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 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We 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] produced with a polarized electron beam and recorded by the SLD experiment at SLAC between 1993 and 1997. Z[sup 0][r-arrow] 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 strange 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 strange quark. To reduce the model dependence of the measurement, the background from primary up and down events is measured from the data, as is the analyzing power of the method for primary strange events. We measure: A[sub s]= 0.82[+-] 0.10(stat.)[+-] 0.08(syst.)(preliminary).

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 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present a preliminary direct measurement of the parity violating coupling of the Z° to strange quarks, A{sub s}, derived from a sample of approximately 300,000 hadronic decays of Z° produced with a polarized electron beam and recorded by the SLD experiment at SLAC between 1993 and 1997. 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 strange 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 strange quark. To reduce the model dependence of the measurement, the background from primary up and down events is measured from the data, as is the analyzing power of the method for primary strange events. We measure: A{sub s} = 0.82 ± 0.10(stat.) {+-} 0.08(syst.)(preliminary).

Download or read book First Direct Measurement of the Parity Violating Coupling of the Z to the S Quark written by and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The authors have made the first direct measurement of the parity-violating coupling of the Z° boson to the strange quark, A{sub s}, using (approximately)550,000 ee− --> Z° --> hadrons event produced with a polarized electron beam and recorded by the SLD experiment. Z° s anti-s events were tagged by the absence of B or D hadrons and the presence in each hemisphere of a high-momentum K{sup "} or K{sub s}°. From the polar angle distributions of the strangeness-signed thrust axis, the authors obtained A{sub s} = 0.895"0.066(stat.){+-}0.062(syst.). The analyzing power and u anti-u + d anti-d background were constrained using the data.

Download or read book Light Quark Fragmentation and a Measurement of A sub S at the SLD written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We have studied the fragmentation process in Z[sup 0][yields] light-flavor (u[bar u], d[bar d], s[bar s]) events by measuring the differential cross sections for the production of the identified hadrons[pi][sup[+-]], K[sup[+-]], p/[bar p], K[sub s][sup 0], [Lambda][sup 0]/[bar[Lambda]][sup 0], K*[sup 0]/[bar K]*[sup 0] and[phi], and by performing a preliminary study of correlations in rapidity between pairs of identified[pi][sup[+-]], K[sup[+-]], and p/[bar p]. Short range charge correlations are observed between all combinations of these three hadron species. A strong long range correlation is observed between all combinations of these three hadron species. A strong long range correlation is observed for high-momentum charged kaon pairs, and weaker[pi][sup+][pi][sup -], [pi][sup+]K[sup -] and pK[sup -] correlations are observed. The SLC beam polarization is used to tag the quark hemisphere in each event, allowing the first study of rapidities signed such that positive rapidity is along the quark rather than antiquark direction. Distributions of signed rapidities and of ordered differences between signed rapidities provide new insights into leading particle production and several new tests of fragmentation models. We have used these correlation studies to perform a preliminary direct measurement of the parity violating coupling of the Z[sup 0] to strange quarks, A[sub s]. Our result is: A[sub s]= 0.82[+-] 0.10(stat.)[+-] 0.08(syst.)(preliminary).

Download or read book Identified Hadron Production and Light Quark Fragmentation in Z Decays written by and published by . This book was released on 1998 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: We have measured the differential cross sections for the production of [pi], K, K°, K*°, [phi], p, [Lambda] and their corresponding antiparticles in separate samples of flavor-tagged Z° 2!light-flavor (u{bar u}, d{bar d}, or s{bar s}), Z° 2!b{bar b} events. Clear flavor dependences are observed, and the results are compared with the predictions of three fragmentation models. We have also performed a direct measurement of A{sub s}, the parity-violating coupling of the Z° to strange quarks, by measuring the left-right-forward-backward production asymmetry in polar angle of the tagged s quark. Our preliminary result is A{sub s} = 0.82 ± 0.10(stat.) ± 0.07(syst.).

Download or read book Identified Hadron Production and Light Quark Fragmentation in Z sup 0 Decays written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We have measured the differential cross sections for the production of[pi][sup+], K[sup+], K[sup 0], K*[sup 0], [phi], p, [Lambda] and their corresponding antiparticles in separate samples of flavor-tagged Z[sup 0][yields] light-flavor (u[bar u], d[bar d], or s[bar s]), Z[sup 0][yields] b[bar b] events. Clear flavor dependences are observed, and the results are compared with the predictions of three fragmentation models. We have also performed a direct measurement of A[sub s], the parity-violating coupling of the Z[sup 0] to strange quarks, by measuring the left-right-forward-backward production asymmetry in polar angle of the tagged s quark. Our preliminary result is A[sub s]= 0.82[+-] 0.10(stat.)[+-] 0.07(syst.).

Download or read book QCD 98 written by S. Narison and published by . This book was released on 1999 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book From Parity Violation to Hadronic Structure and more written by K. de Jager and published by Springer Science & Business Media. This book was released on 2008-06-21 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book contains the proceedings of the third international workshop on From Parity Violation to Hadronic Structure and More. The many applications of parity violation are way beyond the scope of what Lee and Yang could have imagined fifty years after their proposal. For the physics topics discussed during this workshop, the application of parity violation has become a standard work horse allowing for the extraction of many physics topics in different experiments.

Download or read book QCD written by and published by . This book was released on 1998 with total page 490 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Nuclear Physics written by and published by . This book was released on 1999 with total page 490 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book From Parity Violation to Hadronic Structure and more written by Serge Kox and published by Springer Science & Business Media. This book was released on 2007-06-07 with total page 198 pages. Available in PDF, EPUB and Kindle. Book excerpt: Almost 50 years after the proposal of Lee and Young in 1956 to test the hypothesis of parity violation in weak interactions and the subsequent experimental verification of parity violation by C. S. Wu, parity violation has today become a useful property of weak interactions. This is due to the fact that the focus nowadays has changed: parity violation in weak interactions is no more a topic of investigation but is used as a tool in many different fields ranging from nuclear physics to the search for the hidden extra dimensions requested by string theory. For our first workshop which took place June 5-8, 2002, at the Institut fiir Ke- physik of the Johannes Gutenberg-Universitat Mainz, we concentrated on the in vestigation of the strangeness contribution in the nucleon. This book contains the refereed and selected papers of the second workshop "From Parity Violation to Hadron Structure and more (Part II)", which took place June 8-11, in the Labo- toire de Physique Subatomique et de Cosmologie, in Grenoble. These papers appear in EPJAdirect, the electronic-only part of EPJA, and they are accessible without restrictions. They will also appear in printed form and can be ordered through Springer. The excellent presentations show the dramatic and steady progress in the accuracy of measured parity violating asymmetries over the last few years.

Download or read book Introduction to High Energy Physics written by Donald H. Perkins and published by Cambridge University Press. This book was released on 2000-04-13 with total page 454 pages. Available in PDF, EPUB and Kindle. Book excerpt: This highly-regarded text provides a comprehensive introduction to modern particle physics. Extensively rewritten and updated, this 4th edition includes developments in elementary particle physics, as well as its connections with cosmology and astrophysics. As in previous editions, the balance between experiment and theory is continually emphasised. The stress is on the phenomenological approach and basic theoretical concepts rather than rigorous mathematical detail. Short descriptions are given of some of the key experiments in the field, and how they have influenced our thinking. Although most of the material is presented in the context of the Standard Model of quarks and leptons, the shortcomings of this model and new physics beyond its compass (such as supersymmetry, neutrino mass and oscillations, GUTs and superstrings) are also discussed. The text includes many problems and a detailed and annotated further reading list.

Download or read book Measurement of the Strange Quark Contribution to Proton Structure Through Parity Violating Electron Proton Scattering written by Kazutaka Nakahara and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The G0 (G-Zero) forward angle experiment completed in Hall C of the Thomas Jefferson National Accelerator Facility (TJNAF) has measured the parity violating asymmetries in elastic electron-proton scattering over a Q2 range of 0.12

Download or read book Parity Violation in Elastic Electron Scattering written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The goal of Experiment E04-115 (the G0 backward angle measurement) at Jefferson Lab is to investigate the contributions of strange quarks to the fundamental properties of the nucleon. The experiment measures parity-violating asymmetries in elastic electron scattering off hydrogen and quasielastic electron scattering off deuterium at backward angles at Q2 = 0.631 (GeV/c)2 and Q2 = 0.232 (GeV/c)2. The backward angle measurement represents the second phase of the G0 experiment. The first phase, Experiment E00-006 (the G0 forward angle experiment), measured parity-violating asymmetries in elastic electron scattering off hydrogen at forward angles over a Q2 range of 0.1-1.0 (GeV/c)2. The experiments used a polarized electron beam and unpolarized hydrogen and deuterium liquid targets. From these measurements, along with the electromagnetic form factors, one can extract the contribution of the strange quark to the proton's charge and magnetization distributions. This thesis represents a fi.

Download or read book Measurement of the Polarized Forward backward Asymmetry of Z B bar B Using a Lifetime Tag and Momentum weighted Track Charge written by and published by . This book was released on 1995 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present a direct measurement of the parity-violating parameter A{sub b} by analyzing the left-right forward-backward asymmetry of b quarks in ee− --> Z{sup o} --> b{bar b}. The SLD experiment observes hadronic decays of Z{sup o} bosons produced at resonance in collisions of longitudinally polarized electrons and unpolarized positrons at the SLC. Heavy flavor decays of the Z{sup o} are identified by taking advantage of the long lifetime of B hadrons, the small, stable SLC beam spot, and precise tracking from SLD. The asymmetry A{sub b} is measured with a self-calibrating technique employing momentum-weighted track charge from both hemispheres in the tagged events. From our 1994--1995 sample of 3.6 pb−1 of ee− annihilation data with a luminosity-weighted average e− polarization of 77.3%, and our 1993 sample of 1.8 pb−1 with a luminosity-weighted polarization of 63.1%, we obtain A{sub b}(preliminary) = 0.843 " 0.046(stat.) " 0.051(syst.).

Download or read book Measurement of sin 2 theta rm Eff ell and Z light Quark Couplings Using the Forward backward Charge Asymmetry in p bar p to Z gamma to E e Events with cal L written by and published by . This book was released on 2011 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: We measure the mass dependence of the forward-backward charge asymmetry in 157,553 p{bar p} → Z/[gamma]* → e+e− interactions, corresponding to 5.0 fb−1 of integrated luminosity collected by the D0 experiment at the Fermilab Tevatron Collider at √s = 1.96 TeV. The effective weak mixing angle ([theta]{sub eff}{sup {ell}}) from this process involving predominantly the first generation of quarks is extracted as sin2 [theta]{sub eff}{sup {ell}} = 0.2309 ± 0.0008 (stat.) ± 0.0006 (syst.). We also present the most precise direct measurement of the vector and axial-vector couplings of u and d quarks to the Z boson.

Download or read book Parity Violation at 8 12 GeV at Jlab written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Experiments on parity violation in electron scattering measure the asymmetry A = [sigma][sub R] - [sigma][sub L]/[sigma][sub R] + [sigma][sub L] where [sigma][sub R(L)] is the cross section for Right(Left) handed longitudinally polarized electrons. This asymmetry arises, in first order, from the interference between photon and Z-boson exchange amplitudes. Experiments make two basic uses of the Z-boson as a probe in electron-quark or electron-nucleon scattering. Historically the first usage was to test the electroweak theory in regions of kinematics where the hadronic structure is sufficiently understood. They discuss the application of higher energies at Jefferson Lab to repeat the SLAC e-D deep inelastic parity violation experiment [1] at a level of precision [approx] 0.5% in sin[sup 2][theta][sub W] which would be a useful constrain on extensions of the Standard Model [2]. The second, more recent usage of the Z-boson probe is to assume the Standard Model is correct at about the 1% level and use this as a unique method to address fundamental issues of nucleon structure, such as: (1) are the strange quarks an important component of the nucleon [3]; (2) In deep inelastic scattering, are the high momentum quarks u or d quarks? To address the first question, they discuss the feasibility of extending the HAPPEX experiment to higher Q[sup 2]. For the second question, they discuss a possible measurement of the ratio of valence quarks d/u in the proton using deep inelastic parity violation.