page 1424 pages. Available in PDF, EPUB and Kindle. Book excerpt: The 32nd International Conference on High Energy Physics belongs to the Rochester Conference Series, and is the most important international conference in 2004 on high energy physics. The proceedings provide a comprehensive review on the recent developments in experimental and theoretical particle physics. The latest results on Top, Higgs search, CP violation, neutrino mixing, pentaquarks, heavy quark mesons and baryons, search for new particles and new phenomena, String theory, Extra dimension, Black hole and Lattice calculation are discussed extensively. The topics covered include not only those of main interest to the high energy physics community, but also recent research and future plans. Contents: Neutrino Masses and MixingsQuark Matter and Heavy Ion CollisionsParticle Astrophysics and CosmologyElectroweak PhysicsQCD Hard InteractionsQCD Soft InteractionsComputational Quantum Field TheoryCP Violation, Rare Kaon Decay and CKMR&D for Future Accelerator and DetectorHadron Spectroscopy and ExoticsHeavy Quark Mesons and BaryonsBeyond the Standard ModelString Theory Readership: Experimental and theoretical physicists and graduate students in the fields of particle physics, nuclear physics, astrophysics and cosmology.Keywords:High Energy Physics;Particle Physics;Electroweak;QCD;Heavy Quark;Neutrino;Particle Astrophysics;Hadron Spectroscopy;CP Violation;Quark Matter;Future Accelerator

Download or read book Proceedings of the 31st International Conference on High Energy Physics ICHEP 2002 written by S. Bentvelsen and published by Elsevier. This book was released on 2012-12-02 with total page 1004 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first precision measurements on CP violation in the B system are reported. Both the BELLE and the BABAR collaboration presented, among others, results for sin 2ß with much improved accuracy. Results from the Sudbury Neutrino Observatory, SNO, also deserve to be mentioned. The convincing evidence of solar neutrino oscillations had been presented by SNO prior to the conference; a full presentation was given at the conference. An incredibly precise measurement of the anomalous magnetic moment of the muon is reported, a fresh result from the Brookhaven National Laboratory. Apart from these distinct physics highlights, there are also the first results from the new Tevatron run and from the relativistic heavy ion collider RHIC. Theorists write of our ever better understanding of the Standard Model and of what might lie beyond. Risky as it is to highlight only a couple of exciting subjects, it is merely meantto whet the appetite for further reading.