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1. Time localized tilted beams in nearly-degenerate laser cavities

Author

A. Bartolo, N. Vigne, M. Marconi, G. Beaudoin, K. Pantzas, I. Sagnes, A. Garnache, and M. Giudici

Subjects
Medicine, Science
Abstract

Abstract We show that nearly-degenerate Vertical External-Cavity Surface-Emitting Lasers may emit a set of tilted beams of individually addressable mode-locked pulses. These time localized beams feature a Gaussian profile and they are emitted in pairs with opposite transverse k-vector. Because they are phase locked, their interference leads to a non homothetic pattern in the near-field emission of the laser. In the simplest situation, when a single pair is emitted, this is a stripe pattern. Our analysis discloses the role of third order (spherical) aberrations of the cavity in stabilizing this spatio-temporal mode-locked regime and in selecting the value of the transverse k-vector.

Published
2024
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2. Hybrid III-V/Silicon Quantum Photonic Device Generating Broadband Entangled Photon Pairs

Author

J. Schuhmann, L. Lazzari, M. Morassi, A. Lemaître, I. Sagnes, G. Beaudoin, M.I. Amanti, F. Boeuf, F. Raineri, F. Baboux, and S. Ducci

Subjects
Physics, QC1-999, Computer software, QA76.75-76.765
Abstract

The demand for integrated photonic chips combining the generation and manipulation of quantum states of light is steadily increasing, driven by the need for compact and scalable platforms for quantum information technologies. While photonic circuits with diverse functionalities are being developed in different single material platforms, it has become crucial to realize hybrid photonic circuits that harness the advantages of multiple materials while mitigating their respective weaknesses, resulting in enhanced capabilities. Here, we demonstrate a hybrid III-V/silicon quantum photonic device combining the strong second-order nonlinearity and direct band gap of the III-V semiconductor platform with the high maturity and CMOS compatibility of the silicon photonic platform. Our device embeds the spontaneous parametric down-conversion (SPDC) of photon pairs into an AlGaAs source and their vertical routing to an adhesively bonded silicon-on-insulator circuitry, within an evanescent coupling scheme managing both polarization states. This enables the on-chip generation of broadband (>40 nm) telecom photons by type-0 and type-2 SPDC from the hybrid device, at room temperature and with internal pair generation rates exceeding 10^{5}s^{−1} for both types, while the pump beam is strongly rejected. Two-photon interference with 92% visibility (and up to 99% upon 5-nm spectral filtering) proves the high energy-time entanglement quality of the produced quantum state, thereby enabling a wide range of quantum information applications on chip, within a hybrid architecture compliant with electrical pumping and merging the assets of two mature and highly complementary platforms in view of out-of-the-lab deployment of quantum technologies.

Published
2024
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3. Activation of G protein-coupled estradiol receptor 1 in the dorsolateral striatum enhances motivation for cocaine and drug-induced reinstatement in female but not male rats

Author

Jacqueline A. Quigley, Molly K. Logsdon, Brianna C. Graham, Kendra G. Beaudoin, and Jill B. Becker

Subjects
GPER1, Dorsolateral striatum, Sex differences, Motivation, Addiction, Cocaine, Medicine, Physiology, QP1-981
Abstract

Abstract Background Estradiol potentiates drug-taking behaviors, including motivation to self-administer cocaine and reinstatement of drug-seeking after extinction in females, but not males. The dorsolateral stratum (DLS) is a region of the brain implicated in mediating drug-seeking behaviors and, more specifically, is a target brain area to study how estradiol regulates these behaviors. The estradiol receptors α, β, and G protein-coupled estradiol receptor 1 (GPER1) are all present in the DLS. In this study, the effects of activating GPER1 in the DLS on drug-seeking are investigated. Methods Gonad-intact male and female rats were trained to self-administer cocaine (0.4 mg/kg/inf) on a fixed-ratio 1 schedule of reinforcement. For 4 weeks, animals underwent testing on a progressive ratio schedule of reinforcement to determine their motivation to attain cocaine. Halfway through progressive ratio testing, a selective agonist targeting GPER1 (G1) was administered intra-DLS to determine the contribution of GPER1 activation on motivation for cocaine. The effects of intra-DLS GPER1 activation on drug-induced reinstatement after extinction were subsequently determined. Results Activation of GPER1, via intra-DLS G1 administration, potentiated females’ motivation to self-administer cocaine. There was no effect of prior G1 treatment on extinction of cocaine-taking in females; however, G1 treatment resulted in greater drug-induced reinstatement (10 mg/kg cocaine, i.p.). There were no effects of intra-DLS GPER1 activation observed on motivation for cocaine or cocaine-induced reinstatement of responding in males. Conclusions These results support the conclusion that activation of GPER1 in the DLS enhances cocaine-seeking behaviors for female, but not male rats.

Published
2021
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4. Structural geology of the Cadillac Group along the Malartic segment of the Larder Lake Cadillac deformation zone, Quebec, and implications for gold mineralization

Author

B. Samson, B. Lafrance, X. Zhou, M. Hamilton, B. Quesnel, C. Scheffer, G. Beaudoin, and S. Perrouty

Subjects
General Earth and Planetary Sciences
Abstract

The gold-endowed Larder Lake Cadillac deformation zone (LLCDZ) in the Abitibi greenstone belt of the Archean Superior Province generally trends east but swings to the southeast along the Malartic segment in Quebec. Immediately north of the LLCDZ along this segment, deformation of the less than ca. 2687 Ma metasedimentary Cadillac Group began with the formation of isoclinal F1 folds, which are overprinted by post-2676 ± 2.0 Ma regional F2 folds with an axial planar S2 cleavage oriented parallel to the trend of the Malartic segment. Auriferous quartz veins strike east–west (085°) anticlockwise to bedding and S2. They are folded into sigmoidal S-shaped folds due to sinistral shear parallel to bedding. Later dextral shearing segmented the veins and folded the F2 folds into Z-shaped F3 folds. The veins are similar in structural chronology, fluid isotopic composition (calculated [Formula: see text] value between –9.5‰ and –3.4‰ and [Formula: see text] values of 12‰), and isotopic re-equilibration temperatures (469 and 498 °C, quartz–biotite oxygen thermometer) to the veins at the nearby Canadian Malartic deposit to the east. They possess comparable Au–As–Sb association and sericite-arsenopyrite alteration halo, as other Cadillac-Group-hosted veins at the Lapa mine to the west. Collectively, they constitute a vein field that extends across the entire length of the Malartic segment. Contrary to recent interpretations of the Malartic segment as an early accretionary structure that controlled the emplacement of gold deposits, its southeast trend is interpreted as the short limb of a broad Z-shaped flexure that formed during later F3 folding of the LLCDZ.

Published
2022

6. Harmonic generation with multi-layer dielectric metasurfaces

Author

Carlo Gigli, Giuseppe Marino, Stéphan Suffit, Giuseppe Leo, Konstantinos Pantzas, Costantino De Angelis, Pascal Filloux, Isabelle Sagnes, Davide Rocco, and G. Beaudoin

Subjects
Materials science, QC1-999, Nanophotonics, Physics::Optics, 02 engineering and technology, Dielectric, Fourier imaging, 01 natural sciences, 010309 optics, nonlinear metasurfaces triplet, all-dielectric nanophotonics, Mie resonances, nanophotonics, second-harmonic generation, 0103 physical sciences, High harmonic generation, Electrical and Electronic Engineering, Multi layer, fourier imaging, business.industry, Physics, Second-harmonic generation, 021001 nanoscience & nanotechnology, Atomic and Molecular Physics, and Optics, Electronic, Optical and Magnetic Materials, Optoelectronics, mie resonances, 0210 nano-technology, business, Biotechnology
Abstract

Metasurfaces have recently gained extensive interest because of their extraordinary optical behavior as artificial material interfaces with ultrahigh compactness. In this framework, dielectric platforms have newly become very promising for nonlinear nanophotonics, providing opportunities, especially for ultrafast optical switching, and high harmonic generation, opening the research field of nonlinear metaoptics. Up to now, nonlinear metaoptics have been mostly explored using single metasurfaces. However, in a long-term vision, the stacking of optical metasurfaces, very challenging in terms of fabrication, is one key goal of this research field. Here, we demonstrate a three-layer metasurface in the AlGaAs-on-insulator platform, which improves the second harmonic generation efficiency by more than one order of magnitude with respect to its one-layer counterpart. Our achievement paves the way toward phase-shaping multilayer and multifunctional all-dielectric metasurfaces.

Published
2021

8. Surficial geology, Amaruq deposit area, Kivalliq Region, Nunavut, NTS 66-H southeast

Author

N Boulianne-Verschelden, V De Bronac de Vazelhes, I McMartin, and G Beaudoin

Abstract

The Amaruq deposit map area is a glacial landscape dominated by till deposits (72% of map area) forming transverse ridges, hummocky moraine, or plains of varying thickness, occasionally streamlined. Glacial lake sediments cover about 18% of the map area and form thick to thin deposits covering the till. They occur predominantly in lowlands and below approximately 140 m a.s.l., which is the elevation of the highest raised beaches located in the western part of the map area. Some of the glacial lake sediments could have been deposited in a marine environment during high sea levels following deglaciation. Sand and gravel deposits occur in subglacial meltwater corridors forming terraces, esker ridges, and small hummocks, or in proglacial outwash plains. The effects of meltwater at the base of the glacier or by currents and waves in proglacial lake and/or marine basins have resulted in winnowing of fine particles, reworking of sediments, and surface boulder concentrations. Streamlined till landforms and striations indicate that ice flow was dominantly to the north-northwest. This predominant flow was locally succeeded by northwest and west-northwest ice flows as indicated by crosscutting striations. A late deglacial ice-flow direction converging towards a major esker tunnel is observed east of the Amaruq deposit.

Published
2022

9. Temporal localized Turing patterns in mode-locked semiconductor lasers

Author

A. Bartolo, N. Vigne, M. Marconi, G. Beaudoin, K. Pantzas, I. Sagnes, G. Huyet, F. Maucher, S. V. Gurevich, J. Javaloyes, A. Garnache, and M. Giudici

Subjects
Atomic and Molecular Physics, and Optics, Electronic, Optical and Magnetic Materials
Abstract

Spatiotemporal mode-locking is a promising lasing regime for developing coherent sources for multimode nonlinear photonics. In this paper we show that large-aspect-ratio vertical external-cavity surface-emitting lasers (VECSELs) can be operated in this regime. The emitted pulses exhibit a spatial profile resulting from the phase locking between an axial plane wave and a set of tilted waves having a hexagonal arrangement in the Fourier space. Moreover, we show that these pulsating patterns are temporally localized, i.e., they can be individually addressed by pulsing the optical pump. The theoretical analysis discloses that the emergence of these pulsating patterns is a signature of a Turing instability whose critical wave vector depends on the spherical aberrations of the optical elements. Our result reveals that large-aspect-ratio VECSELs offer unique opportunities for studying fully developed spatiotemporal dynamics and for applications to multidimensional control of light.

Published
2022

10. Activation of G-protein Coupled Estradiol Receptor 1 in the Dorsolateral Striatum Enhances Motivation for Cocaine and Drug-Induced Reinstatement in Female Rats

Author

Jacqueline Quigley, Molly K. Logsdon, Brianna C. Graham, Kendra G. Beaudoin, and Jill B Becker

Abstract

BackgroundEstradiol potentiates drug-taking behaviors, including motivation to self-administer cocaine and reinstatement of drug-seeking after extinction in females, but not males. The dorsolateral stratum (DLS) is a region of the brain implicated in mediating drug-seeking behaviors and more specifically, is a target brain area to study how estradiol regulates these behaviors. The estradiol receptors α, β, and G-protein coupled estradiol receptor 1 (GPER1) are all present in the DLS. In this study the effects of activating GPER1 in the DLS on drug-seeking are investigated. MethodsGonad-intact male and female rats were trained to self-administer cocaine (0.4 mg/kg/inf) on an fixed-ratio 1 schedule of reinforcement. For four weeks, animals underwent testing on a progressive ratio schedule of reinforcement to determine their motivation to attain cocaine. Halfway through progressive ratio testing, a selective agonist targeting GPER1 (G1) was administered intra-DLS to determine the contribution of GPER1 activation on motivation for cocaine. The effects of intra-GPER1 activation on drug-induced reinstatement after extinction was subsequently determined. ResultsActivation of GPER1, via G1 administration intra-DLS potentiated females’ motivation to self-administer cocaine. There was no effect of prior G1 treatment on extinction of cocaine-taking in females, however, G1 treatment resulted in greater drug-induced reinstatement (10 mg/kg cocaine, i.p.). There were no effects of intra-DLS GPER1 activation observed on motivation for cocaine or cocaine-induced reinstatement of responding in males. Conclusions These results support the conclusion that activation of GPER1 in the DLS enhances cocaine seeking behaviors for female, but not male rats.

Published
2021

11. Coherent and Tunable THz Emission Driven by an Integrated III–V Semiconductor Laser

Author

Guillaume Ducournau, Isabelle Sagnes, P. Latzel, R. Paquet, Stéphane Blin, Jean-Francois Lampin, Arnaud Garnache, Mikhael Myara, M. Sellahi, L. Le Gratiet, G. Beaudoin, Baptiste Chomet, Institut d’Electronique et des Systèmes (IES), Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Térahertz, hyperfréquence et optique (TéHO), Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de photonique et de nanostructures (LPN), Centre National de la Recherche Scientifique (CNRS), Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520 (IEMN), Centrale Lille-Institut supérieur de l'électronique et du numérique (ISEN)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF), Photonique THz - IEMN (PHOTONIQUE THz - IEMN), and Centrale Lille-Institut supérieur de l'électronique et du numérique (ISEN)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF)-Centrale Lille-Institut supérieur de l'électronique et du numérique (ISEN)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF)

Subjects
Terahertz radiation, Physics::Optics, Optical power, 02 engineering and technology, 01 natural sciences, law.invention, 010309 optics, Laser linewidth, Optics, law, 0103 physical sciences, Emission spectrum, Electrical and Electronic Engineering, ComputingMilieux_MISCELLANEOUS, Physics, business.industry, 021001 nanoscience & nanotechnology, Laser, Atomic and Molecular Physics, and Optics, [SPI.TRON]Engineering Sciences [physics]/Electronics, Photodiode, Semiconductor, Optoelectronics, 0210 nano-technology, business, Excitation
Abstract

We demonstrate coherent and tunable THz emission by excitation of a unitraveling-carrier photodiode by a dual-frequency III–V semiconductor laser emitting up to 80 mW of optical power around 1 $\mu$ m. The laser is an optically-pumped vertical-external-cavity surface-emitting laser that operates simultaneously on two transverse Laguerre–Gauss modes. Modes frequency difference is driven by thermal effects, band-filling effects and/or phase masks, allowing THz emission from 50 GHz to few THz. To reach THz emission from a pigtailed photodiode, we detail quantitatively how orthogonal transverse modes can be coupled within a single-mode fiber, leading to more than 20% beat efficiency. Coherent THz emission spectrum is presented with a linewidth of about 150 kHz for 3-ms acquisition time, and an output power limited by the photodiode (typically 1 $\mu$ W at 300 GHz). Frequency noise is measured for the optical transverse modes along with the THz signal. The latter presents a frequency noise that is about 20-dB lower than the optical ones, thus proving that the dual-frequency concept allows frequency noise reduction by correlating part of the technical noise of the two modes.

Published
2017

12. Semiconductor disk laser in bi-frequency operation by laser ablation micromachining of a laser mirror

Author

Theo Chen Sverre, Vasilis Apostolopoulos, Jonathan Woods, Stéphane Blin, Ben Keenlyside, Arnaud Garnache, Anne C. Tropper, Jake Daykin, Isabelle Sagnes, G. Beaudoin, Ben Mills, Daniel J. Heath, Institut d’Electronique et des Systèmes (IES), Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Photonique et Térahertz (PhoTéra), Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de photonique et de nanostructures (LPN), Centre National de la Recherche Scientifique (CNRS), and Térahertz, hyperfréquence et optique (TéHO)

Subjects
Laser ablation, Materials science, business.industry, Physics::Optics, 02 engineering and technology, 021001 nanoscience & nanotechnology, Laser, 01 natural sciences, Vertical-external-cavity surface-emitting-laser, Atomic and Molecular Physics, and Optics, law.invention, Semiconductor laser theory, 010309 optics, [SPI]Engineering Sciences [physics], Optics, [PHYS.QPHY]Physics [physics]/Quantum Physics [quant-ph], law, Optical cavity, Fiber laser, 0103 physical sciences, Disk laser, 0210 nano-technology, business, Lasing threshold, ComputingMilieux_MISCELLANEOUS
Abstract

International audience; We present bi-frequency continuous wave oscillation in a semiconductor disk laser through direct writing of loss-inducing patterns onto an intra-cavity high reflector mirror. The laser is a Vertical External Cavity Surface Emitting Laser which is optically pumped by up to 1.1 W of 808 nm light from a fibre coupled multi-mode diode laser, and oscillates on two Hermite-Gaussian spatial modes simultaneously, achieving wavelength separations between 0.2 nm and 5 nm around 995 nm. We use a Digital Micromirror Device (DMD) enabled laser ablation system to define spatially specific loss regions on a laser mirror by machining away the Bragg layers from the mirror surface. The ablated pattern is comprised of two orthogonal lines with the centermost region undamaged, and is positioned in the laser cavity so as to interact with the lasing mode, thereby promoting the simultaneous oscillation of the fundamental and a higher order spatial mode. We demonstrate bi-frequency oscillation over a range of mask gap sizes and pump powers.

Published
2019

13. Towards transverse multiplexing of THz photo-driven emitters driven by a dual-transverse-mode dual-frequency laser

Author

Alaeddine Abbes, Mikhael Myara, G. Beaudoin, Arnaud Garnache, Baptiste Chomet, Isabelle Sagnes, Stéphane Blin, Institut d’Electronique et des Systèmes (IES), Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Térahertz, hyperfréquence et optique (TéHO), and Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, business.industry, Terahertz radiation, 02 engineering and technology, Laser, 01 natural sciences, Multiplexing, Transverse mode, Dual (category theory), law.invention, 010309 optics, Transverse plane, 020210 optoelectronics & photonics, Optics, law, 0103 physical sciences, [SPI.OPTI]Engineering Sciences [physics]/Optics / Photonic, 0202 electrical engineering, electronic engineering, information engineering, Dual frequency, business, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2019

14. Polarization- and diffraction-controlled second-harmonic generation from semiconductor metasurfaces

Author

Carlo Gigli, Konstantinos Pantzas, Gilles Patriarche, Ivan Favero, Isabelle Sagnes, Stéphan Suffit, Giuseppe Leo, G. Beaudoin, Giuseppe Marino, Laboratoire Matériaux et Phénomènes Quantiques (MPQ (UMR_7162)), Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de photonique et de nanostructures (LPN), Centre National de la Recherche Scientifique (CNRS), Centre de Nanosciences et de Nanotechnologies [Marcoussis] (C2N), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), and Université Paris-Sud - Paris 11 (UP11)-Université Paris Diderot - Paris 7 (UPD7)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)

Subjects
Diffraction, [PHYS]Physics [physics], Materials science, business.industry, Scattering, Solid angle, Physics::Optics, Second-harmonic generation, Statistical and Nonlinear Physics, Chemical vapor deposition, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, Polarization (waves), 7. Clean energy, 01 natural sciences, Atomic and Molecular Physics, and Optics, 010309 optics, Semiconductor, Geometric phase, 0103 physical sciences, Optoelectronics, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], business, ComputingMilieux_MISCELLANEOUS
Abstract

We experimentally demonstrate the capability of semiconductor monolithic metasurfaces to control the polarization state of optical second-harmonic generation. Based on the properties of single Mie-resonator scattering, we design and fabricate AlGaAs-on-insulator metasurfaces whose spatial periodicity allows us to decouple polarization and diffraction features. This enables collection of a polarization-engineered harmonic field in a small solid angle around the zero-diffraction order. Our metasurfaces rely on a AlGaAs/AlAs/GaAs metal-organic chemical vapor deposition structure, which makes them promising for optoelectronic integration.

Published
2019

15. Spiking and pulse train dynamics in a neuromimetic micropillar laser (Conference Presentation)

Author

Bernd Krauskopf, Isabelle Sagnes, Louis Andreoli, F. Selmi, Neil G. R. Broderick, Soizic Terrien, Rémy Braive, Sylvain Barbay, and G. Beaudoin

Subjects
Physics, Artificial neural network, business.industry, Detector, Physics::Optics, Saturable absorption, Laser, law.invention, Optics, law, Dissipative system, Pulse wave, Train, business, Retiming
Abstract

Processing of information with optical spikes could present an alternative path with a reduced energy consumption. It could also be well suited in the framework of novel brain-inspired computation paradigms. We investigate the spiking and pulse train dynamics in a micropillar laser with integrated saturable absorber. The optically-pumped microcavity laser is based on a specifically optimized design. The solitary laser can emit sub-nanosecond Q-switched pulses above laser threshold. Below threshold, the laser is in the so-called excitable regime, a generic all-or-none kind of response also found in biological neurons. We demonstrate several neuromimetic properties of the micropillar laser including the relative and absolute refractory periods and the temporal summation. The latter gives rise to sensitive and fast coincidence detectors of optical signals. In the configuration with delayed optical feedback, the system is shown experimentally and theoretically to sustain controllable trains of dissipative temporal solitons controlled by adequate optical perturbations. We show that the pulse train can be started or resynchronized (retiming) with a single perturbation and that the system can store a large variety of temporal pulse patterns. We discuss the role of pump noise that may terminate a pulse train. We demonstrate a strong asymmetry in the effect of noise on the switch on and off processes, as well as a peculiar role played by noise timing. Besides its interest as a compact source of controllable pulses, this system can be arranged if needed in arrays leading to interesting prospects for artificial optical neural networks.

Published
2018

17. GENERATION OF NEW SPATIAL AND TEMPORAL COHERENT LIGHT STATES USING III-V SEMICONDUCTOR METASURFACE BASED LASER TECHNOLOGY: VORTEX, CONTINUUM, DUAL FREQUENCY FOR THz

Author

P. Lalanne, Mohamed Seghilani, I. Sagnes, Baptiste Chomet, M. Myara, Stéphane Blin, R. Paquet, M. Sellahi, L. Legratiet, G. Beaudoin, and Arnaud Garnache

Subjects
Physics, Laser technology, Optics, Semiconductor, Continuum (measurement), business.industry, Terahertz radiation, Optoelectronics, Dual frequency, business, Vortex
Published
2017

18. Generation of new coherent light states using III-V semiconductor laser technology: VORTEX, continuum, dual frequency for THz and integration

Author

M. Myara, L. Legratiet, M. Sellahi, Isabelle Sagnes, Arnaud Garnache, P. Lalanne, R. Paquet, Baptiste Chomet, G. Beaudoin, Mohamed Seghilani, Stéphane Blin, Institut d’Electronique et des Systèmes (IES), Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Térahertz, hyperfréquence et optique (TéHO), Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de l'Accélérateur Linéaire (LAL), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Centre de Nanosciences et de Nanotechnologies [Marcoussis] (C2N), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de photonique et de nanostructures (LPN), and Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, business.industry, Quantum limit, Shot noise, Physics::Optics, Nonlinear optics, 02 engineering and technology, 021001 nanoscience & nanotechnology, Laser, 01 natural sciences, law.invention, Vertical-cavity surface-emitting laser, [SPI.TRON]Engineering Sciences [physics]/Electronics, 010309 optics, Optics, law, Optical cavity, 0103 physical sciences, Coherent states, Optoelectronics, 0210 nano-technology, business, ComputingMilieux_MISCELLANEOUS, Coherence (physics)
Abstract

Since years, III-V semiconductor based external-cavity VCSEL (VECSEL) concept [I] is pointed out as a technology of choice for beyond-state-of-the-art laser light sources, demonstrating wavelength flexibility, high power, high spatial, temporal and polarization coherence, CW or fs ultra-short pulsed operation, compactness and functionalities. The targeted coherent state is typically a common circular low divergence fundamental gaussian TEM00 mode, linearly polarized state, single frequency state or modelocked comb. Such high-Q laser cavity exhibits a class-A dynamics with low intensity noise at shot noise level in MHz-GHz RF range, as well as a quantum limit optical frequency noise at the Hz level. Integration and packaging of such high performances sources is in progress (by Coherent, Innoptics [2], Fraunhofer ILT…). In this work, we take advantage of diode-pumped VECSEL based on III-V nanotechnologies integrating flat-photonics (quantum-well gain, Bragg mirror, metasurface, metallic mask), and fundamental physical features (axial symmetry of laser design, orthogonality of cavity modes, high finesse cavity, homogeneous gain, optical gain structure anisotropy, spatial hole burning…) for the generation of non-conventional coherent states, thanks to the insertion of new intracavity functions: beam carrying Orbital-Angular-Momentum, dual-frequency optical source for THz, coherent modeless light source.

Published
2017

19. (Invited) Strain Engineering for Optical Gain in Germanium

Author

R. Jakomin, Philippe Boucaud, Malo de Kersauson, A. Ghrib, G. Ndong, Isabelle Sagnes, Sébastien Sauvage, Marc Chaigneau, Razvigor Ossikovski, Ludovic Largeau, G. Beaudoin, Olivia Mauguin, Moustafa El Kurdi, and Mathias Prost

Subjects
Strain engineering, Materials science, chemistry, business.industry, Optoelectronics, chemistry.chemical_element, Germanium, business
Abstract

Room temperature optical gain and lasing have been recently demonstrated in germanium. One key ingredient to obtain positive gain is to reduce the splitting between the conduction indirect and direct valleys by introducing tensile strain. We have investigated two distinct approaches to apply a large tensile strain in germanium. The first approach relies on the growth of germanium on InGaAs buffer templates. Biaxial tensile strains up to 0.8% have been achieved by this method. The second approach relies on stress transfer through silicon nitride layers. It offers the advantage of a full compatibility with CMOS processing. We have successfully fabricated tensile-strained photonic wires which exhibit optical gain under cw optical pumping.

Published
2013

23. Cancer in Renal Allograft Recipients

Author

R. D. Guttmann, A. Gonda, D. D. Morehouse, J. G. Beaudoin, P. G. Chassot, and L. D. MacLean

Subjects
medicine.medical_specialty, business.industry, medicine, Urology, Renal allograft, Cancer, medicine.disease, business
Published
2015

24. Metallogeny

Author

H. Scott Swinden, S.M. Dunsworth, G. Beaudoin, R.C. Boehner, J.L. Davies, W.L. Dickson, G. Duquette, D.T.W. Evans, J.H. Fowler, L.R. Fyffe, M. Gauthier, A.F. Howse, B.F. Kean, T. Lane, M. Malo, S.R. McCutcheon, C.F. O’Driscoll, A.A. Ruitenberg, R.J. Ryan, A.L. Sangster, C.M. Saunders, and C.R. van Staal

Published
2015

27. Chytridiomycosis impacts predator-prey interactions in larval amphibian communities

Author

Joseph G. Beaudoin and Matthew J. Parris

Subjects
Amphibian, Time Factors, Population Dynamics, Population, Hyla chrysoscelis, Communicable Diseases, Emerging, biology.animal, Animals, Chytridiomycosis, education, Ecosystem, Ecology, Evolution, Behavior and Systematics, Population Density, Analysis of Variance, Chytridiomycota, education.field_of_study, biology, Ecology, Notophthalmus, Salamandridae, biology.organism_classification, Hyla, Tennessee, Gray treefrog, Larva, Predatory Behavior, Body Constitution, Anura
Abstract

Despite ecologists increasingly recognizing pathogens as playing significant roles in community dynamics, few experimental studies have quantified patterns of disease impacts on natural systems. Amphibians are experiencing population declines, and a fungal pathogen ( Batrachochytrium dendrobatidis; Chytridiomycota) is a suspected causal agent in many declines. We studied the effects of a pathogenic fungus on community interactions between the gray treefrog, Hyla chrysoscelis, and eastern newts, Notophthalmus viridescens. Recent studies have characterized chytridiomycosis as an emerging infectious disease, whose suspected rapid range expansion and widespread occurrence pose a significant risk for amphibian populations worldwide. We reared larvae in outdoor polyethylene experimental tanks and tested the effects of initial larval density, predator presence, and fungal exposure on Hyla recruitment and predator-prey interactions between Hyla and Notophthalmus. Newts reduced treefrog survival, and high intraspecific density decreased metamorphic body mass independent of B. dendrobatidis. The presence of fungi reduced treefrog body mass at metamorphosis by 34%, but had no significant main effect on survival or larval period length. B. dendrobatidis differentially affected larval development in the presence of predators; Hyla developed slower when reared with the pathogen, but only when newts were present. This significant predator-by-pathogen interaction suggests that the impact of chytridiomycosis on larval amphibians may be exacerbated in complex communities. Our data suggest that B. dendrobatidis effects on host life history may be complex and indirect. Direct measurements of the community-level effects of pathogens offer an important opportunity to understand a significant threat to global biodiversity-declining amphibian populations.

Published
2004

28. Absolute and relative refractory periods in a micropillar laser with saturable absorber

Author

Robert Kuszelewicz, Rémy Braive, F. Selmi, G. Beaudoin, Sylvain Barbay, and Isabelle Sagnes

Subjects
Physics, Signal processing, Wave propagation, Refractory period, business.industry, Saturable absorption, Laser, law.invention, Nonlinear system, Amplitude, Optics, Semiconductor, law, business
Abstract

We study the nonlinear dynamics of semiconductor micropillar lasers with intracavity saturable absorber in the excitable regime. The excitable regime is characterized by an all-or-none type of response to an input perturbation: when the perturbation amplitude is below the excitable threshold, the system remains in its quiet, stable state; when the perturbation exceeds the excitable threshold, a calibrated response pulse is emitted. It is believed to have great potential for fast neuromorphic optical processing, in addition to being also interesting for the study of nonlinear wave propagation. Fast excitable, neuron-like, dynamics is experimentally evidenced with response times in the 200ps range. We also show the presence of an absolute and a relative refractory periods in this system, analog to what is found in biological neurons but with several orders of magnitude faster response times. The absolute refractory period is the amount of time after a first excitable pulse has been emitted during which it is not possible to excite the system anymore. The relative refractory period is the time after a first excitable pulse during which an inhibited response is emitted and has been often overlooked in optical systems. Both these times are of fundamental importance regarding the propagation of stable excitable waves, and in view of designing spike-time based optical signal processing systems. The experimental results are well described qualitatively by a simple model of a laser with saturable absorber.

Published
2014

29. Tensile-strained germanium microdisks using Si3N4 stressors

Author

M. de Kersauson, I. Sagnes, Sébastien Sauvage, Xavier Checoury, Mathias Prost, G. Beaudoin, G. Ndong, M. El Kurdi, P. Boucaud, M. Chaigneau, A. Ghrib, and Razvigor Ossikovski

Subjects
Materials science, business.industry, chemistry.chemical_element, Germanium, Tensile strain, chemistry.chemical_compound, Quality (physics), Silicon nitride, chemistry, Q factor, Ultimate tensile strength, Optoelectronics, Whispering-gallery wave, Free carrier absorption, business
Abstract

A strong tensile strain (1% biaxial) is applied to germanium microdisks using silicon nitride stressors. Both Fabry-Perot and whispering gallery modes are observed with quality factors up to 1350 limited by free carrier absorption.

Published
2013

31. Freezing of molecular hydrogen and its isotopes in porous vycor glass

Author

John Beamish, G. Beaudoin, P. C. Haljan, and Mark Paetkau

Subjects
Argon, Materials science, Hydrogen, Triple point, chemistry.chemical_element, Thermodynamics, Condensed Matter Physics, Molecular physics, Atomic and Molecular Physics, and Optics, chemistry.chemical_compound, chemistry, Deuterium, Solid hydrogen, General Materials Science, Hydrogen deuteride, Supercooling, Helium
Abstract

The authors have made a detailed ultrasonic study of freezing and melting of molecular H{sub 2}, HD and D{sub 2} in the pores of Vycor glass. The behavior was similar to that seen in previous measurements with argon and helium. The hydrogen liquids undercooled about 2.5 K below their bulk triple points before freezing began and there was substantial hysteresis between freezing and melting. The velocity and attenuation began to increase suddenly at the onset of freezing. The velocity continued to increase to the lowest temperatures (2K) and the attenuation had a broad peak at about two thirds of the freezing temperature. The authors attribute these effects to stress relaxation via thermally activated vacancy motion in the solid hydrogen, an interpretation confirmed by looking at the frequency dependence of the velocity and attenuation. The magnitude of the velocity and attenuation changes increased in going from H{sub 2} to HD to D{sub 2}, as expected based on their increasing densities and elastic constants. However, there were no qualitative differences between the boson (H{sub 2} and D{sub 2}) and fermion (HD) cases nor, for that matter, between hydrogen and argon. The authors believe that essentially all the hydrogen was frozen a fewmore » tenths of a kelvin below T{sub F}, at the point where the melting;freezing hysteresis began. If even a few per cent of the hydrogen had remained liquid and become superfluid at some lower temperature, it would have been seen as a further increase in the velocity and a critical attenuation peak. The sensitivity of the ultrasonic measurements allowed the authors to make accurate measurements of the freezing and melting temperatures of the different liquids in Vycor. They found that the fractional undercooling, (T{sub B} {minus} T{sub F})/T{sub B}, increased as the molecular mass decreased which may indicate the importance of quantum effects on the liquid-solid interfacial energy {sigma}{sub Is}.« less

Published
1996

33. Iron oxide compositions in till and bedrock samples from the Sue-Dianne IOCG deposit, Northwest Territories and the Pipe Ni-Cu deposit, Manitoba

Author

M B McClenaghan, Isabelle McMartin, C. Dupuis, G Beaudoin, M. Pozza, and Anne-Aurélie Sappin

Subjects
geography, chemistry.chemical_compound, geography.geographical_feature_category, chemistry, Bedrock, Iron oxide, Geochemistry, Iron oxide copper gold ore deposits, Geology
Abstract

This open file reports the chemical compositions of Fe oxide mineral grains (mainly magnetite and minor hematite) from the ferromagnetic fraction of bedrock and till from the iron oxide copper-gold (IOCG) Sue-Dianne deposit in the Great Bear magmatic zone, NWT and from till around the Pipe magmatic Ni-Cu deposit in the Thompson Nickel Belt, Manitoba. These data were collected in support of research by the DIVEX research network and the Geological Survey of Canada into the use of magnetite as an indicator mineral for mineral exploration in glaciated terrain.

Published
2012

34. Updated measurement of the τ lifetime

Author

R. Van Kooten, D. Pitman, M. H. Lehto, E. Lefebvre, S. L. Chu, T. G. Shears, F. Odorici, F. Liu, Margret Fincke-Keeler, D. M. Gingrich, G. Giacomelli, B. C. Shen, P. Schenk, P. Berlich, Siegfried Bethke, T. Hilse, A. K. Honma, B. Nijjhar, W. G. Scott, H. M. Fischer, M. S. Dixit, O. Runolfsson, J. Mildenberger, Gideon Bella, Frans Meijers, H. J. Burckhart, Gordon H. Hanson, Jacqueline Batley, C. M. Hawkes, Daniel Lellouch, A. Michelini, C. Beeston, M. Fanti, James Pinfold, Claudio Grandi, R. D. Heuer, M. J. Losty, Fabrizio Fabbri, P. Pfister, D. Van den plas, D. R. Rust, Takehiko Mori, P. Igo-Kemenes, F. S. Merritt, M. Yurko, D. G. Fong, M. W. Redmond, A. M. Lee, G. Beaudoin, J. Gascon, W. R. Gibson, H. Jeremie, H. von der Schmitt, P. W. Jeffreys, S. W. O'Neale, P. E.L. Clarke, U. C. Dunwoody, M. K. Jones, Xinchou Lou, S. A. Robins, H. Mes, R. E. Hughes-Jones, U. Maur, J. Steuerer, R.J. Akers, I. P. Duerdoth, A. Beck, E. Heflin, K. J. Anderson, J. P. Martin, J. W. Gary, M. J. Oreglia, Matthias Schröder, R. M. Brown, A. Höcker, Lorne Levinson, R. Lahmann, Silvia Arcelli, P. D. Phillips, J. A. McKenna, Tohru Takeshita, D. C. Imrie, P. Bright-Thomas, B. Stockhausen, Paul Kyberd, F. K. Loebinger, S. De Jong, Marcello Mannelli, J. E. Duboscq, Shlomo Dado, Sachio Komamiya, P. Poffenberger, E. do Couto e Silva, Georges Azuelos, Barry King, Peter Fischer, J. J. Ward, P. Scharff-Hansen, E. Barberio, Theodoros Geralis, D. A. Hinshaw, D. E. Plane, O. Schaile, K. W. Bell, E. Ros, A. T. Watson, Erez Etzion, G. P. Siroli, J. King, P. Schütz, M. A. Thomson, J. C. Hill, I. J. Bloodworth, P. Bentkowski, R. Bartoldus, C. Moisan, G. A. Beck, Marco Cuffiani, A. M. Smith, Christoph Schwick, G. M. Dallavalle, Achim Stahl, J. R. Carter, H. O. Ogren, Christoph Geich-Gimbel, Misao Sasaki, Stefan Kluth, Shlomit Tarem, G. N. Patrick, P. Teixeira-Dias, P. Le Du, B. Fabbro, M. Settles, G. Vasseur, B. Lorazo, Otmar Biebel, R. Giacomelli, T. Behnke, S. Rossberg, C. J. Oram, D. G. Charlton, D. L. Wagner, Kiyotomo Kawagoe, T. P. Kokott, A. Luig, Andris Skuja, Yoram Rozen, J. G. Layter, M. Foucher, Stephen Lloyd, G. D. Long, C. Y. Chang, B. Schmitt, H. Deng, R. Humbert, M. Tecchio, Tetsuro Mashimo, R. P. Middleton, C. Charlesworth, A. I. McNab, F. X. Gentit, J. E. Conboy, G. W. Wilson, A. Fürtjes, Michael Kobel, J. Goldberg, P. Weber, Gregor Herten, A. M. Rossi, H. Przysiezniak, D. Axen, A. Jawahery, Giora Mikenberg, D. Karlen, B. Nellen, W. Gorn, S. G. Clowes, C. Burgard, D. Hochman, P. A. Hart, B. Wilkens, P. Leblanc, T. Tsukamoto, Ehud Duchovni, Paolo Giacomelli, M. Hansroul, M. Fierro, H. Lafoux, T. J. Smith, K. Stephens, Peter Sherwood, M. Jimack, Z. Li, Norbert Wermes, Sherry Towers, Hans-Christian Schultz-Coulon, T. Kawamoto, A. Buijs, J. R. McNutt, M. J. Pearce, D. M. Strom, H. Ihssen, R. W. Springer, Alexander Wagner, J. Hagemann, C. H. Shepherd-Themistocleous, H. G. Evans, J. Ludwig, J. E. Pilcher, C. Dallapiccolla, S. W. Gensler, M. J. Goodrick, K. Runge, P. Bock, I. Cohen, John Allison, C. Darling, S. Orito, M. F. Turner-Watson, M. Morii, M. Rosvick, S. J. Hillier, R. J. Homer, T. Kobayashi, Randall Sobie, Peter R Hobson, S. Braibant, Gunter Wolf, M. Hauschild, P. Gagnon, C. Stegmann, N. I. Geddes, Michael Schulz, G. D. Lafferty, P. Routenburg, V. Gibson, R. Ströhmer, C. Markus, P. Mättig, Shoji Asai, G. T. Zorn, A. Astbury, U. Müller, S. Wotton, B. Poli, H. M. Bosch, R. Kowalewski, A. J. Martin, Wolfram Dietrich Zeuner, H. Fukui, A. Yeaman, P. D. Grannis, Gideon Alexander, J. M. Roney, R. G. Kellogg, Paolo Capiluppi, D. R. Ward, G. A. Snow, C. K. Hargrove, C. P. Ward, D. L. Rees, D. S. Koetke, J. C. Clayton, Stefano Marcellini, T. W. Pritchard, James Letts, Madjid Boutemeur, P. S. Wells, Guenter Duckeck, Terry Richard Wyatt, P. G. Estabrooks, R. K. Keeler, M. Coupland, P. M. Watkins, R. Howard, Claude Leroy, J. P. Pansart, V. H. Winterer, P. Szymanski, C. Jui, Stan Bentvelsen, C. Sbarra, Michael Dittmar, G. Yekutieli, A. A. Carter, Ron Folman, Roger Jones, M. G. Rison, T. J. McMahon, J. Schwiening, R. K. Carnegie, J. A. Wilson, J. von Krogh, J. Hart, Dave Robinson, J. D. Gillies, R. J. Barlow, D. J. Miller, D. Rigby, R. J. Hemingway, B. W. Kennedy, P. Jovanovic, Austin Ball, Peter Krieger, N. K. Watson, Manuella Vincter, Alessandro Montanari, R. Mir, J. Lauber, H. Takeda, F. G. Oakham, W. Mohr, A. Posthaus, P. A. Elcombe, J. Becker, F. Scharf, A. D. Schaile, A. Skillman, E. K. U. Gross, A. Gaidot, T. Wlodek, M. Sproston, and N. Tesch

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Particle physics, Electron–positron annihilation, High Energy Physics::Experiment, Particle Physics - Experiment, Charged particle, Lepton
Abstract

We present an update of our measurement of the τ lepton lifetime, using data taken during 1992 and 1993 with the OPAL detector at LEP. The lifetime is determined from analyses of the impact parameters of tracks from τ decays to a single charged particle, and the reconstructed decay lenghts from the τ decays to three charged particles. With the added statistics (which increase the τ pair event sample size by more than a factor of four over our 1990 and 1991 data sample), the updated lifetime measurement is: ττ = 288.8 ± 2.2 (stat) ± 1.4 (sys) fs. When combined with world-average measurements of the tau leptonic branching fractions (assuming e-μ universality), the ratio of charged-current couplings is: ( g τ g μ ) = 1.005 ± 0.007 , in agreement with the hypothesis of τ-μ charged-current universality.

Published
1994

35. Measurement of $$\Gamma (Z^0 \to b\bar b)/\Gamma (Z^0 \to hadrons)$$ using impact parameters and leptons

Author

R. Lahmann, D. C. Imrie, J. C. Clayton, B. C. Shen, G. P. Siroli, J. King, A. K. Honma, Christoph Schwick, W. G. Scott, Gideon Bella, H. J. Burckhart, M. Jones, Jacqueline Batley, G. A. Snow, C. P. Ward, M. J. Pearce, Horst Breuker, Margret Fincke-Keeler, D. L. Rees, M. J. Losty, Otmar Biebel, P. Igo-Kemenes, C. Jui, J. Hart, C. Sbarra, S. Barnett, Claude Leroy, A. Astbury, J. P. Pansart, J. D. Gillies, P. Pfister, R. Bartoldus, H. Jeremie, U. Müller, James Pinfold, G. E. Richards, D. Pitman, A. J. Martin, F. C. Grant, M. H. Lehto, D. G. Charlton, D. L. Wagner, R. J. Barlow, R. E. Hughes-Jones, U. Maur, D. Hochman, D. G. Fong, H. O. Ogren, Michael Dittmar, G. Yekutieli, D. J. Miller, Christoph Geich-Gimbel, G. Beaudoin, C. K. Hargrove, N. I. Geddes, Matthias Schröder, H. Lafoux, N. Paz-Jaoshvili, J. Steuerer, J. Gascon, H. von der Schmitt, T. G. Shears, B. Boden, K. Stephens, J. R. McNutt, R.J. Akers, J. Lauber, E. do Couto e Silva, A. Buijs, D. M. Strom, C. Stegmann, H. Takeda, D. M. Gingrich, D. E. Plane, P. Bentkowski, A. A. Carter, Roger Jones, R. Van Kooten, M. G. Rison, T. J. McMahon, B. Poli, F. G. Oakham, G. M. Dallavalle, M. Hansroul, Madjid Boutemeur, E. Lefebvre, J. W. Gary, Marcello Mannelli, J. E. Duboscq, H. Deng, R. Humbert, Shlomo Dado, Tohru Takeshita, J. Schwiening, R. K. Carnegie, F. X. Gentit, B. Fabbro, O. Schaile, P. Berlich, J. A. Wilson, F. Odorici, J. E. Conboy, B. Panzer-Steindel, R. Kowalewski, R. Yaari, D. J.P. Dumas, R. J. Hemingway, Georges Azuelos, P. G. Estabrooks, R. K. Keeler, P. M. Watkins, V. Gibson, S. Bethke, P. Scharff-Hansen, G. Quast, J. M. Lorah, W. Schappert, P. Kroll, Marco Cuffiani, John Baines, X. C. Lou, Silvia Arcelli, W. R. Gibson, A. M. Rossi, C. H. Shepherd-Themistocleous, P. Jovanovic, T. Tsukamoto, W. Mohr, J. F. Kral, Austin Ball, H. M. Fischer, M. A. Whallev, K. W. Bell, Max Weber, D. Menszner, Randall Sobie, G. D. Lafferty, S. L. Chu, A. Beck, J. C. Hill, A. Michelini, H. Mes, Norbert Wermes, J. von Krogh, I. P. Duerdoth, A. C. Janissen, J. M. Roney, E. Heflin, Sherry Towers, P. S. Wells, Misao Sasaki, R. J. Homer, M. Hauschild, Alessandro Montanari, R. M. Brown, T. Kawamoto, A. M. Smith, P. M. Hattersley, J. Banks, Lorne Levinson, G. Vasseur, Dave Robinson, Gideon Alexander, P. A. Elcombe, Giora Mikenberg, C. Markus, P. Paschievici, Terry Richard Wyatt, B. Lorazo, D. R. Ward, L. A. del Pozo, C. Y. Chang, M. F. Turner, B. W. Kennedy, T. W. Pritchard, E. Torrente-Lujan, G. Transtromer, Paolo Capiluppi, Kiyotomo Kawagoe, John Hobbs, C. Moisan, R. D. Heuer, M. Coupland, Andris Skuja, G. A. Beck, Fabrizio Fabbri, Achim Stahl, S. Orito, M. Rosvick, J. Becker, P. Teixeira-Dias, D. Van den plas, P. Weber, F. S. Merritt, F. Scharf, Tetsuro Mashimo, G. J. VanDalen, R. Mir, Gregor Herten, D. R. Rust, C. Wahl, B. Schmitt, B. Wilkens, A. Skillman, A. M. Lee, J. E. Pilcher, W. Gorn, A. Gaidot, T. Wlodek, M. Sproston, G. Giacomelli, J. A. McKenna, M. J. Oreglia, N. Tesch, A. Dieckmann, A. D. Schaile, V. H. Winterer, P. Schenk, J. R. Carter, P. F. Harrison, G. N. Patrick, Stephen Lloyd, M. Tecchio, M. S. Dixit, Ehud Duchovni, M. Jimack, H. Ihssen, Frans Meijers, S. W. Gensler, S. J. Hillier, T. Kobayashi, P. E.L. Clarke, H. Przysiezniak, M. Fierro, M. Yurko, S. A. Robins, J. P. Martin, P. W. Jeffreys, S. De Jong, P. Bright-Thomas, S. W. O'Neale, M. A. Thomson, K. J. Anderson, J. G. Layter, T. Hilse, O. Runolfsson, P. Poffenberger, C. Beeston, Claudio Grandi, D. A. Hinshaw, T. Behnke, D. Axen, A. Jawahery, Peter Sherwood, I. J. Bloodworth, R. W. Springer, Alexander Wagner, J. Hagemann, J. Ludwig, K. Runge, P. Bock, G. Duckeck, R. Ströhmer, G. T. Zorn, H. M. Bosch, Wolfram Dietrich Zeuner, A. Yeaman, M. Settles, M. Foucher, N. K. Watson, G. W. Wilson, D. Karlen, C. Burgard, C. M. Hawkes, M. Cooper, Erez Etzion, Daniel Lellouch, Takehiko Mori, Stefan Kluth, Shlomit Tarem, S. Rossberg, C. J. Oram, R. P. Middleton, J. Goldberg, B. Nellen, P. Leblanc, M. Morii, T. J. Smith, Peter R Hobson, H. G. Evans, M. J. Goodrick, I. Cohen, P. Routenburg, Gunter Wolf, P. Mättig, Sachio Komamiya, N. J. Tesilian, E. Ros, A. T. Watson, S. Wotton, T. P. Kokott, A. Luig, Paul Kyberd, F. K. Loebinger, A. Rollnik, R. Giacomelli, J. Mildenberger, Harold Nguyen, Gordon H. Hanson, M. W. Redmond, John Allison, R. G. Kellogg, D. S. Koetke, Stefano Marcellini, and James Letts

Subjects
Physics, Particle physics, Physics and Astronomy (miscellaneous), Astrophysics::High Energy Astrophysical Phenomena, Electron–positron annihilation, High Energy Physics::Phenomenology, Hadron, Elementary particle, Bottom quark, Charm quark, Nuclear physics, High Energy Physics::Experiment, Production (computer science), Impact parameter, Engineering (miscellaneous), Particle Physics - Experiment, Bar (unit)
Abstract

A measurement of\(\Gamma _{b\bar b} /\Gamma _{had} \equiv \Gamma (Z^0 \to b\bar b)/\Gamma (Z^0 \to hadrons)\) is presented using a “mixed tag” method involving the identification of\(Z^0 \to b\bar b\) events by two different techniques. The first uses the large impact parameter of tracks emerging from the decay ofb-flavoured hadrons and the second their semi-leptonic decay. The identification efficiencies are measured from the data using all possible combinations of the two tags in opposite hemispheres. The method is therefore insensitive to Monte Carlo modelling of bottom quark production and ofb-flavoured hadron production and decay properties, and depends only weakly on the simulation of the detector. The data sample collected by OPAL at LEP in 1990 and 1991 is considered. The result is: $$\frac{{\Gamma _{b\bar b} }}{{\Gamma _{had} }} = 0.218 \pm 0.006(stat) \pm 0.007(syst) \pm 0.007(\Gamma _{c\bar c} /\Gamma _{had} ),$$ where the systematic uncertainty due to the charm quark partial width has been separated from the other systematic uncertainties. Combination with previous OPAL measurements gives: $$\frac{{\Gamma _{b\bar b} }}{{\Gamma _{had} }} = 0.220 \pm 0.004(stat) \pm 0.006(syst) \pm 0.006(\Gamma _{c\bar c} /\Gamma _{had} ),$$

Published
1994

36. Measurement of the time dependence of mixing using a jet charge technique

Author

W. R. Gibson, A. Beck, E. Heflin, P. S. Wells, R. M. Brown, Lorne Levinson, C. Y. Chang, M. F. Turner, James Pinfold, Terry Richard Wyatt, G. Beaudoin, D. G. Fong, R. Bartoldus, B. W. Kennedy, E. Torrente-Lujan, J. Gascon, H. von der Schmitt, N. K. Watson, Michael Kobel, Gregor Herten, M. Coupland, John Allison, Shlomo Dado, R. G. Kellogg, D. S. Koetke, Stefano Marcellini, James Letts, H. O. Ogren, C. Wahl, C. Sbarra, B. Wilkens, Christoph Geich-Gimbel, H. Lafoux, Paul Kyberd, Paolo Giacomelli, F. K. Loebinger, Otmar Biebel, M. Hansroul, N. J. Tresilian, A. Rollnik, R. Giacomelli, Michael Dittmar, R. J. Hemingway, J. W. Gary, G. E. Richards, Georges Azuelos, D. G. Charlton, D. L. Wagner, T. J. Smith, K. Stephens, G. Yekutieli, J. Kroll, R. D. Heuer, Marcello Mannelli, J. E. Duboscq, Fabrizio Fabbri, D. Van den plas, J. E. Pilcher, F. C. Grant, K. W. Bell, W. Mohr, J. Mildenberger, Giora Mikenberg, Harold Nguyen, F. X. Gentit, J. E. Conboy, A. Fürtjes, R. Van Kooten, D. Pitman, P. Jovanovic, M. W. Redmond, J. R. McNutt, A. A. Carter, Ron Folman, Roger Jones, H. Deng, R. Humbert, Kiyotomo Kawagoe, M. H. Lehto, T. G. Shears, P. Poffenberger, Gideon Bella, H. J. Burckhart, Jacqueline Batley, J. C. Hill, Misao Sasaki, H. Przysiezniak, Austin Ball, M. Fierro, G. G. Hanson, A. Buijs, D. M. Strom, C. Stegmann, S. L. Chu, I. J. Bloodworth, P. Scharff-Hansen, D. M. Gingrich, P. A. Elcombe, B. C. Shen, D. A. Hinshaw, C. H. Shepherd-Themistocleous, Manuella Vincter, Alessandro Montanari, P. Schütz, M. G. Rison, E. Lefebvre, R. J. Homer, D. E. Plane, H. Fukui, T. Hilse, Hans-Christian Schultz-Coulon, Randall Sobie, Michael Schulz, G. D. Lafferty, Siegfried Bethke, G. Giacomelli, J. Hart, F. S. Merritt, P. Berlich, M. Hauschild, A. K. Honma, A. M. Smith, F. Odorici, C. Dallapiccola, W. G. Scott, O. Runolfsson, P. Bentkowski, Sherry Towers, T. Kawamoto, T. J. McMahon, T. W. Pritchard, J. D. Gillies, G. M. Dallavalle, G. A. Snow, C. P. Ward, J. Becker, A. D. Schaile, G. Vasseur, B. Lorazo, C. Markus, D. R. Rust, P. Paschievici, V. Gibson, D. L. Rees, Xinchou Lou, Z. Li, J. Schwiening, G. Quast, C. Beeston, R. K. Carnegie, F. Scharf, P. Schenk, P. Weber, Claudio Grandi, M. Settles, C. Moisan, J. A. McKenna, G. J. VanDalen, G. A. Beck, P. F. Harrison, Andris Skuja, Achim Stahl, T. Behnke, M. Yurko, Guenter Duckeck, P. W. Jeffreys, M. J. Losty, J. A. Wilson, R. J. Barlow, S. Orito, M. Rosvick, D. J.P. Dumas, D. J. Miller, A. M. Lee, P. Teixeira-Dias, Stephen Lloyd, G. D. Long, M. S. Dixit, R. Mir, Tetsuro Mashimo, Frans Meijers, P. Bright-Thomas, A. Skillman, R.J. Akers, J. J. Ward, M. Tecchio, M. A. Thomson, A. Gaidot, D. R. Ward, P. Le Du, B. Fabbro, H. Mes, I. P. Duerdoth, T. Wlodek, M. Sproston, B. Schmitt, M. Morii, M. Foucher, D. Axen, C. Jui, P. E.L. Clarke, A. Jawahery, O. Schaile, R. Howard, M. K. Jones, J. Lauber, S. W. O'Neale, Margret Fincke-Keeler, A. M. Rossi, Peter R Hobson, Claude Leroy, S. Barnett, N. Wermes, W. Gorn, J. P. Pansart, J. P. Martin, N. Tesch, K. J. Anderson, D. Hochman, H. Takeda, V. H. Winterer, M. J. Oreglia, Peter Sherwood, R. W. Springer, Alexander Wagner, F. G. Oakham, T. Tsukamoto, P. Pfister, J. Hagemann, J. Ludwig, K. Runge, P. Bock, J. C. Clayton, J. R. Carter, G. N. Patrick, S. De Jong, P. Routenburg, J. Goldberg, J. von Krogh, B. Nellen, P. M. Hattersley, P. Leblanc, J. Steuerer, R. Ströhmer, N. I. Geddes, H. G. Evans, Dave Robinson, M. J. Goodrick, I. Cohen, G. T. Zorn, R. Lahmann, Gunter Wolf, L. A. del Pozo, B. Boden, B. Poli, D. C. Imrie, G. W. Wilson, H. M. Bosch, Wolfram Dietrich Zeuner, S. Wotton, R. Yaari, Madjid Boutemeur, Marco Cuffiani, H. M. Fischer, J. G. Layter, G. P. Siroli, J. King, Christoph Schwick, P. G. Estabrooks, Erez Etzion, R. K. Keeler, A. Yeaman, A. Michelini, Stefan Kluth, Shlomit Tarem, D. Karlen, C. Charlesworth, S. Rossberg, C. J. Oram, C. Burgard, R. P. Middleton, S. A. Robins, P. M. Watkins, Sachio Komamiya, Theodoros Geralis, E. Ros, A. T. Watson, Silvia Arcelli, T. P. Kokott, A. Luig, J. M. Roney, C. Darling, P. A. Hart, P. Igo-Kemenes, H. Jeremie, R. E. Hughes-Jones, U. Maur, P. Mättig, Shoji Asai, E. do Couto e Silva, M. J. Pearce, C. M. Hawkes, M. Cooper, Daniel Lellouch, Takehiko Mori, Ehud Duchovni, M. Jimack, H. Ihssen, S. W. Gensler, S. J. Hillier, T. Kobayashi, Matthias Schröder, R. Kowalewski, Gideon Alexander, Paolo Capiluppi, A. Astbury, U. Müller, A. J. Martin, and C. K. Hargrove

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Jet (fluid), Particle decay, Particle physics, Meson, Oscillation, Electron–positron annihilation, High Energy Physics::Experiment, Charge (physics), Electric charge, Lepton
Abstract

The observation and measurement of the time-dependence of B0d↔B0d mixing are described. The B0d meson is reconstructed in final states that contain a D∗− and an l+, where the b flavour of the B0d at decay time is tagged by the electric charge of the lepton. A new and efficient method, using a jet charge technique, is developed for identifying the b flavour of the produced B0d. From a sample of 556 D∗±l∓ candidates reconstructed in the OPAL data collected during 1990–1993, the B0d↔B0d oscillation frequency is measured to be Δmd = 0.508 ± 0.075 (stat) ±0.025(syst) ps−1 giving an oscillation parameter of χd = 0.73 ± 0.11 (stat) ±0.08 (syst), where 0.076 of the systematic error on χd arises from the uncertainty on the B0d lifetime.

Published
1994

37. Measurement of the τ− → h− π0ντ and τ− → h− ⩾ 2π0ντ branching ratios

Author

John Allison, M. Hauschild, R. G. Kellogg, K. Stephens, C. Markus, D. S. Koetke, Otmar Biebel, G. E. Richards, D. G. Charlton, D. L. Wagner, P. Pfister, Stefano Marcellini, James Letts, S. Wotton, I. J. Bloodworth, Paul Kyberd, F. K. Loebinger, H. Deng, R. Humbert, P R Poffenberger, A. Rollnik, N. J. Tresilian, R. Giacomelli, Madjid Boutemeur, J. Mildenberger, Harold Nguyen, Gordon H. Hanson, S. Bethke, M. W. Redmond, D. C. Imrie, M. Settles, P. G. Estabrooks, R. D. Heuer, R. Ströhmer, P. Igo-Kemenes, Matthias Schröder, H. Przysiezniak, Fabrizio Fabbri, J. M. Roney, M. Foucher, D. Van den plas, M. Fierro, H. M. Fischer, P. M. Watkins, G. T. Zorn, V. Gibson, A. Michelini, Norbert Wermes, Sherry Towers, T. Kawamoto, D. G. Fong, S. L. Chu, P. Schütz, C. Darling, C. Moisan, G. A. Beck, G. W. Wilson, T. Wlodek, H. Jeremie, R. E. Hughes-Jones, Achim Stahl, H. M. Bosch, E. Duchovni, D. Karlen, S. Orito, Gregor Herten, Wolfram Dietrich Zeuner, Erez Etzion, R. Van Kooten, D. Pitman, P. Teixeira-Dias, M. H. Lehto, G. Giacomelli, J. Gascon, U. Maur, G. Yekutieli, Silvia Arcelli, T. Hilse, W. R. Gibson, P. Le Du, B. Fabbro, C. Wahl, B. Wilkens, Stefan Kluth, Shlomit Tarem, O. Runolfsson, D. Hochman, C. Y. Chang, Georges Azuelos, H. O. Ogren, P. M. Hattersley, P. Schenk, J. Steuerr, M. F. Turner, J. Pinfold, A. Beck, S. Wolf, B. Schmitt, J. E. Pilcher, K. W. Bell, T. J. Smith, T. G. Shears, S. A. Robins, S. Rossberg, C. J. Oram, Michael Kobel, D. A. Hinshaw, E. Heflin, C. Beeston, M. S. Dixit, Gideon Bella, Claudio Grandi, Frans Meijers, P. Bright-Thomas, R. M. Brown, E. do Couto e Silva, J. C. Hill, P. Mättig, Kiyotomo Kawagoe, H. Mes, I. P. Duerdoth, R. P. Middleton, M. J. Oreglia, H. J. Burckhart, R.J. Akers, M. Yurko, Jacqueline Batley, Misao Sasaki, H. Lafoux, P. A. Hart, D. R. Ward, G. A. Snow, C. P. Ward, J. W. Gary, C. M. Hawkes, M. Cooper, J. Goldberg, B. W. Kennedy, P. W. Jeffreys, B. Nellen, E. Torrente-Lujan, A. P. Wagner, Takehiko Mori, P. E.L. Clarke, P. Paschievici, A. M. Lee, B. C. Shen, Marcello Mannelli, J. E. Duboscq, O. Schaile, R. Yaari, D. L. Rees, M. K. Jones, A. K. Honma, M. J. Pearce, P. Leblanc, Paolo Giacomelli, R. Howard, M. Hansroul, P. Berlich, W. G. Scott, P. Weber, J. P. Martin, G. Beaudoin, J. R. Carter, G. N. Patrick, C. Burgard, C. H. Shepherd-Themistocleous, D. Axen, S. De Jong, S. W. O'Neale, K. J. Anderson, H. G. Evans, M. J. Goodrick, I. Cohen, J. J. Ward, M. A. Thomson, A. Jawahery, R. J. Homer, J. C. Clayton, Xinchou Lou, R. Mir, Shlomo Dado, D. R. Rust, R. Kowalewski, A. Astbury, D. M. Gingrich, R. Lahmann, Peter Sherwood, U. Müller, R. W. Springer, M. J. Losty, P. Scharff-Hansen, Hans-Christian Schultz-Coulon, A. J. Martin, J. Hagemann, J. Ludwig, Michael Schulz, G. D. Lafferty, K. Runge, P. Bock, T. Behnke, G. Quast, G. P. Siroli, J. King, Christoph Schwick, Marco Cuffiani, E. Lefebvre, T. W. Pritchard, L. Levinson, F. Odorici, Z. Li, C. K. Hargrove, Guenter Duckeck, P. S. Wells, A. M. Smith, G. Vasseur, D. Lellouch, Gideon Alexander, Paolo Capiluppi, G. Mikenberg, J. G. Layter, B. Lorazo, A. M. Rossi, D. E. Plane, Terry Richard Wyatt, Andris Skuja, M. Rosvick, T. Tsukamoto, V. H. Winterer, P. Bentkowski, C. Charlesworth, G. D. Long, G. M. Dallavalle, M. Coupland, Tetsuro Mashimo, S. Barnett, W. Gorn, N. I. Geddes, D. J.P. Dumas, Richard Keeler, P. F. Harrison, B. Boden, B. Poli, Stephen Lloyd, M. Tecchio, C. Jui, A. D. Schaile, J. R. McNutt, Claude Leroy, J. P. Pansart, F. C. Grant, M. Jimack, H. Ihssen, A. Buijs, S. W. Gensler, D. M. Strom, C. Stegmann, S. J. Hillier, T. Kobayashi, A. Syoosi, F. S. Merritt, J. Lauber, H. Takeda, F. G. Oakham, J. A. McKenna, J. Hart, C. Dallapiccola, R. Bartoldus, J. D. Gillies, Christoph Geich-Gimbel, R. J. Barlow, J. Kroll, D. J. Miller, F. X. Gentit, J. E. Conboy, A. Fürtjes, R. J. Hemingway, P. Jovanovic, Sachio Komamiya, Austin Ball, Theodoros Geralis, E. Ros, A. T. Watson, T. P. Kokott, A. Luig, Manuella Vincter, Alessandro Montanari, C. Sbarra, Michael Dittmar, A. Yeaman, A. A. Carter, Ron Folman, Roger Jones, M. Morii, Peter R Hobson, M. G. Rison, J. von Krogh, Dave Robinson, L. A. del Pozo, T. J. McMahon, J. Schwiening, H. von der Scmitt, R. K. Carnegie, J. A. Wilson, M. Fincke-Keeler, N. K. Watson, W. Mohr, A. Skillman, A. Gaidot, M. Sproston, P. Routenburg, N. Tesch, P. A. Elcombe, J. Becker, F. Scharf, G. J. VanDalen, and R. Sobie

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Particle decay, Branching fraction, Electron–positron annihilation, Analytical chemistry, Branching (polymer chemistry), Selection criterion
Abstract

The branching ratios of the τ− → h− π0vτ and τ− → h− ⩾ 2π0vτ decays (where h− is either a π− or K−) are measured using the OPAL detector at LEP. The two branching ratios are simultaneously measured using separate selection criteria and are found to be Bh− π0 = (26.25 ± 0.35 ± 0.52)%, Bh− ⩾ 2π0 = (9.89 ± 0.34 ± 0.55)%Bh− π0 + Bh− ⩾ 2π0 = (36.14 ± 0.33 ± 0.58)%, where the first error is statistical and the second is systematic.

Published
1994

39. A measurement ofΓ (Z 0→b $$\Gamma ({\rm Z}^0 \to b\bar b)$$ /Γ(Z 0→hadrons) using an impact parameter technique

Author

Sachio Komamiya, E. Ros, A. T. Watson, A. Astbury, A. Skillman, U. Müller, T. P. Kokott, A. J. Martin, A. Luig, G. A. Snow, C. P. Ward, A. Gaidot, D. L. Rees, P. E.L. Clarke, I. J. Bloodworth, D. A. Hinshaw, James Pinfold, M. Kuwano, T. Wlodek, M. Sproston, J. Steuerer, D. G. Fong, Randall Sobie, G. D. Lafferty, J. Gascon, H. von der Schmitt, H. Przysiezniak, M. Fierro, P. Routenburg, N. Tesch, A. Dieckmann, M. Settles, T. W. Pritchard, F. Lamarche, R. J. Hemingway, C. K. Hargrove, G. Beaudoin, T. Behnke, Silvia Arcelli, P. Jovanovic, M. Foucher, T. Hilse, J. Mildenberger, Harold Nguyen, H. Takeda, F. G. Oakham, J. W. Gary, O. Runolfsson, F. S. Merritt, Austin Ball, Marcello Mannelli, J. E. Duboscq, D. Menszner, R. Yaari, Tohru Takeshita, Shlomo Dado, G. W. Wilson, Alessandro Montanari, D. Karlen, C. Beeston, C. Burgard, J. Hart, Claudio Grandi, S. Bethke, Marco Cuffiani, J. D. Gillies, M. W. Redmond, Otmar Biebel, Andris Skuja, R. J. Barlow, D. J. Miller, X. C. Lou, P. Igo-Kemenes, Georges Azuelos, G. Duckeck, R. Ströhmer, J. M. Lorah, M. J. Pearce, Horst Breuker, G. E. Richards, M. Yurko, Tetsuro Mashimo, P. W. Jeffreys, H. Jeremie, C. M. Hawkes, M. Cooper, J. F. Kral, U. Maur, K. W. Bell, D. G. Charlton, D. L. Wagner, G. T. Zorn, Giora Mikenberg, Daniel Lellouch, John Allison, W. Mohr, S. L. Chu, Gunter Wolf, Gregor Herten, Takehiko Mori, Max Weber, C. Wahl, J. C. Hill, Misao Sasaki, C. Jui, H. M. Bosch, Wolfram Dietrich Zeuner, J. M. Roney, P. Bright-Thomas, B. Wilkens, Matthias Schröder, E. do Couto e Silva, H. Mes, W. Gorn, P. A. Elcombe, I. P. Duerdoth, D. Axen, A. Jawahery, M. A. Thomson, R. G. Kellogg, M. Morii, H. Deng, R. Humbert, H. Lafoux, B. C. Shen, D. S. Koetke, Madjid Boutemeur, Peter Sherwood, J. A. McKenna, John Hobbs, Peter R Hobson, J. E. Pilcher, N. Paz-Jaoshvili, A. K. Honma, W. G. Scott, R. W. Springer, Alexander Wagner, Stefano Marcellini, James Letts, J. Hagemann, J. Ludwig, P. Scharff-Hansen, B. Fabbro, P. G. Estabrooks, R. K. Keeler, B. Panzer-Steindel, K. Runge, P. Bock, A. D. Schaile, R. Kowalewski, J. Becker, M. Hauschild, C. Markus, P. Paschievici, P. M. Watkins, M. J. Losty, Paul Kyberd, F. K. Loebinger, Gideon Bella, V. H. Winterer, A. M. Smith, G. J. VanDalen, Ehud Duchovni, S. Wotton, H. J. Burckhart, G. Vasseur, Jacqueline Batley, B. Lorazo, Norbert Wermes, P. Mättig, Sherry Towers, T. Kawamoto, R.J. Akers, R. Lahmann, D. C. Imrie, A. Rollnik, R. Giacomelli, O. Schaile, R. Bartoldus, J. Goldberg, S. Orito, M. Rosvick, B. Nellen, R. Mir, P. Leblanc, F. Odorici, H. G. Evans, M. J. Goodrick, I. Cohen, H. O. Ogren, Christoph Geich-Gimbel, M. Jimack, M. J. Oreglia, A. Yeaman, N. K. Watson, Erez Etzion, Stefan Kluth, Shlomit Tarem, J. R. Carter, S. Rossberg, C. J. Oram, G. N. Patrick, R. P. Middleton, J. Kroll, F. X. Gentit, J. E. Conboy, A. Pouladdej, H. Ihssen, S. W. O'Neale, S. W. Gensler, G. P. Siroli, K. J. Anderson, S. J. Hillier, Christoph Schwick, T. Kobayashi, C. J. Virtue, P. Poffenberger, Kiyotomo Kawagoe, W. R. Gibson, C. Y. Chang, M. F. Turner, A. Beck, E. Heflin, R. M. Brown, Lorne Levinson, P. Weber, B. W. Kennedy, E. Torrente-Lujan, D. E. Plane, P. Bentkowski, G. M. Dallavalle, D. J.P. Dumas, Gideon Alexander, Paolo Capiluppi, P. M. Hattersley, P. F. Harrison, P. D. Acton, Stephen Lloyd, M. Tecchio, T. J. Smith, K. Stephens, J. R. McNutt, V. Gibson, G. Quast, John Baines, D. R. Ward, G. Transtromer, A. M. Rossi, J. C. Clayton, T. Tsukamoto, S. Levegrün, H. M. Fischer, A. Michelini, A. C. Janissen, D. R. Rust, S. A. Robins, A. M. Lee, S. Barnett, C. Sbarra, D. Hochman, Michael Dittmar, G. Yekutieli, A. A. Carter, Roger Jones, J. Banks, N. J. Tresilian, R. D. Heuer, R. Van Kooten, Fabrizio Fabbri, D. Van den plas, N. I. Geddes, D. Pitman, M. H. Lehto, B. Boden, B. Poli, T. G. Shears, D. M. Gingrich, P. Berlich, L. Köpke, J. P. Martin, T. J. McMahon, M. Hansroul, S. De Jong, J. Schwiening, R. K. Carnegie, C. H. Shepherd-Themistocleous, J. A. Wilson, R. J. Homer, W. Schappert, Margret Fincke-Keeler, J. G. Layter, R. E. Hughes-Jones, J. von Krogh, P. Pfister, G. G. Hanson, G. Giacomelli, Dave Robinson, P. Schenk, M. S. Dixit, Frans Meijers, L. A. del Pozo, C. Moisan, G. A. Beck, Achim Stahl, P. Teixeira-Dias, B. Schmitt, P. S. Wells, Terry Richard Wyatt, M. Coupland, F. C. Grant, M. A. Whalley, A. Buijs, D. M. Strom, C. Stegmann, M. Jones, Claude Leroy, and J. P. Pansart

Subjects
Quark, Physics, Partial width, Physics and Astronomy (miscellaneous), Astrophysics::High Energy Astrophysical Phenomena, Electron–positron annihilation, High Energy Physics::Phenomenology, Hadron, Analytical chemistry, Elementary particle, Standard Model, High Energy Physics::Experiment, Impact parameter, Engineering (miscellaneous), Bar (unit)
Abstract

The fractional partial width of theZ0 tob quarks,\(\Gamma _{b\bar b} /\Gamma _{had} \), has been measured by OPAL using an impact parameter technique. The method has been developed using 130 000 hadronic events collected by OPAL in 1990. We find: $$\frac{{\Gamma _{b\bar b} }}{{\Gamma _{had} }} = 0.222 \pm 0.007(stat) \pm 0.008(sys).$$ The measurement assumes the relative rates of theZ0 touds andc quarks given by the Standard Model. Varying the charm fraction from the Standard Model value of\(\Gamma _{c\bar c} /\Gamma _{had} = 0.171\) changes the result by an additional\(\Delta \Gamma _{b\bar b} /\Gamma _{b\bar b} = - 0.135 \times \Delta \Gamma _{c\bar c} /\Gamma _{c\bar c} \).

Published
1993

40. A test of the flavour independence of the strong interaction for five flavours

Author

James Pinfold, D. G. Fong, J. Gascon, H. von der Schmitt, J. W. Gary, Marcello Mannelli, J. E. Duboscq, Andris Skuja, Tetsuro Mashimo, W. Gorn, P. Scharff-Hansen, A. M. Smith, G. Vasseur, B. Lorazo, P. A. Elcombe, G. Beaudoin, Tohru Takeshita, Gregor Herten, Gideon Bella, J. Becker, Sachio Komamiya, Otmar Biebel, C. Wahl, P. M. Hattersley, B. Wilkens, H. J. Burckhart, Georges Azuelos, P. Igo-Kemenes, F. C. Grant, D. G. Charlton, D. L. Wagner, M. A. Whalley, F. Scharf, Jacqueline Batley, K. Stephens, E. Ros, A. T. Watson, Shlomo Dado, Madjid Boutemeur, J. F. Kral, J. R. McNutt, F. S. Merritt, H. Mes, K. W. Bell, I. P. Duerdoth, Max Weber, J. E. Pilcher, R. Lahmann, J. C. Hill, D. C. Imrie, H. Deng, R. Humbert, X. C. Lou, H. Jeremie, Misao Sasaki, B. C. Shen, M. Hansroul, C. Y. Chang, N. I. Geddes, R.J. Akers, Giora Mikenberg, G. P. Siroli, J. King, A. K. Honma, R. E. Hughes-Jones, A. Buijs, U. Maur, D. M. Strom, Christoph Schwick, W. R. Gibson, P. G. Estabrooks, W. G. Scott, B. Boden, M. F. Turner, O. Schaile, B. Poli, T. P. Kokott, C. Stegmann, A. Luig, J. M. Lorah, R. K. Keeler, V. Gibson, J. A. McKenna, Norbert Wermes, A. Beck, Sherry Towers, T. Kawamoto, G. Quast, R. Kowalewski, E. Heflin, R. M. Brown, Kiyotomo Kawagoe, E. do Couto e Silva, W. Mohr, Lorne Levinson, John Baines, M. J. Losty, R. Bartoldus, P. M. Watkins, G. A. Snow, C. P. Ward, D. L. Rees, C. H. Shepherd-Themistocleous, R. J. Homer, B. W. Kennedy, E. Torrente-Lujan, A. Skillman, P. Weber, A. Gaidot, S. Orito, M. Rosvick, R. Mir, H. Przysiezniak, H. O. Ogren, Christoph Geich-Gimbel, M. Hauschild, D. E. Plane, Margret Fincke-Keeler, M. Fierro, D. R. Ward, G. Transtromer, T. Wlodek, G. T. Zorn, M. Sproston, C. Markus, P. Paschievici, P. Bentkowski, G. M. Dallavalle, Silvia Arcelli, Matthias Schröder, G. J. VanDDalen, B. Fabbro, N. Tesch, A. Dieckmann, E. Lefebvre, P. Poffenberger, J. Banks, M. J. Oreglia, J. Kroll, J. C. Clayton, B. Panzer-Steindel, A. M. Rossi, P. Pfister, F. Odorici, T. Hilse, F. X. Gentit, H. Lafoux, D. J.P. Dumas, T. Tsukamoto, H. M. Fischer, N. Paz-Jaoshvili, N. J. Tresilian, O. Runolfsson, P. S. Wells, A. Michelini, A. C. Janissen, M. Mori, J. R. Carter, G. N. Patrick, Terry Richard Wyatt, Peter R Hobson, C. Beeston, R. D. Heuer, M. Coupland, C. Moisan, Claudio Grandi, Gideon Alexander, P. Routenburg, M. Yurko, G. A. Beck, Fabrizio Fabbri, J. M. Roney, A. Astbury, S. A. Robins, P. W. Jeffreys, Paolo Capiluppi, Achim Stahl, P. Teixeira-Dias, D. Van den plas, U. Müller, M. Jones, A. J. Martin, B. Schmitt, D. Pitman, P. Bright-Thomas, G. Giacomelli, J. Hart, S. W. O'Neale, K. J. Anderson, M. H. Lehto, G. Yukutieli, J. D. Gillies, P. Ma:attig, M. A. Thomson, P. Schenk, A. Yeaman, S. Barnett, J. von Krogh, T. G. Shears, Claude Leroy, N. K. Watson, J. Steuerer, R. J. Barlow, D. Hochman, J. P. Pansart, C. K. Hargrove, M. S. Dixit, D. J. Miller, Frans Meijers, D. M. Gingrich, Dave Robinson, P. F. Harrison, P. E.L. Clarke, M. J. Pearce, Horst Breuker, Stephen Lloyd, J. P. Martin, L. A. del Pozo, C. Sbarra, P. Berlich, J. Lauber, R. Yaari, M. Tecchio, S. Bethke, S. De Jong, Marco Cuffiani, H. Takeda, F. G. Oakham, Michael Dittmar, D. R. Rust, S. L. Chu, Ehud Duchovni, R. J. Hemingway, Erez Etzion, M. Jimack, P. Jovanovic, H. Ihssen, Austin Ball, D. Menszner, A. M. Lee, Stefan Kluth, Shlomit Tarem, J. G. Layter, John Hobbs, Alessandro Montanari, J. E. Conboy, A. A. Carter, S. W. Gensler, S. J. Hillier, Roger Jones, T. Kobayashi, D. Axen, A. Jawahery, R. Van Kooten, S. Rossberg, C. J. Oram, Peter Sherwood, R. W. Springer, Alexander Wagner, M. G. Rison, J. Hagemann, R. P. Middleton, J. Ludwig, K. Runge, P. Bock, Gunter Wolf, T. J. McMahon, G. Duckeck, R. Ströhmer, J. Schwiening, R. K. Carnegie, H. M. Bosch, Wolfram Dietrich Zeuner, J. A. Wilson, S. Wotton, W. Schappert, D. A. Hinshaw, J. Goldberg, T. Behnke, B. Nellen, P. Leblanc, H. G. Evans, M. J. Goodrick, I. Cohen, Randall Sobie, G. D. Lafferty, T. W. Pritchard, A. D. Schaile, V. H. Winterer, G. E. Richard, C. Jui, C. M. Hawkes, M. Cooper, Daniel Lellouch, I. J. Bloodworth, M. Settles, M. Foucher, G. W. Wilson, D. Karlen, C. Burgard, J. Mildenberger, Harold Nguyen, T. J. Smith, Gordon H. Hanson, M. W. Redmond, John Allison, R. G. Kellogg, D. S. Koetke, Stefano Marcellini, James Letts, Paul Kyberd, F. K. Loebinger, A. Rollnik, and R. Giacomelli

Subjects
Quark, Physics, Strange quark, Particle physics, Muon, Annihilation, Physics and Astronomy (miscellaneous), Meson, High Energy Physics::Lattice, High Energy Physics::Phenomenology, Strong interaction, Charge (physics), High Energy Physics::Experiment, Production (computer science), Engineering (miscellaneous), Particle Physics - Experiment
Abstract

We report on a measurement of the ratio of the strong coupling constants\(\alpha _s (M_{Z^0 } )\) for various data samples with different quark flavour compositions obtained frome+e− annihilation at LEP. We select events with muons, electrons, andD*± mesons from charm and bottom decays, events with highly energeticKs0 mesons originating predominantly from strange quarks, and events with highly energetic stable charged particles from a combination of up, down and strange quarks. From the jet production rates in these events we obtain from these samples the relative value of αs for the individual quark flavours as $$\begin{gathered} \frac{{\alpha _s^b }}{{\alpha _s^{udsc} }} = 1.017 \pm 0.036,\frac{{\alpha _s^c }}{{\alpha _s^{udsb} }} = 0.918 \pm 0.115, \hfill \\ \frac{{\alpha _s^s }}{{\alpha _s^{udcb} }} = 1.158 \pm 0.164,\frac{{\alpha _s^{uds} }}{{\alpha _s^{cb} }} = 1.038 \pm 0.221, \hfill \\ \end{gathered}$$ with quadratically combined statistical and systematic errors. We also compare the αs values for quarks of diffrent weak isospin, charge and generation. No evidence for a dependence of αs on any of these quark properties is observed. Finally, combining all samples and determining the αsf/αsincl ratio for each flavour, we do not find any dependence of the strong coupling constant on flavour.

Published
1993

41. Studies of strong and electroweak interactions using final state photon emission in hadronicZ 0 decays

Author

B. C. Shen, Gideon Bella, A. K. Honma, H. J. Burckhart, Jacqueline Batley, W. G. Scott, V. Gibson, G. Quast, Tara Shears, John Baines, R. Kowalewski, Horst Breuker, M. J. Losty, R. Lahmann, D. C. Imrie, T. J. Smith, M. Morii, D. R. Ward, G. Transtromer, Peter R Hobson, P. Mättig, H. O. Ogren, R. Mir, I. J. Bloodworth, P. S. Wells, James Pinfold, T. Mouthuy, C. Y. Chang, M. F. Turner, G. P. Siroli, P. A. Elcombe, Christoph Schwick, Terry Richard Wyatt, S. Barnett, P. Taras, J. Mildenberger, M. Settles, M. Coupland, Christoph Geich-Gimbel, D. G. Fong, Sachio Komamiya, Harold Nguyen, G. T. Zorn, G. Beaudoin, D. Hochman, N. J. Thackray, E. Ros, J. Gascon, H. von der Schmitt, A. Astbury, Mitsuaki Nozaki, M. J. Oreglia, M. Foucher, O. Ganel, F. C. Grant, M. A. Whalley, A. J. Martin, J. Becker, J. Goldberg, A. M. Rossi, C. K. Hargrove, T. P. Kokott, Carla Sbarra, F. Odorici, N. Paz-Jaoshvili, M. Hauschild, Shlomo Dado, J. W. Gary, T. Tsukamoto, B. Nellen, P. Leblanc, S. Levegrün, G. J. VanDalen, G. W. Wilson, J. C. Clayton, D. Karlen, C. Burgard, Marcello Mannelli, J. E. Duboscq, A. Buijs, D. M. Strom, X. C. Lou, C. Markus, P. Paschievici, J. R. Carter, G. N. Patrick, Tohru Takeshita, H. G. Evans, P. Igo-Kemenes, G. Maringer, M. J. Goodrick, I. Cohen, Giora Mikenberg, D. Axen, A. Jawahery, H. Jeremie, Kiyotomo Kawagoe, A. Simon, Otmar Biebel, Georges Azuelos, C. M. Hawkes, P. E.L. Clarke, J. Steuerer, Andris Skuja, M. Cooper, P. Singh, G. Tysarczyk-Niemeyer, R. E. Hughes-Jones, U. Maur, Erez Etzion, G. E. Richards, Daniel Lellouch, D. L. Wagner, C. Jui, Tetsuro Mashimo, Stefan Kluth, Shlomit Tarem, Peter Sherwood, H. Deng, R. Humbert, J. F. Kral, K. W. Bell, P. G. Estabrooks, Max Weber, S. W. O'Neale, Paul Kyberd, F. K. Loebinger, N. I. Geddes, R. W. L. Jones, K. J. Anderson, R. W. Springer, Alexander Wagner, Takehiko Mori, H. Mes, S. Rossberg, C. J. Oram, J. C. Hill, Misao Sasaki, M. Hansroul, J. Hagemann, E. do Couto e Silva, I. P. Duerdoth, M. W. Redmond, W. Gorn, Richard Keeler, J. Ludwig, K. Runge, R. P. Middleton, F. G. Oakham, P. M. Watkins, B. Boden, P. Weber, A. Yeaman, B. Poli, Norbert Wermes, J. Kroll, P. Bock, B. Panzer-Steindel, G. A. Snow, C. P. Ward, A. Rollnik, R. Giacomelli, M. Jobes, U. Binder, J. M. Lorah, P. Scharff-Hansen, C. H. Shepherd-Themistocleous, D. L. Rees, T. Kawamoto, J. Hart, O. Schaile, F. X. Gentit, P. Poffenberger, S. Wotton, R. J. Homer, H. M. Fischer, S. Orito, M. Rosvick, J. D. Gillies, A. Michelini, J. E. Conboy, W. Mohr, J. Banks, Claude Leroy, J. P. Pansart, Silvia Arcelli, A. C. Janissen, M. Jimack, John Allison, R. Yaari, S. Bethke, Marco Cuffiani, A. D. Schaile, N. J. Tresilian, G. Duckeck, R. Ströhmer, N. K. Watson, C. Moisan, J. P. Walker, M. A. Thomson, A. M. Smith, G. A. Beck, D. G. Charton, R. J. Barlow, G. Vasseur, B. Lorazo, R. D. Heuer, P. Teixeira-Dias, Fabrizio Fabbri, A. Gaidot, R. G. Kellogg, D. J. Miller, A. Pouladdej, D. Van den plas, M. Kuwano, T. Wlodek, M. Sproston, D. S. Koetke, Stefano Marcellini, P. M. Hattersley, D. R. Rust, B. Schmitt, H. M. Bosch, S. L. Chu, J. M. Roney, P. Routenburg, James Letts, N. Tesch, A. Dieckmann, Wolfram Dietrich Zeuner, Margret Fincke-Keeler, F. Lamarche, V. H. Winterer, F. S. Merritt, D. A. Hinshaw, R. J. Hemingway, D. Pitman, M. H. Lehto, T. Behnke, P. Jovanovic, J. A. McKenna, Austin Ball, D. Menszner, R. F. McGowan, G. A. Bahn, John Hobbs, P. Berlich, Alessandro Montanari, L. Köpke, W. J. Collins, C. Wahl, Randall Sobie, G. D. Lafferty, J. E. Pilcher, T. W. Pritchard, S. Schreiber, T. J. McMahon, J. Schwiening, R. K. Carnegie, J. A. Wilson, W. Schappert, J. von Krogh, Dave Robinson, L. A. del Pozo, Michael Dittmar, G. Yekutieli, A. A. Carter, R. Van Kooten, W. R. Gibson, A. Beck, E. Heflin, R. M. Brown, Lorne Levinson, B. W. Kennedy, E. Torrente-Lujan, M. Yurko, P. W. Jeffreys, A. M. Lee, D. E. Plane, P. Bentkowski, P. Bright-Thomas, G. M. Dallavalle, Alan Watson, D. J.P. Dumas, H. Przysiezniak, M. Fierro, P. F. Harrison, T. Hilse, P. D. Acton, Stephen Lloyd, O. Runolfsson, M. Tecchio, Phillip Allport, Gideon Alexander, Paolo Capiluppi, Claudio Grandi, Ehud Duchovni, R. Shypit, H. Ihssen, S. W. Gensler, S. J. Hillier, T. Kobayashi, C. J. Virtue, P. Pfister, J. G. Layter, J. P. Martin, S. De Jong, G. G. Hanson, G. Giacomelli, P. Schenk, M. S. Dixit, Frans Meijers, K. Stephens, and J. R. McNutt

Subjects
Quantum chromodynamics, Physics, Quark, Particle physics, Photon, Physics and Astronomy (miscellaneous), Hadron, Electroweak interaction, Type (model theory), Jet (particle physics), Standard Model, Nuclear physics, High Energy Physics::Experiment, Engineering (miscellaneous), Particle Physics - Experiment
Abstract

The cross section and jet rates ofZ0 decays into photons and quarks are compared with matrix element Monte Carlos ofO(ααs). Good agreement is found between data and theoretical predictions. From the ratio of events with three jets plus a photon to those with two jets plus a photon, αs in first order is determined to be 0.176±0.010. Combining the cross section of final state photon events with the LEP average hadronic partial decay width of theZ0, the widths of theZ0 into up and down type quarks can be calculated. The results $$\begin{gathered} \Gamma _{u - type} = 242 \pm 46MeV; \hfill \\ \Gamma _{d - type} = 419 \pm 30MeV \hfill \\ \end{gathered} $$ are in good agreement with the standard model expectation. A comparison of the measured cross section as a function ofycut with predictions of QCD shower models shows that, at the current level of accuracy ARIADNE and, to a lesser extent, HERWIG and JETSET can reproduce the measurement.

Published
1993

42. Search for massive, unstable photinos that violate R parity

Author

R. Bartoldus, C. Y. Chang, M. F. Turner, H. O. Ogren, S. W. O'Neale, K. J. Anderson, B. C. Shen, Christoph Geich-Gimbel, M. Yurko, G. Beaudoin, P. Poffenberger, James Pinfold, C. Moisan, G. A. Beck, H. Mes, I. P. Duerdoth, Erez Etzion, D. Axen, A. Jawahery, Silvia Arcelli, D. G. Fong, J. Gascon, H. von der Schmitt, A. K. Honma, P. W. Jeffreys, Stefan Kluth, M. Jones, Richard Keeler, Shlomit Tarem, Gideon Bella, W. G. Scott, G. Giacomelli, G. T. Zorn, Shlomo Dado, S. L. Chu, R. Kowalewski, Otmar Biebel, Peter Sherwood, G. E. Richards, J. Hart, T. J. Smith, Achim Stahl, P. Teixeira-Dias, R. W. Springer, Alexander Wagner, J. D. Gillies, R.J. Akers, B. Schmitt, J. W. Gary, H. J. Burckhart, Jacqueline Batley, J. C. Clayton, R. J. Barlow, J. Kroll, P. Schenk, O. Schaile, J. Hagemann, J. Ludwig, K. Runge, P. Bock, P. Igo-Kemenes, A. M. Rossi, T. Tsukamoto, S. Levegrün, Marcello Mannelli, J. E. Duboscq, P. Bright-Thomas, H. Jeremie, D. J. Miller, S. Rossberg, C. J. Oram, M. J. Losty, F. X. Gentit, X. C. Lou, Giora Mikenberg, C. Jui, J. E. Conboy, D. G. Charlton, D. L. Wagner, M. S. Dixit, Frans Meijers, P. Mättig, Claude Leroy, J. P. Pansart, U. Maur, I. J. Bloodworth, R. P. Middleton, H. Deng, R. Humbert, N. I. Geddes, A. Pouladdej, F. Odorici, R. Lahmann, J. G. Layter, M. Hansroul, P. Scharff-Hansen, D. A. Hinshaw, D. C. Imrie, J. Goldberg, B. Boden, B. Poli, Gregor Herten, J. M. Roney, M. Settles, Norbert Wermes, A. D. Schaile, Sherry Towers, T. Kawamoto, B. Nellen, F. S. Merritt, C. Wahl, M. Morii, E. do Couto e Silva, M. Foucher, C. H. Shepherd-Themistocleous, Tohru Takeshita, H. M. Fischer, G. A. Snow, B. Wilkens, C. P. Ward, A. M. Smith, H. Takeda, P. Leblanc, John Hobbs, Peter R Hobson, S. Orito, M. Rosvick, R. J. Homer, A. Michelini, A. C. Janissen, D. L. Rees, F. G. Oakham, Madjid Boutemeur, G. W. Wilson, V. H. Winterer, T. Behnke, R. Mir, G. P. Siroli, Georges Azuelos, G. Vasseur, Margret Fincke-Keeler, B. Lorazo, J. E. Pilcher, D. Karlen, C. Burgard, H. Przysiezniak, Andris Skuja, Christoph Schwick, F. Lamarche, P. G. Estabrooks, C. M. Hawkes, M. Cooper, Daniel Lellouch, S. A. Robins, M. Fierro, J. F. Kral, K. W. Bell, J. P. Martin, R. J. Hemingway, J. A. McKenna, M. Hauschild, Tetsuro Mashimo, Takehiko Mori, P. Pfister, P. E.L. Clarke, P. S. Wells, P. M. Watkins, H. G. Evans, S. Barnett, M. J. Oreglia, J. Steuerer, S. De Jong, Max Weber, P. Jovanovic, Austin Ball, M. J. Goodrick, D. Menszner, T. Hilse, Randall Sobie, I. Cohen, G. D. Lafferty, Terry Richard Wyatt, O. Runolfsson, W. Gorn, B. Fabbro, A. Yeaman, B. Panzer-Steindel, J. C. Hill, N. K. Watson, Misao Sasaki, Alessandro Montanari, J. R. Carter, T. W. Pritchard, G. N. Patrick, C. Beeston, M. Coupland, Claudio Grandi, D. Hochman, Sachio Komamiya, Gideon Alexander, Paolo Capiluppi, E. Ros, Gunter Wolf, F. C. Grant, M. A. Whalley, P. M. Hattersley, T. P. Kokott, A. Luig, R. Yaari, S. Bethke, Marco Cuffiani, A. Buijs, D. M. Strom, C. Stegmann, K. Stephens, Kiyotomo Kawagoe, P. F. Harrison, J. R. McNutt, P. D. Acton, Stephen Lloyd, M. Tecchio, Ehud Duchovni, S. Wotton, M. Jimack, P. Weber, H. Ihssen, S. W. Gensler, S. J. Hillier, T. Kobayashi, G. Duckeck, R. Ströhmer, C. J. Virtue, V. Gibson, G. Quast, John Baines, H. M. Bosch, Wolfram Dietrich Zeuner, D. R. Ward, G. Transtromer, A. Astbury, U. Müller, A. J. Martin, Paul Kyberd, F. K. Loebinger, A. Rollnik, R. Giacomelli, John Allison, R. G. Kellogg, D. S. Koetke, Stefano Marcellini, James Letts, J. Mildenberger, Harold Nguyen, Gordon H. Hanson, M. W. Redmond, C. K. Hargrove, Matthias Schröder, H. Lafoux, N. Paz-Jaoshvili, Tara Shears, M. J. Pearce, Horst Breuker, C. Markus, P. Paschievici, D. Pitman, M. H. Lehto, D. M. Gingrich, P. Berlich, L. Köpke, D. R. Rust, A. M. Lee, J. Banks, N. J. Tresilian, R. D. Heuer, Fabrizio Fabbri, D. Van den plas, D. E. Plane, P. Bentkowski, G. M. Dallavalle, Alan Watson, D. J.P. Dumas, W. R. Gibson, A. Beck, E. Heflin, R. M. Brown, Lorne Levinson, B. W. Kennedy, E. Torrente-Lujan, C. Sbarra, Michael Dittmar, G. Yekutieli, A. A. Carter, Roger Jones, R. Van Kooten, R. E. Hughes-Jones, J. von Krogh, Dave Robinson, L. A. del Pozo, T. J. McMahon, J. Schwiening, R. K. Carnegie, J. A. Wilson, W. Schappert, A. Skillman, M. A. Thomson, A. Gaidot, M. Kuwano, T. Wlodek, M. Sproston, P. Routenburg, N. Tesch, A. Dieckmann, P. A. Elcombe, J. Becker, G. J. VanDalen, J. M. Lorah, and W. Mohr

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Magnetic moment, Solar neutrino, High Energy Physics::Phenomenology, Supersymmetry, Parameter space, lcsh:QC1-999, Nuclear physics, R-parity, High Energy Physics::Experiment, Neutrino, Photino, Particle Physics - Experiment, lcsh:Physics, Lepton
Abstract

A search for unstable, massive photinos pair produced in e + e − collisions has been performed using the OPAL detector at LEP. The data sample corresponds to an integrated luminosity of 21 pb −1 collected at center-of-mass energies near the Z 0 resonance. The unstable photino is assumed to decay into τ ± / gn l ( l = e or μ ) final states, thereby violating individual lepton numbers and R parity. This search is inspired by a particular model of supersymmetry which is of interest within the context of solar neutrino experiments because it allows for a large neutrino magnetic moment. The present search excludes a large portion of the parameter space allowed by the model.

Published
1993

43. Measurement of the B0 and B+ lifetimes

Author

W. R. Gibson, A. Beck, E. Heflin, R. M. Brown, G. Transtromer, B. W. Kennedy, E. Torrente-Lujan, M. Fincke-Keeler, D. E. Plane, P. Bentkowski, Alan Watson, D. J.P. Dumas, Silvia Arcelli, Tara Shears, P. Igo-Kemenes, G. Maringer, R. Sobie, H. Jeremie, R. E. Hughes-Jones, U. Maur, P. Bright-Thomas, Horst Breuker, H. M. Fischer, E. do Couto e Silva, J. Pinfold, C. Burgard, F. C. Grant, P. E.L. Clarke, M. A. Whalley, A. Michelini, A. C. Janissen, O. Ganel, G. A. Snow, C. P. Ward, R. Yaari, H. O. Ogren, Christoph Geich-Gimbel, A. Simon, D. L. Rees, A. Buijs, M. Jobes, Otmar Biebel, G. E. Richards, U. Binder, D. G. Charlton, D. L. Wagner, P. G. Estabrooks, N. Paz-Jaoshvili, P. Scharff-Hansen, J. Kroll, G. Yekutieli, F. X. Gentit, H. Deng, R. Humbert, J. E. Conboy, P. M. Watkins, G. Beaudoin, D. R. Rust, A. Pouladdej, Paul Kyberd, F. K. Loebinger, B. C. Shen, C. Schwick, A. M. Smith, F. S. Merritt, J. Steuerer, D. Strom, G. Vasseur, B. Lorazo, Kiyotomo Kawagoe, A. Astbury, M. W. Redmond, W. G. Scott, Richard Keeler, Norbert Wermes, T. Kawamoto, G. M. Dallavale, N. I. Geddes, A. J. Martin, J. A. McKenna, Shlomo Dado, A. Rollnik, R. Giacomelli, F. G. Oakham, D. Hochman, C. Y. Chang, M. F. Turner, M. Morii, S. Bethke, P. Taras, Peter R Hobson, R. Kowalewski, B. Boden, Marco Cuffiani, Mitsuaki Nozaki, R. F. McGowan, Claude Leroy, D. G. Fong, J. P. Pansart, B. Poli, J. Gascon, J. Hart, S. Orito, P. Weber, S. Tarem, T. Behnke, Sachio Komamiya, E. Ros, X. C. Lou, H. von der Schmitt, M. J. Losty, M. Jimack, H. Ihssen, John Allison, G. Quast, C. K. Hargrove, S. L. Chu, J. R. McNutt, J. D. Gillies, Gideon Bella, P. Pfister, R. Mir, S. W. Gensler, T. P. Kokott, Carla Sbarra, T. Hilse, J. Banks, J. W. Gary, H. J. Burckhart, Jacqueline Batley, T. Mouthuy, S. J. Hillier, P. Paschievici, T. Kobayashi, C. J. Virtue, N. J. Tresilian, P. S. Wells, Terry Richard Wyatt, Marcello Mannelli, J. E. Duboscq, R. D. Heuer, R. G. Kellogg, J. von Krogh, O. Runolfsson, Andris Skuja, Fabrizio Fabbri, M. Coupland, R. J. Barlow, D. Van den plas, G. T. Zorn, O. Schaile, S. Barnett, D. J. Miller, D. S. Koetke, A. D. Schaile, John Hobbs, Tetsuro Mashimo, Dave Robinson, Stefano Marcellini, T. Wlodek, Tohru Takeshita, M. H. Lehto, L. A. del Pozo, James Letts, N. J. Thackray, V. H. Winterer, A. M. Rossi, T. Tsukamoto, S. Levegrün, K. Stephens, Michael Dittmar, F. Lamarche, Claudio Grandi, Georges Azuelos, P. F. Harrison, W. Gorn, M. J. Oreglia, A. Yeaman, J. Mildenberger, Harold Nguyen, R. J. Hemingway, M. A. Thomson, J. F. Kral, K. W. Bell, G. A. Bahan, D. Pitman, A. A. Carter, P. Singh, N. K. Watson, Stephen Lloyd, P. M. Hattersley, Max Weber, M. Tecchio, C. Moisan, J. P. Walker, R. Van Kooten, V. Gibson, P. Berlich, P. Jovanovic, A. Gaidot, M. Sproston, L. Köpke, W. J. Collins, M. Hauschild, J. C. Hill, Misao Sasaki, G. A. Beck, J. R. Carter, Austin Ball, R. W. L. Jones, G. N. Patrick, John Baines, G. D. Lafferty, P. Poffenberger, R. Lahmann, D. Menszner, P. Teixeira-Dias, Phillip Allport, S. W. O'Neale, B. Panzer-Steindel, S. Schreiber, P. Routenburg, C. Markus, C. J. Oram, N. Tesch, A. Dieckmann, Alessandro Montanari, T. W. Pritchard, T. J. McMahon, K. J. Anderson, G. P. Siroli, J. Schwiening, D. R. Ward, J. P. Martin, R. K. Carnegie, P. A. Elcombe, J. Hagemann, D. C. Imrie, H. Przysiezniak, B. Schmitt, J. C. Clayton, J. A. Wilson, S. De Jong, M. Fierro, M. Yurko, M. Rosvick, J. Becker, W. Schappert, A. Wagner, P. W. Jeffreys, A. M. Lee, C. Wahl, G. J. VanDalen, L. Levinson, R. Shypit, M. Hansroul, C. Jui, J. E. Pilcher, D. Lellouch, C. H. Shepherd-Themistocleous, R. J. Homer, J. M. Lorah, W. Mohr, Gideon Alexander, Paolo Capiluppi, D. A. Hinshaw, D. Axen, A. Jawahery, G. Tysarczyk-Niemeyer, Peter Sherwood, R. W. Springer, J. Ludwig, K. Runge, P. Bock, G. Duckeck, R. Ströhmer, F. Odorici, H. M. Bosch, Wolfram Dietrich Zeuner, G. Mikenberg, H. Mes, I. P. Duerdoth, M. Kwano, J. M. Roney, I. J. Bloodworth, M. Settles, M. Foucher, G. W. Wilson, D. Karlen, A. K. Honma, T. J. Smith, P. Mättig, C. M. Hawkes, M. Cooper, Takehiko Mori, P. D. Acton, E. Duchovni, Erez Etzion, Stefan Kluth, S. Rossberg, J. G. Layter, R. P. Middleton, S. Wotton, G. G. Hanson, J. Goldberg, B. Nellen, P. Leblanc, G. Giacomelli, H. G. Evans, M. J. Goodrick, I. Cohen, P. Schenk, M. S. Dixit, and Frans Meijers

Subjects
Nuclear physics, Physics, Hadronic decay, Nuclear and High Energy Physics, Meson, Silicon, chemistry, Electron–positron annihilation, Hadron, chemistry.chemical_element, Particle Physics - Experiment
Abstract

From a data sample of approximately 240 000 hadronic Z 0 decays recorded during 1991 a sample of about 130 semileptonic B hadron decays containing a D 0 , D + or D ∗+ has been isolated. Using silicon microvertex detector information the decay vertices in these events have been reconstructed. The average B hadron lifetime of the mix of B hadrons in this event sample is measured to be 1.51 −0.14 +0.16 ±0.11 ps. From the distribution of decay times in the different samples the lifetimes of the B 0 and B + mesons are determined to be 1.51 −0.23−0.14 +0.24+0.12 ps and 1.51 −0.28−0.14 +0.30+0.12 ps, respectively. The measured ratio of the B + to B 0 lifetimes of 1.00 −0.25 +0.33 ±0.08 supports expectations that the lifetimes are similar.

Published
1993

44. Measurement of the averageb hadron lifetime inZ 0 decays

Author

J. Mildenberger, Harold Nguyen, A. Astbury, G. Beaudoin, C. Moisan, G. A. Beck, U. Müller, A. J. Martin, Erez Etzion, Achim Stahl, P. Teixeira-Dias, Tohru Takeshita, I. J. Bloodworth, Shlomo Dado, K. Stephens, Stefan Kluth, A. Skillman, J. R. McNutt, F. S. Merritt, B. Schmitt, Shlomit Tarem, J. G. Layter, Georges Azuelos, A. Gaidot, M. Kuwano, T. Wlodek, D. Axen, C. K. Hargrove, M. Settles, X. C. Lou, A. Jawahery, F. Odorici, M. Sproston, J. F. Kral, K. W. Bell, R. Batoldus, V. Gibson, H. Takeda, G. Quast, Madjid Boutemeur, James Pinfold, D. G. Fong, J. Hart, J. D. Gillies, F. G. Oakham, D. Pitman, S. Rossberg, C. J. Oram, John Baines, T. J. McMahon, M. Foucher, D. J. Miller, J. Gascon, H. von der Schmitt, Gideon Bella, P. Routenburg, N. I. Geddes, Max Weber, Peter Sherwood, F. Lamarche, Margret Fincke-Keeler, Matthias Schröder, Giora Mikenberg, P. Jovanovic, H. J. Burckhart, Sachio Komamiya, C. Jui, Austin Ball, M. H. Lehto, P. G. Estabrooks, R. K. Keeler, N. Tesch, A. Dieckmann, D. Menszner, E. Ros, A. T. Watson, Alessandro Montanari, Paul Kyberd, F. K. Loebinger, J. C. Hill, Misao Sasaki, R. W. Springer, Alexander Wagner, Gideon Alexander, H. Lafoux, R. P. Middleton, Otmar Biebel, Paolo Capiluppi, S. L. Chu, Marcello Mannelli, J. E. Duboscq, G. W. Wilson, D. R. Ward, G. E. Richards, D. E. Plane, C. Y. Chang, J. Schwiening, D. Karlen, C. Burgard, J. Hagemann, J. Ludwig, B. C. Shen, Andris Skuja, T. G. Shears, J. A. McKenna, N. Paz-Jaoshvili, G. Transtromer, D. G. Charlton, D. L. Wagner, B. Boden, K. Runge, Gunter Wolf, A. D. Schaile, Tetsuro Mashimo, P. Bentkowski, T. P. Kokott, P. M. Watkins, P. Igo-Kemenes, P. A. Elcombe, R. K. Carnegie, A. Luig, P. Bock, J. P. Martin, B. Poli, A. K. Honma, Ehud Duchovni, V. H. Winterer, C. M. Hawkes, M. Cooper, M. W. Redmond, P. M. Hattersley, H. Deng, R. Humbert, Daniel Lellouch, J. R. Batley, D. M. Gingrich, Silvia Arcelli, G. A. Snow, C. P. Ward, D. J.P. Dumas, S. De Jong, W. G. Scott, H. Ihssen, H. Jeremie, W. Gorn, P. Pfister, A. Rollnik, R. Giacomelli, J. A. Wilson, H. M. Fischer, D. L. Rees, Takehiko Mori, John Hobbs, W. R. Gibson, J. Becker, S. W. Gensler, R. Kowalewski, R. Lahmann, H. Mes, U. Maur, P. Berlich, A. Michelini, A. C. Janissen, S. Wotton, S. J. Hillier, T. Kobayashi, C. J. Virtue, L. Köpke, J. C. Clayton, D. C. Imrie, D. A. Hinshaw, P. Scharff-Hansen, J. W. Gary, W. Schappert, Randall Sobie, G. D. Lafferty, A. Beck, I. P. Duerdoth, M. J. Losty, J. M. Roney, S. A. Robins, A. M. Smith, E. Heflin, P. E.L. Clarke, T. W. Pritchard, Norbert Wermes, Sherry Towers, G. P. Siroli, Christoph Schwick, J. Steuerer, D. R. Rust, G. Vasseur, B. Lorazo, J. Goldberg, R. M. Brown, Lorne Levinson, G. J. VanDalen, M. Morii, M. Jimack, Peter R Hobson, M. J. Pearce, Horst Breuker, B. Nellen, P. F. Harrison, G. M. Dallavalle, E. do Couto e Silva, P. Leblanc, P. D. Acton, Stephen Lloyd, M. Tecchio, E. Torrente-Lujan, Roger Barlow, John Allison, G. G. Hanson, R. E. Hughes-Jones, H. O. Ogren, T. Behnke, Kiyotomo Kawagoe, Christoph Geich-Gimbel, S. Orito, M. Rosvick, M. Hansroul, H. G. Evans, M. J. Goodrick, R. Yaari, J. von Krogh, A. M. Lee, T. J. Smith, S. Bethke, Marco Cuffiani, I. Cohen, R. Mir, P. Schenk, P. Weber, J. E. Conboy, R. G. Kellogg, M. S. Dixit, A. Yeaman, Frans Meijers, Dave Robinson, D. S. Koetke, A. M. Rossi, N. K. Watson, J. M. Lorah, C. H. Shepherd-Themistocleous, L. A. del Pozo, C. Sbarra, T. Tsukamoto, Stefano Marcellini, S. Levegrün, J. Kroll, R. J. Homer, G. Duckeck, R. Ströhmer, James Letts, W. Mohr, P. Mättig, Michael Dittmar, G. Yekutieli, F. X. Gentit, G. T. Zorn, A. A. Carter, M. J. Oreglia, Roger Jones, R. Van Kooten, H. M. Bosch, Wolfram Dietrich Zeuner, A. Pouladdej, B. Fabbro, J. R. Carter, B. Panzer-Steindel, G. N. Patrick, G. Giacomelli, J. Banks, N. J. Tresilian, R. D. Heuer, Fabrizio Fabbri, D. Van den plas, S. Barnett, D. Hochman, M. Yurko, P. W. Jeffreys, P. Bright-Thomas, R. J. Hemingway, M. A. Thomson, T. Hilse, O. Runolfsson, C. Beeston, Claudio Grandi, H. Przysiezniak, M. Fierro, P. Poffenberger, M. Hauschild, C. Markus, P. Paschievici, F. C. Grant, R.J. Akers, O. Schaile, M. A. Whalley, Gregor Herten, C. Wahl, B. Wilkens, J. E. Pilcher, S. W. O'Neale, K. J. Anderson, M. F. Turner, B. W. Kennedy, A. Buijs, D. M. Strom, C. Stegmann, Tatsuo Kawamoto, M. Jones, Claude Leroy, J. P. Pansart, P. S. Wells, Terry Richard Wyatt, and M. Coupland

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Muon, Physics and Astronomy (miscellaneous), Maximum likelihood, Electron–positron annihilation, High Energy Physics::Phenomenology, Hadron, Detector, Elementary particle, Electron, Nuclear physics, High Energy Physics::Experiment, Quantum field theory, Engineering (miscellaneous), Particle Physics - Experiment, Lepton
Abstract

A sample of 2610 electron candidates and 2762 muon candidates identified in hadronicZ0 decays has been used to measure the averageb hadron lifetime. These data were recorded with the OPAL detector during 1990 and 1991. Maximum likelihood fits to the distributions of the lepton impact parameters yield an averageb hadron lifetime of $$\tau _b = 1523 \pm 34 \pm 38fs$$ , where the first error is statistical and the second systematic. This result is a weighted average over the semileptonic branching fractions and production rates of theb hadrons produced inZ0 decays.

Published
1993

45. Precision measurements of the neutral current from hadron and lepton production at LEP

Author

D. Pitman, M. H. Lehto, A. Astbury, H. O. Ogren, Christoph Geich-Gimbel, A. D. Schaile, O. Ganel, A. J. Martin, G. M. Dallavalle, J. E. Conboy, V. H. Winterer, J. von Krogh, J. Kroll, C. Wahl, C. K. Hargrove, P. E.L. Clarke, Dave Robinson, F. X. Gentit, L. A. del Pozo, P. Berlich, J. E. Pilcher, B. Boden, Kiyotomo Kawagoe, J. C. Clayton, J. Steuerer, P. M. Hattersley, A. Pouladdej, T. Hilse, L. Köpke, C. Moisan, J. P. Walker, G. A. Beck, B. Poli, Tohru Takeshita, P. Weber, S. Wotton, A. Simon, Otmar Biebel, G. E. Richards, James Pinfold, Michael Dittmar, G. Yekutieli, O. Runolfsson, P. Teixeira-Dias, J. R. Batley, P. S. Wells, Georges Azuelos, D. G. Charlton, D. L. Wagner, N. Paz-Jaoshvili, S. J. Hiller, R. Lahmann, D. C. Imrie, D. G. Fong, F. Lamarche, A. A. Carter, R. Van Kooten, G. P. Siroli, Christoph Schwick, T. Mouthuy, Terry Richard Wyatt, B. Schmitt, J. M. Lorah, J. Goldberg, K. W. Bell, N. I. Geddes, Max Weber, H. Deng, R. Humbert, Paul Kyberd, F. K. Loebinger, M. Coupland, F. S. Merritt, Silvia Arcelli, W. Mohr, O. Schaile, J. Gascon, H. von der Schmitt, B. Nellen, W. J. Collins, P. Leblanc, G. T. Zorn, J. Banks, Randall Sobie, J. C. Hill, Misao Sasaki, B. C. Shen, H. Mes, R. Yaari, M. W. Redmond, S. Bethke, Tara Shears, P. A. Elcombe, G. D. Lafferty, A. Rollnik, R. Giacomelli, P. Igo-Kemenes, G. Maringer, R. D. Heuer, Fabrizio Fabbri, C. Leroy, A. K. Honma, Richard Keeler, I. P. Duerdoth, Marco Cuffiani, D. E. Plane, C. Y. Chang, Margret Fincke-Keeler, S. Schreiber, T. J. McMahon, J. F. Kral, Horst Breuker, H. Jeremie, D. Van den plas, R. E. Hughes-Jones, A. M. Rossi, T. W. Pritchard, P. Jovanovic, H. G. Evans, J. Becker, P. F. Harrison, W. G. Scott, M. J. Goodrick, I. Cohen, Norbert Wermes, Claudio Grandi, Austin Ball, D. Menszner, G. J. VanDalen, S. W. O'Neale, J. Schwiening, R. K. Carnegie, U. Maur, J. A. McKenna, D. R. Rust, P. D. Acton, Stephen Lloyd, G. A. Snow, C. P. Ward, T. Tsukamoto, K. J. Anderson, R. Kowalewski, S. Levegrün, H. M. Fischer, M. Tecchio, P. Bentkowski, S. L. Chu, S. Barnett, J. Mildenberger, J. P. Pansart, Marcello Mannelli, J. E. Duboscq, Andris Skuja, J. A. Wilson, Harold Nguyen, E. do Coto e Silva, D. L. Rees, A. Michelini, M. A. Thomson, P. Pfister, Alessandro Montanari, A. C. Janissen, M. J. Losty, S. Orito, M. Rosvick, D. Hochman, N. J. Thackray, A. Gaidot, M. F. Turner, M. Kuwano, T. Wlodek, Ehud Duchovni, R. Shypit, R. F. McGowan, P. Taras, J. M. Roney, M. Sproston, Erez Etzion, Tetsuro Mashimo, Stefan Kluth, Shlomit Tarem, M. Hauschild, F. C. Grant, M. A. Whalley, P. Routenburg, N. Tesch, A. Dieckmann, R. Mir, Alan Watson, Mitsuaki Nozaki, W. Schappert, G. Beaudoin, K. Stephens, B. W. Kennedy, J. R. McNutt, H. Ihssen, C. Markus, S. Rossberg, C. J. Oram, P. Paschievici, W. Gorn, John Hobbs, D. J.P. Dumas, G. A. Bahan, M. Jimack, John Allison, P. G. Estabrooks, S. W. Gensler, R. P. Middleton, T. Kobayashi, V. Gibson, F. Odorici, A. Buijs, C. J. Virtue, G. Quast, M. Jobes, U. Binder, P. Poffenberger, C. Jui, P. Scharff-Hansen, W. R. Gibson, Shlomo Dado, M. J. Oreglia, M. Hansroul, D. M. Strom, John Baines, R. G. Kellogg, J. W. Gary, F. G. Oakham, A. M. Smith, P. M. Watkins, Phillip Allport, A. Beck, E. Heflin, C. H. Shepherd-Themistocleous, G. Vasseur, X. C. Lou, B. Lorazo, J. Hart, Tatsuo Kawamoto, R. J. Homer, R. M. Brown, D. S. Koetke, Lorne Levinson, Stefano Marcellini, J. R. Carter, G. N. Patrick, J. D. Gillies, Giora Mikenberg, D. R. Ward, G. Transtromer, E. Torrente-Lujan, Roger Barlow, Gideon Alexander, Paolo Capiluppi, D. J. Miller, James Letts, J. G. Layter, H. Przysiezniak, M. Fierro, M. Yurko, P. W. Jeffreys, J. P. Martin, A. M. Lee, S. De Jong, P. Bright-Thomas, R. J. Hemingway, G. G. Hanson, P. Schenk, M. S. Dixit, Frans Meijers, D. Axen, A. Jawahery, G. Tysarczyk-Niemeyer, Peter Sherwood, Sachio Komamiya, N. J. Tresilan, R. W. Springer, Alexander Wagner, E. Ros, P. Singh, J. Hagemann, R. W. L. Jones, T. P. Kokott, Carla Sbarra, C. M. Hawkes, M. Cooper, Daniel Lellouch, J. Ludwig, K. Runge, P. Bock, Takehiko Mori, B. Panzer-Steindel, G. Giacomelli, Gideon Bella, H. J. Burckhart, D. A. Hinshaw, A. Yeaman, N. K. Watson, T. J. Smith, T. Behnke, P. Mättig, I. J. Bloodworth, M. Morii, Peter R Hobson, M. Settles, M. Foucher, G. Duckeck, G. W. Wilson, R. Ströhmer, D. Karlen, C. Burgard, H. M. Bosch, and Wolfram Dietrich Zeuner

Subjects
Physics, Particle physics, Physics and Astronomy (miscellaneous), Neutral current, Electron–positron annihilation, High Energy Physics::Phenomenology, Hadron, Electroweak interaction, Nuclear physics, Pair production, High Energy Physics::Experiment, Born approximation, Engineering (miscellaneous), Particle Physics - Experiment, Bhabha scattering, Lepton
Abstract

New measurements of the hadronic and leptonic cross sections and of the leptonic forward-backward asymmetries ine+e− collisions are presented. The analysis includes data recorded up to the end of 1991 by the OPAL experiment at LEP, with centre-of-mass energies within ±3 GeV of the Z0 mass. The results are based on a recorded total of 454 000 hadronic and 58 000 leptonic events. A model independent analysis of Z0 parameters based on an extension of the improved Born approximation is presented leading to test of lepton universality and an interpretation of the results within the Standard Model framework. The determination of the mass and width of the Z0 benefit from an improved understanding of the LEP energy calibration.

Published
1993

46. QCD coherence studies using two particle azimuthal correlations

Author

P. Singh, M. Hauschild, C. Markus, P. Paschievici, T. R. Wyatt, Silvia Arcelli, R. W. L. Jones, M. Hansroul, H. Przysiezniak, P. Le Du, J. C. Clayton, B. Panzer-Steindel, Sachio Komamiya, E. Ros, J. P. Martin, J. Hart, G. Beaudoin, G. Giacomelli, Andris Skuja, C. Wahl, J. D. Gillies, C. P. Howarth, C. H. Shepherd-Themistocleous, J. E. Pilcher, Tetsuro Mashimo, M. Jimack, John Allison, O. Schaile, R. J. Homer, D. Axen, A. Jawahery, S. De Jong, Gideon Bella, Tohru Takeshita, T. J. Smith, D. J. Miller, Shlomo Dado, T. Hilse, A. Simon, T. P. Kokott, Carla Sbarra, Otmar Biebel, G. Tysarczyk-Niemeyer, P. Mättig, O. Runolfsson, G. E. Richards, P. M. Watklins, F. C. Grant, D. G. Charlton, D. L. Wagner, P. Poffenberger, M. A. Whalley, F. S. Merritt, F. Lamarche, C. Moisan, J. P. Walker, Peter Sherwood, Georges Azuelos, W. Gorn, C. M. Hawkes, M. Cooper, Daniel Lellouch, X. C. Lou, R. Van Kooten, P. A. Elcombe, R. W. Springer, Alexander Wagner, D. Pitman, P. Teixeira-Dias, J. F. Kral, K. W. Bell, G. A. Bahan, Takehiko Mori, Claudio Grandi, N. I. Geddes, Max Weber, H. Deng, R. Humbert, G. D. Lafferty, H. Mes, P. Jovanovic, D. C. Imrie, A. Buijs, Giora Mikenberg, J. C. Hill, M. H. Lehto, Austin Ball, D. Menszner, I. P. Duerdoth, M. Yurko, Misao Sasaki, D. M. Strom, P. W. Jeffreys, B. C. Shen, I. J. Bloodworth, C. Jui, J. Hagemann, P. Igo-Kemenes, J. Ludwig, K. Runge, P. Bock, T. Mouthuy, A. M. Lee, Tatsuo Kawamoto, Alessandro Montanari, H. J. Burckardt, R. G. Kellogg, Margret Fincke-Keeler, G. Maringer, A. K. Honma, M. Settles, R. J. Hemingway, P. G. Estabrooks, D. L. Rees, J. Becker, John Hobbs, Stefano Marcellini, W. G. Scott, D. G. Fong, M. Foucher, G. J. VanDalen, A. D. Schaile, James Letts, H. Jeremie, R. E. Hughes-Jones, U. Maur, R. Kowalewski, G. P. Siroli, J. Gascon, H. von der Schmitt, P. Pfister, G. W. Wilson, A. Astbury, K. J. Anderson, D. Karlen, G. A. Snow, C. P. Ward, S. Orito, M. Rosvick, R. Mir, J. A. McKenna, C. Burgard, G. T. Zorn, S. Wotton, F. G. Oakham, G. Duckeck, V. H. Winterer, Christoph Schwick, O. Ganel, J. Mildenberger, Harold Nguyen, V. Gibson, M. J. Losty, R. Ströhmer, P. Berlich, L. Köpke, E. do Couto e Silva, A. J. Martin, P. Taras, A. Yeaman, A. M. Rossi, P. S. Wells, Marcello Mannelli, J. E. Duboscq, Mitsuaki Nozaki, T. Tsukamoto, M. J. Oreglia, B. W. Kennedy, H. M. Fischer, J. Goldberg, P. E.L. Clarke, J. Steuerer, N. K. Watson, R. F. McGowan, M. Jobes, U. Binder, A. Michelini, A. C. Janissen, J. M. Lorah, M. Coupland, B. Nellen, J. Banks, P. Scharff-Hansen, Kiyotomo Kawagoe, W. J. Collins, Randall Sobie, W. Mohr, P. Leblanc, H. M. Bosch, Wolfram Dietrich Zeuner, Paul Kyberd, F. K. Loebinger, N. J. Tresilian, S. Weisz, G. N. Patrick, J. W. Gary, S. Bougerolle, R. D. Heuer, Fabrizio Fabbri, H. O. Ogren, D. Van den plas, Richard Keeler, M. W. Redmond, Christoph Geich-Gimbel, A. M. Smith, G. Vasseur, C. K. Hargrove, T. W. Pritchard, S. Levergrün, A. Rollnik, J. M. Roney, B. Lorazo, J. R. Carter, H. G. Evans, D. R. Rust, M. J. Goodrick, F. Odorici, J. E. Conboy, N. Paz-Jaoshvili, Claude Leroy, P. Lennert, Phillip Allport, I. Cohen, J. P. Pansart, P. Weber, J. Kroll, A. Gaidot, F. X. Gentit, R. Yaari, M. Kuwano, T. Wlodek, M. Sproston, S. Bethke, B. Boden, D. A. Hinshaw, Marco Cuffiani, P. Routenburg, B. Poli, A. Pouladdej, N. Tesch, A. Dieckmann, Erez Etzion, Tara Shears, J. R. Batley, D. E. Plane, C. Y. Chang, Stefan Kluth, Shlomit Tarem, M. Morii, S. W. O'Neale, Stephen Hillier, Peter R Hobson, T. Behnke, S. Rossberg, C. J. Oram, Gideon Alexander, R. P. Middleton, Horst Breuker, Paolo Capiluppi, P. Schenk, Alan Watson, D. J.P. Dumas, P. M. Hattersley, W. R. Gibson, A. Beck, P. F. Harrison, E. Heflin, P. D. Acton, Stephen Lloyd, R. M. Brown, M. Tecchio, Lorne Levinson, N. Wermes, Ehud Duchovni, R. Shypit, Roger Barlow, G. G. Hanson, E.J. Prebys, M. S. Dixit, Frans Meijers, H. Ihssen, S. W. Gensler, T. Kobayashi, C. J. Virtue, G. M. Dallavalle, J. von Krogh, Dave Robinson, L. A. del Pozo, Michael Dittmar, G. Yekutieli, A. A. Carter, S. Schreiber, T. J. McMahon, J. Schwiening, R. K. Carnegie, J. A. Wilson, W. Schappert, S. Barnett, D. Hochman, N. J. Thackray, K. Stephens, J. R. McNutt, G. Quast, John Baines, D. R. Ward, G. Transtromer, J. G. Layter, and M. F. Turner

Subjects
Quantum chromodynamics, Physics, Particle physics, Physics and Astronomy (miscellaneous), Electron–positron annihilation, High Energy Physics::Phenomenology, Hadron, Monte Carlo method, Perturbative QCD, Parton, Nuclear physics, High Energy Physics::Experiment, Nuclear Experiment, Parton shower, Engineering (miscellaneous), Particle Physics - Experiment, Coherence (physics)
Abstract

From a sample of 146900 hadronicZ 0 decays recorded by the OPAL detector at LEP, we have studied the azimuthal correlations of particles in hadronic events. It is expected that these correlations are sensitive to interference effects in QCD. We have compared the data to QCD Monte Carlo models which include and which do not include interference effects. We find that the distributions of azimuthal correlations are not reproduced by the parton shower models we have tested unless interference effects are included, no matter which hadronisation scheme is used.

Published
1993

47. Evidence for chain-like production of strange baryon pairs in jets

Author

T. P. Kokott, G. Tysarczyk-Niemeyer, F. X. Gentit, A. Beck, C. Markus, S. Komamiya, W. R. Gibson, G. G. Hanson, S. Dado, John Hobbs, A. M. Lee, F. Odorici, G. A. Snow, C. P. Ward, T. Hilse, J. Schwiening, F. S. Merritt, T. Mashimo, G. W. Wilson, H. O. Ogren, D. L. Rees, K. Stephens, D. Pitman, A. Dieckmann, J. E. Conboy, J. Kroll, S. Bethke, Tara Shears, R. M. Brown, R. J. Hemingway, S. Rossberg, H. Jeremie, Andris Skuja, S. Barnett, J. A. McKenna, H. M. Fischer, M. W. Redmond, W. Mohr, Frans Meijers, Peter R Hobson, G. Duckeck, P. Routenburg, E. Heflin, P. E.L. Clarke, A. Simon, C. Wahl, F. G. Oakham, J. Letts, G. Quast, E. Duchovni, A. Wagner, M. Morii, T. Mori, Horst Breuker, P. A. Elcombe, B. Lorazo, Otmar Biebel, G. N. Patrick, E. do Couto e Silva, M. Cooper, T. Mouthuy, J. Ludwig, A. Yeaman, J. Pinfold, P. M. Watkins, D. C. Imrie, S. Tarem, A. Gaidot, D. Menszner, M. Hansroul, H. G. Evans, T. J. McMahon, P. Weber, D. G. Charlton, D. L. Wagner, M. J. Goodrick, S. De Jong, S. Levegrün, J. Hart, Tohru Takeshita, P. Sherwood, H. M. Bosch, F. Lamarche, M. Yurko, P. Mättig, D. Hochman, W. J. Collins, P. Pfister, H. Przysiezniak, H. Deng, Harold Nguyen, N. K. Watson, P. Bentkowski, J. P. Martin, J. D. Gillies, C. Moisan, G. T. Zorn, M. Jimack, B. Panzer-Steindel, C. Jui, Richard Keeler, G. Beaudoin, T. J. Smith, M. Sasaki, P. Berlich, X. C. Lou, R. Humbert, J. Mildenberger, D. E. Plane, C. Y. Chang, S. Marcellini, J. F. Kral, G. P. Siroli, D. R. Rust, J. C. Clayton, N. Paz-Jaoshvili, P. G. Estabrooks, K. J. Anderson, P. Poffenberger, I. Cohen, C. M. Hawkes, A. Pouladdej, R. E. Hughes-Jones, M. Coupland, C. Burgard, V. Gibson, John Baines, P. Bock, O. Runolfsson, E. Ros, G. Giacomelli, Gideon Bella, J. Hagemann, R. K. Carnegie, C. Leroy, A. C. Janissen, N. I. Geddes, G. Yekutieli, G. Transtromer, M. Kuwano, U. Binder, B. C. Shen, R. Lahmann, W. Schappert, J. C. Hill, H. J. Burckhart, A. Michelini, B. Poli, Carla Sbarra, A. Jawahery, J. P. Pansart, J. R. McNutt, E. Etzion, J. Becker, U. Maur, M. Fierro, T. W. Pritchard, John Allison, R. G. Kellogg, D. S. Koetke, R. W.L. Jones, R. W. Springer, D. R. Ward, B. Boden, P. W. Jeffreys, M. F. Turner, R. Yaari, Mitsuaki Nozaki, B. W. Kennedy, S. Arcelli, V. H. Winterer, G. M. Dallavalle, S. L. Chu, P. Igo-Kemenes, J. von Krogh, P. F. Harrison, H. Mes, Dave Robinson, G. Azuelos, L. A. del Pozo, G. A. Bahan, M. Hauschild, Alan Watson, P. Kyberd, P. D. Acton, R. F. McGowan, C. K. Hargrove, J. A. Wilson, W. G. Scott, A. Rollnik, M. J. Losty, J. M. Lorah, M. Sproston, A. M. Rossi, M. Jobes, G. D. Lafferty, A. J. Martin, P. Leblanc, D. Lellouch, I. P. Duerdoth, C. H. Shepherd-Themistocleous, H. Ihssen, F. K. Loebinger, M. A. Thomson, J. G. Layter, R. Kowalewski, S. Wotton, R. Ströhmer, L. Levinson, M. Rosvick, G. Alexander, P.P. Singh, F. C. Grant, W. Gorn, P. Bright-Thomas, A. Buijs, Kiyotomo Kawagoe, D. M. Strom, C. Grandi, Tatsuo Kawamoto, O. Schaile, S. Schreiber, R. Giacomelli, K. Runge, N. J. Tresilian, B. Nellen, R. Van Kooten, D. J. Miller, M. Dittmar, J. Steuerer, T. Kobayashi, M. Fincke-Keeler, D. Karlen, J. Goldberg, D. Axen, P. Paschievici, A. K. Honma, C. J. Oram, O. Ganel, G. Vasseur, M. Weber, R. Mir, M. Settles, M. Foucher, M. J. Oreglia, T. Wlodek, P. Schenk, J. E. Pilcher, Wolfram Dietrich Zeuner, G. Maringer, N. J. Thackray, M. H. Lehto, G. J. VanDalen, E. Torrente-Lujan, Roger Barlow, M. Cuffiani, G. A. Beck, Ian J Bloodworth, A. A. Carter, G. E. Richards, A. Astbury, P. M. Hattersley, S. Orito, T. Tsukamoto, Austin Ball, A. Montanari, P. Jovanovic, J. Banks, J. R. Carter, N. Tesch, C. J. Virtue, M. A. Whalley, G. Mikenberg, T. R. Wyatt, S. W. O'Neale, L. Köpke, Stefan Kluth, J. R. Batley, R. Sobie, R. P. Middleton, C. Geich-Gimbel, P. S. Wells, R. J. Homer, R. Shypit, R. D. Heuer, Fabrizio Fabbri, D. Van den plas, T. Behnke, J. P. Walker, D. G. Fong, J. Gascon, H. von der Schmitt, J. M. Roney, Marcello Mannelli, J. E. Duboscq, N. Wermes, P. Scharff-Hansen, P. Teixeira-Dias, B. Schmitt, J. W. Gary, A. M. Smith, D. J.P. Dumas, D. A. Hinshaw, A. D. Schaile, K. W. Bell, Stephen Lloyd, M. Tecchio, S. W. Gensler, S. J. Hillier, P. Taras, Phillip Allport, Paolo Capiluppi, C. Schwick, and M. S. Dixit

Subjects
Quark, Physics, Nuclear and High Energy Physics, Particle physics, Electron–positron annihilation, High Energy Physics::Phenomenology, Nuclear Theory, Monte Carlo method, Hadron, Strangeness, Nuclear physics, Baryon, High Energy Physics::Experiment, Rapidity, Baryon number, Nuclear Experiment, Particle Physics - Experiment
Abstract

The production dynamics of baryon-antibaryon pairs are investigated using hadronic Z0 decays, recorded with the OPAL detector, which contain at least two identified Λ baryons. The rapidly difference for Λ Λ pairs shows the correlations expected from models with a chain-like production of baryon-antibaryon pairs. If the baryon number of a Λ is compensated by a Λ , the Λ is found with a probability of 53% in an interval of ±0.6 around the Λ rapidity. This correlation strength is weaker than predicted by the Herwig Monte Carlo and the Jetset Monte Carlo with a production chain of baryon-antibaryon, and stronger than predicted by the UCLA model. The observed rapidity correlations can be described by the Jetset Monte Carlo with a dominant production chain of baryon-meson-antibaryon, the popcorn mechanism. In addition to the short range correlations, one finds an indication of a correlation of Λ Λ pairs in opposite hemispheres if both the Λ and the Λ have large rapidities. Such long range correlations are expected if the primary quark flavours are compensated in opposite hemispheres and if these quarks are found in energetic baryons. Rates for simultaneous baryon and strangeness number compensation for Λ Λ , Ξ − Ξ + and Ξ − Λ ( Λ + Λ ) are measured and compared with different Monte Carlo models.

Published
1993

48. A measurement of (892)± production in hadronic Z0 decays

Author

J. Steuerer, T. Kobayashi, M. Fincke-Keeler, P. D. Acton, S. Bethke, A. Astbury, P. M. Hattersley, J. Letts, G. Quast, E. Duchovni, L. Köpke, W. Mohr, D. R. Rust, P. A. Elcombe, J. Schwiening, S. J. Hillier, F. Odorici, P. Routenburg, C. Geich-Gimbel, J. Hart, R. Shypit, F. G. Oakham, S. Weisz, R. D. Heuer, Fabrizio Fabbri, Tara Shears, A. Simon, J. A. Wilson, D. Van den plas, P. Igo-Kemenes, K. Runge, E. Ros, R. M. Brown, S. Tarem, S. Levegrün, T. Mori, P. Bentkowski, T. J. McMahon, Otmar Biebel, D. G. Charlton, D. L. Wagner, N. J. Tresilian, G. Mikenberg, B. Nellen, P. S. Wells, G. Duckeck, C. M. Hawkes, A. Pouladdej, H. Przysiezniak, H. Deng, E. Torrente-Lujan, X. C. Lou, B. Poli, Tohru Takeshita, R. Humbert, S. W. O'Neale, W. Schappert, Carla Sbarra, Roger Barlow, R. J. Homer, G. G. Hanson, S. Dado, Horst Breuker, H. G. Evans, M. J. Goodrick, G. Beaudoin, S. Wotton, R. Ströhmer, D. Karlen, F. Lamarche, R. Yaari, M. H. Lehto, J. Goldberg, F. C. Grant, C. Markus, G. Giacomelli, T. Hilse, B. C. Shen, L. Levinson, W. Gorn, R. Sobie, G. N. Patrick, H. O. Ogren, S. Bougerolle, E.J. Prebys, P. Paschievici, C. J. Virtue, O. Ganel, S. Komamiya, J. F. Kral, A. M. Lee, D. Axen, D. Pitman, A. K. Honma, G. P. Siroli, N. I. Geddes, T. Wlodek, N. Tesch, Frans Meijers, P. Bright-Thomas, A. Buijs, D. M. Strom, T. P. Kokott, C. Grandi, T. R. Wyatt, S. Arcelli, S. Rossberg, H. Jeremie, M. Jimack, B. Panzer-Steindel, C. Jui, A. Dieckmann, J. E. Conboy, J. C. Hill, Tatsuo Kawamoto, M. Cooper, G. J. VanDalen, Stefan Kluth, S. Schreiber, W. J. Collins, Peter R Hobson, R. J. Hemingway, J. Banks, G. Tysarczyk-Niemeyer, F. X. Gentit, R. Mir, D. J. Miller, P. Weber, J. Kroll, C. J. Oram, F. K. Loebinger, Gideon Bella, G. Yekutieli, D. E. Plane, J. Ludwig, A. Yeaman, M. A. Thomson, E. do Couto e Silva, G. A. Snow, C. P. Ward, E. Heflin, D. L. Rees, K. Stephens, H. J. Burckhart, D. Hochman, J. Pinfold, Jacqueline Batley, Richard Keeler, C. K. Hargrove, M. J. Oreglia, P. Pfister, P. Sherwood, S. Marcellini, Ian J Bloodworth, C. Wahl, T. J. Smith, M. Cuffani, N. K. Watson, A. Beck, C. Moisan, P. M. Watkins, Alan Watson, G. Transtromer, G. Azuelos, D. J.P. Dumas, O. Runolfsson, A. Gaidot, S. Orito, F. S. Merritt, A. Rollnik, W. R. Gibson, M. Sasaki, A. Montanari, S. W. Gensler, R. K. Carnegie, C. Leroy, A. D. Schaile, J. R. Carter, John Hobbs, U. Binder, J. R. McNutt, Austin Ball, A. C. Janissen, C. Y. Chang, M. F. Turner, G. Vasseur, P. Berlich, S. De Jong, M. Weber, E. Etzion, J. Becker, U. Maur, T. Mashimo, M. J. Losty, P. Mättig, M. Sproston, M. Settles, G. A. Bahan, T. Tsukamoto, G. W. Wilson, Mitsuaki Nozaki, J. A. McKenna, J. P. Martin, M. Foucher, J. D. Gillies, J. Mildenberger, B. Lorazo, H. M. Fischer, R. E. Hughes-Jones, A. Wagner, M. Coupland, P. Schenk, B. W. Kennedy, D. C. Imrie, C. Burgard, M. A. Whalley, J. E. Pilcher, V. Gibson, V. H. Winterer, John Baines, G. M. Dallavalle, D. R. Ward, B. Boden, M. Hansroul, P. Teixeira-Dias, P. Taras, J. von Krogh, P. Poffenberger, P. F. Harrison, H. Mes, J. P. Pansart, Phillip Allport, Peter Clarke, Dave Robinson, L. A. del Pozo, M. Hauschild, J. C. Clayton, N. Paz-Jaoshvili, P. G. Estabrooks, I. Cohen, K. J. Anderson, P. Kyberd, W. G. Scott, T. W. Pritchard, John Allison, Paolo Capiluppi, C. Schwick, J. M. Lorah, A. M. Rossi, R. F. McGowan, M. S. Dixit, M. Jobes, G. D. Lafferty, Kiyotomo Kawagoe, P. Leblanc, R. G. Kellogg, D. S. Koetke, R. W.L. Jones, G. E. Richards, K. W. Bell, Stephen Lloyd, M. Tecchio, O. Schaile, D. Menszner, Harold Nguyen, R. P. Middleton, J. Hagemann, P. Bock, A. Michelini, M. Kuwano, R. Lahmann, G. Alexander, P.P. Singh, M. W. Redmond, M. Rosvick, H. M. Bosch, A. A. Carter, T. Mouthuy, G. T. Zorn, N. Wermes, P. Scharff-Hansen, B. Schmitt, J. W. Gary, A. M. Smith, M. Yurko, P. W. Jeffreys, D. A. Hinshaw, Wolfram Dietrich Zeuner, P. Jovanovic, J. P. Walker, D. G. Fong, A. Jawahery, J. Gascon, H. von der Schmitt, J. M. Roney, R. W. Springer, Marcello Mannelli, J. E. Duboscq, Andris Skuja, S. Barnett, A. J. Martin, D. Lellouch, T. Behnke, I. P. Duerdoth, C. H. Shepherd-Themistocleous, H. Ihssen, J. G. Layter, R. Kowalewski, G. Maringer, N. J. Thackray, R. Van Kooten, and M. Dittmar

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Cross section (physics), Particle physics, Meson, Electron–positron annihilation, High Energy Physics::Phenomenology, Hadron, High Energy Physics::Experiment, Event (particle physics), Particle Physics - Experiment
Abstract

This is the post-print version of the Article - Copyright @ 1993 Elsevier. Measurements are presented of the inclusive cross section for K∗(892)± production in hadronic decays of the Z0 using a sample of about half a million events recorded with the OPAL experiment at LEP. Charged K∗ mesons are reconstructed in the decay channel K0Sπ±. A mean rate of 0.72±0.02±0.08 K∗ mesons per hadronic event is found. Comparison of the results with predictions of the JETSET and HERWIG models shows that JETSET overestimates the K∗± production cross section while HERWIG is consistent with the data. This study was supported by the Department of Energy, USA, National Science Foundation, USA, Science and Engineering Research Council, UK, Natural Sciences and Engineering Research Council, Canada, Israeli Ministry of Science, Minerva Gesellschaft, Japanese Ministry of Education, Science and Culture (the Monbusho) and a grant under the Monbusho International Science Research Program, American Israeli Bi-national Science Foundation, Direction des Sciences de la Matibre du Commissariat ~ l'Energie Atomique, France, Bundesministerium f'fir Forschung und Technologie, FRG, National Research Council of Canada, Canada, A.P. Sloan Foundation and Junta Nacional de Investigag~o Ciendfica e Tecnolrgica, Portugal.

Published
1993

49. A study of the electric charge distributions of quark and gluon jets in hadronic Z0 decays

Author

T. W. Pritchard, D. E. Plane, J. Gascon, J. A. Wilson, Horst Breuker, K. Stephens, G. Yekutieli, R. Giacomelli, H. M. Bosch, S. Levegrün, M. Cuffiani, A. Jawahery, D. J. Miller, Tohru Takeshita, M. A. Thomson, I. Cohen, R. F. McGowan, Alan Watson, J. P. Walker, A. M. Rossi, Richard Keeler, J. Mildenberger, M. Weber, I. J. Bloodworth, R. Mir, G. D. Lafferty, R. W. Springer, John Carter, John Hobbs, D. J.P. Dumas, M. Jimack, M. Kuwano, P. Bright-Thomas, P. Kyberd, J. P. Pansart, J. F. Kral, J. Allison, J. Steuerer, D. Karlen, T. Wlodek, R. J. Hemingway, C. J. Oram, A. Gaidot, Gideon Bella, W. R. Gibson, S. W. O'Neale, H. J. Burckhart, P. M. Hattersley, A. Wagner, H. Przysiezniak, F. C. Grant, J. Hagemann, O. Runolfsson, R. Ströhmer, D. C. Imrie, S. Wotton, D. A. Hinshaw, B. Panzer-Steindel, E. Ros, R. J. Homer, J. Hart, A. Astbury, J. P. Martin, A. Rollnik, U. Maur, H. Mes, K. Runge, S. Kluth, G. Vasseur, W. Gorn, D. Hochman, P. Mättig, Carla Sbarra, P. Igo-Kemenes, R. D. Heuer, P. Berlich, B. C. Shen, R. W.L. Jones, J. C. Hill, J. D. Gillies, J. R. Batley, T. J. McMahon, M. A. Whalley, P. Bentkowski, P. A. Elcombe, J. C. Clayton, T. Kawamoto, T. Hilse, J. Pinfold, P. G. Estabrooks, N. Paz-Jaoshvili, D. Van den plas, T. Tsukamoto, A. Beck, D. Menszner, John Baines, J. Becker, G. G. Hanson, P. S. Wells, C. Geich-Gimbel, R. G. Kellogg, G. P. Siroli, J. M. Lorah, G. Transtromer, G. Alexander, A. Pouladdej, Phillip Allport, D. Lellouch, J. Letts, S. Orito, G. J. VanDalen, T. Behnke, Andris Skuja, J. Kroll, M. Dittmar, C. K. Hargrove, D. S. Koetke, G. Maringer, D. R. Ward, V. H. Winterer, R. M. Brown, P. M. Watkins, U. Binder, M. Yurko, T. R. Wyatt, R. J. Barlow, A. M. Lee, M. J. Oreglia, G. T. Zorn, M. Hansroul, B. Nellen, P. Taras, C. Moisan, J. Goldberg, O. Biebel, R. Sobie, S. Bethke, C. Burgard, P. Bock, A. Buijs, C. Schwick, G. Mikenberg, M. Sasaki, N. I. Geddes, T. P. Kokott, L. Levinson, P. Singh, D. M. Strom, S. Tarem, A. Dieckmann, C. J. Virtue, N. J. Tresilian, F. G. Oakham, D. R. Rust, A. A. Carter, T. Mashimo, A. J. Martin, R. P. Middleton, F. S. Merritt, J. E. Pilcher, T. J. Smith, F. X. Gentit, Austin Ball, K. J. Anderson, W. J. Collins, W. Schappert, S. Barnett, Maurice Goodrick, Paolo Capiluppi, E. Heflin, N. K. Watson, C. P. Ward, F. Lamarche, M. Nozaki, B. Schmitt, R. E. Hughes-Jones, G. W. Wilson, P. Poffenberger, O. Ganel, P. Routenburg, C. Wahl, B. Lorazo, J. W. Gary, Harold Nguyen, H. G. Evans, A. D. Schaile, C. Grandi, T. Mori, P. Weber, E. do Couto e Silva, L. Köpke, D. G. Charlton, D. L. Wagner, P. Teixeira-Dias, T. Kobayashi, G. Quast, G. Duckeck, G. Azuelos, W. G. Scott, J. A. McKenna, M. Hauschild, M. S. Dixit, A. Montanari, E. Torrente-Lujan, J. Ludwig, S. De Jong, Wolfram Dietrich Zeuner, H. Deng, S. Marcellini, C. M. Hawkes, J. Schwiening, C. Y. Chang, M. F. Turner, X. C. Lou, P. D. Acton, Stephen Lloyd, M. J. Losty, P. Scharff-Hansen, D. Axen, R. Yaari, P. Pfister, F. Odorici, E. Etzion, M. Rosvick, S. Arcelli, M. Tecchio, M. Coupland, P. Sherwood, G. A. Beck, C. Markus, G. Giacomelli, J. R. McNutt, A. Simon, P. Jovanovic, M. Cooper, H. M. Fischer, S. Rossberg, P. W. Jeffreys, M. Fincke-Keeler, A. M. Smith, H. O. Ogren, M. Settles, M. W. Redmond, R. Shypit, R. Kowalewski, O. Schaile, M. Sproston, G. N. Patrick, K. W. Bell, G. A. Bahan, S. W. Gensler, F. K. Loebinger, B. Poli, S. J. Hillier, M. H. Lehto, J. E. Conboy, P. E.L. Clarke, M. Fierro, D. G. Fong, H. von der Schmitt, H. Jeremie, J. G. Layter, N. Wermes, I. P. Duerdoth, A. Michelini, M. Foucher, P. Leblanc, M. Jobes, Marcello Mannelli, J. E. Duboscq, N. J. Thackray, B. W. Kennedy, T. Mouthuy, P. Paschievici, A. C. Janissen, J. M. Roney, R. Lahmann, H. Ihssen, A. Yeaman, S. Dado, A. K. Honma, S. Komamiya, P. R. Hobson, W. Mohr, Frans Meijers, R. Humbert, J. Banks, P. Schenk, E. Duchovni, G. A. Snow, D. L. Rees, C. Leroy, S. L. Chu, S. Schreiber, V. Gibson, C. Jui, G. Tysarczyk-Niemeyer, K. Kawagoe, P. F. Harrison, R. K. Carnegie, B. Boden, G. M. Dallavalle, J. von Krogh, C. H. Shepherd-Themistocleous, Dave Robinson, N. Tesch, L. A. del Pozo, G. Beaudoin, D. Pitman, G. E. Richards, R. Van Kooten, Franco Luigi Fabbri, and Tara Shears

Subjects
Quark, Physics, Nuclear and High Energy Physics, Particle physics, Charge conservation, High Energy Physics::Lattice, Astrophysics::High Energy Astrophysical Phenomena, Nuclear Theory, High Energy Physics::Phenomenology, Charge (physics), Jet (particle physics), Bottom quark, Electric charge, Gluon, Nuclear physics, High Energy Physics::Experiment, Particle Physics - Experiment, Lepton
Abstract

A sample of three-jet events containing a lepton with high momentum and transverse momentum is selected from hadronic decays of the Z0. The presence of the lepton indicates the semi-leptonic decay of a bottom quark and allows us, in combination with energy ordering of the jets, to distinguish between quark and gluon jets. The sign of the lepton charge is used to identify jets originating from positively and negatively charged quarks, for the jets with the lepton and for the high energy jets. Defining the jet charge by summing the charge of the particles assigned to a jet, it is observed that the mean jet charge of the quark jets is incompatible with zero and that the sign of the jet charge corresponds to that expected from the charge of the primary quark. In contrast, the mean charge of the gluon jets is consistent with zero.

Published
1993

50. The forward-backward asymmetry of $$e^ + e^ - \to b\bar b and e^ + e^ - \to c\bar c$$ using leptons in hadronicZ 0 decays

Author

Madjid Boutemeur, Tohru Takeshita, James Pinfold, D. G. Fong, J. Gascon, H. von der Schmitt, S. L. Chu, P. G. Estabrooks, R. K. Keeler, Georges Azuelos, D. Pitman, S. Barnett, P. M. Hattersley, M. H. Lehto, P. M. Watkins, J. F. Kral, K. W. Bell, C. Y. Chang, M. F. Turner, F. Odorici, J. W. Gary, Max Weber, H. Mes, I. P. Duerdoth, R. Mir, D. Hochman, C. Sbarra, Marcello Mannelli, J. E. Duboscq, J. C. Hill, T. G. Shears, Misao Sasaki, M. Yurko, John Hobbs, Erez Etzion, Michael Dittmar, R. Lahmann, H. M. Fischer, M. J. Pearce, Horst Breuker, F. S. Merritt, G. Yekutieli, J. C. Clayton, Silvia Arcelli, Stefan Kluth, D. M. Gingrich, Shlomit Tarem, D. C. Imrie, B. C. Shen, B. Fabbro, B. Panzer-Steindel, J. G. Layter, P. W. Jeffreys, A. K. Honma, C. Moisan, P. Scharff-Hansen, M. J. Oreglia, S. Rossberg, P. Berlich, C. J. Oram, L. Köpke, G. P. Siroli, R. P. Middleton, W. G. Scott, G. Beaudoin, A. A. Carter, G. A. Beck, Christoph Schwick, Achim Stahl, J. Mildenberger, Harold Nguyen, P. Teixeira-Dias, P. E.L. Clarke, A. D. Schaile, J. Steuerer, Matthias Schröder, Gunter Wolf, Roger Jones, R. Van Kooten, P. F. Harrison, J. A. McKenna, A. M. Smith, G. Vasseur, R. Kowalewski, M. J. Losty, J. M. Lorah, D. R. Rust, Gideon Bella, H. J. Burckhart, Jacqueline Batley, H. Lafoux, N. Paz-Jaoshvili, S. Wotton, A. Michelini, J. R. Carter, G. N. Patrick, Otmar Biebel, P. D. Acton, Stephen Lloyd, A. Yeaman, G. E. Richards, D. G. Charlton, D. L. Wagner, P. Bright-Thomas, M. Tecchio, G. A. Snow, C. P. Ward, Kiyotomo Kawagoe, B. Lorazo, B. Schmitt, J. M. Roney, Andris Skuja, V. H. Winterer, A. M. Lee, M. W. Redmond, P. Igo-Kemenes, H. Jeremie, T. J. Smith, A. C. Janissen, K. Stephens, H. Deng, Margret Fincke-Keeler, N. K. Watson, J. R. McNutt, Sachio Komamiya, T. J. McMahon, R. Humbert, P. Mättig, R. Bartoldus, D. A. Hinshaw, D. L. Rees, R. Yaari, Tetsuro Mashimo, J. Goldberg, M. A. Thomson, H. O. Ogren, W. Mohr, J. Schwiening, U. Maur, B. Nellen, P. Leblanc, E. Ros, A. T. Watson, P. Weber, S. A. Robins, R. K. Carnegie, S. Bethke, Christoph Geich-Gimbel, Marco Cuffiani, A. Astbury, V. Gibson, G. Quast, J. A. Wilson, T. P. Kokott, H. G. Evans, A. Luig, U. Müller, Paul Kyberd, I. J. Bloodworth, P. Pfister, F. K. Loebinger, T. Behnke, J. Kroll, R.J. Akers, Gideon Alexander, P. S. Wells, M. J. Goodrick, Paolo Capiluppi, Norbert Wermes, W. J. Collins, Sherry Towers, John Baines, I. Cohen, T. Kawamoto, T. Hilse, A. J. Martin, P. A. Elcombe, S. W. O'Neale, F. X. Gentit, K. J. Anderson, J. E. Conboy, Randall Sobie, G. D. Lafferty, W. Schappert, O. Runolfsson, J. Banks, Ehud Duchovni, R. Shypit, S. Orito, M. Rosvick, M. Settles, A. Pouladdej, Shlomo Dado, G. Duckeck, R. Ströhmer, M. Jimack, Terry Richard Wyatt, G. T. Zorn, H. Ihssen, N. J. Tresilian, D. R. Ward, T. W. Pritchard, E. do Couto e Silva, G. Transtromer, S. W. Gensler, R. D. Heuer, A. Rollnik, R. Giacomelli, H. M. Bosch, C. K. Hargrove, Wolfram Dietrich Zeuner, M. Foucher, C. Beeston, X. C. Lou, Fabrizio Fabbri, S. J. Hillier, T. Kobayashi, M. Coupland, Claudio Grandi, C. J. Virtue, M. Morii, Peter R Hobson, P. Poffenberger, R. E. Hughes-Jones, O. Schaile, D. Axen, A. Jawahery, C. Gorn, Peter Sherwood, D. Van del Plas, J. Becker, R. W. Springer, Alexander Wagner, M. Hansroul, John Allison, G. W. Wilson, D. Karlen, J. Hagemann, J. Ludwig, Giora Mikenberg, K. Runge, J. von Krogh, P. Bock, M. Jones, C. Burgard, A. M. Rossi, T. Tsukamoto, S. Levegrün, C. M. Hawkes, G. J. VanDalen, M. Cooper, Daniel Lellouch, C. H. Shepherd-Themistocleous, Dave Robinson, R. G. Kellogg, R. J. Homer, Takehiko Mori, W. R. Gibson, L. A. del Pozo, D. S. Koetke, N. I. Geddes, Stefano Marcellini, James Letts, Claude Leroy, J. P. Pansart, B. Boden, B. Poli, C. Jui, A. Skillman, F. C. Grant, M. A. Whalley, M. Hauschild, A. Beck, A. Buijs, D. M. Strom, A. Gaidot, M. Kuwano, C. Stegmann, E. Heflin, R. M. Brown, Lorne Levinson, T. Wlodek, M. Sproston, C. Markus, H. Przysiezniak, P. Routenburg, P. Paschievici, N. Tesch, A. Dieckmann, B. W. Kennedy, M. Fierro, E. Torrente-Lujan, D. E. Plane, P. Bentkowski, G. M. Dallavalle, D. J.P. Dumas, Gregor Herten, C. Wahl, B. Wilkens, J. E. Pilcher, G. G. Hanson, G. Giacomelli, P. Schenk, M. S. Dixit, Frans Meijers, J. P. Martin, S. De Jong, J. Hart, J. D. Gillies, R. J. Barlow, D. J. Miller, F. Lamarche, R. J. Hemingway, P. Jovanovic, Austin Ball, D. Menszner, Alessandro Montanari, H. Takeda, and F. G. Oakham

Subjects
Physics, Particle physics, Muon, Physics and Astronomy (miscellaneous), Electron–positron annihilation, media_common.quotation_subject, Hadron, Asymmetry, Nuclear physics, Momentum, Engineering (miscellaneous), Energy (signal processing), Lepton, Bar (unit), media_common
Abstract

The forward-backward asymmetries of $$e^ + e^ - \to Z^0 \to b\bar b and e^ + e^ - \to Z^0 \to c\bar c$$ have been measured by the OPAL Collaboration using samples of hadronicZ 0 decays in which electron or muon candidates were observed. The asymmetries were measured simultaneously in a two parameter fit, which used the distributions of the track momentum and transverse momentum component with respect to the associated jet to distinguish lepton candidates from different sources. From a sample of 360 000 hadronic events with centre-of-mass energies within ±0.5 GeV of theZ 0 mass and mean energy 91.24. GeV, the values obtained for the $$b\bar b$$ asymmetry before and after correcting, for the effect of $$B^0 \overline {B^0 } $$ mixing, and for the $$c\bar c$$ asymmetry are, respectively: $$\begin{gathered} A_{FB}^{b,mix} = 0.070 \pm 0.014(stat) \pm 0.005(sys), \hfill \\ A_{FB}^b = 0.092 \pm 0.018(stat) \pm 0.007(sys) \hfill \\ \pm 0.003(mix), \hfill \\ A_{FB}^c = 0.014 \pm 0.030(stat) \pm 0.020(sys). \hfill \\ \end{gathered} $$ The measurement of the $$b\bar b$$ asymmetry is confirmed by a measurement using only leptons with high transverse momentum. This sample is highly enriched in semileptonic decays ofb hadrons. Measurements using high transverse momentum leptons were also performed using samples of events with centre-of-mass energies further from theZ 0 mass. After correcting for the effect of $$B^0 \overline {B^0 } $$ mixing, the results are: $$\begin{gathered} A_{FB}^b (\langle \sqrt s \rangle = 89.66GeV) \hfill \\ = 0.071 \pm 0.054(stat) \pm 0.007(sys) \pm 0.002(mix), \hfill \\ A_{FB}^b (\langle \sqrt s \rangle = 92.75GeV) \hfill \\ = 0.131 \pm 0.047(stat) \pm 0.012(sys) \pm 0.004(mix). \hfill \\ \end{gathered} $$

Published
1993

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