Studies of Multiparticle Production in Hadronic Z° Decays
Studies of Multiparticle Production in Hadronic Z° Decays

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Publisher:

Published: 1996

Total Pages: 160

ISBN-13:

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Hadronic decays of Z° bosons produced in ee− annihilation are ideal for testing QCD. This thesis presents a measurement of the charged-particle multiplicity distribution and the first experimental study of the ratio of cumulant to factorial moments, using hadronic Z° decays collected by the SLD experiment at SLAC. The author finds that this ratio, as a function of the moment-rank q, decreases sharply to a negative minimum at q = 5, which is followed by quasi-oscillations. These features are in qualitative agreement with expectations from higher-order perturbative QCD. The author also presents an analysis of the intermittency in rapidity phase space using the method of scaled factorial moments. It is found that both parton cascade and hard-gluon radiations contribute to the growth of the moments by studying the event-shape and jet-topology dependencies. All aspects of the data appear to be reproduced reasonably well by the QCD-based Monte Carlo model.

Qcd And Multiparticle Production - Proceedings Of The Xxix International Symposium On Multiparticle Dynamics
Qcd And Multiparticle Production - Proceedings Of The Xxix International Symposium On Multiparticle Dynamics

Author: Ina Sarcevic

Publisher: World Scientific

Published: 2000-07-05

Total Pages: 542

ISBN-13: 9814542938

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This volume concentrates on three main areas of current research in high energy physics: (1) multiparticle and diffractive production in perturbative and nonperturbative QCD, (2) confinement-deconfinement mechanism and the RHIC physics, and (3) interface between high-energy collisions and cosmic-ray/astro-physics. The specific topics covered include: QCD at high energies, diffractive production, and small-x physics, multiparticle production and systematics: correlations and fluctuations, hadronic final states in e+e-, lepton-hadron and hadron-hadron collisions, relativistic heavy ion collisions, interface between high-energy collisions and cosmic-ray physics, and recent development in deconfinement.

Multiparticle Dynamics - Proceedings Of The Xxiii International Symposium
Multiparticle Dynamics - Proceedings Of The Xxiii International Symposium

Author: M M Block

Publisher: World Scientific

Published: 1994-04-26

Total Pages: 650

ISBN-13: 9814550841

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This international meeting on ultrahigh energy multiparticle phenomena started with a summary of neutrino physics, followed by a detailed review of LEP results. It moved on to the fast-breaking field of rapidity gaps, hard pomeron and small-x structure functions at both Hera and the FermiLab Tevatron. The major collider experiments at FermiLab, and in particular, the results of the top quark search were presented in complete detail. The fields of intermittency, multiplicities, correlation functions, heavy quarks, soft and semihard hadronic physics, and the particle physics aspects of cosmic rays were subjects of spirited debate.

Study of Hadronic Final States of Z Boson Decays
Study of Hadronic Final States of Z Boson Decays

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Publisher:

Published: 1989

Total Pages: 4

ISBN-13:

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We have studied hadronic final states produced in the decays of Z bosons using the Mark II detector at SLC. We have measured the distributions of global shape parameters, inclusive charged particle distributions, charge particle multiplicity and jet multiplicity. The results are compared to predictions of QCD-based models optimized at the PEP energy. The data and models agree within the present statistical precision. We have also investigated a new method to determine the QCD scale parameter [Lambda]{sub {ovr MS}} using differential jet multiplicity. 9 refs., 5 figs.

Properties of Leading Particles in Hadronic Z° Decays
Properties of Leading Particles in Hadronic Z° Decays

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Publisher:

Published: 1996

Total Pages: 10

ISBN-13:

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The authors present studies of leading particle production in Z° decays into light, c, and b quarks performed with the SLD experiment at SLAC. The SLD precision vertex detector was exploited to tag light-flavor events, to tag charmed meson vertices and separate the prompt and B-decay components, and to reconstruct B-hadrons partially. The relative production of prompt pseudoscalar and vector D-mesons was measured to be P{sub V} = 0.53 " 0.06(stat.) " 0.02(syst.) (preliminary). The shape of the B-hadron energy spectrum was found to be consistent with the predictions of a number of models, and the average energy fraction was measured to be x{sub E} = 0.697 " 0.012(stat.) " 0.028(syst.) (preliminary). Separation of light quark and antiquark jets was achieved using the highly polarized SLC electron beam, and hadrons were identified using the SLD Cherenkov Ring Imaging Detector. Production of particles and antiparticles in quark jets was compared, allowing the first direct observation of leading particles in ee− --> u{anti u}, d{anti d}, s{anti s} events. More high momentum baryons and K−'s than antibaryons and K's were observed, providing evidence for leading baryon and kaon production, as well as for strangeness suppression at high momentum.

Strange Particle Production in Hadronic Z[sup 0] Decays
Strange Particle Production in Hadronic Z[sup 0] Decays

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Published: 2001

Total Pages:

ISBN-13:

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A study has been made of neutral strange baryons and pseudoscalar mesons produced in hadronic decays of the weak gauge boson V. The experiment was performed at the Stanford Linear Accelerator Center, which has the unique capability of colliding highly polarized electrons with unpolarized positrons. Overall production rates and spectra of the K[sup 0] and the[Lambda][sup 0] (+[Lambda][sup 0]) were measured and compared with other experiments as well as with Quantum Chromodynamics calculations. The combination of the small, stable beam spots produced by the SLAC Linear Collider (SLC) and the precision vertexing capabilities of the SLC Large Detector (SLD) permitted the separation of the hadronic events into three quark flavor-enriched samples. An unfolding was performed to obtain flavor-pure samples, and for the first time measurements were made of K[sup 0] and[Lambda][sup 0] (+[Lambda][sup 0]) production rates and spectra in uds, c, and b quark events at the Z[sup 0] pole. This measurement revealed significant production differences. Utilizing the large quark production asymmetry due to the polarized electron beam, high-purity quark and antiquark jet samples were obtained. The first measurement of production differences of the[Lambda][sup 0] baryon in quark and antiquark jets was performed, which provided clear evidence for a leading particle effect at high momenta.