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2. Low-temperature magnetic crossover in the topological kagome magnet TbMn6Sn6

Author

C. Mielke III, W. L. Ma, V. Pomjakushin, O. Zaharko, S. Sturniolo, X. Liu, V. Ukleev, J. S. White, J.-X. Yin, S. S. Tsirkin, C. B. Larsen, T. A. Cochran, M. Medarde, V. Porée, D. Das, R. Gupta, C. N. Wang, J. Chang, Z. Q. Wang, R. Khasanov, T. Neupert, A. Amato, L. Liborio, S. Jia, M. Z. Hasan, H. Luetkens, and Z. Guguchia

Subjects
Astrophysics, QB460-466, Physics, QC1-999
Abstract

Kagome metals house a range of competing ground states leading to superconducting as well as topological features and so there has been significant recent interest in their underlying physics. Here, the authors use muon-spin rotation to identify slow fluctuations and low-temperature volume-wise magnetic evolution of the static c-axis ferrimagnetic patches in TbMn6Sn6, which seems to be intimately coupled to its topological electronic properties.

Published
2022
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3. Vital role of magnetocrystalline anisotropy in cubic chiral skyrmion hosts

Author

M. Preißinger, K. Karube, D. Ehlers, B. Szigeti, H.-A. Krug von Nidda, J. S. White, V. Ukleev, H. M. Rønnow, Y. Tokunaga, A. Kikkawa, Y. Tokura, Y. Taguchi, and I. Kézsmárki

Subjects
Materials of engineering and construction. Mechanics of materials, TA401-492, Atomic physics. Constitution and properties of matter, QC170-197
Abstract

Abstract Magnetic anisotropy is anticipated to govern the formation of exotic spin textures reported recently in cubic chiral magnets, like low-temperature tilted conical and skyrmion lattice (SkL) states and metastable SkLs with various lattice geometry. Motivated by these findings, we quantified the cubic anisotropy in a series of CoZnMn-type cubic chiral magnets. We found that the strength of anisotropy is highly enhanced towards low temperatures. Moreover, not only the magnitude but also the character of cubic anisotropy drastically varies upon changing the Co/Mn ratio. We correlate these changes with temperature- and composition-induced variations of the helical modulation vectors, deformations of skyrmions, structural rearrangements of the metastable SkLs and the large enhancement of Gilbert damping. Similar studies on magnetic anisotropy are required for the quantitative, unified description of the known stable and metastable modulated spin textures and for the systematic exploration of novel ones in this large class of skyrmion hosts.

Published
2021
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4. Frustration-driven magnetic fluctuations as the origin of the low-temperature skyrmion phase in Co7Zn7Mn6

Author

V. Ukleev, K. Karube, P. M. Derlet, C. N. Wang, H. Luetkens, D. Morikawa, A. Kikkawa, L. Mangin-Thro, A. R. Wildes, Y. Yamasaki, Y. Yokoyama, L. Yu, C. Piamonteze, N. Jaouen, Y. Tokunaga, H. M. Rønnow, T. Arima, Y. Tokura, Y. Taguchi, and J. S. White

Subjects
Materials of engineering and construction. Mechanics of materials, TA401-492, Atomic physics. Constitution and properties of matter, QC170-197
Abstract

Abstract In chiral cubic helimagnets, phases of magnetic skyrmions—topologically protected spin whirls—are stabilized by thermal fluctuations over a narrow region directly below the magnetic ordering temperature T c. Due to often being touted for use in applications, there is a high demand to identify new ways to stabilize equilibrium skyrmion phases far below T c where they may display an enhanced robustness against external perturbation due to a larger magnetic order parameter. Here, from quantum beam experiments on the chiral magnet Co7Zn7Mn6, we unveil a direct correlation between the stability of its second skyrmion phase-stable far from T c, and a concomitant enhancement of an underlying magnetic fluctuation rate that is driven by geometric magnetic frustration. The influences of other leading skyrmion stability mechanisms, such as those derived from thermal fluctuations and low T cubic anisotropies, are shown to be weak in this system. We therefore advance the existence of a fundamental mechanism for stabilizing topological skyrmions in Co7Zn7Mn6 chiral magnet that draws upon magnetic frustration as the key ingredient.

Published
2021
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5. Spin wave stiffness and damping in a frustrated chiral helimagnet Co_{8}Zn_{8}Mn_{4} as measured by small-angle neutron scattering

Author

V. Ukleev, K. A. Pschenichnyi, O. Utesov, K. Karube, S. Mühlbauer, R. Cubitt, Y. Tokura, Y. Taguchi, J. S. White, and S. V. Grigoriev

Subjects
Physics, QC1-999
Abstract

Multiple intriguing low-temperature phenomena have recently been discovered in the family of chiral cubic Co-Zn-Mn compounds with a β-Mn-type structure. In particular, Co_{8}Zn_{8}Mn_{4} displays a reduction of the helical spiral pitch on cooling along with lattice shape transformations of metastable skyrmions and the manifestation of peculiar magnetic textures due to strong magnetocrystalline anisotropy. Here we report on temperature-dependent measurements of helimagnon excitations in the field polarized regime Co_{8}Zn_{8}Mn_{4} using the spin-wave (SW) small-angle neutron-scattering technique. By applying a new analytical expression to interpret the data, quantitative estimates for both SW stiffness and damping are extracted across a wide temperature range between 70 and 250 K. We speculate that their nontrivial temperature dependencies arise due to the effects of magnetic frustration arising from Mn magnetic moments, which is further reflected in continuous variations of both exchange and Dzyaloshinskii-Moriya interactions.

Published
2022
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9. Equilibrium Skyrmion Lattice Ground State in a Polar Easy-plane Magnet

Author

S. Bordács, A. Butykai, B. G. Szigeti, J. S. White, R. Cubitt, A. O. Leonov, S. Widmann, D. Ehlers, H.-A. Krug von Nidda, V. Tsurkan, A. Loidl, and I. Kézsmárki

Subjects
Medicine, Science
Abstract

Abstract The skyrmion lattice state (SkL), a crystal built of mesoscopic spin vortices, gains its stability via thermal fluctuations in all bulk skyrmion host materials known to date. Therefore, its existence is limited to a narrow temperature region below the paramagnetic state. This stability range can drastically increase in systems with restricted geometries, such as thin films, interfaces and nanowires. Thermal quenching can also promote the SkL as a metastable state over extended temperature ranges. Here, we demonstrate more generally that a proper choice of material parameters alone guarantees the thermodynamic stability of the SkL over the full temperature range below the paramagnetic state down to zero kelvin. We found that GaV4Se8, a polar magnet with easy-plane anisotropy, hosts a robust Néel-type SkL even in its ground state. Our supporting theory confirms that polar magnets with weak uniaxial anisotropy are ideal candidates to realize SkLs with wide stability ranges.

Published
2017
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10. Coupled multiferroic domain switching in the canted conical spin spiral system Mn2GeO4

Author

T. Honda, J. S. White, A. B. Harris, L. C. Chapon, A. Fennell, B. Roessli, O. Zaharko, Y. Murakami, M. Kenzelmann, and T. Kimura

Subjects
Science
Abstract

The coexistence of ferromagnetism and ferroelectricity in a multiferroic material often arises from complex magnetoelectric couplings. Here, the authors observe switching of domains in Mn2GeO4using neutron diffraction and develop a phenomenological theory to explain their results.

Published
2017
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15. Topological magnetic structures in MnGe: Neutron diffraction and symmetry analysis

Author

V. Pomjakushin, I. Plokhikh, J. S. White, Y. Fujishiro, N. Kanazawa, Y. Tokura, and E. Pomjakushina

Subjects
Condensed Matter - Other Condensed Matter, Condensed Matter - Strongly Correlated Electrons, Strongly Correlated Electrons (cond-mat.str-el), FOS: Physical sciences, Other Condensed Matter (cond-mat.other)
Abstract

From new neutron powder diffraction experiments on the chiral cubic ($P2{_1}3$) magnet manganese germanide MnGe, we analyse all of the possible crystal symmetry-allowed magnetic superstructures that are determined successfully from the data. The incommensurate propagation vectors $k$ of the magnetic structure are found to be aligned with the [100] cubic axes, and correspond to a magnetic periodicity of about 30 $\r{A}$ at 1.8 K. Several maximal crystallographic symmetry magnetic structures are found to fit the data equally well and are presented. These include topologically non-trivial magnetic hedgehog and "skyrmion'' structures in multi-$k$ cubic or orthorhombic 3+3 and orthorhombic 3+2 dimensional magnetic superspace groups respectively, with either potentially responsible for topological Hall effect. The presence of orthorhombic distortions in the space group $P2_12_12_1$ caused by the transition to the magnetically ordered state does not favour the cubic magnetic hedgehog structure, and leave both orthorhombic hedgehog and "skyrmion'' models as equal candidates for the magnetic structures. We also report on a new combined mechanochemical and solid-state chemical route to synthesise MnGe at ambient pressures and moderate temperatures, and compare with samples obtained by the traditional high pressure synthesis., Comment: New high-resolution neutron diffraction data are added that allows us to unambiguously determine a preference for the orthorhombic symmetry

Published
2022

17. Metamagnetic texture in a polar antiferromagnet

Author

D. A. Sokolov, N. Kikugawa, T. Helm, H. Borrmann, U. Burkhardt, R. Cubitt, J. S. White, E. Ressouche, M. Bleuel, K. Kummer, A. P. Mackenzie, U. K. Rößler, University of St Andrews. School of Physics and Astronomy, University of St Andrews. Condensed Matter Physics, Deutsches Zentrum für Luft- und Raumfahrt [Oberpfaffenhofen-Wessling] (DLR), Institut Laue-Langevin (ILL), ILL, College of Information Science and Engineering, Ritsumeikan University, Magnétisme et Diffusion Neutronique (MDN), Modélisation et Exploration des Matériaux (MEM), Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), European Synchrotron Radiation Facility (ESRF), Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)

Subjects
Physics, Phase transition, Strongly Correlated Electrons (cond-mat.str-el), Condensed matter physics, Thermodynamic state, FOS: Physical sciences, General Physics and Astronomy, DAS, Physics and Astronomy(all), 01 natural sciences, Landau theory, 010305 fluids & plasmas, Condensed Matter - Strongly Correlated Electrons, Paramagnetism, QC Physics, Ferromagnetism, 0103 physical sciences, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Antiferromagnetism, Condensed Matter::Strongly Correlated Electrons, Symmetry breaking, 010306 general physics, ComputingMilieux_MISCELLANEOUS, QC, Metamagnetism
Abstract

The notion of a simple ordered state implies homogeneity. If the order is established by a broken symmetry, elementary Landau theory of phase transitions shows that only one symmetry mode describes this state. Precisely at points of phase coexistence domain states formed of large regions of different phases can be stabilized by long range interactions. In uniaxial antiferromagnets the so-called metamagnetism is an example of such a behavior, when an antiferromagnetic and field-induced spin-polarized paramagnetic/ferromagnetic state co-exist at a jump-like transition in the magnetic phase diagram. Here, combining experiment with theoretical analysis, we show that a different type of mixed state between antiferromagnetism and ferromagnetism can be created in certain acentric materials. In the small-angle neutron scattering experiments we observe a field-driven spin-state in the layered antiferromagnet Ca3Ru2O7, which is modulated on a scale between 8 and 20 nm and has both antiferromagnetic and ferromagnetic parts. We call this state a metamagnetic texture and explain its appearance by the chiral twisting effects of the asymmetric Dzyaloshinskii-Moriya (DM) exchange. The observation can be understood as an extraordinary coexistence, in one thermodynamic state, of spin orders belonging to different symmetries. Experimentally, the complex nature of this metamagnetic state is demonstrated by measurements of anomalies in electronic transport which reflect the spin-polarization in the metamagnetic texture, determination of the magnetic orbital moments, which supports the existence of strong spin-orbit effects, a pre-requisite for the mechanism of twisted magnetic states in this material., Comment: Supplementary materials included

Published
2019

20. Radiative Double-Electron Capture by Bare and One-Electron Ions on Gas Targets

Author

Asghar Kayani, J. A. Tanis, D. S. La Mantia, P. N. S. Kumara, C. P. McCoy, J. S. White, S. L. Buglione, and C. J. Taylor

Subjects
Physics, Photon, Electron capture, 0103 physical sciences, Radiative transfer, General Physics and Astronomy, Inverse, Charge (physics), Electron, Atomic physics, 010306 general physics, 01 natural sciences, Ion
Abstract

Radiative double-electron capture (RDEC) involves the transfer of two electrons with the simultaneous emission of a single photon. This process, which can be viewed as the inverse of double photoionzation, has been studied for $2.11\text{ }\text{ }\mathrm{MeV}/\mathrm{u}$ ${\mathrm{F}}^{9+}$ and ${\mathrm{F}}^{8+}$ ions striking gas targets of ${\mathrm{N}}_{2}$ and Ne. The existence of RDEC is conclusively shown for both targets and the results are compared with earlier ${\mathrm{O}}^{8+}$ and ${\mathrm{F}}^{9+}$ findings for thin-foil carbon and with theory. The data for the carbon target showed some evidence for the existence of RDEC, but the interpretation was clouded by high-probability, unavoidable multiple collisions causing the exiting charge state to be increased.

Published
2019

21. Radiative double electron capture for 2.11 MeV/u F9+,8+ + N2, Ne

Author

C. P. McCoy, J. A. Tanis, D. S. La Mantia, P. N. S. Kumara, S. L. Buglione, C. J. Taylor, J. S. White, and Asghar Kayani

Subjects
Physics, History, Projectile, Electron capture, Radiative transfer, Charge (physics), Atomic physics, Computer Science Applications, Education
Abstract

Synopsis The first successful observation of radiative double electron capture for gas targets is reported. RDEC has been observed for 2.11 MeV/u F9+,8++N2, Ne collisions. Cross sections for both projectile charge states and targets were determined and compared with previous results and theory. This abstract gives an overview of the results found for both gas targets.

Published
2020

22. Multiple

Author

R, Takagi, J S, White, S, Hayami, R, Arita, D, Honecker, H M, Rønnow, Y, Tokura, and S, Seki

Subjects
Physics::Atomic and Molecular Clusters, Physics::Optics, SciAdv r-articles, Condensed Matter::Strongly Correlated Electrons, Condensed Matter Physics, Research Articles, Research Article
Abstract

Neutron-scattering experiments reveal a hexagonally crystallized form of noncollinear magnetic order in an itinerant magnet., Multiple-q spin order, i.e., a spin texture characterized by a multiple number of coexisting magnetic modulation vectors q, has recently attracted attention as a source of nontrivial magnetic topology and associated emergent phenomena. One typical example is the triple-q skyrmion lattice state stabilized by Dzyaloshinskii-Moriya interactions in noncentrosymmetric magnets, while the emergence of various multiple-q states of different origins is expected according to the latest theories. Here, we investigated the magnetic structure of the itinerant polar hexagonal magnet Y3Co8Sn4, in which several distinctive mechanisms favoring multiple-q states are allowed to become active. Small-angle neutron-scattering experiments suggest the formation of incommensurate triple-q magnetic order with an in-plane vortex-like spin texture, which can be most consistently explained in terms of the novel four-spin interaction mechanism inherent to itinerant magnets. The present results suggest a new route to realizing exotic multiple-q orders and that itinerant hexagonal magnets, including the R3M8Sn4 family with wide chemical tunability, can be a unique material platform to explore their rich phase diagrams.

Published
2018

23. A programmable SDN+NFV-based architecture for UAV telemetry monitoring

Author

Dimitrios P. Pezaros, Kyle J. S. White, Ewen Denney, Angelos K. Mamerides, and Matt Knudson

Subjects
020301 aerospace & aeronautics, Computer science, business.industry, Wireless ad hoc network, ComputerApplications_COMPUTERSINOTHERSYSTEMS, 020206 networking & telecommunications, 02 engineering and technology, Network monitoring, 0203 mechanical engineering, Container (abstract data type), 0202 electrical engineering, electronic engineering, information engineering, Anomaly detection, Architecture, Resilience (network), business, Software-defined networking, Mobility management, Computer network
Abstract

The explosive growth in the worldwide use of\ud Unmanned Aerial Vehicles (UAVs) has raised a critical concern\ud with respect to the adequate management of their ad hoc network\ud configuration as required by their mobility management process.\ud As UAVs migrate among ground control stations, associated\ud network services, routing and operational control must also\ud rapidly migrate to ensure a seamless transition. In this paper,\ud we present a novel, lightweight and modular architecture which\ud supports high mobility and situational-awareness through the\ud application of Software Defined Networking (SDN) and Network\ud Function Virtualization (NFV) principles on top of the UAV\ud infrastructure. By combining SDN+NFV programmability we\ud can achieve a robust migration of UAV-related network services,\ud such as network monitoring and anomaly detection as well as\ud smooth UAV migration that confronts high mobility requirements.\ud The proposed container-based monitoring and anomaly detection\ud Network Functions (NFs) as employed within our architecture\ud can be tuned to specific UAV types providing operators better\ud insight during live, high-mobility deployments. We evaluate our\ud architecture against telemetry from over 80 flights from a\ud scientific research UAV infrastructure showing our ability to tune\ud and detect emerging challenges.

Published
2017

24. Strength training for partially paralysed muscles in people with recent spinal cord injury: a within-participant randomised controlled trial

Author

Mohit Arora, Emilie Gollan, Joanne V. Glinsky, Elizabeth A Bye, J L Bowden, Simon C. Gandevia, C Kataria, J S White, K E Tranter, N Malik, Lisa A. Harvey, C P Lam, and A Gambhir

Subjects
Male, 030506 rehabilitation, medicine.medical_specialty, Strength training, Elbow, Electric Stimulation Therapy, Isometric exercise, law.invention, 03 medical and health sciences, 0302 clinical medicine, Physical medicine and rehabilitation, Randomized controlled trial, law, medicine, Humans, Paralysis, Spasticity, Muscle Strength, Muscle, Skeletal, Spinal cord injury, Spinal Cord Injuries, Muscle Weakness, business.industry, Resistance Training, General Medicine, medicine.disease, Confidence interval, medicine.anatomical_structure, Treatment Outcome, Neurology, Muscle Spasticity, Physical therapy, Female, Neurology (clinical), medicine.symptom, 0305 other medical science, business, Control muscle, 030217 neurology & neurosurgery
Abstract

Within-participant randomised controlled trial. To determine whether strength training combined with usual care increases strength in partially paralysed muscles of people with recent spinal cord injury (SCI) more than usual care alone. SCI units in Australia and India. Thirty people with recent SCI undergoing inpatient rehabilitation participated in this 12-week trial. One of the following muscle groups was selected as the target muscle group for each participant: the elbow flexors, elbow extensors, knee flexors or knee extensors. The target muscle on one side of the body was randomly allocated to the experimental group and the same muscle on the other side of the body was allocated to the control group. Strength training was administered to the experimental muscle but not to the control muscle. Participants were assessed at baseline and 12 weeks later. The primary outcome was maximal isometric muscle strength, and the secondary outcomes were spasticity, fatigue and participants’ perception of function and strength. There were no dropouts, and participants received 98% of the training sessions. The mean (95% confidence interval (CI)) between-group difference for isometric strength was 4.3 Nm (1.9–6.8) with a clinically meaningful treatment effect of 2.7 Nm. The mean (95% CI) between-group difference for spasticity was 0.03/5 points (−0.25 to 0.32). Strength training increases strength in partially paralysed muscles of people with recent SCI, although it is not clear whether the size of the treatment effect is clinically meaningful. Strength training has no deleterious effects on spasticity.

Published
2016

25. Using Programmable Data Networks to Detect Critical Infrastructure Challenges

Author

Kyle J. S. White, Dimitrios P. Pezaros, and Chris Johnson

Subjects
Programmable networking, Computer science, Modular architecture, Computer security, computer.software_genre, Resilience (network), Set (psychology), computer, Critical infrastructure, Domain (software engineering)
Abstract

Critical infrastructures must be better protected against challenges to their data communications in the face of increasing numbers of emerging challenges, complexity and society’s demand and intolerance of failures. In this paper, we present a set of challenges and their characteristics by reviewing reported incidents. Using domain specific attributes we discuss how these could be mitigated. We advocate the adoption of the latest programmable networking approaches in critical infrastructure networks and we present our proposed modular architecture with configurable monitoring and security components. Lastly, we show results from a network challenge simulation which highlights the benefits of our approach in providing rapid, precise and effective challenge detection and mitigation.

Published
2016

26. Phase transitions and phase decomposition of La1−xSrxCoO3−δ in low oxygen partial pressures

Author

J S White, James Ovenstone, and Scott T. Misture

Subjects
Phase transition, Renewable Energy, Sustainability and the Environment, Chemistry, Rietveld refinement, Thermal decomposition, Analytical chemistry, Solid oxygen, Energy Engineering and Power Technology, chemistry.chemical_element, Partial pressure, engineering.material, Oxygen, Phase (matter), engineering, Brownmillerite, Electrical and Electronic Engineering, Physical and Theoretical Chemistry, Nuclear chemistry
Abstract

High-temperature X-ray diffraction has been used to investigate the phase stability of lanthanum strontium cobalt oxide (LSC) for a range of materials with the formula La1−xSrxCoO3−δ (x = 0.7, 0.4, and 0.2). The stability of LSC increases with La content in low oxygen partial pressures at high temperature. Oxygen vacancy ordering has been observed for all three compositions in either low oxygen pressure or under reducing gas, as evidenced by the formation of the brownmillerite phase. The crystal structure of the vacancy-ordered phase was determined using Rietveld analysis of synchrotron X-ray diffraction data. The decomposition products under low oxygen pressure and in reducing conditions have been identified and characterized, including the phase transition and thermal expansion of the primary decomposition products, LaSrCoO4 and LaSrCoO3.5.

Published
2008

27. Phase stability of BSCF in low oxygen partial pressures

Author

James Ovenstone, Jae-Il Jung, Doreen D. Edwards, J S White, and Scott T. Misture

Subjects
Barium oxide, Thermal decomposition, Inorganic chemistry, Analytical chemistry, chemistry.chemical_element, Partial pressure, Condensed Matter Physics, Thermal expansion, Electronic, Optical and Magnetic Materials, Inorganic Chemistry, chemistry.chemical_compound, chemistry, Materials Chemistry, Ceramics and Composites, Physical and Theoretical Chemistry, Strontium oxide, Cobalt oxide, Cobalt, Perovskite (structure)
Abstract

In situ X-ray diffraction has been used to investigate the phase stability of barium strontium cobalt iron oxide (BSCF) with the formula Ba0.5Sr0.5Fe1−xCoxO3−δ (x=0, 0.2, 0.4, 0.6, 0.8, and 1). The thermal decomposition processes in both low partial pressures of oxygen (air −10−5 atm pO2) and in reducing conditions have been detailed. BSCF manifests excellent stability down to 10−5 atm pO2; however, it decomposes through a complex series of oxides under reducing conditions. Increasing the cobalt content results in a decrease in the temperature range of stability of the material under 4% H2 in N2, with the initial decomposition taking place at 375, 425, 550, 600, 650 and 675 °C, for x=1, 0.8, 0.6, 0.4, 0.2 and 0, respectively. Further, the thermal expansion is a strong function of the oxygen activity and Co content. The x=0, 1 end member, BSC, undergoes a phase transition from rhombohedral to cubic symmetry at ∼800 °C under 10−5 atm pO2, resulting in an ideal perovskite with a=3.9892(3) A at room temperature.

Published
2008

28. Structures and anisotropic thermal expansion of the α, β, γ, and δ polymorphs of Y2Si2O7

Author

B Harlan, S C Bancheri, Scott T. Misture, M. M. Hall, B Bewlay, Michael D. Dolan, and J S White

Subjects
Diffraction, Phase transition, Radiation, Materials science, Rietveld refinement, Crystal structure, Condensed Matter Physics, Thermal expansion, Crystallography, Phase (matter), General Materials Science, Isostructural, Instrumentation, Powder diffraction
Abstract

The α, β, γ, and δ polymorphs of Y2Si2O7 were synthesized using sol-gel and solid-state methods. The structures of the α and γ polymorphs were determined by identification of isostructural rare-earth disilicates, and the structures were refined using Rietveld analysis of X-ray powder diffraction data. The α polymorph crystallizes in space group P1, with a=6.5872(6) Å, b=6.6387(7) Å, c=12.032(1) Å, α=94.501(7)°, β=90.984(8)°, γ=91.771(7)°, and volume=524.16(9) Å3. The γ form is described by space group P21/c, a=4.68824(5) Å, b=10.84072(9) Å, c=5.58219(6) Å, and γ=96.0325(3)°. The anisotropic thermal expansion of each phase was measured using high temperature diffraction up to 1200 or 1400 °C, depending on the stability of the polymorph. The thermal expansion is highly anisotropic for all polymorphs, with the low-expansion direction normal to the long axis of the corner-shared SiO4 tetrahedra.

Published
2008

29. Container-based network function virtualization for software-defined networks

Author

Simon Jouet, Dimitrios P. Pezaros, Kyle J. S. White, and Richard Cziva

Subjects
Exploit, Computer science, business.industry, Middlebox, Hypervisor, Virtualization, computer.software_genre, Software deployment, Server, business, Software-defined networking, Virtual network, computer, Computer network
Abstract

Today's enterprise networks almost ubiquitously deploy middlebox services to improve in-network security and performance. Although virtualization of middleboxes attracts a significant attention, studies show that such implementations are still proprietary and deployed in a static manner at the boundaries of organisations, hindering open innovation. In this paper, we present an open framework to create, deploy and manage virtual network functions (NF)s in OpenFlow-enabled networks. We exploit container-based NFs to achieve low performance overhead, fast deployment and high reusability missing from today's NFV deployments. Through an SDN northbound API, NFs can be instantiated, traffic can be steered through the desired policy chain and applications can raise notifications. We demonstrate the systems operation through the development of exemplar NFs from common Operating System utility binaries, and we show that container-based NFV improves function instantiation time by up to 68% over existing hypervisor-based alternatives, and scales to one hundred co-located NFs while incurring sub-millisecond latency.

Published
2015

32. Measurement of the branching ratio for →τ decays

Author

J. Letts, A. Leins, Shlomo Dado, K. Graham, Tara Shears, P. Gagnon, D. Toya, A. W. Lloyd, C. Pahl, Paolo Giacomelli, M. Hauschild, Giora Mikenberg, G. D. Lafferty, J. Allison, Zoltan Laszlo Trocsanyi, M. Harin-Dirac, C. H. Shepherd-Themistocleous, Kiyotomo Kawagoe, Dong Hee Kim, R. J. Homer, I. J. Bloodworth, A. K. Honma, O. Runolfsson, Gideon Bella, Claudio Grandi, J. S. White, Claudia Schmitt, W. J. McDonald, B. C. Shen, David Futyan, Yoram Rozen, H. J. Burckhart, D. J. Miller, M. Donkers, Naoko Kanaya, Siegfried Bethke, Alexander Oh, S. Yamashita, P. Igo-Kemenes, M. A. Thomson, P. F. Åkesson, D. Lanske, G. W. Wilson, Junichi Kanzaki, P. G. Estabrooks, R. K. Keeler, G. Gaycken, Gregor Herten, W. G. Scott, J. Polok, D. Karlen, T. Trefzger, S. Spagnolo, K. Ishii, H. Jeremie, S. D. Talbot, C. Hensel, Daniel Lellouch, I. Nakamura, Richard J. K. Taylor, T. Behnke, Takehiko Mori, C. R. Jones, A. Okpara, J. W. Gary, Arnulf Quadt, P. M. Watkins, C. F. Vollmer, T. R. Wyatt, R. J. Barlow, H. Landsman, J. E. Pilcher, Erez Etzion, K. R. Hossain, P. Mättig, D. Zer-Zion, O. Schaile, M. Verzocchi, A. J. Martin, Christoph Geich-Gimbel, P. Mendez-Lorenzo, Thorsten Wengler, Stefan Kluth, Shlomit Tarem, B. Caron, D. Axen, P. Renkel, A. Jawahery, Oana Elena Vickey Boeriu, D. Glenzinski, Marek Tasevsky, F. G. Oakham, A. D. Schaile, Gabriella Pasztor, Dezso Horvath, M. J. Losty, E. L. Barberio, F. Spano, Peter Sherwood, A. Macchiolo, J. Couchman, W. Mader, F. Odorici, T. Kress, B. Surrow, A. A. Carter, P. Vannerem, G. A. Snow, C. P. Ward, J. Ludwig, K. Runge, P. Bock, G. Benelli, L. Brigliadori, Shoji Asai, E. A. De Wolf, S. Rosati, Sachio Komamiya, Giovanni Abbiendi, M. J. Oreglia, A. Csilling, S. Söldner-Rembold, Dave Charlton, J. G. Layter, S. W. O'Neale, K. Hoffman, A. Harel, S.J. Dallison, T. P. Kokott, D. Waller, P. O. Günther, T. Saeki, Rolf Seuster, M. Gruwé, G. N. Patrick, P. E.L. Clarke, Ikuo Ueda, D. M. Strom, K. J. Anderson, V. Kartvelishvili, J. P. Martin, T. Kuhl, R. D. Heuer, Richard Nisius, W. Menges, Achim Stahl, J. Lu, Satoshi Mihara, Guenter Duckeck, H. Rick, C. Y. Chang, Marco Cuffiani, M. Ford, G. Anagnostou, Katja Klein, L. Stumpf, H. Voss, H. Mes, I. P. Duerdoth, S. Braibant, K. Sachs, J. R. Carter, Norbert Wermes, Sherry Towers, T. Kawamoto, G. G. Hanson, N. K. Watson, G. Giacomelli, J. Grunhaus, S. Orito, G. P. Siroli, I. Lawson, Frank Fiedler, A. De Roeck, M. Kobel, Christoph Schwick, J. Böhme, M. S. Dixit, T. R. Junk, Raimund Ströhmer, Richard Teuscher, Frans Meijers, Juergen Thomas, Matthias Schröder, P. S. Wells, T. Kämer, C. Ainsley, P. Hüntemeyer, A. T. Watson, Andris Skuja, A. M. Rossi, Georges Azuelos, B. Vachon, O. Sahr, E. Tsur, C. M. Hawkes, R. Liebisch, Isabel Marian Trigger, K. W. Bell, A. Macpherson, R. J. Hemingway, Tetsuro Mashimo, R. Kowalewski, J. C. Hill, J. Lillich, M. F. Turner-Watson, Beatrix Dienes, Paul Kyberd, F. K. Loebinger, B. W. Kennedy, R. J. Sobie, Joost Vossebeld, P. Jovanovic, E. Torrence, Austin Ball, S. Arcelli, Klaus Desch, R. Howard, Peter Krieger, Alessandro Montanari, M. Kupper, K. Stephens, Ivor Fleck, Joleen Pater, Edward K. G. Sarkisyan, A. Klier, H. A. Neal, Alain Bellerive, N. L. Rodning, Thomas E Marchant, C. Littlewood, P. Dervan, B. Poli, P. Scharff-Hansen, A. M. Smith, Daniele Bonacorsi, D. Krop, J. von Krogh, Gideon Alexander, James Pinfold, R. J. Hawkings, Oliver Pooth, D. Wetterling, Paolo Capiluppi, T. J. McMahon, J. Dubbert, R. K. Carnegie, M. Schumacher, Richard Batley, V. Zacek, J. A. Wilson, D. R. Ward, G. Karapetian, R. G. Kellogg, C. Sbarra, Csaba Hajdu, Stefano Marcellini, J. Goldberg, I. Cohen, Christoph Rembser, A. Fürtjes, Lutz Feld, M. Fanti, Ehud Duchovni, M. Boutemeur, F. S. Merritt, J. A. McKenna, A. Michelini, Robert McPherson, T. Kobayashi, Fabrizio Fabbri, A. Frey, J. Cammin, K. Harder, R. M. Brown, Lorne Levinson, G. D. Long, I. R. Bailey, Klaus Rabbertz, Stephen Lloyd, O. Biebel, D. R. Rust, D. E. Plane, G. M. Dallavalle, K. Roscoe, A. Gupta, E. Clay, J. M. Roney, Koichi Nagai, W. Mohr, P. Ferrari, German Martinez, E. K. U. Gross, and M. Sproston

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Meson, 010308 nuclear & particles physics, Branching fraction, Electron–positron annihilation, Hadron, 01 natural sciences, Nuclear physics, 0103 physical sciences, High Energy Physics::Experiment, Exponential decay, Nuclear Experiment, 010306 general physics
Abstract

Using about 3.9 million hadronic Z decays from e + e − collisions recorded by the OPAL detector at LEP at centre-of-mass energies s ≈M Z , the branching ratio for the decay D − s →τ − ν τ has been measured to be BR ( D − s →τ − ν τ )=(7.0±2.1( stat )±2.0( syst ))%. This result can be used to derive the decay constant of the D − s meson: f D s =(286±44( stat )±41( syst )) MeV .

Published
2001

33. Search for anomalous production of acoplanar di-lepton events in ${\rm e^+e^-}$ collisions at $\sqrt{s} =$ 183 and 189 GeV

Author

P. Ferrari, Randall Sobie, H. Mes, Naoko Kanaya, R. J. Hemingway, G. D. Lafferty, I. P. Duerdoth, S. Braibant, J. Lillich, Christopher Hawkes, German Martinez, K. Stephens, H. O. Ogren, B. W. Kennedy, P. Jovanovic, C. Littlewood, Christoph Geich-Gimbel, Gideon Bella, K. Stoll, Andris Skuja, S. Petzold, Austin Ball, Guenter Duckeck, A. A. Faust, P. Hüntemeyer, Daniel Lellouch, L. Brigliadori, H. J. Burckhart, Jacqueline Batley, Peter R Hobson, D. Zer-Zion, Takehiko Mori, Peter Krieger, Vakhtang Kartvelishvili, Tetsuro Mashimo, S. W. O'Neale, M. F. Turner-Watson, K. J. Anderson, Sachio Komamiya, A. Okpara, P. Mättig, T. J. McMahon, Richard Teuscher, R. Kowalewski, Erez Etzion, M. A. Thomson, A. T. Watson, Matthias Schröder, D. E. Plane, F. Fiedler, M. Thiergen, J. E. Conboy, A. Fürtjes, S. Arcelli, Alessandro Montanari, I. Meyer, C. Couyoumtzelis, T. P. Kokott, J. Dubbert, D. Waller, E. K. U. Gross, M. Verzocchi, W. Gorn, R. K. Carnegie, Shlomit Tarem, Lutz Feld, R. Van Kooten, T. Saeki, G. M. Dallavalle, Alessandra Fanfani, R. Davis, G. Gaycken, P. G. Bright-Thomas, J. A. Wilson, M. Sproston, C. R. Jones, J. Böhme, B. Surrow, M. Schumacher, M. Boutemeur, F. S. Merritt, Gideon Alexander, Thomas E Marchant, Paolo Capiluppi, Michael Hildreth, Achim Stahl, I. Trigger, Stefan Schmitt, Alain Bellerive, M. Kolrep, N. L. Rodning, T. Kuhl, Paul Kyberd, F. K. Loebinger, P. Dervan, S. Yamashita, P. Scharff-Hansen, B. Poli, F. Odorici, K. Graham, F. Wäckerle, D. R. Ward, Tara Shears, H. Voss, R. J. Barlow, Georges Azuelos, Ivor Fleck, Richard Nisius, B. List, Ekg Sarkisyan, D. M. Gingrich, P. Igo-Kemenes, E. Tsur, Ehud Duchovni, D. Axen, A. Jawahery, Oana Elena Vickey Boeriu, J. Grunhaus, J. Bechtluft, J. A. McKenna, D. J. Miller, Joleen Pater, K. W. Bell, J. Goldberg, Dave Charlton, Marco Cuffiani, K. Ishii, H. Jeremie, S. B. Anderson, Shoji Asai, M. Jimack, A. M. Smith, K. Hoffman, A. Klier, A. Michelini, Juergen Thomas, M. Przybycień, H. A. Neal, M. Fanti, T. Kress, J. C. Hill, J. M. Roney, S. Spagnolo, A. M. Rossi, W. R. Gibson, W. J. McDonald, B. C. Shen, A. A. Carter, I. J. Bloodworth, M. Donkers, Kiyotomo Kawagoe, K. Harder, Siegfried Bethke, D. Liu, A. K. Honma, Robert McPherson, Paolo Giacomelli, T. Kobayashi, Stan Bentvelsen, O. Schaile, M. Hansroul, Koichi Nagai, John Allison, W. G. Scott, J. Schieck, R. Hawkings, I. Nakamura, H. Landsman, Peter Sherwood, I. Cohen, R. D. Heuer, Christoph Rembser, James Pinfold, S. Robertson, Yoram Rozen, W. Mohr, Fabrizio Fabbri, A. Frey, R. Perez-Ochoa, R. Seuster, Giovanni Abbiendi, A. J. Martin, Claudia Ciocca, M. Harin-Dirac, S. A. Robins, R. L. Coxe, T. Trefzger, R. J. Homer, R. G. Kellogg, Junichi Kanzaki, J. Polok, R. M. Brown, D. Karlen, D. R. Rust, P. Mendez-Lorenzo, F. G. Oakham, R. Liebisch, K. Ackerstaff, Alexander Wagner, A. Macchiolo, J. Ludwig, A. Hocker, Daniele Bonacorsi, K. Runge, P. Bock, Lorne Levinson, Csaba Hajdu, D. Glenzinski, Dezso Horvath, M. J. Losty, Stefano Marcellini, E. L. Barberio, D. Chrisman, G. D. Long, V. Zacek, K. R. Hossain, W. M. Sang, J. Couchman, W. Mader, O. C. Cooke, P. Pfeifenschneider, J. W. Gary, Marcello Mannelli, C. K. Hargrove, Stephen Lloyd, J. Patt, D. C. Imrie, André Schöning, C. H. Shepherd-Themistocleous, J. von Krogh, O. Sahr, C. Sbarra, F. R. Jacob, G. P. Siroli, M. Gruwé, D. Wetterling, Christoph Schwick, K. Roscoe, P. Gagnon, S. Baumann, E. Torrence, Zoltan Laszlo Trocsanyi, E. Clay, Dong Hee Kim, J. Lauber, E. A. Mckigney, S. D. Talbot, T. Behnke, Satoshi Mihara, T. R. Junk, D. Lanske, D. I. Futyan, P. S. Wells, Terry Richard Wyatt, O. Runolfsson, P. G. Estabrooks, R. K. Keeler, N. K. Watson, Arnulf Quadt, P. M. Watkins, Claudio Grandi, J. S. White, M. Fierro, S. Rosati, A. Harel, Ikuo Ueda, D. M. Strom, A. D. Schaile, Gabriella Pasztor, J. Lu, P. Vannerem, G. A. Snow, C. P. Ward, Raimund Ströhmer, S. Söldner-Rembold, P. Poffenberger, Beatrix Dienes, J. Letts, C. Y. Chang, P. Taras, A. Macpherson, K. Sachs, Shlomo Dado, Giora Mikenberg, Klaus Desch, S. F. Ashby, R. Howard, Otmar Biebel, P. I. Kayal, Norbert Wermes, Sherry Towers, T. Kawamoto, S. Orito, S. Betts, M. Hapke, M. J. Oreglia, Gregor Herten, J. E. Pilcher, A. W. Lloyd, G. W. Wilson, M. Hauschild, S.J. Dallison, J. R. Carter, G. N. Patrick, A. Biguzzi, J. G. Layter, P. E.L. Clarke, J. P. Martin, S. De Jong, H. Rick, G. G. Hanson, G. Giacomelli, I. Lawson, A. De Roeck, M. Kobel, M. S. Dixit, and Frans Meijers

Subjects
Physics, Particle physics, Physics and Astronomy (miscellaneous), Branching fraction, Electron–positron annihilation, High Energy Physics::Phenomenology, Standard Model, Nuclear physics, Chargino, Neutralino, Higgs boson, High Energy Physics::Experiment, Nuclear Experiment, Engineering (miscellaneous), Minimal Supersymmetric Standard Model, Lepton
Abstract

A selection of di-lepton events with significant missing transverse momentum has been performed using a total data sample of 237.4 pb-1 at e+e- centre-of-rnass energies of approximately 183 GeV and 189 GeV. The observed numbers of events - 78 at 183 GeV and 301 at 189 GeV - are consistent with the numbers expected from Standard Model processes, which arise predominantly from W+W- production with both W bosons decaying leptonically. This topology is also an experimental signature for the pair production of new particles that decay to a charged lepton accompanied by one or more invisible particles. Discrimination techniques are described that optimise the sensitivity to particular new physics channels. No evidence for new phenomena is apparent. Upper limits on the production cross-section times branching ratio squared for sleptons and for leptonically decaying charginos and charged Higgs are presented in a manner intended to minimise the number of model assumptions. Assuming a 100% branching ratio for the decay l±R → l±χ01, where χ01 is the lightest neutralino, we exclude at 95% CL: right-handed smuons with masses below 82.3 GeV for mμ- - mχ01 > 3 GeV and right-handed staus with masses below 81.0 GeV for mτ- -mχ01 > 8 GeV. Right-handed selectrons are excluded at 95% CL for masses below 87.1 GeV for mẽ - mχ01 > 5 GeV, within the framework of the Minimal Supersymmetric Standard Model assuming μ, < - 100 GeV and tan β= 1.5. Charged Higgs bosons, H±, are excluded at 95% CL for masses below 82.8 GeV, assuming a 100% branching ratio for the decay H± → τ ± vτ.

Published
2000

34. A study of parton fragmentation in hadronic Z $^0$ decays using $\Lambda\bar\Lambda$ correlations

Author

B. Nellen, H. G. Evans, I. Cohen, Tara Shears, Christoph Rembser, C. Hartmann, D. E. Plane, T. J. McMahon, C. Couyoumtzelis, Stephen Hillier, G. Gaycken, P. G. Bright-Thomas, J. Dubbert, G. M. Dallavalle, S. A. Robins, R. K. Carnegie, M. Schumacher, M. Herndon, M. Bobinski, R. Liebisch, K. Stoll, P. G. Estabrooks, R. K. Keeler, J. A. Wilson, J. Böhme, Andris Skuja, K. Ackerstaff, Matthias Schröder, M. Thiergen, Gregor Herten, N. K. Watson, Dave Charlton, S. Petzold, P. M. Watkins, D. Lazic, A. Macpherson, M. Fierro, Randall Sobie, G. D. Lafferty, A. J. Martin, F. Odorici, Tetsuro Mashimo, S. R. Lautenschlager, J. Grunhaus, W. Mader, Erez Etzion, C. K. Hargrove, S. Betts, M. Hapke, S. Yamashita, J. E. Pilcher, Stefan Kluth, Shlomit Tarem, Stefan Schmitt, K. Roscoe, H. A. Neal, R. Bürgin, B. Surrow, C. Y. Chang, D. R. Rust, A. W. Lloyd, P. Igo-Kemenes, Georges Azuelos, P. E.L. Clarke, O. Runolfsson, A. D. Schaile, Gabriella Pasztor, E. Tsur, P. Vannerem, M. J. Oreglia, Klaus Kurt Desch, G. W. Wilson, W. Gorn, K. Ishii, H. Jeremie, M. Hauschild, C. Markopoulos, John Allison, J. Lauber, G. Yekutieli, S. Baumann, M. Przybycień, Guenter Duckeck, Sachio Komamiya, A. T. Watson, A. A. Carter, R. Howard, M. Verzocchi, K. W. Bell, P. Taras, Ron Folman, A. M. Lee, E. von Törne, E. A. Mckigney, E. Torrence, Claudio Grandi, J. S. White, J. Pálinkás, T. P. Kokott, G. A. Snow, C. P. Ward, J. P. Martin, J. R. Carter, S. Söldner-Rembold, G. N. Patrick, R. Mir, R. Hawkings, Otmar Biebel, E. Clay, Shoji Asai, Gideon Bella, Ekg Sarkisyan, T. Saeki, R. Davis, J. C. Hill, J. Letts, M. Fanti, O. Schaile, H. J. Burckhart, Daniel Lellouch, D. I. Futyan, Jacqueline Batley, P. I. Kayal, Takehiko Mori, H. Mes, James Pinfold, R. Perez-Ochoa, R. Seuster, Giovanni Abbiendi, S. De Jong, Claire Shepherd-Themistocleous, S. Robertson, Daniele Bonacorsi, S. B. Anderson, K. Sachs, Shlomo Dado, I. P. Duerdoth, S. Braibant, Norbert Wermes, Sherry Towers, T. Kawamoto, W. J. McDonald, W. R. Gibson, B. C. Shen, Robert McPherson, M. Boutemeur, F. S. Merritt, D. M. Strom, P. Mättig, J. Gascon, S. Orito, K. Harder, F. G. Oakham, B. Schmitt, E. L. Barberio, R. E. Schmitz, R. D. Heuer, Fabrizio Fabbri, Sven Menke, D. Lanske, Siegfried Bethke, D. Liu, Giora Mikenberg, S. F. Ashby, H. Rick, V. Zacek, R. Van Kooten, Stan Bentvelsen, J. von Krogh, P. Hüntemeyer, Raimund Ströhmer, R. J. Hemingway, A. A. Faust, A. K. Honma, W. G. Scott, S. D. Talbot, J. W. Gary, C. R. Jones, D. S. Koetke, R. M. Brown, Lorne Levinson, M. F. Turner-Watson, M. Gruwé, L. A. del Pozo, Marcello Mannelli, Peter R Hobson, I. Nakamura, B. W. Kennedy, P. Jovanovic, D. M. Gingrich, P. Scharff-Hansen, J. Bechtluft, Richard Teuscher, I. J. Bloodworth, D. Zer-Zion, A. S. Turcot, F. Fiedler, P. Poffenberger, J. A. McKenna, T. R. Junk, D. Eatough, Austin Ball, Peter Krieger, A. Macchiolo, A. M. Smith, P. S. Wells, D. Glenzinski, Dezso Horvath, M. J. Losty, R. G. Kellogg, G. G. Hanson, Jean-Arcady Meyer, Terry Richard Wyatt, C. M. Hawkes, Yoram Rozen, M. Kolrep, T. Behnke, R. Bartoldus, Alessandro Montanari, T. Kuhl, H. O. Ogren, J. Polok, G. Giacomelli, I. Lawson, Richard Nisius, Christoph Geich-Gimbel, D. Karlen, A. De Roeck, M. Kobel, O. C. Cooke, Beatrix Dienes, B. List, Marco Cuffiani, P. Pfeifenschneider, M. S. Dixit, Frans Meijers, Vakhtang Kartvelishvili, J. E. Conboy, A. Fürtjes, P. Gagnon, Stefano Marcellini, L. Brigliadori, N. Altekamp, H. Voss, R. J. Barlow, A. Biguzzi, D. J. Miller, J. Patt, J. G. Layter, A. Sittler, Zoltan Laszlo Trocsanyi, André Schöning, O. Sahr, W. M. Sang, S. W. O'Neale, K. J. Anderson, S. D. Bird, D. Axen, A. Jawahery, Peter Sherwood, Alexander Wagner, J. Ludwig, K. Runge, P. Bock, Paolo Giacomelli, C. Sbarra, F. R. Jacob, M. Hansroul, Paul Kyberd, F. K. Loebinger, J. Steuerer, Ivor Fleck, C. Burgard, Joleen Pater, A. Klier, R. J. Homer, Satoshi Mihara, Kiyotomo Kawagoe, Achim Stahl, K. R. Hossain, D. C. Imrie, G. P. Siroli, K. Stephens, Christoph Schwick, C. Littlewood, V. Gibson, I. Trigger, F. Scharf, German Martinez, D. R. Ward, T. Kress, J. M. Roney, Ehud Duchovni, Koichi Nagai, J. Schieck, W. Mohr, M. Jimack, M. A. Thomson, A. Michelini, Claudia Ciocca, F. Wöckerle, E. K. U. Gross, M. Sproston, S. M. Gascon-Shotkin, Satoshi Tanaka, T. Kobayashi, A. M. Rossi, R. L. Coxe, A. Hocker, D. Chrisman, G. D. Long, Volker Blobel, Michael Hildreth, Alain Bellerive, Stephen Lloyd, N. L. Rodning, R. Kowalewski, S. Arcelli, Gideon Alexander, Paolo Capiluppi, and J. Goldberg

Subjects
Physics, Particle physics, Physics and Astronomy (miscellaneous), Electron–positron annihilation, Hadron, Hyperon, Parton, Lambda, Lambda baryon, Nuclear physics, Baryon, High Energy Physics::Experiment, Rapidity, Engineering (miscellaneous)
Abstract

The correlated production of \(\Lambda\) and \(\bar\Lambda\) baryons has been studied using 4.3 million multihadronic \({\rm Z}^0\) decays recorded with the Opal detector at Lep. Lambda pairs were investigated in the full data sample and for the first time also in 2-jet and 3-jet events selected with the \(k_\perp\) algorithm. The distributions of rapidity differences from correlated \(\Lambda\bar\Lambda\) pairs exhibit short-range, local correlations and prove to be a sensitive tool to test models, particularly for 2-jet events. The Jetset model describes the data best but some extra parameter tuning is needed to improve agreement with the experimental results in the rates and the rapidity spectra simultaneously. The recently developed modification of Jetset, the MOdified Popcorn Scenarium (Mops), and also Herwig do not give satisfactory results. This study of di-lambda production in 2- and 3-jet events supports the short-range compensation of quantum numbers.

Published
2000

35. A study of $\mathrm{B_s^0}$ meson oscillation using hadronic $\mathrm Z^0$ decays containing leptons

Author

H. O. Ogren, Erez Etzion, Christoph Geich-Gimbel, Shlomit Tarem, Sachio Komamiya, D. Axen, S. Yamashita, A. T. Watson, A. Jawahery, B. Surrow, Richard Teuscher, P. Igo-Kemenes, Vakhtang Kartvelishvili, F. Fiedler, A. Biguzzi, J. E. Conboy, A. Fürtjes, J. G. Layter, K. Ishii, H. Jeremie, Peter Sherwood, Daniele Bonacorsi, J. von Krogh, M. Gruwé, D. Wetterling, T. P. Kokott, T. Saeki, Lutz Feld, Kiyotomo Kawagoe, O. C. Cooke, Alexander Wagner, A. Macchiolo, W. R. Gibson, P. Pfeifenschneider, T. J. McMahon, C. Couyoumtzelis, S. Betts, A. Macpherson, J. Dubbert, J. Ludwig, M. Hapke, K. Harder, S. A. Robins, R. Liebisch, K. Ackerstaff, J. Letts, R. K. Carnegie, G. Gaycken, P. G. Bright-Thomas, J. A. Wilson, J. Böhme, Raimund Ströhmer, M. Kolrep, Alessandra Fanfani, R. Davis, S. Baumann, K. Runge, P. Bock, M. Przybycień, T. Kress, E. A. Mckigney, A. A. Carter, I. J. Bloodworth, J. Patt, André Schöning, O. Schaile, W. J. McDonald, Giovanni Abbiendi, M. Schumacher, Matthias Schröder, B. C. Shen, R. J. Hemingway, M. A. Thomson, J. Lauber, M. Boutemeur, F. S. Merritt, O. Sahr, Klaus Desch, P. E.L. Clarke, R. Howard, S. Robertson, P. Poffenberger, Siegfried Bethke, D. Liu, A. K. Honma, K. R. Hossain, C. H. Shepherd-Themistocleous, K. Sachs, Christopher Hawkes, W. M. Sang, S. B. Anderson, Shlomo Dado, J. Grunhaus, E. K. U. Gross, R. L. Coxe, M. Thiergen, F. Odorici, W. G. Scott, Yoram Rozen, J. P. Martin, B. W. Kennedy, T. Kuhl, S. De Jong, I. Nakamura, Richard Nisius, J. Goldberg, J. Bechtluft, M. Sproston, P. Jovanovic, M. J. Oreglia, Stan Bentvelsen, Austin Ball, K. Stoll, S. D. Talbot, R. M. Brown, Lorne Levinson, Andris Skuja, Peter Krieger, B. List, H. Rick, Marco Cuffiani, P. Mendez-Lorenzo, Junichi Kanzaki, J. Polok, D. I. Futyan, Gregor Herten, K. Hoffman, Giora Mikenberg, S. F. Ashby, D. Glenzinski, Paolo Giacomelli, D. Karlen, T. Behnke, R. D. Heuer, Alessandro Montanari, Daniel Lellouch, T. R. Junk, P. S. Wells, M. Hansroul, Beatrix Dienes, A. Hocker, J. A. McKenna, I. Cohen, S. Petzold, Juergen Thomas, Tetsuro Mashimo, M. F. Turner-Watson, A. D. Schaile, Randall Sobie, G. D. Lafferty, R. Hawkings, Christoph Rembser, Dezso Horvath, M. J. Losty, Takehiko Mori, A. Okpara, Terry Richard Wyatt, P. Mättig, G. D. Long, G. G. Hanson, C. Y. Chang, Gabriella Pasztor, P. Gagnon, H. Landsman, J. M. Roney, M. Verzocchi, J. E. Pilcher, H. Mes, P. G. Estabrooks, R. K. Keeler, N. K. Watson, M. Harin-Dirac, P. Vannerem, G. A. Snow, C. P. Ward, D. C. Imrie, R. J. Homer, G. Giacomelli, I. Lawson, A. De Roeck, M. Kobel, Arnulf Quadt, Naoko Kanaya, P. M. Watkins, Guenter Duckeck, A. Sittler, Zoltan Laszlo Trocsanyi, I. P. Duerdoth, S. Braibant, F. G. Oakham, P. Taras, Dong Hee Kim, Koichi Nagai, J. Schieck, C. Sbarra, F. R. Jacob, Stefan Schmitt, G. P. Siroli, S. Söldner-Rembold, W. Gorn, J. R. Carter, G. N. Patrick, E. L. Barberio, A. J. Martin, M. S. Dixit, Stephen Lloyd, Frans Meijers, Satoshi Mihara, P. Hüntemeyer, Christoph Schwick, K. Roscoe, W. Mohr, John Allison, Otmar Biebel, Georges Azuelos, E. Tsur, Shoji Asai, P. Scharff-Hansen, A. A. Faust, Achim Stahl, O. Runolfsson, K. W. Bell, N. Altekamp, H. Voss, A. W. Lloyd, E. Torrence, R. J. Barlow, D. J. Miller, J. Couchman, W. Mader, Ehud Duchovni, A. M. Smith, R. G. Kellogg, K. Stephens, J. C. Hill, E. Clay, C. K. Hargrove, K. Graham, G. W. Wilson, M. Jimack, Csaba Hajdu, S. Spagnolo, C. Littlewood, Tara Shears, P. I. Kayal, Claudio Grandi, J. S. White, Stefano Marcellini, M. Hauschild, German Martinez, Ekg Sarkisyan, James Pinfold, L. Brigliadori, R. Perez-Ochoa, R. Seuster, V. Gibson, A. Michelini, Norbert Wermes, Sherry Towers, D. E. Plane, T. Kawamoto, D. Lanske, V. Zacek, Paul Kyberd, F. K. Loebinger, I. Trigger, T. Kobayashi, J. W. Gary, J. Steuerer, Ivor Fleck, D. R. Ward, S. Orito, G. M. Dallavalle, Marcello Mannelli, Joleen Pater, A. Klier, H. A. Neal, M. Fierro, R. Kowalewski, S. W. O'Neale, S. Arcelli, K. J. Anderson, Gideon Alexander, Paolo Capiluppi, Gideon Bella, H. J. Burckhart, Jacqueline Batley, C. R. Jones, M. Fanti, Peter R Hobson, D. Zer-Zion, Robert McPherson, Fabrizio Fabbri, A. Frey, R. Van Kooten, Claudia Ciocca, F. Wäckerle, D. M. Gingrich, A. M. Rossi, Michael Hildreth, Alain Bellerive, N. L. Rodning, P. Dervan, B. Poli, D. R. Rust, S. Rosati, A. Harel, Ikuo Ueda, D. M. Strom, and J. Lu

Subjects
Physics, Particle physics, Physics and Astronomy (miscellaneous), Meson, Oscillation, Electron–positron annihilation, High Energy Physics::Phenomenology, Hadron, Charge (physics), Jet (particle physics), Nuclear physics, High Energy Physics::Experiment, Production (computer science), Engineering (miscellaneous), Lepton
Abstract

A sample of \({\rm Z}^0\) decays containing b-flavoured hadrons is tagged using leptons, and events having precise proper time measurements are selected. These events are used to study \({\rm B}^0_{\rm s}\) oscillations. The flavour (b or \(\rm \bar{b}\)) at decay is determined from the lepton charge while the flavour at production is determined from jet charge or the charge of a second lepton, where available. The experiment was not able to resolve the oscillatory behaviour, and we deduce that the \({\rm B}^0_{\rm s}\) oscillation frequency \(\Delta m_{\rm s} > 5.2\) ps\(^{-1}\) at the 95% confidence level.

Published
1999

36. Intermittency and correlations in hadronic Z $^0$ decays

Author

K. Stephens, M. Schumacher, P. G. Estabrooks, F. Odorici, N. K. Watson, D. R. Rust, C. Littlewood, H. A. Neal, Otmar Biebel, P. Scharff-Hansen, P. M. Watkins, K. Hoffman, V. Gibson, Claire Shepherd-Themistocleous, A. M. Lee, J. Goldberg, Erez Etzion, Shlomit Tarem, B. Surrow, G. G. Hanson, Richard Teuscher, A. S. Turcot, N. Altekamp, H. Voss, A. Macpherson, H. O. Ogren, Christoph Geich-Gimbel, I. Trigger, F. Fiedler, Richard Keeler, D. R. Ward, A. M. Smith, P. I. Kayal, K. Stoll, G. Giacomelli, S. Yamashita, I. Lawson, R. J. Barlow, D. J. Miller, I. Cohen, Christoph Rembser, H. Mes, I. P. Duerdoth, S. Braibant, D. Axen, A. Jawahery, T. J. McMahon, A. De Roeck, M. Kobel, P. Igo-Kemenes, M. Hoch, K. Ishii, H. Jeremie, Dave Charlton, C. Couyoumtzelis, M. Fanti, S. A. Robins, M. S. Dixit, O. C. Cooke, S. Spagnolo, Andris Skuja, S. Petzold, Tetsuro Mashimo, A. A. Faust, Peter Sherwood, Alexander Wagner, R. Liebisch, K. Ackerstaff, Norbert Wermes, Sherry Towers, T. Kawamoto, Frans Meijers, J. Dubbert, P. Pfeifenschneider, M. F. Turner-Watson, I. J. Bloodworth, Vakhtang Kartvelishvili, P. Hüntemeyer, R. K. Carnegie, A. J. Martin, R. Kowalewski, J. E. Conboy, A. Fürtjes, R. Howard, P. E.L. Clarke, J. Ludwig, K. Runge, R. Mir, P. Bock, M. Kolrep, J. Patt, R. Hawkings, Satoshi Mihara, Paul Kyberd, S. Orito, S. Arcelli, M. Herndon, F. K. Loebinger, S. Baumann, J. A. Wilson, J. Böhme, Michael Hildreth, Alain Bellerive, André Schöning, Robert McPherson, J. P. Martin, O. Sahr, H. Landsman, P. Gagnon, J. Steuerer, Ivor Fleck, O. Schaile, S. Robertson, R. D. Heuer, E. A. Mckigney, Gideon Alexander, N. L. Rodning, W. Gorn, W. Mader, Paolo Capiluppi, Joleen Pater, P. Dervan, B. Poli, Peter R Hobson, S. De Jong, A. Klier, F. G. Oakham, A. Sittler, D. Zer-Zion, D. C. Imrie, C. K. Hargrove, S. Betts, Yoram Rozen, S. B. Anderson, Matthias Schröder, W. R. Gibson, Gregor Herten, R. L. Coxe, Georges Azuelos, K. Harder, Fabrizio Fabbri, A. Frey, H. Rick, E. L. Barberio, D. Lazic, A. Macchiolo, Zoltan Laszlo Trocsanyi, Dong Hee Kim, M. Hapke, A. Hocker, M. Thiergen, Gideon Bella, H. J. Burckhart, Jacqueline Batley, D. Chrisman, G. D. Long, E. Tsur, D. I. Futyan, Volker Blobel, R. J. Hemingway, T. Kuhl, J. Lauber, R. Van Kooten, S. M. Gascon-Shotkin, Paolo Giacomelli, Sven Menke, Christopher Hawkes, G. Yekutieli, M. Verzocchi, K. W. Bell, J. Pálinkás, J. Grunhaus, G. P. Siroli, M. Przybycień, Junichi Kanzaki, J. Polok, M. Boutemeur, F. S. Merritt, B. W. Kennedy, W. M. Sang, P. Jovanovic, Richard Nisius, D. Karlen, M. Hansroul, S. D. Talbot, Stan Bentvelsen, Christoph Schwick, T. Kress, M. J. Oreglia, J. E. Pilcher, Stephen Lloyd, Austin Ball, J. C. Hill, T. R. Junk, K. Graham, A. A. Carter, Ron Folman, P. S. Wells, B. List, Peter Krieger, Marco Cuffiani, Tara Shears, R. M. Brown, Ehud Duchovni, Lorne Levinson, Alessandro Montanari, W. J. McDonald, M. Jimack, B. C. Shen, A. M. Rossi, A. Biguzzi, J. G. Layter, F. Wäckerle, Terry Richard Wyatt, D. M. Gingrich, Randall Sobie, G. D. Lafferty, Giovanni Abbiendi, A. Michelini, J. R. Carter, C. R. Jones, Siegfried Bethke, D. Liu, A. K. Honma, W. G. Scott, T. Kobayashi, Juergen Thomas, J. Bechtluft, J. A. McKenna, Stefan Schmitt, G. N. Patrick, Daniele Bonacorsi, I. Nakamura, S. Rosati, R. J. Homer, C. Sbarra, F. R. Jacob, Sachio Komamiya, A. T. Watson, A. Harel, Ikuo Ueda, D. M. Strom, J. von Krogh, Guenter Duckeck, D. Glenzinski, J. Lu, Dezso Horvath, M. J. Losty, John Allison, T. P. Kokott, T. Saeki, Claudia Ciocca, K. Roscoe, Jean-Arcady Meyer, Klaus Kurt Desch, M. Gruwé, Shoji Asai, Alessandra Fanfani, R. Davis, E. Torrence, E. Clay, Achim Stahl, R. G. Kellogg, Daniel Lellouch, T. Behnke, Stefano Marcellini, A. W. Lloyd, Kiyotomo Kawagoe, G. W. Wilson, Takehiko Mori, D. E. Plane, P. Mättig, M. Hauschild, C. Markopoulos, G. M. Dallavalle, K. R. Hossain, James Pinfold, R. Perez-Ochoa, R. Seuster, J. Gascon, V. Zacek, M. A. Thomson, J. W. Gary, L. Brigliadori, Ekg Sarkisyan, E. K. U. Gross, Marcello Mannelli, M. Sproston, S. W. O'Neale, K. J. Anderson, Raimund Ströhmer, J. Letts, P. Poffenberger, German Martinez, Beatrix Dienes, J. M. Roney, C. Y. Chang, P. Taras, D. Lanske, Koichi Nagai, J. Schieck, W. Mohr, M. Fierro, S. R. Lautenschlager, K. Sachs, O. Runolfsson, Shlomo Dado, Claudio Grandi, J. S. White, Giora Mikenberg, S. F. Ashby, A. D. Schaile, Gabriella Pasztor, P. Vannerem, G. A. Snow, C. P. Ward, S. Söldner-Rembold, G. Gaycken, and P. G. Bright-Thomas

Subjects
Physics, Quantum chromodynamics, Particle physics, Annihilation, Physics and Astronomy (miscellaneous), Hadron, Monte Carlo method, Fizikai tudományok, Multiplicity (mathematics), Bose–Einstein correlations, law.invention, Nuclear physics, Természettudományok, law, Intermittency, High Energy Physics::Experiment, Engineering (miscellaneous), Cumulant, Particle Physics - Experiment
Abstract

A multidimensional study of local multiplicity fluctuations and multiparticle correlations of hadrons produced in Z decays is performed. The study is based on the data sample of more than 4 million events recorded with the OPAL detector at LEP. The fluctuations and correlations are analysed in terms of the normalized scaled factorial moments and cumulants up to the fifth order. The moments are observed to have intermittency-like behaviour, which is found to be more pronounced with increasing dimension. The large data sample allows for the first time a study of the factorial cumulants in e+e- annihilation. The analysis of the cumulants shows the existence of genuine multiparticle correlations with a strong intermittency rise up to higher orders. These correlations are found to be stronger in higher dimensions. The decomposition of the factorial moments into lower-order correlations that the dynamical fluctuations have important contributions from genuine many-particle correlations. The Monte Carlo models JETSET 7.4 and HERWIG 5.9 are found to reproduce the trend of the measured moments and cumulants but they underestimate the magnitudes. The results are found to be consistent with QCD jet formation dynamics, although additional contributions from other mechanisms in the hadronization process cannot be excluded. A multidimensional study of local multiplicity fluctuations and multiparticle correlations of hadrons produced in Z decays is performed. The study is based on the data sample of more than 4 million events recorded with the OPAL detector at LEP. The fluctuations and correlations are analysed in terms of the normalized scaled factorial moments and cumulants up to the fifth order. The moments are observed to have intermittency-like behaviour, which is found to be more pronounced with increasing dimension. The large data sample allows for the first time a study of the factorial cumulants in e+e- annihilation. The analysis of the cumulants shows the existence of genuine multiparticle correlations with a strong intermittency rise up to higher orders. These correlations are found to be stronger in higher dimensions. The decomposition of the factorial moments into lower-order correlations shows that the dynamical fluctuations have important contributions from genuine many-particle correlations. The Monte Carlo models JETSET 7.4 and HERWIG 5.9 are found to reproduce the trend of the measured moments and cumulants but they underestimate the magnitudes. The results are found to be consistent with QCD jet formation dynamics, although additional contributions from other mechanisms in the hadronization process cannot be excluded.

Published
1999

37. Correlation of cytogenetics, BCR-ABL PCR studies and fluorescencein situhybridisation (FISH) in adult acute lymphoblastic leukaemia

Author

E. H. Januszewicz, J. S. White, A. Martinow, Patricia M. Michael, Kathleen C. Rayeroux, and Lynda J. Campbell

Subjects
Adult, Male, medicine.medical_specialty, Adolescent, Fusion Proteins, bcr-abl, Chromosomal translocation, Biology, Philadelphia chromosome, hemic and lymphatic diseases, Acute lymphocytic leukemia, Internal Medicine, medicine, Humans, Philadelphia Chromosome, Metaphase, In Situ Hybridization, Fluorescence, Aged, Retrospective Studies, ABL, medicine.diagnostic_test, Reverse Transcriptase Polymerase Chain Reaction, Cytogenetics, breakpoint cluster region, Middle Aged, Precursor Cell Lymphoblastic Leukemia-Lymphoma, Prognosis, medicine.disease, Molecular biology, Cytogenetic Analysis, Female, Fluorescence in situ hybridization
Abstract

Background: Philadelphia positive (Ph+) acute lymphoblastic leukaemia (ALL) accounts for 11–29% of adult ALL. Reverse transcriptase polymerase chain reaction (RT-PCR) for the BCR-ABL fusion mRNA has identified patients with the fusion mRNA without cytogenetic evidence of the 9;22 translocation. The reason for discrepancies between cytogenetic and molecular diagnoses is unclear. Aim: Our aim was to study cases of ALL with discordant cytogenetic and RT-PCR results and identify any reasons for such discrepancies. Methods: Laboratory records were scanned for cases of ALL tested by both RT-PCR and cytogenetics and positive by either for the 9;22 translocation. Fluorescence in situ hybridisation (FISH) was used to study discordant results where a specimen was available. Results: We identified 15 patients with ALL who had both cytogenetic and RT-PCR studies for BCR-ABL. Seven had discordant results; five patients had positive RT-PCR studies with normal (four/five) or abnormal but Ph negative cytogenetics (one/five), and two were Ph+ but RT-PCR negative. FISH, using Vysis LSI bcr/abl translocation probes, showed fused signals in 12% interphase cells but not in metaphase cells in one specimen with normal cytogenetics, and 6% interphase cells in the Ph negative patient with abnormal cytogenetics. This second patient subsequently relapsed with a minor Ph+ cell line derived from the Ph negative line. Conclusions: These results confirmed the need for both cytogenetics and RT-PCR to identify Ph+ ALL. FISH did not show sub-microscopic rearrangements of BCR-ABL in normal metaphases. Failure to identify the Philadelphia chromosome cytogenetically appeared due rather to Ph+ cells failing to divide.

Published
1999

38. A measurement of the product branching ratio $f ({\rm b} \to \Lambda_{\rm b}) \cdot{\rm BR} (\Lambda_{\rm b} \to \Lambda {\rm X})$ in ${\rm Z}^0$ decays

Author

Raimund Ströhmer, A. Harel, Ikuo Ueda, D. M. Strom, P. G. Estabrooks, R. K. Keeler, P. Poffenberger, Dave Charlton, N. K. Watson, Michael Hildreth, Sachio Komamiya, Alain Bellerive, A. T. Watson, Claire Shepherd-Themistocleous, N. L. Rodning, P. Dervan, Otmar Biebel, F. Scharf, German Martinez, W. M. Sang, Beatrix Dienes, P. M. Watkins, S. Yamashita, A. Macpherson, R. D. Heuer, T. P. Kokott, S. M. Gascon-Shotkin, P. Igo-Kemenes, M. Hoch, K. Ishii, H. Jeremie, T. J. McMahon, C. Couyoumtzelis, T. Saeki, Gideon Bella, Achim Stahl, R. Howard, T. R. Junk, J. Dubbert, P. S. Wells, R. Davis, Terry Richard Wyatt, A. M. Rossi, R. K. Carnegie, H. J. Burckhart, Jacqueline Batley, P. I. Kayal, M. Herndon, A. A. Faust, O. Schaile, R. L. Coxe, D. R. Rust, J. A. Wilson, J. Böhme, J. Lauber, C. Sbarra, Norbert Wermes, F. R. Jacob, J. Grunhaus, Sherry Towers, T. Kawamoto, S. Robertson, L. Brigliadori, M. A. Thomson, M. Boutemeur, F. S. Merritt, H. Mes, A. Hocker, E. K. U. Gross, D. Lazic, I. P. Duerdoth, S. Braibant, C. R. Jones, S. Orito, Sven Menke, O. C. Cooke, A. M. Lee, John Allison, E. von Törne, M. Sproston, D. Chrisman, G. D. Long, Volker Blobel, P. Pfeifenschneider, Kiyotomo Kawagoe, Claudia Ciocca, A. W. Lloyd, Juergen Thomas, G. W. Wilson, S. R. Lautenschlager, G. Yekutieli, J. Patt, André Schöning, P. Hüntemeyer, M. Przybycień, Stephen Lloyd, T. Kress, R. G. Kellogg, O. Sahr, J. Bechtluft, M. Fanti, A. A. Carter, S. W. O'Neale, J. A. McKenna, Ron Folman, M. Hauschild, C. Markopoulos, K. J. Anderson, Stefano Marcellini, R. Mir, R. Hawkings, O. Runolfsson, J. M. Roney, S. D. Talbot, Ehud Duchovni, C. Y. Chang, Robert McPherson, G. Gaycken, P. G. Bright-Thomas, Paul Kyberd, Giovanni Abbiendi, F. K. Loebinger, Peter R Hobson, M. Jimack, H. Landsman, Koichi Nagai, Paolo Giacomelli, Claudio Grandi, D. Zer-Zion, R. Bartoldus, M. Hansroul, J. Schieck, H. O. Ogren, M. Schumacher, Fabrizio Fabbri, P. Taras, W. Mohr, J. Steuerer, Ivor Fleck, A. Michelini, A. Macchiolo, J. S. White, Ekg Sarkisyan, K. Stephens, Joleen Pater, J. Letts, A. Klier, Christoph Geich-Gimbel, F. Odorici, S. Baumann, Daniele Bonacorsi, R. Van Kooten, E. A. Mckigney, C. Hartmann, D. E. Plane, C. Littlewood, D. Eatough, Satoshi Tanaka, H. A. Neal, T. Kobayashi, R. J. Homer, T. Behnke, V. Gibson, K. R. Hossain, Vakhtang Kartvelishvili, F. G. Oakham, J. von Krogh, T. Kuhl, B. Schmitt, K. Hoffman, E. L. Barberio, G. M. Dallavalle, F. Wäckerle, D. M. Gingrich, J. E. Conboy, A. Fürtjes, Stefan Schmitt, M. Gruwé, I. Trigger, D. R. Ward, Richard Nisius, D. Lanske, B. List, D. C. Imrie, Gregor Herten, N. Altekamp, H. Voss, R. Kowalewski, Satoshi Mihara, S. Arcelli, R. J. Barlow, D. J. Miller, K. Roscoe, J. E. Pilcher, Marco Cuffiani, P. Gagnon, Gideon Alexander, S. Spagnolo, Klaus Kurt Desch, D. I. Futyan, Paolo Capiluppi, G. P. Siroli, M. Fierro, R. J. Hemingway, E. Torrence, E. Clay, K. Sachs, Christoph Schwick, Christopher Hawkes, B. W. Kennedy, P. Jovanovic, Austin Ball, Peter Krieger, Alessandro Montanari, C. Darling, W. R. Gibson, K. Harder, W. J. McDonald, B. C. Shen, A. Sittler, Zoltan Laszlo Trocsanyi, Shlomo Dado, Dong Hee Kim, R. M. Brown, Lorne Levinson, Siegfried Bethke, D. Liu, A. K. Honma, W. G. Scott, I. Nakamura, S. D. Bird, D. Axen, A. Jawahery, Peter Sherwood, Alexander Wagner, J. Ludwig, D. Glenzinski, Shoji Asai, Dezso Horvath, M. J. Losty, Jean-Arcady Meyer, Giora Mikenberg, S. F. Ashby, K. Runge, P. Bock, I. J. Bloodworth, A. D. Schaile, Gabriella Pasztor, P. Vannerem, Georges Azuelos, E. Tsur, S. A. Robins, G. A. Snow, C. P. Ward, S. Söldner-Rembold, M. Verzocchi, Yoram Rozen, K. W. Bell, R. Liebisch, K. Ackerstaff, J. Pálinkás, J. C. Hill, J. Polok, D. Karlen, Daniel Lellouch, Erez Etzion, Takehiko Mori, Stefan Kluth, P. Mättig, Shlomit Tarem, B. Surrow, J. Goldberg, B. Nellen, I. Cohen, Christoph Rembser, Matthias Schröder, M. Thiergen, K. Graham, Tara Shears, A. J. Martin, W. Mader, C. K. Hargrove, A. Biguzzi, J. G. Layter, S. Betts, M. Hapke, P. E.L. Clarke, J. P. Martin, M. J. Oreglia, S. De Jong, H. Rick, G. G. Hanson, J. R. Carter, G. Giacomelli, I. Lawson, James Pinfold, R. Perez-Ochoa, R. Seuster, J. Gascon, G. N. Patrick, A. De Roeck, M. Kobel, V. Zacek, J. W. Gary, M. S. Dixit, Frans Meijers, D. S. Koetke, Marcello Mannelli, K. Stoll, Andris Skuja, S. Petzold, Randall Sobie, G. D. Lafferty, Tetsuro Mashimo, M. F. Turner-Watson, Guenter Duckeck, Richard Teuscher, A. S. Turcot, F. Fiedler, W. Gorn, M. Kolrep, S. B. Anderson, P. Scharff-Hansen, Stan Bentvelsen, and A. M. Smith

Subjects
Physics, Physics and Astronomy (miscellaneous), Branching fraction, High Energy Physics::Phenomenology, High Energy Physics::Experiment, B meson, Atomic physics, Lambda, Engineering (miscellaneous)
Abstract

The product branching ratio, \(f ({\rm b} \to \Lambda_{\rm b}) \cdot{\rm BR} (\Lambda_{\rm b} \to \Lambda{\rm X})\), where \(\Lambda_{\rm b}\) denotes any weakly-decaying b–baryon, has been measured using the OPAL detector at LEP. \(\Lambda_{\rm b}\)'s are selected by the presence of energetic \(\Lambda\) particles in bottom events tagged by the presence of displaced secondary vertices. A fit to the momenta of the \(\Lambda\) particles separates signal from B meson and fragmentation backgrounds. The measured product branching ratio is \(\) Combined with a previous OPAL measurement, one obtains \(\)

Published
1999

39. Search for anomalous photonic events with missing energy in ${\rm e}^+{\rm e}^-$ collisions at $\sqrt{s}$ = 130, 136 and 183 GeV

Author

Sachio Komamiya, A. T. Watson, M. Boutemeur, F. S. Merritt, F. Scharf, T. P. Kokott, J. Letts, T. Saeki, Satoshi Mihara, German Martinez, J. Bechtluft, J. A. McKenna, G. G. Hanson, P. Scharff-Hansen, R. Davis, Randall Sobie, G. D. Lafferty, K. Sachs, S. Betts, M. Hapke, M. Fanti, G. Giacomelli, M. J. Oreglia, I. Lawson, Shlomo Dado, J. R. Carter, G. N. Patrick, A. M. Smith, Dave Charlton, R. Bartoldus, A. De Roeck, W. R. Gibson, H. O. Ogren, Christoph Geich-Gimbel, N. Altekamp, H. Voss, Guenter Duckeck, J. M. Roney, Robert McPherson, J. Grunhaus, S. R. Lautenschlager, K. Stoll, Andris Skuja, D. M. Strom, Gregor Herten, K. Harder, R. J. Barlow, G. Gaycken, P. G. Bright-Thomas, R. D. Heuer, D. J. Miller, Fabrizio Fabbri, D. C. Imrie, Claire Shepherd-Themistocleous, M. Schumacher, S. Petzold, R. Bürgin, O. Runolfsson, R. M. Brown, Lorne Levinson, M. S. Dixit, Frans Meijers, Giora Mikenberg, S. F. Ashby, Koichi Nagai, J. Schieck, Tetsuro Mashimo, Achim Stahl, Vakhtang Kartvelishvili, Paul Kyberd, J. E. Conboy, A. Fürtjes, C. Y. Chang, Ehud Duchovni, W. Mohr, M. Jimack, G. P. Siroli, J. E. Pilcher, F. Odorici, R. Van Kooten, T. R. Junk, A. Biguzzi, A. A. Faust, W. Gorn, P. Taras, F. K. Loebinger, P. S. Wells, Claudio Grandi, J. S. White, Christoph Schwick, A. Michelini, J. Steuerer, J. G. Layter, A. W. Lloyd, Ekg Sarkisyan, R. J. Hemingway, C. Hartmann, S. B. Anderson, D. E. Plane, Terry Richard Wyatt, Gideon Bella, K. Stephens, Stephen Hillier, H. A. Neal, G. M. Dallavalle, Ivor Fleck, G. W. Wilson, Satoshi Tanaka, Joleen Pater, A. D. Schaile, Gabriella Pasztor, M. Hauschild, C. Markopoulos, P. Vannerem, M. A. Thomson, A. Macpherson, H. J. Burckhart, Jacqueline Batley, F. Wäckerle, C. Littlewood, B. W. Kennedy, James Pinfold, R. Perez-Ochoa, R. Seuster, P. Jovanovic, A. Klier, Austin Ball, D. M. Gingrich, T. Kobayashi, E. K. U. Gross, L. Brigliadori, V. Gibson, H. Mes, S. M. Gascon-Shotkin, Peter Krieger, J. Gascon, R. Howard, Stan Bentvelsen, M. Sproston, K. Roscoe, G. A. Snow, C. P. Ward, Alessandro Montanari, D. Lanske, M. F. Turner-Watson, I. Trigger, I. P. Duerdoth, S. Braibant, A. Macchiolo, Peter R Hobson, D. R. Rust, P. E.L. Clarke, Klaus Kurt Desch, E. Torrence, M. Kobel, S. Söldner-Rembold, D. R. Ward, T. Kress, C. M. Hawkes, R. Mir, J. P. Martin, E. Clay, Otmar Biebel, R. Kowalewski, V. Zacek, R. Hawkings, S. W. O'Neale, K. J. Anderson, D. Zer-Zion, O. C. Cooke, P. Hüntemeyer, S. Arcelli, A. M. Lee, P. I. Kayal, Georges Azuelos, P. Pfeifenschneider, T. Kuhl, John Allison, J. W. Gary, Raimund Ströhmer, Norbert Wermes, E. von Törne, Sherry Towers, T. Kawamoto, S. De Jong, E. Tsur, D. S. Koetke, Marcello Mannelli, Richard Teuscher, A. S. Turcot, C. R. Jones, S. Orito, J. Patt, Richard Nisius, A. M. Rossi, André Schöning, P. Poffenberger, M. Fierro, M. Verzocchi, K. W. Bell, H. Rick, O. Sahr, F. G. Oakham, B. List, Marco Cuffiani, F. Fiedler, J. Pálinkás, Kiyotomo Kawagoe, B. Schmitt, E. L. Barberio, Gideon Alexander, Paolo Giacomelli, M. Hansroul, Paolo Capiluppi, J. C. Hill, Beatrix Dienes, C. Burgard, R. J. Homer, R. G. Kellogg, R. L. Coxe, W. J. McDonald, B. C. Shen, A. Hocker, M. Kolrep, Siegfried Bethke, D. Liu, A. K. Honma, D. Chrisman, G. D. Long, K. R. Hossain, Stefano Marcellini, Volker Blobel, W. G. Scott, I. Nakamura, Stephen Lloyd, W. M. Sang, Claudia Ciocca, D. Glenzinski, Dezso Horvath, M. J. Losty, Jean-Arcady Meyer, Michael Hildreth, Alain Bellerive, N. L. Rodning, C. Sbarra, F. R. Jacob, Daniele Bonacorsi, J. Lauber, J. von Krogh, S. D. Talbot, M. Gruwé, L. A. del Pozo, T. J. McMahon, C. Couyoumtzelis, J. Dubbert, R. K. Carnegie, M. Herndon, D. Eatough, T. Behnke, M. Bobinski, J. A. Wilson, J. Böhme, D. Lazic, P. Gagnon, G. Yekutieli, M. Przybycień, A. A. Carter, Ron Folman, A. Sittler, Zoltan Laszlo Trocsanyi, Giovanni Abbiendi, S. D. Bird, D. Axen, A. Jawahery, Peter Sherwood, Stefan Schmitt, Alexander Wagner, J. Ludwig, K. Runge, P. Bock, Shoji Asai, P. G. Estabrooks, R. K. Keeler, Daniel Lellouch, N. K. Watson, Takehiko Mori, P. Mättig, P. M. Watkins, I. J. Bloodworth, S. Baumann, Yoram Rozen, E. A. Mckigney, J. Polok, D. Karlen, D. I. Futyan, J. Goldberg, B. Nellen, H. G. Evans, I. Cohen, Christoph Rembser, Erez Etzion, Stefan Kluth, Shlomit Tarem, B. Surrow, S. A. Robins, R. Liebisch, K. Ackerstaff, A. J. Martin, S. Yamashita, P. Igo-Kemenes, K. Ishii, H. Jeremie, W. Mader, O. Schaile, C. K. Hargrove, S. Robertson, Matthias Schröder, Sven Menke, M. Thiergen, and Tara Shears

Subjects
Physics, Particle physics, Missing energy, Physics and Astronomy (miscellaneous), Physics beyond the Standard Model, Standard Model, Nuclear physics, Pair production, Neutralino, High Energy Physics::Experiment, Gravitino, Production (computer science), Engineering (miscellaneous), Energy (signal processing)
Abstract

Photonic events with large missing energy have been observed in $\mathrm e^+e^-$ collisions at centre-of-mass energies of 130, 136 and 183 GeV collected in 1997 using the OPAL detector at LEP. Results are presented for event topologies with a single photon and missing transverse energy or with an acoplanar photon pair. Cross-section measurements are performed within the kinematic acceptance of each selection. These results are compared with the expectations from the Standard Model process ${\rm e}^+{\rm e}^-\to\nu\overline{\nu}$ + photon(s). No evidence is observed for new physics contributions to these final states. Using the data at $\sqrt{s}$ = 183 GeV, upper limits on ${\sigma({\rm e^+e^-}\to{\rm XY})\cdot{\rm BR}(\rm X \to Y \gamma)}$ and ${\sigma({\rm e^+e^-}\to{\rm XX})\cdot{\rm BR}^2(\rm X \to Y \gamma)}$ are derived for the case of stable and invisible Y. These limits apply to single and pair production of excited neutrinos ( $\rm X = \nu^*, Y = \nu$ ), to neutralino production ( $\rm X={{\tilde{\chi}}^{0}}_{2}, Y={{\tilde{\chi}}^{0}}_{1}$ ) and to supersymmetric models in which $\rm X = {{\tilde{\chi}}^{0}}_{1}$ and $\rm Y=\tilde{\mathrm{G}}$ is a light gravitino.

Published
1999

40. Measurements of flavour-dependent fragmentation functions in ${\bf Z^{0} \rightarrow{\rm q}\bar{\rm q}}$ events

Author

J. von Krogh, R. Bartoldus, G. Yekutieli, M. Przybycień, A. A. Carter, Ron Folman, J. Letts, M. Gruwé, L. A. del Pozo, P. G. Bright-Thomas, K. Stephens, M. Fanti, T. J. McMahon, C. Couyoumtzelis, J. Dubbert, R. K. Carnegie, M. Herndon, Daniel Lellouch, M. Bobinski, C. Y. Chang, J. A. Wilson, J. Böhme, H. O. Ogren, K. Roscoe, M. Schumacher, E. Lefebvre, D. Lazic, Takehiko Mori, P. Mättig, F. Odorici, Randall Sobie, T. Schorner, S. D. Bird, John Allison, Reda Tafirout, Klaus Kurt Desch, G. D. Lafferty, Christoph Geich-Gimbel, S. M. Gascon-Shotkin, Achim Stahl, James Pinfold, R. Perez-Ochoa, R. Seuster, C. Littlewood, V. Gibson, E. Torrence, F. Scharf, K. Sachs, Shlomo Dado, Georges Azuelos, E. Tsur, German Martinez, J. Gascon, T. R. Junk, D. Axen, P. E.L. Clarke, A. Jawahery, Robert McPherson, M. Verzocchi, H. A. Neal, I. Trigger, E. Clay, K. W. Bell, R. G. Kellogg, J. Pálinkás, D. R. Ward, T. Kress, J. C. Hill, J. P. Martin, Dave Charlton, P. G. Estabrooks, Vakhtang Kartvelishvili, Mathieu Doucet, V. Zacek, T. Behnke, W. J. McDonald, Peter Sherwood, R. K. Keeler, B. C. Shen, Stefano Marcellini, M. F. Turner-Watson, J. W. Gary, R. D. Heuer, D. S. Koetke, W. R. Gibson, Stefan Schmitt, Siegfried Bethke, J. E. Conboy, R. Kowalewski, S. De Jong, Marcello Mannelli, Fabrizio Fabbri, M. A. Thomson, A. K. Honma, W. G. Scott, Guenter Duckeck, A. Fürtjes, N. K. Watson, W. M. Sang, Kiyotomo Kawagoe, Peter R Hobson, R. Bürgin, Alexander Wagner, I. Nakamura, E. K. U. Gross, H. Mes, P. Scharff-Hansen, A. M. Rossi, K. Nagai, I. P. Duerdoth, S. Braibant, J. Ludwig, D. Zer-Zion, K. Runge, P. Bock, P. M. Watkins, M. Sproston, A. Macchiolo, O. C. Cooke, Gregor Herten, P. Pfeifenschneider, H. Rick, Shoji Asai, Giora Mikenberg, A. Joly, R. M. Brown, Lorne Levinson, A. M. Smith, S. F. Ashby, K. R. Hossain, D. R. Rust, C. M. Hawkes, D. Glenzinski, J. Patt, André Schöning, K. Stoll, Andris Skuja, M. Boutemeur, F. S. Merritt, I. J. Bloodworth, P. Hüntemeyer, S. B. Anderson, P. Gagnon, S. Petzold, C. Sbarra, Satoshi Mihara, Gideon Alexander, Dezso Horvath, M. J. Losty, F. R. Jacob, Jean-Arcady Meyer, Tetsuro Mashimo, O. Sahr, Paolo Capiluppi, J. Grunhaus, C. Hartmann, D. E. Plane, A. M. Lee, Gideon Bella, A. D. Schaile, W. Gorn, Paul Kyberd, F. K. Loebinger, A. Sittler, Stephen Hillier, E. von Törne, Gabriella Pasztor, J. M. Roney, R. L. Coxe, Zoltan Laszlo Trocsanyi, Richard Nisius, Stan Bentvelsen, M. Fierro, G. M. Dallavalle, Yoram Rozen, H. J. Burckhart, Jacqueline Batley, P. Vannerem, Michael Hildreth, J. Steuerer, Ivor Fleck, Silvia Arcelli, J. Bechtluft, B. List, J. A. McKenna, D. Lui, A. Hocker, Paolo Giacomelli, Joleen Pater, Marco Cuffiani, Richard Teuscher, G. A. Snow, A. Klier, A. S. Turcot, F. Fiedler, D. Chrisman, G. D. Long, M. Hansroul, Ekg Sarkisyan, C. P. Ward, Sachio Komamiya, N. L. Rodning, R. Van Kooten, Theodoros Geralis, J. Lauber, J. Schieck, Volker Blobel, A. T. Watson, W. Mohr, G. G. Hanson, C. Burgard, S. Söldner-Rembold, B. Poli, R. J. Homer, T. P. Kokott, Stephen Lloyd, T. Saeki, G. Giacomelli, I. Lawson, F. Wäckerle, S. D. Talbot, J. E. Pilcher, D. M. Gingrich, Alessandra Fanfani, R. Davis, Claire Shepherd-Themistocleous, Ehud Duchovni, S. Baumann, J. Polok, A. De Roeck, M. Kobel, D. Karlen, M. Kolrep, D. Eatough, M. Jimack, C. R. Jones, G. W. Wilson, A. Michelini, H. M. Fischer, E. A. Mckigney, M. S. Dixit, D. C. Imrie, P. Vikas, A. A. Faust, Frans Meijers, Satoshi Tanaka, T. Kobayashi, D. Lanske, S. Betts, M. Hapke, G. P. Siroli, S. R. Lautenschlager, A. Biguzzi, J. G. Layter, Christoph Schwick, Claudia Ciocca, O. Runolfsson, D. I. Futyan, Claudio Grandi, M. J. Oreglia, A. W. Lloyd, S. Yamashita, P. Igo-Kemenes, S. A. Robins, K. Ishii, H. Jeremie, M. Hauschild, C. Markopoulos, R. Liebisch, K. Ackerstaff, J. R. Carter, G. N. Patrick, O. Schaile, Otmar Biebel, S. Robertson, P. Taras, Raimund Ströhmer, P. Poffenberger, Beatrix Dienes, Sven Menke, S. W. O'Neale, K. J. Anderson, P. I. Kayal, Erez Etzion, Stefan Kluth, Shlomit Tarem, Norbert Wermes, Sherry Towers, T. Kawamoto, S. Orito, J. Goldberg, B. Nellen, H. G. Evans, I. Cohen, Christoph Rembser, P. S. Wells, Terry Richard Wyatt, A. Macpherson, A. J. Martin, C. K. Hargrove, Tara Shears, R. Howard, R. Mir, R. Hawkings, J. S. White, Matthias Schröder, M. Thiergen, D. M. Strom, F. G. Oakham, B. Schmitt, E. L. Barberio, N. Altekamp, H. Voss, R. J. Barlow, D. J. Miller, R. J. Hemingway, B. W. Kennedy, P. Jovanovic, Austin Ball, Peter Krieger, and Alessandro Montanari

Subjects
Quark, Physics, Particle physics, Physics and Astronomy (miscellaneous), Meson, 010308 nuclear & particles physics, High Energy Physics::Lattice, Electron–positron annihilation, High Energy Physics::Phenomenology, Flavour, 01 natural sciences, Bottom quark, Charged particle, Nuclear physics, 0103 physical sciences, High Energy Physics::Experiment, Charm (quantum number), 010306 general physics, Maxima, Engineering (miscellaneous)
Abstract

Fragmentation functions for charged particles in \({\rm Z}^0 \rightarrow {\rm q}\bar{\rm q}\) events have been measured for bottom (b), charm (c) and light (uds) quarks as well as for all flavours together. The results are based on data recorded between 1990 and 1995 using the OPAL detector at LEP. Event samples with different flavour compositions were formed using reconstructed \({\rm D}^{*\pm}\) mesons and secondary vertices. The \(\xi_{\rm p} =\ln(1/x_{\rm p})\) distributions and the position of their maxima \(\xi_0\) are also presented separately for uds, c and b quark events. The fragmentation function for b quarks is significantly softer than for uds quarks.

Published
1999

41. A measurement of the τ→ν branching ratio

Author

S. M. Gascon-Shotkin, P. Poffenberger, A. D. Schaile, Gabriella Pasztor, John Allison, G. Gaycken, P. G. Bright-Thomas, J. Lauber, Erez Etzion, G. Yekutieli, A. J. Martin, M. Przybycień, Stefan Kluth, Shlomit Tarem, Beatrix Dienes, M. Schumacher, P. Gagnon, P. Vannerem, S. D. Talbot, A. Sittler, Zoltan Laszlo Trocsanyi, Dong Hee Kim, T. Kress, Daniel Lellouch, R. G. Kellogg, A. M. Rossi, A. A. Carter, Ron Folman, D. Eatough, Takehiko Mori, F. Odorici, B. Surrow, G. A. Snow, C. P. Ward, T. Behnke, W. Mader, Stefano Marcellini, S. D. Bird, P. Mättig, C. K. Hargrove, S. Söldner-Rembold, H. A. Neal, D. Axen, A. Jawahery, M. Fanti, C. Y. Chang, S. A. Robins, P. G. Estabrooks, R. K. Keeler, D. C. Imrie, Dave Charlton, Claire Shepherd-Themistocleous, Peter Sherwood, Alexander Wagner, Giovanni Abbiendi, J. Ludwig, K. Runge, P. Bock, N. K. Watson, Matthias Schröder, P. Taras, Paul Kyberd, F. K. Loebinger, K. Hoffman, R. Liebisch, K. Ackerstaff, J. Steuerer, T. R. Junk, G. P. Siroli, E. Tsur, Ivor Fleck, M. Thiergen, S. R. Lautenschlager, Stefan Schmitt, P. S. Wells, P. M. Watkins, T. J. McMahon, M. Verzocchi, K. W. Bell, Joleen Pater, C. Couyoumtzelis, A. Klier, Christoph Schwick, R. J. Hemingway, J. Pálinkás, S. B. Anderson, M. Boutemeur, F. S. Merritt, A. A. Faust, R. D. Heuer, J. Dubbert, R. K. Carnegie, K. Sachs, M. Herndon, James Pinfold, R. Perez-Ochoa, R. Seuster, Terry Richard Wyatt, J. C. Hill, Robert McPherson, Christopher Hawkes, J. A. Wilson, J. Böhme, Shoji Asai, W. M. Sang, Shlomo Dado, L. Brigliadori, O. Runolfsson, Claudia Ciocca, B. W. Kennedy, P. Jovanovic, Gideon Bella, I. J. Bloodworth, Gregor Herten, W. J. McDonald, B. C. Shen, J. Gascon, S. Baumann, D. Lazic, K. Graham, H. J. Burckhart, Jacqueline Batley, A. Macpherson, Tara Shears, Daniele Bonacorsi, Fabrizio Fabbri, Giora Mikenberg, J. Goldberg, Siegfried Bethke, D. Liu, A. K. Honma, E. A. Mckigney, Austin Ball, Yoram Rozen, J. Bechtluft, J. A. McKenna, Peter Krieger, V. Zacek, Claudio Grandi, W. G. Scott, Michael Hildreth, B. Nellen, Stan Bentvelsen, C. Sbarra, G. Azuelos, F. R. Jacob, S. F. Ashby, I. Nakamura, J. S. White, Ekg Sarkisyan, R. Van Kooten, Kiyotomo Kawagoe, J. E. Pilcher, J. W. Gary, N. L. Rodning, D. S. Koetke, A. Macchiolo, J. von Krogh, S. W. O'Neale, J. Letts, Marcello Mannelli, R. Bartoldus, P. Dervan, J. Polok, D. Karlen, Alessandro Montanari, D. Glenzinski, H. Mes, I. P. Duerdoth, A. W. Lloyd, H. O. Ogren, K. J. Anderson, C. R. Jones, K. Stoll, Andris Skuja, S. Petzold, Dezso Horvath, M. J. Losty, M. Gruwé, D. I. Futyan, Christoph Geich-Gimbel, R. Howard, Jean-Arcady Meyer, G. W. Wilson, Tetsuro Mashimo, T. Kuhl, Richard Nisius, M. F. Turner-Watson, M. Hauschild, C. Markopoulos, F. Wäckerle, S. Braibant, A. Bellerive, B. List, Vakhtang Kartvelishvili, R. Mir, D. M. Gingrich, Randall Sobie, G. D. Lafferty, Marco Cuffiani, J. E. Conboy, A. Fürtjes, K. R. Hossain, W. Gorn, I. Cohen, R. Hawkings, Christoph Rembser, D. Lanske, A. Harel, P. Hüntemeyer, Ikuo Ueda, D. M. Strom, P. Scharff-Hansen, H. Landsman, D. R. Rust, A. M. Smith, Guenter Duckeck, M. Fierro, A. M. Lee, Richard Teuscher, A. S. Turcot, E. von Törne, F. Fiedler, M. Kolrep, F. G. Oakham, B. Schmitt, E. L. Barberio, N. Altekamp, H. Voss, R. J. Barlow, D. J. Miller, S. Spagnolo, S. Yamashita, P. Igo-Kemenes, M. Hoch, K. Ishii, H. Jeremie, O. Schaile, S. Robertson, Sven Menke, Ehud Duchovni, M. Jimack, A. Michelini, Satoshi Tanaka, T. Kobayashi, Peter R Hobson, J. M. Roney, R. L. Coxe, D. Zer-Zion, Sachio Komamiya, A. T. Watson, A. Hocker, Koichi Nagai, J. Schieck, D. Chrisman, G. D. Long, T. P. Kokott, W. Mohr, Volker Blobel, Achim Stahl, T. Saeki, R. Davis, Stephen Lloyd, J. Grunhaus, R. Kowalewski, S. Arcelli, F. Scharf, German Martinez, Juergen Thomas, A. Biguzzi, J. G. Layter, Gideon Alexander, M. A. Thomson, Paolo Capiluppi, P. E.L. Clarke, J. P. Martin, E. K. U. Gross, S. De Jong, H. Rick, M. Sproston, G. G. Hanson, G. Giacomelli, I. Lawson, K. Stephens, A. De Roeck, M. Kobel, C. Littlewood, M. S. Dixit, Frans Meijers, O. C. Cooke, P. Pfeifenschneider, V. Gibson, I. Trigger, D. R. Ward, J. Patt, André Schöning, O. Sahr, Satoshi Mihara, Otmar Biebel, Paolo Giacomelli, M. Hansroul, R. J. Homer, P. I. Kayal, Norbert Wermes, Sherry Towers, T. Kawamoto, W. R. Gibson, S. Orito, K. Harder, S. Betts, M. Hapke, M. J. Oreglia, J. R. Carter, G. N. Patrick, R. M. Brown, Lorne Levinson, C. Hartmann, D. E. Plane, G. M. Dallavalle, K. Roscoe, Klaus Kurt Desch, E. Torrence, E. Clay, and Raimund Ströhmer

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Electron energy spectrum, 010308 nuclear & particles physics, Branching fraction, Electron–positron annihilation, 0103 physical sciences, Strong coupling, Analytical chemistry, Mass scale, 010306 general physics, 01 natural sciences
Abstract

The branching ratio for the decay τ − → e − ν e ν τ has been measured using Z 0 decay data collected by the OPAL experiment at LEP. In total 33 073 τ − → e − ν e ν τ candidates were identified from a sample of 186 197 selected τ decays, giving a branching ratio of B (τ − → e − ν e ν τ )=(17.81±0.09 (stat) ±0.06 (syst) )% . This result is combined with other measurements to test e - μ and μ - τ universality in charged-current weak interactions. Additionally, the strong coupling constant α s ( m τ 2 ) has been extracted from B (τ − → e − ν e ν τ ) and evolved to the Z 0 mass scale, giving α s ( m Z 2 )=0.1204±0.0011 (exp)±0.0019 (theory).

Published
1999

42. Search for scalar top and scalar bottom quarks at $\sqrt{s}$ = 183 GeV at LEP

Author

S. Petzold, W. J. McDonald, B. C. Shen, Tetsuro Mashimo, Matthias Schröder, K. Nagai, K. Stephens, R. Bartoldus, Siegfried Bethke, A. K. Honma, W. G. Scott, M. Thiergen, I. Nakamura, H. O. Ogren, W. Gorn, Christoph Geich-Gimbel, D. R. Rust, D. Glenzinski, Dezso Horvath, M. J. Losty, Jean-Arcady Meyer, V. Gibson, A. M. Lee, E. von Törne, S. Yamashita, P. Igo-Kemenes, K. Ishii, H. Jeremie, Vakhtang Kartvelishvili, T. R. Junk, J. E. Conboy, A. Fürtjes, I. Trigger, D. R. Ward, T. Kress, R. W. Springer, R. Van Kooten, M. Boutemeur, F. S. Merritt, S. Braibant, Georges Azuelos, E. Tsur, A. D. Schaile, Gabriella Pasztor, J. Bechtluft, J. A. McKenna, O. Schaile, M. Verzocchi, K. W. Bell, S. B. Anderson, P. Szymanski, J. Pálinkás, M. Schumacher, F. Wäckerle, E. Lefebvre, G. Yekutieli, E. do Couto e Silva, S. Robertson, Gregor Herten, J. C. Hill, U. Jost, R. Mir, R. Hawkings, B. Wilkens, D. M. Gingrich, Sven Menke, J. Lauber, S. D. Talbot, D. Eatough, A. A. Carter, Ron Folman, F. Odorici, G. A. Snow, C. P. Ward, C. Hartmann, D. E. Plane, J. E. Pilcher, R. Lahmann, Stephen Hillier, Stan Bentvelsen, G. M. Dallavalle, S. Söldner-Rembold, L. Brigliadori, U. Müller, A. J. Martin, D. C. Imrie, P. Utzat, U. Ruppel, N. J. Oldershaw, John Allison, G. P. Siroli, P. G. Estabrooks, R. K. Keeler, M. R. Ingram, Christoph Schwick, H. M. Fischer, N. K. Watson, P. M. Watkins, W. R. Gibson, J. M. Roney, C. K. Hargrove, M. Fanti, B. T. Bouwens, Daniele Bonacorsi, R. G. Kellogg, James Pinfold, R. Perez-Ochoa, D. G. Fong, J. Gascon, J. Letts, Gideon Alexander, Paolo Capiluppi, Kiyotomo Kawagoe, Claire Shepherd-Themistocleous, R. M. Brown, Lorne Levinson, Csaba Hajdu, Robert McPherson, G. W. Wilson, P. S. Wells, V. Zacek, Richard Teuscher, Stefano Marcellini, A. Skillman, A. S. Turcot, M. Hauschild, K. Sachs, Mathieu Doucet, Tara Shears, R. D. Heuer, Fabrizio Fabbri, F. Fiedler, J. von Krogh, C. Markus, A. A. Faust, H. Mes, I. P. Duerdoth, Terry Richard Wyatt, Shlomo Dado, J. W. Gary, P. A. Hart, J. Schieck, D. S. Koetke, Stefan Kluth, Marcello Mannelli, Otmar Biebel, Silvia Arcelli, J. E. Bloomer, G. T. Jones, E. H. Vokurka, K. R. Hossain, T. Behnke, Satoshi Mihara, L. A. del Pozo, P. Scharff-Hansen, W. Mohr, Shlomit Tarem, S. Baumann, P. Hüntemeyer, Reda Tafirout, Klaus Kurt Desch, T. J. McMahon, M. J. Pearce, F. G. Oakham, Giora Mikenberg, B. Schmitt, M. Kolrep, B. Stockhausen, Paul Kyberd, E. A. Mckigney, A. Macchiolo, E. L. Barberio, R. K. Carnegie, A. Posthaus, D. Chrisman, G. D. Long, F. K. Loebinger, Hans-Christian Schultz-Coulon, M. Herndon, Volker Blobel, Randall Sobie, M. Gruwé, M. Bobinski, P. I. Kayal, G. D. Lafferty, C. M. Hawkes, W. P. Lai, J. A. Wilson, A. M. Smith, C. Dallapiccola, J. Steuerer, Ivor Fleck, Richard Nisius, S. W. O'Neale, Guenter Duckeck, D. M. Strom, K. J. Anderson, Marco Cuffiani, Joleen Pater, Norbert Wermes, Sherry Towers, T. Kawamoto, D. Lazic, M. A. Thomson, A. Klier, E. K. U. Gross, N. Altekamp, H. Voss, Stephen Lloyd, R. Rylko, R. Giacomelli, S. Orito, O. C. Cooke, P. Pfeifenschneider, M. Sproston, D. I. Futyan, R. J. Barlow, D. J. Miller, J. Goldberg, M. Hapke, B. Nellen, A. Oh, A. Macpherson, N. I. Geddes, Michael Hildreth, J. Patt, P. Poffenberger, D. E. Hutchcroft, André Schöning, Ehud Duchovni, N. L. Rodning, M. J. Oreglia, H. G. Evans, B. Poli, M. J. Goodrick, R. Howard, J. S. White, I. Cohen, S. A. Robins, D. L. Rees, J. R. Carter, G. N. Patrick, M. Jimack, Paolo Giacomelli, M. Hansroul, Gunter Wolf, K. Ackerstaff, D. Rigby, R. J. Hemingway, A. Joly, F. Scharf, German Martinez, Beatrix Dienes, S. M. Gascon-Shotkin, C. Burgard, C. Sbarra, R. J. Homer, A. Michelini, Matthew Evans, A. M. Rossi, C. Y. Chang, P. Taras, Michael Kobel, Allen Mincer, Satoshi Tanaka, T. Kobayashi, B. W. Kennedy, Julie Kirk, Ekg Sarkisyan, P. Jovanovic, P. W. Jeffreys, Austin Ball, Peter Krieger, P. Vikas, Alessandro Montanari, D. Lanske, M. Fierro, J. E.G. Edwards, S. R. Lautenschlager, H. A. Neal, O. Runolfsson, C. Beeston, Claudio Grandi, G. G. Hanson, G. Giacomelli, M. S. Dixit, Frans Meijers, A. Biguzzi, A. Rooke, J. G. Layter, P. E.L. Clarke, M. K. Jones, J. P. Martin, S. De Jong, A. N. Bell, P. Gagnon, A. Sittler, Peter Schleper, Zoltan Laszlo Trocsanyi, S. D. Bird, P. Schenk, D. Axen, A. Jawahery, Peter Sherwood, Alexander Wagner, J. Ludwig, K. Runge, P. Bock, Gideon Bella, H. J. Burckhart, Jacqueline Batley, Sachio Komamiya, Theodoros Geralis, E. Ros, A. T. Watson, I. J. Bloodworth, C. R. Jones, T. P. Kokott, Dave Charlton, R. Bürgin, T. Saeki, Yoram Rozen, R. Davis, M. Foucher, J. Grunhaus, D. Karlen, M. F. Turner-Watson, M. Morii, Peter R Hobson, Stefan Schmitt, D. Zer-Zion, P. Routenburg, P. Mättig, Shoji Asai, Daniel Lellouch, Takehiko Mori, K. Stoll, and Andris Skuja

Subjects
Physics, Stop squark, Top quark, Particle physics, Physics and Astronomy (miscellaneous), High Energy Physics::Lattice, High Energy Physics::Phenomenology, Top quark condensate, Bottom quark, Nuclear physics, Quark star, Neutralino, Up quark, High Energy Physics::Experiment, B meson, Nuclear Experiment, Engineering (miscellaneous), Particle Physics - Experiment
Abstract

Searches for a scalar top quark and a scalar bottom quark have been performed using a total data sample of 56.8 pb-1 at a centre-of-mass energy of 183 GeV collected with the OPAL detector at LEP. No candidate events were observed. Combining this result with those obtained at lower centre-of-mass energies, the 95% C.L. lower limit on the scalar top quark mass is 85.0 GeV if the mixing angle between the supersymmetric partners of the left- and right-handed states of the top quark is zero. The lower limit is 81.3 GeV, even if the scalar top quark decouples from the Z boson. These limits were obtained assuming that the scalar top quark decays into a charm quark and the lightest neutralino, and that the mass difference between the scalar top quark and the lightest neutralino is larger than 10 GeV. Assuming a relatively light scalar neutrino, The complementary decay mode of the scalar top quark in which it decays into a bottom quark, a charged lepton and a scalar neutrino was also studied. From a similar analysis, a mass limit on the light scalar bottom quark was set at 82.7 GeV for a mass difference between the scalar bottom quark and the lightest neutralino larger than 7 GeV, and at 84.0 GeV for the mass difference larger 10 GeV and the lightest neutralino heavier than 30 GeV. These limits were obtained assuming that the scalar bottom quark decays into a bottom quark and the lightest neutralino, and that a mixing angle between the supersymmetric partners of the left- and right-handed states of the bottom quark is zero. Searches for a scalar top quark and a scalar bottom quark have been performed using a total data sample of 56.8 pb-1 at a centre-of-mass energy of 183 GeV collected with the OPAL detector at LEP. No candidate events were observed. Combining this result with those obtained at lower centre-of-mass energies, the 95% C.L. lower limit on the scalar top quark mass is 85.0 GeV if the mixing angle between the supersymmetric partners of the left- and right-handed states of the top quark is zero. The lower limit is 81.3 GeV, even if the scalar top quark decouples from the Z boson. These limits were obtained assuming that the scalar top quark decays into a charm quark and the lightest neutralino, and that the mass difference between the scalar top quark and the lightest neutralino is larger than 10 GeV. Assuming a relatively light scalar neutrino, The complementary decay mode of the scalar top quark in which it decays into a bottom quark, a charged lepton and a scalar neutrino was also studied. From a similar analysis, a mass limit on the light scalar bottom quark was set at 82.7 GeV for a mass difference between the scalar bottom quark and the lightest neutralino larger than 7 GeV, and at 84.0 GeV for the mass difference larger 10 GeV and the lightest neutralino heavier than 30 GeV. These limits were obtained assuming that the scalar bottom quark decays into a bottom quark and the lightest neutralino, and that a mixing angle between the supersymmetric partners of the left- and right-handed states of the bottom quark is zero.

Published
1999

43. Observations of isoprene chemistry and its role in ozone production at a semirural site during the 1995 Southern Oxidants Study

Author

Paul B. Shepson, S. B. Bertman, Bryan G. Splawn, K. J. Olszyna, Daniel D. Riemer, T. K. Starn, J. S. White, and Rod G. Zika

Subjects
chemistry.chemical_classification, Atmospheric Science, Ozone, Ecology, Paleontology, Soil Science, Forestry, Methacrolein, Aquatic Science, Total ozone, Oceanography, chemistry.chemical_compound, Geophysics, Hydrocarbon, chemistry, Space and Planetary Science, Geochemistry and Petrology, Environmental chemistry, Methyl vinyl ketone, Earth and Planetary Sciences (miscellaneous), Volatile organic compound, Nitrogen oxide, Isoprene, Earth-Surface Processes, Water Science and Technology
Abstract

Isoprene and its oxidation products, methyl vinyl ketone (MVK) and methacrolein (MACR), were measured in a semirural environment that was occasionally heavily impacted by urban emissions. At this site, isoprene was the most important hydrocarbon in terms of kOH·[hydrocarbon], but the aldehydes HCHO and CH3CHO also appear to be very important. The local isoprene photochemistry appears to be occasionally enhanced in NOx-rich urban plumes that are adverted to the site over intermediate forested land. When O3 was being rapidly produced in urban plumes adverted to this forested site, isoprene was found to contribute ≈28% of the total ozone production. We observe that many of the peaks in isoprene oxidation products at this surface site arise from downward mixing of more photochemically processed air aloft, as the nocturnal inversion breaks up in the morning. We estimate that, in the daytime, typically 1–2% of the NOy at this NOx-rich site is composed of isoprene nitrates.

Published
1998

44. Investigation of CP violation in $\mathrm{B^0} \rightarrow \mathrm{J}/\psi \mathrm{K^0_S}$ decays at LEP

Author

G. W. Wilson, Richard Teuscher, A. S. Turcot, M. Hauschild, C. Markopoulos, F. Fiedler, A. Biguzzi, A. Rooke, R. Bartoldus, A. Macpherson, C. Markus, I. J. Bloodworth, J. G. Layter, H. O. Ogren, R. Kowalewski, Christoph Geich-Gimbel, Yoram Rozen, M. Foucher, R. Davis, E. H. Vokurka, M. Kolrep, K. Stephens, H. M. Fischer, R. Howard, J. S. White, Gideon Alexander, Junichi Kanzaki, D. Karlen, M. Schumacher, E. Lefebvre, Paolo Capiluppi, P. G. Estabrooks, R. K. Keeler, A. Michelini, Vakhtang Kartvelishvili, P. Gagnon, F. Odorici, M. Fierro, V. Gibson, Randall Sobie, N. K. Watson, P. M. Watkins, Daniel Lellouch, J. E. Conboy, A. Fürtjes, J. Letts, S. R. Lautenschlager, G. D. Lafferty, Stefan Schmitt, L. Brigliadori, Shoji Asai, Takehiko Mori, R. W. Springer, P. Mättig, V. Zacek, A. Sittler, T. R. Junk, H. A. Neal, Lutz Feld, G. G. Hanson, Peter Schleper, I. Trigger, O. Runolfsson, K. Sachs, Zoltan Laszlo Trocsanyi, R. L. Coxe, D. R. Ward, T. Kress, John Allison, Shlomo Dado, N. J. Oldershaw, C. Dallapiccola, J. Goldberg, Silvia Arcelli, G. Giacomelli, I. Lawson, U. Ruppel, A. Hocker, D. Chrisman, G. D. Long, Volker Blobel, M. Boutemeur, F. S. Merritt, Matthias Schröder, B. Nellen, S. Yamashita, P. Igo-Kemenes, Guenter Duckeck, A. De Roeck, K. Ishii, H. Jeremie, P. Scharff-Hansen, Claudio Grandi, P. S. Wells, M. F. Turner-Watson, Peter R Hobson, S. W. O'Neale, M. S. Dixit, Frans Meijers, Georges Azuelos, E. Tsur, Stephen Lloyd, M. Thiergen, Giora Mikenberg, Terry Richard Wyatt, S. F. Ashby, K. J. Anderson, M. Verzocchi, K. W. Bell, Ekg Sarkisyan, S. D. Bird, J. Pálinkás, S. B. Anderson, S. M. Gascon-Shotkin, P. Szymanski, R. G. Kellogg, D. Zer-Zion, S. Baumann, E. A. Mckigney, Raimund Ströhmer, P. Routenburg, P. W. Jeffreys, J. Bechtluft, J. A. McKenna, Ehud Duchovni, J. C. Hill, O. Schaile, M. Jimack, P. E.L. Clarke, M. K. Jones, J. P. Martin, W. P. Lai, H. G. Evans, A. M. Smith, Csaba Hajdu, M. J. Goodrick, I. Cohen, S. Robertson, P. Poffenberger, J. M. Roney, S. De Jong, D. I. Futyan, W. J. McDonald, Stefano Marcellini, Gregor Herten, B. C. Shen, A. D. Schaile, Gabriella Pasztor, P. Vannerem, D. Lui, Anna Macchiolo, Stan Bentvelsen, Christoph Rembser, Satoshi Mihara, J. Grunhaus, D. Axen, Ikuo Ueda, D. M. Strom, Sven Menke, A. Jawahery, N. Altekamp, H. Voss, P. Vikas, T. Kobayashi, Siegfried Bethke, A. K. Honma, K. Stoll, Matthew Evans, A. M. Rossi, G. A. Snow, C. P. Ward, D. Lanske, W. M. Sang, W. G. Scott, J. E. Pilcher, I. Nakamura, S. Söldner-Rembold, A. J. Martin, Andris Skuja, Beatrix Dienes, R. J. Barlow, S. Petzold, Sachio Komamiya, R VanKooten, Theodoros Geralis, Peter Sherwood, Erez Etzion, C. Y. Chang, C. K. Hargrove, D. Glenzinski, A. T. Watson, Tara Shears, Tetsuro Mashimo, P. Taras, Dezso Horvath, M. J. Losty, Jean-Arcady Meyer, P. A. Hart, Michael Kobel, D. J. Miller, T. P. Kokott, A. Joly, Stefan Kluth, Shlomit Tarem, Allen Mincer, Marcello Fanti, T. Saeki, Alexander Wagner, J. Ludwig, Julie Kirk, K. Runge, P. Bock, Alessandra Fanfani, N. I. Geddes, Michael Hildreth, C. Sbarra, J. Lauber, N. L. Rodning, B. Poli, W. Gorn, B. Stockhausen, Paul Kyberd, F. K. Loebinger, U. Jost, S. A. Robins, R. Mir, J. Steuerer, Ivor Fleck, R. Hawkings, Joleen Pater, A. Klier, S. D. Talbot, R. Giacomelli, A. Oh, K. Ackerstaff, D. Eatough, James Pinfold, R. Perez-Ochoa, D. G. Fong, F. G. Oakham, B. Schmitt, J. Gascon, E. L. Barberio, Paolo Giacomelli, M. Hansroul, R. J. Hemingway, B. W. Kennedy, C. Burgard, P. Jovanovic, Austin Ball, Peter Krieger, Alessandro Montanari, R. J. Homer, J. W. Gary, D. S. Koetke, O. C. Cooke, P. Pfeifenschneider, Marcello Mannelli, J. Patt, André Schöning, O. Sahr, M. A. Thomson, H. Mes, I. P. Duerdoth, S. Braibant, P. Hüntemeyer, E. K. U. Gross, M. Sproston, C. Hartmann, D. E. Plane, Stephen Hillier, G. M. Dallavalle, Reda Tafirout, Klaus Kurt Desch, E. Torrence, W. R. Gibson, T. J. McMahon, C. Couyoumtzelis, R. M. Brown, Lorne Levinson, A. Skillman, R. K. Carnegie, M. Herndon, M. Bobinski, J. A. Wilson, F. Scharf, T. Behnke, C. M. Hawkes, German Martinez, Richard Nisius, B. List, D. Lazic, Marco Cuffiani, Dave Charlton, Daniele Bonacorsi, Claire Shepherd-Themistocleous, F. Wäckerle, D. M. Gingrich, J. von Krogh, R. Bürgin, A. A. Faust, M. Gruwé, L. A. del Pozo, G. Yekutieli, Robert McPherson, Mathieu Doucet, R. D. Heuer, A. A. Carter, Ron Folman, Fabrizio Fabbri, K. Nagai, P. Utzat, D. R. Rust, Gideon Bella, J. Schieck, A. M. Lee, E. von Törne, H. J. Burckhart, Jacqueline Batley, W. Mohr, A. Posthaus, C. R. Jones, R. Lahmann, D. C. Imrie, G. P. Siroli, Otmar Biebel, Christoph Schwick, P. I. Kayal, Kiyotomo Kawagoe, Norbert Wermes, Sherry Towers, T. Kawamoto, S. Orito, K. R. Hossain, S. Betts, M. Hapke, D. E. Hutchcroft, M. J. Oreglia, J. R. Carter, and G. N. Patrick

Subjects
Physics, Nuclear physics, Particle physics, Physics and Astronomy (miscellaneous), media_common.quotation_subject, Electron–positron annihilation, Hadron, Detector, CP violation, Engineering (miscellaneous), Asymmetry, media_common, Standard Model
Abstract

An investigation of CP violation was performed using a total of 24 candidates for B0→J/ψK0SB0→J/ψKS0 decay, with a purity of about 60%. These events were selected from 4.4 million hadronic Z0Z0 decays recorded by the OPAL detector at LEP. An analysis procedure, involving techniques to reconstruct the proper decay times and tag the produced b-flavours, B0B0 or B¯0B¯0 , has been developed to allow a first direct study of the time dependent CP asymmetry that, in the Standard Model, is sin2βsin⁡2β . The result is where the first error is statistical and the second systematic. This result is used to determine probabilities for different values of sin2βsin⁡2β in the physical region from −1−1 to +1.

Published
1998

45. Determination of the production rate of D*0 mesons and of the ratio V/(V+P) in $$Z^0 \to c\bar c$$ decays

Author

K. Ackerstaff, G. Alexander, J. Allison, N. Altekamp, K. J. Anderson, S. Anderson, S. Arcelli, S. Asai, S. F. Ashby, D. Axen, G. Azuelos, A. H. Ball, E. Barberio, R. J. Barlow, R. Bartoldus, J. R. Batley, S. Baumann, J. Bechtluft, T. Behnke, K. W. Bell, G. Bella, S. Bentvelsen, S. Bethke, S. Betts, O. Biebel, A. Biguzzi, S. D. Bird, V. Blobel, I. J. Bloodworth, M. Bobinski, P. Bock, D. Bonacorsi, M. Boutemeur, S. Braibant, L. Brigliadori, R. M. Brown, H. J. Burckhart, C. Burgard, R. Bürgin, P. Capiluppi, R. K. Carnegie, A. A. Carter, J. R.Carter, C. Y. Chang, D. G. Charlton, D. Chrisman, P. E. L. Clarke, I. Cohen, J. E. Conboy, O. C. Cooke, C. Couyoumtzelis, R. L. Coxe, M. Cuffiani, S. Dado, C. Dallapiccola, G. M. Dallavalle, R. Davis, S. De Jong, L. A. del Pozo, A. de Roeck, K. Desch, B. Dienes, M. S. Dixit, M. Doucet, E. Duchovni, G. Duckeck, I. P. Duerdoth, D. Eatough, P. G. Estabrooks, E. Etzion, H. G. Evans, M. Evans, F. Fabbri, A. Fanfani, M. Fanti, A. A. Faust, L. Feld, F. Fiedler, M. Fierro, H. M. Fischer, I. Fleck, R. Folman, D. G. Fong, M. Foucher, A. Fürtjes, D. I. Futyan, P. Gagnon, J. W. Gary, J. Gascon, S. M. Gascon-Shotkin, N. I. Geddes, C. Geich-Gimbel, T. Geralis, G. Giacomelli, P. Giacomelli, R. Giacomelli, V. Gibson, W. R. Gibson, D. M. Gingrich, D. Glenzinski, J. Goldberg, M. J. Goodrick, W. Gorn, C. Grandi, E. Gross, J. Grunhaus, M. Gruwé, C. Hajdu, G. G. Hanson, M. Hansroul, M. Hapke, C. K. Hargrove, P. A. Hart, C. Hartmann, M. Hauschild, C. M. Hawkes, R. Hawkings, R. J. Hemingway, M. Herndon, G. Herten, R. D. Heuer, M. D. Hildreth, J. C. Hill, S. J. Hillier, P. R. Hobson, A. Hocker, R. J. Homer, A. K. Honma, D. Horvath, K. R. Hossain, R. Howard, P. Hüntemeyer, D. E. Hutchcroft, P. Igo-Kemenes, D. C. Imrie, K. Ishii, A. Jawahery, P. W. Jeffreys, H. Jeremie, M. Jimack, A. Joly, C. R. Jones, M. Jones, U. Jost, P. Jovanovic, T. R. Junk, J. Kanzaki, D. Karlen, V. Kartvelishvili, K. Kawagoe, T. Kawamoto, P. I. Kayal, R. K. Keeler, R. G. Kellogg, B. W. Kennedy, J. Kirk, A. Klier, S. Kluth, T. Kobayashi, M. Kobel, D. S. Koetke, T. P. Kokott, M. Kolrep, S. Komamiya, R. V. Kowalewski, T. Kress, P. Krieger, J. von Krogh, P. Kyberd, G. D. Lafferty, R. Lahmann, W. P. Lai, D. Lanske, J. Lauber, S. R. Lautenschlager, I. Lawson, J. G. Layter, D. Lazic, A. M. Lee, E. Lefebvre, D. Lellouch, J. Letts, L. Levinson, B. List, S. L. Lloyd, F. K. Loebinger, G. D. Long, M. J. Losty, J. Ludwig, D. Lui, A. Macchiolo, A. Macpherson, M. Mannelli, S. Marcellini, C. Markopoulos, C. Markus, A. J. Martin, J. P. Martin, G. Martinez, T. Mashimo, P. Mättig, W. J. McDonald, J. McKenna, E. A. Mckigney, T. J. McMahon, R. A. McPherson, F. Meijers, S. Menke, F. S. Merritt, H. Mes, J. Meyer, A. Michelini, S. Mihara, G. Mikenberg, D. J. Miller, A. Mincer, R. Mir, W. Mohr, A. Montanari, T. Mori, K. Nagai, I. Nakamura, H. A. Neal, B. Nellen, R. Nisius, S. W. O’Neale, F. G. Oakham, F. Odorici, H. O. Ogren, A. Oh, N. J. Oldershaw, M. J. Oreglia, S. Orito, J. Pálinkás, G. Pásztor, J. R. Pater, G. N. Patrick, J. Patt, R. Perez-Ochoa, S. Petzold, P. Pfeifenschneider, J. E. Pilcher, J. Pinfold, D. E. Plane, P. Poffenberger, B. Poli, A. Posthaus, C. Rembser, S. Robertson, S. A. Robins, N. Rodning, J. M. Roney, A. Rooke, A. M. Rossi, P. Routenburg, Y. Rozen, K. Runge, O. Runolfsson, U. Ruppel, D. R. Rust, K. Sachs, T. Saeki, O. Sahr, W. M. Sang, E. K. G. Sarkisyan, C. Sbarra, A. D. Schaile, O. Schaile, F. Scharf, P. Scharff-Hansen, J. Schieck, P. Schleper, B. Schmitt, S. Schmitt, A. Schöming, M. Schröder, M. Schumacher, C. Schwick, W. G. Scott, T. G. Shears, B. C. Shen, C. H. Shepherd-Themistocleous, P. Sherwood, G. P. Siroli, A. Sittler, A. Skillman, A. Skuja, A. M. Smith, G. A. Snow, R. Sobie, S. Söldner-Rembold, R. W. Springer, M. Sproston, K. Stephens, J. Steuerer, B. Stockhausen, K. Stoll, D. Strom, R. Ströhmer, P. Szymanski, R. Tafirout, S. D. Talbot, P. Taras, S. Tarem, R. Teuscher, M. Thiergen, M. A. Thomson, E. von Törne, E. Torrence, S. Towers, I. Trigger, Z. Trócsányi, E. Tsur, A. S. Turcot, M. F. Turner-Watson, I. Ueda, P. Utzat, R. Van Kooten, P. Vannerem, M. Verzocchi, P. Vikas, E. H. Vokurka, H. Voss, F. Wäckerle, A. Wagner, C. P. Ward, D. R. Ward, P. M. Watkins, A. T. Watson, N. K. Watson, P. S. Wells, N. Wermes, J. S. White, G. W. Wilson, J. A. Wilson, T. R. Wyatt, S. Yamashita, G. Yekutieli, V. Zacek, and D. Zer-Zion

Subjects
Systematic error, Physics, Particle physics, Annihilation, Physics and Astronomy (miscellaneous), Meson, Electron–positron annihilation, High Energy Physics::Phenomenology, Hadron, Nuclear physics, Pseudoscalar, Excited state, High Energy Physics::Experiment, Nuclear Experiment, Engineering (miscellaneous), Production rate
Abstract

In e+e2212 collisions at centre-of-mass energies around 91 GeV, D*0 mesons have been reconstructed using data collected with the OPAL detector at LEP. The hadronisation fraction has been measured to be f(c→D*0)=0.218±0.054±0.045±0.007, where the errors correspond to the statistical and systematic errors specific to this analysis, and to systematic uncertainties from externally measured branching fractions, respectively. Together with previous OPAL measurements of the hadronisation fractions of other charmed mesons, this value is used to investigate the relative production of observed vector and pseudoscalar charmed mesons in \(Z^0 \to c\bar c\) decays. The production ratio is determined to be PeffV = V/(V+P)=0.57±0.05. The relative primary production of vector and pseudoscalar mesons, Pvrim, is studied in the context of the production and decay of orbitally excited charmed resonances. The first measurement of the inclusive Ds*+ production rate in hadronic Z0 decays is presented.

Published
1998

46. An upper limit for the $\tau$ –neutrino mass from $\tau\rightarrow 5\pi^{\pm}\nu_{\tau}$ decays

Author

R. Bartoldus, H. M. Fischer, H. O. Ogren, Christoph Geich-Gimbel, P. G. Bright-Thomas, N. Altekamp, H. Voss, Gideon Bella, M. Schumacher, E. Lefebvre, S. B. Anderson, D. J. Miller, Vakhtang Kartvelishvili, S. L. Lloyd, F. Odorici, Otmar Biebel, P. I. Kayal, A. J. Martin, Norbert Wermes, Sherry Towers, T. Kawamoto, J. E. Conboy, A. Fürtjes, S. Orito, H. A. Neal, B. C. Shen, S. W. O'Neale, H. J. Burckhart, Jacqueline Batley, Stan Bentvelsen, J. A. McKenna, Daniel Lellouch, Takehiko Mori, J. Grunhaus, P. Gagnon, J. Allison, Siegfried Bethke, A. K. Honma, W. G. Scott, I. Nakamura, Silvia Arcelli, R. J. Hemingway, B. W. Kennedy, P. Jovanovic, P. Mättig, R. Kowalewski, Austin Ball, Peter Krieger, C. K. Hargrove, Claudia Ciocca, M. Boutemeur, F. S. Merritt, Alessandro Montanari, S. A. Robins, H. Mes, I. P. Duerdoth, A. Sittler, R. Mir, Zoltan Laszlo Trocsanyi, Matthias Schröder, J. W. Gary, K. J. Anderson, R. Hawkings, Raimund Ströhmer, J. R. Carter, P. Igo-Kemenes, T. Schorner, M. Thiergen, S. Braibant, Gideon Alexander, Paolo Capiluppi, S. Baumann, K. Ishii, H. Jeremie, S. Betts, M. Hapke, Stefan Schmitt, J. Bechtluft, R. Liebisch, K. Ackerstaff, E. A. Mckigney, James Pinfold, R. Perez-Ochoa, R. Seuster, M. J. Oreglia, G. Duckeck, C. R. Jones, F. G. Oakham, D. Glenzinski, B. Schmitt, E. L. Barberio, G. N. Patrick, G. Mikenberg, P. Hüntemeyer, J. Gascon, V. Gibson, O. Schaile, Dezso Horvath, M. J. Losty, Ehud Duchovni, R. J. Barlow, Jean-Arcady Meyer, A. D. Schaile, Gabriella Pasztor, V. Zacek, K. Roscoe, W.J. McDonald, J. Lauber, S. Robertson, M. F. Turner-Watson, F. Scharf, M. Fierro, M. Jimack, Ekg Sarkisyan, R. G. Kellogg, T. Kobayashi, P. Vannerem, German Martinez, N. K. Watson, Tara Shears, D. Lui, S. M. Gascon-Shotkin, Shoji Asai, A. Michelini, Beatrix Dienes, Peter R Hobson, D. S. Koetke, Reda Tafirout, Klaus Kurt Desch, G. D. Lafferty, D. I. Futyan, Sven Menke, Marcello Mannelli, I. J. Bloodworth, E. Torrence, Richard Teuscher, A. S. Turcot, Dave Charlton, D. Zer-Zion, K. Stoll, G. A. Snow, Andris Skuja, J. Goldberg, Claire Shepherd-Themistocleous, Stefano Marcellini, F. Fiedler, B. Nellen, C. P. Ward, S. D. Talbot, S. Petzold, C. Y. Chang, E. Clay, Sachio Komamiya, R. L. Coxe, M. Przybzien, M. A. Thomson, Theodoros Geralis, G. W. Wilson, P. G. Estabrooks, R. K. Keeler, W. M. Sang, S. Söldner-Rembold, Tetsuro Mashimo, Yoram Rozen, P. Taras, A. Hocker, R. Bürgin, P. Vikas, E. K. U. Gross, D. Eatough, D. Chrisman, G. D. Long, D. Lanske, J. Letts, A. A. Faust, W. R. Gibson, Volker Blobel, S. R. Lautenschlager, M. Sproston, T. P. Kokott, P. M. Watkins, H. G. Evans, M. Kolrep, W. Gorn, T. Saeki, S. D. Bird, I. Cohen, Georges Azuelos, T. Behnke, E. Tsur, J. Polok, A. Joly, D. Karlen, O. Runolfsson, Christoph Rembser, Alessandra Fanfani, D. Axen, R. Davis, Satoru Yamashita, M. Verzocchi, K. W. Bell, A. M. Rossi, K. Sachs, Shlomo Dado, A. Jawahery, A. Macchiolo, Claudio Grandi, P. Scharff-Hansen, J. Pálinkás, R. M. Brown, C. M. Hawkes, C. Sbarra, Lorne Levinson, Stefan Kluth, Peter Sherwood, Alexander Wagner, Shlomit Tarem, J. M. Roney, J. C. Hill, F. R. Jacob, J. Ludwig, K. Runge, Richard Nisius, A. M. Smith, P. Bock, B. List, Marco Cuffiani, S. F. Ashby, J. Schieck, W. Mohr, C. Hartmann, D. E. Plane, Stephen Hillier, Paul Kyberd, F. K. Loebinger, G. M. Dallavalle, Michael Hildreth, J. Steuerer, Ivor Fleck, N. L. Rodning, B. Poli, Joleen Pater, A. Klier, P. Poffenberger, Satoshi Mihara, K. Stephens, C. Littlewood, G. Yekutieli, T. R. Junk, I. Trigger, D. R. Ward, T. Kress, A. A. Carter, Ron Folman, T. J. McMahon, C. Couyoumtzelis, J. Dubbert, R. K. Carnegie, M. Herndon, M. Bobinski, J. A. Wilson, J. Böhme, P. E.L. Clarke, J. P. Martin, D. Lazic, S. De Jong, H. Rick, J. von Krogh, M. Gruwé, L. A. del Pozo, G. G. Hanson, G. Giacomelli, I. Lawson, A. De Roeck, M. Kobel, M. S. Dixit, Frans Meijers, O. C. Cooke, P. Pfeifenschneider, J. Patt, André Schöning, O. Sahr, A. Biguzzi, J. G. Layter, Paolo Giacomelli, M. Hansroul, C. Burgard, R. J. Homer, Achim Stahl, Kiyotomo Kawagoe, R. Van Kooten, K. R. Hossain, D. C. Imrie, G. P. Siroli, Christoph Schwick, F. Wäckerle, D. M. Gingrich, D. M. Strom, M. Fanti, Robert McPherson, Mathieu Doucet, R. D. Heuer, Fabrizio Fabbri, K. Nagai, Shigenori Tanaka, D. R. Rust, A. M. Lee, E. von Törne, P. S. Wells, Terry Richard Wyatt, A. T. Watson, A. Macpherson, R. J. Sobie, R. Howard, J. S. White, Gregor Herten, J. E. Pilcher, A. W. Lloyd, M. Hauschild, and C. Markopoulos

Subjects
Physics, Particle physics, Energy distribution, Physics and Astronomy (miscellaneous), High Energy Physics::Phenomenology, Particle identification, Nuclear physics, Tau neutrino, Pi, High Energy Physics::Experiment, Invariant mass, Limit (mathematics), Engineering (miscellaneous), ALEPH experiment
Abstract

An upper limit for the \(\tau\)–neutrino mass has been determined from the decay \(\tau\rightarrow 5\pi^{\pm}\nu_{\tau}\) using data collected with the OPAL detector from 1991 to 1995 in \(\rm e^{+}e^{-}\) collisions at \(\sqrt{s}\approx M_\mathrm{Z}\). A limit of 43.2 MeV at 95% CL is obtained using a two–dimensional method in the \(5\pi\) invariant mass and energy distribution from 22 selected events. Combining this result with OPAL's previously published measurement using \(\rm \tau^{+}\tau^{-}\rightarrow 3h^{\pm}\bar{\nu}_{\tau}+3h^{\mp}\nu_{\tau}\) decays, a new combined limit of \(m_{\nu_{\tau}}

Published
1998

47. Bose-Einstein correlations of three charged pions in hadronic Z $^{\bf 0}$ decays

Author

Erez Etzion, Stefan Kluth, Shlomit Tarem, S. A. Robins, T. Schorner, J. Grunhaus, Tara Shears, R. Liebisch, K. Ackerstaff, Sachio Komamiya, Theodoros Geralis, A. T. Watson, T. P. Kokott, T. Saeki, Alessandra Fanfani, G. Yekutieli, Otmar Biebel, G. G. Hanson, W. R. Gibson, H. M. Fischer, M. Przybycień, M. F. Turner-Watson, Peter R Hobson, J. Goldberg, D. Zer-Zion, M. Fierro, B. Nellen, S. R. Lautenschlager, A. A. Carter, Ron Folman, G. Giacomelli, I. Lawson, M. Boutemeur, F. S. Merritt, H. G. Evans, Gideon Bella, H. J. Burckhart, I. Cohen, Christoph Rembser, A. De Roeck, M. Kobel, O. Runolfsson, M. S. Dixit, Frans Meijers, J. Letts, R. M. Brown, Lorne Levinson, Matthias Schröder, A. W. Lloyd, P. I. Kayal, P. Gagnon, W. M. Sang, Jacqueline Batley, Claudio Grandi, M. Thiergen, J. Bechtluft, J. A. McKenna, Satoshi Mihara, Ekg Sarkisyan, P. E.L. Clarke, S. Yamashita, Kiyotomo Kawagoe, J. P. Martin, Ehud Duchovni, K. Sachs, K. Roscoe, J. von Krogh, M. Hauschild, C. Markopoulos, Norbert Wermes, Sherry Towers, S. De Jong, A. Sittler, Shlomo Dado, T. Kawamoto, Zoltan Laszlo Trocsanyi, P. Vikas, M. Jimack, Claire Shepherd-Themistocleous, P. Igo-Kemenes, P. G. Estabrooks, N. K. Watson, M. Gruwé, Reda Tafirout, Klaus Kurt Desch, A. J. Martin, H. Rick, R. Bartoldus, G. W. Wilson, A. Joly, D. Lanske, S. Orito, L. A. del Pozo, Claudia Ciocca, K. Ishii, H. Jeremie, A. Michelini, E. Torrence, Achim Stahl, E. Clay, H. O. Ogren, S. Betts, M. Hapke, Giora Mikenberg, Satoshi Tanaka, T. Kobayashi, P. M. Watkins, Georges Azuelos, K. Stephens, S. D. Bird, C. Sbarra, F. R. Jacob, E. Tsur, T. J. McMahon, C. Couyoumtzelis, J. Dubbert, R. K. Carnegie, M. Herndon, C. K. Hargrove, K. Nagai, Michael Hildreth, M. Bobinski, J. A. Wilson, S. F. Ashby, K. R. Hossain, N. L. Rodning, J. Böhme, A. D. Schaile, Gabriella Pasztor, C. Hartmann, Christoph Geich-Gimbel, P. S. Wells, Vakhtang Kartvelishvili, P. Vannerem, M. Verzocchi, K. W. Bell, J. Pálinkás, J. C. Hill, O. Schaile, B. Poli, D. Axen, A. Jawahery, Stefan Schmitt, C. Littlewood, A. Biguzzi, D. E. Plane, R. L. Coxe, Silvia Arcelli, M. J. Oreglia, Stephen Hillier, D. Lui, Paul Kyberd, F. K. Loebinger, J. G. Layter, J. E. Conboy, G. M. Dallavalle, A. Fürtjes, James Pinfold, R. Perez-Ochoa, R. Seuster, W. J. McDonald, B. C. Shen, V. Gibson, D. Lazic, G. A. Snow, C. P. Ward, A. Hocker, Terry Richard Wyatt, D. R. Rust, C. R. Jones, J. Steuerer, Ivor Fleck, J. R. Carter, G. N. Patrick, Siegfried Bethke, A. K. Honma, W. G. Scott, Randall Sobie, S. M. Gascon-Shotkin, S. Söldner-Rembold, S. Baumann, S. Robertson, Joleen Pater, D. Chrisman, G. D. Long, Peter Sherwood, G. D. Lafferty, Gregor Herten, T. R. Junk, S. W. O'Neale, I. Nakamura, A. Klier, E. A. Mckigney, Volker Blobel, Alexander Wagner, I. Trigger, K. J. Anderson, Sven Menke, A. M. Rossi, J. Ludwig, Raimund Ströhmer, D. R. Ward, N. Altekamp, H. Voss, K. Runge, T. Kress, P. Bock, D. Glenzinski, Dezso Horvath, M. J. Losty, J. M. Roney, J. Lauber, Stephen Lloyd, J. E. Pilcher, Jean-Arcady Meyer, Dave Charlton, D. I. Futyan, R. J. Barlow, A. M. Lee, D. J. Miller, J. Gascon, P. Poffenberger, D. C. Imrie, John Allison, D. M. Strom, E. von Törne, R. Bürgin, S. D. Talbot, Guenter Duckeck, Paolo Giacomelli, R. Kowalewski, D. Eatough, G. P. Siroli, Shoji Asai, M. Hansroul, Christoph Schwick, Beatrix Dienes, C. Burgard, R. G. Kellogg, M. Fanti, Gideon Alexander, R. J. Homer, Paolo Capiluppi, S. B. Anderson, Daniel Lellouch, R. Mir, C. Y. Chang, R. Hawkings, A. Macpherson, Stefano Marcellini, Richard Keeler, O. C. Cooke, J. W. Gary, Takehiko Mori, P. Taras, P. Pfeifenschneider, Robert McPherson, R. Howard, D. S. Koetke, J. S. White, Mathieu Doucet, J. Patt, André Schöning, P. Mättig, R. D. Heuer, Fabrizio Fabbri, Marcello Mannelli, O. Sahr, Stan Bentvelsen, R. Van Kooten, K. Stoll, V. Zacek, F. Wäckerle, Andris Skuja, D. M. Gingrich, S. Petzold, Tetsuro Mashimo, Richard Teuscher, A. S. Turcot, F. Fiedler, F. G. Oakham, W. Gorn, B. Schmitt, E. L. Barberio, M. Kolrep, I. J. Bloodworth, P. Scharff-Hansen, R. J. Hemingway, B. W. Kennedy, P. Jovanovic, Austin Ball, Yoram Rozen, Peter Krieger, Alessandro Montanari, A. M. Smith, J. Polok, D. Karlen, A. A. Faust, T. Behnke, A. Macchiolo, C. M. Hawkes, Richard Nisius, B. List, Marco Cuffiani, H. Mes, I. P. Duerdoth, S. Braibant, P. Hüntemeyer, R. Davis, P. G. Bright-Thomas, M. Schumacher, E. Lefebvre, F. Odorici, H. A. Neal, F. Scharf, German Martinez, M. A. Thomson, E. K. U. Gross, M. Sproston, J. Schieck, and W. Mohr

Subjects
Physics, Particle physics, Physics and Astronomy (miscellaneous), High Energy Physics::Phenomenology, Nuclear Theory, Hadron, Bose–Einstein correlations, Lambda, Nuclear physics, Near threshold, Pion, Coulomb, High Energy Physics::Experiment, Nuclear Experiment, Coulomb effect, Engineering (miscellaneous)
Abstract

Bose-Einstein Correlations (BEC) of three identical charged pions were studied in $4 \times 10^6$ hadronic ${\rm Z}^0$ decays recorded with the OPAL detector at LEP. The genuine three-pion correlations, corrected for the Coulomb effect, were separated from the known two-pion correlations by a new subtraction procedure. A significant genuine three-pion BEC enhancement near threshold was observed having an emitter source radius of $r_3 = 0.580 \pm 0.004 \mbox{ (stat.)} \pm 0.029 \mbox{ (syst.)} \mbox{ fm}$ and a strength of $\lambda_3 = 0.504 \pm 0.010 \mbox{ (stat.)}\pm 0.041 \mbox{ (syst.)}$ . The Coulomb correction was found to increase the $\lambda_3$ value by $\sim $ 9% and to reduce $r_3$ by $\sim $ 6%. The measured $\lambda_3$ corresponds to a value of $0.707 \pm 0.014 \mbox{ (stat.)} \pm 0.078 \mbox{ (syst.)}$ when one takes into account the three-pion sample purity. A relation between the two-pion and the three-pion source parameters is discussed.

Published
1998

48. Production of ${\rm f_0}(980)$ , ${\rm f}_2(1270)$ and $\phi(1020)$ in hadronic ${\rm Z}^0$ decay

Author

S. Betts, S. Yamashita, M. Hapke, J. Letts, P. Igo-Kemenes, D. E. Hutchcroft, K. Ishii, H. Jeremie, K. Sachs, A. Biguzzi, A. Rooke, J. G. Layter, Paolo Giacomelli, P. S. Wells, M. J. Oreglia, Shlomo Dado, O. Schaile, M. Hansroul, S. R. Lautenschlager, Terry Richard Wyatt, R. Lahmann, D. C. Imrie, L. Brigliadori, Sven Menke, Gideon Bella, T. Behnke, J. R. Carter, C. Burgard, G. N. Patrick, Stefan Schmitt, C. Hartmann, D. E. Plane, Stephen Hillier, G. M. Dallavalle, H. J. Burckhart, Jacqueline Batley, H. M. Fischer, R. J. Hemingway, Giora Mikenberg, S. F. Ashby, R. W. Springer, A. Macpherson, G. P. Siroli, Otmar Biebel, R. J. Homer, B. W. Kennedy, Christoph Schwick, A. Macchiolo, Tara Shears, P. Jovanovic, C. R. Jones, W. M. Sang, Austin Ball, O. Runolfsson, N. J. Oldershaw, J. Lauber, C. M. Hawkes, Peter Krieger, P. A. Hart, Kiyotomo Kawagoe, S. W. O'Neale, Georges Azuelos, Shoji Asai, G. G. Hanson, G. Yekutieli, E. Tsur, M. Boutemeur, F. S. Merritt, K. J. Anderson, M. Verzocchi, Richard Nisius, Alessandro Montanari, Richard Teuscher, A. D. Schaile, K. W. Bell, P. I. Kayal, J. Pálinkás, Gabriella Pasztor, H. A. Neal, R. Howard, M. F. Turner-Watson, J. S. White, A. S. Turcot, F. Fiedler, G. Giacomelli, J. C. Hill, B. List, I. Lawson, Daniel Lellouch, C. Y. Chang, W. J. McDonald, Dave Charlton, A. De Roeck, P. Vannerem, U. Ruppel, A. A. Carter, Marco Cuffiani, Norbert Wermes, B. C. Shen, Peter R Hobson, H. Mes, Ron Folman, P. Taras, G. W. Wilson, D. Zer-Zion, D. Lui, K. R. Hossain, R. Bürgin, Michael Kobel, Siegfried Bethke, A. K. Honma, M. Hauschild, C. Markopoulos, U. Jost, R. Mir, R. Hawkings, M. S. Dixit, I. P. Duerdoth, W. G. Scott, Sherry Towers, I. Nakamura, C. Markus, Frans Meijers, T. Kawamoto, Claudio Grandi, S. Braibant, P. Utzat, P. Routenburg, Matthias Schröder, E. H. Vokurka, P. E.L. Clarke, J. Grunhaus, Allen Mincer, M. K. Jones, Erez Etzion, Stefan Kluth, Shlomit Tarem, Takehiko Mori, P. Mättig, J. P. Martin, G. A. Snow, C. P. Ward, A. Joly, V. Zacek, D. Glenzinski, Dezso Horvath, M. J. Losty, S. Robertson, Julie Kirk, M. Thiergen, Gregor Herten, Jean-Arcady Meyer, Ikuo Ueda, D. M. Strom, S. Orito, J. Bechtluft, Raimund Ströhmer, Daniele Bonacorsi, R. L. Coxe, S. De Jong, P. G. Estabrooks, R. K. Keeler, N. K. Watson, P. M. Watkins, S. D. Talbot, F. G. Oakham, B. Schmitt, O. C. Cooke, Claire Shepherd-Themistocleous, P. Pfeifenschneider, M. Kolrep, E. L. Barberio, J. A. McKenna, J. E. Pilcher, S. Söldner-Rembold, P. Hüntemeyer, C. Sbarra, D. Eatough, Sachio Komamiya, C. Dallapiccola, P. Poffenberger, Theodoros Geralis, A. T. Watson, Randall Sobie, G. D. Lafferty, J. Patt, André Schöning, J. von Krogh, A. A. Faust, S. A. Robins, O. Sahr, N. Altekamp, H. Voss, T. P. Kokott, M. Gruwé, R. J. Barlow, T. Saeki, D. J. Miller, R. Bartoldus, A. J. Martin, R. Davis, L. A. del Pozo, B. Stockhausen, Paul Kyberd, F. K. Loebinger, Alessandra Fanfani, K. Ackerstaff, P. Scharff-Hansen, T. J. McMahon, Beatrix Dienes, I. J. Bloodworth, A. Hocker, H. O. Ogren, J. Steuerer, C. Couyoumtzelis, Ivor Fleck, Silvia Arcelli, M. Schumacher, E. Lefebvre, S. M. Gascon-Shotkin, R. K. Carnegie, Guenter Duckeck, Satoshi Mihara, Joleen Pater, M. Herndon, Christoph Geich-Gimbel, A. Klier, M. Bobinski, J. A. Wilson, C. K. Hargrove, R. Giacomelli, A. Oh, F. Odorici, M. Fierro, P. Gagnon, S. Baumann, Ekg Sarkisyan, Yoram Rozen, S. B. Anderson, M. Foucher, D. Chrisman, G. D. Long, D. Lazic, Matthew Evans, A. M. Rossi, John Allison, P. Szymanski, E. A. Mckigney, P. W. Jeffreys, W. P. Lai, Vakhtang Kartvelishvili, K. Stephens, Junichi Kanzaki, R. G. Kellogg, J. E. Conboy, A. Fürtjes, Csaba Hajdu, D. Karlen, A. Sittler, Stefano Marcellini, J. Goldberg, J. M. Roney, Stan Bentvelsen, Lutz Feld, N. I. Geddes, Peter Schleper, Michael Hildreth, V. Gibson, N. L. Rodning, Zoltan Laszlo Trocsanyi, B. Poli, D. I. Futyan, B. Nellen, Volker Blobel, T. R. Junk, P. Vikas, D. Lanske, I. Trigger, D. R. Ward, T. Kress, A. M. Smith, S. D. Bird, D. Axen, A. Jawahery, H. G. Evans, Peter Sherwood, M. J. Goodrick, I. Cohen, Christoph Rembser, Alexander Wagner, J. Ludwig, K. Runge, P. Bock, Stephen Lloyd, James Pinfold, R. Perez-Ochoa, D. G. Fong, J. Gascon, Ehud Duchovni, M. Jimack, J. W. Gary, D. S. Koetke, A. Michelini, Marcello Mannelli, K. Stoll, Andris Skuja, T. Kobayashi, S. Petzold, Tetsuro Mashimo, W. Gorn, R. Kowalewski, R. Van Kooten, Gideon Alexander, Paolo Capiluppi, F. Wäckerle, D. M. Gingrich, M. Fanti, W. R. Gibson, Robert McPherson, Mathieu Doucet, R. M. Brown, Lorne Levinson, A. Skillman, R. D. Heuer, Reda Tafirout, Klaus Kurt Desch, Fabrizio Fabbri, E. Torrence, K. Nagai, D. R. Rust, A. M. Lee, E. von Törne, F. Scharf, German Martinez, M. A. Thomson, E. K. U. Gross, M. Sproston, J. Schieck, W. Mohr, and A. Posthaus

Subjects
Physics, Particle physics, Physics and Astronomy (miscellaneous), Meson, Hadron, Fragmentation function, High Energy Physics::Experiment, Channel analysis, Scalar meson, Engineering (miscellaneous)
Abstract

Inclusive production of the \({\rm f_0}(980)\), \({\rm f}_2(1270)\) and \(\phi(1020)\) resonances has been studied in a sample of 4.3 million hadronic \({\rm Z}^0\) decays from the OPAL experiment at LEP. A coupled channel analysis has been used for the \({\rm f}_0\) in simultaneous fits to the resonances in inclusive \(\pi^+\pi^-\) and \({\rm K^+K^-}\) mass spectra. Fragmentation functions are reported for the three states. Total inclusive rates are measured to be \(0.141 \pm 0.007 \pm 0.011\)\({\rm f}_0\), \(0.155\pm0.011\pm0.018\)\({\rm f}_2\) and \(0.091\pm0.002\pm0.003\)\(\phi\) mesons per hadronic \({\rm Z}^0\) decay. The production properties of the \({\rm f}_0\), including those in three-jet events, are compared with those of the \({\rm f}_2\) and \(\phi\), and with the Lund string model of hadron production. All measurements are consistent with the hypothesis that the \({\rm f_0}(980)\) is a conventional \({\rm q\bar q}\) scalar meson.

Published
1998

49. Search for anomalous production of photonic events with missing energy in ${\rm e^+e^-}$ collisions at $\sqrt{s} = 130$ –172 GeV

Author

A. Klier, P. Routenburg, C. Dallapiccola, M. Hauschild, C. Markopoulos, C. Markus, G. T. Jones, E. H. Vokurka, N. Altekamp, H. Voss, S. Orito, W. Gorn, S. R. Lautenschlager, H. A. Neal, R. J. Barlow, D. J. Miller, Stefan Kluth, E. K.G. Sarkisyan, U. Ruppel, M. R. Ingram, J. Lauber, S. Betts, M. Hapke, W. J. McDonald, A. Sittler, P. G. Estabrooks, O. Runolfsson, G. W. Wilson, V. Zacek, D. E. Hutchcroft, N. J. Oldershaw, Gideon Bella, R. Howard, U. Jost, N. K. Watson, S. D. Talbot, G. Yekutieli, P. Scharff-Hansen, A. D. Schaile, H. J. Burckhart, Jacqueline Batley, C. Beeston, M. J. Oreglia, W. M. Sang, Gregor Herten, B. Wilkens, A. Biguzzi, Raimund Ströhmer, N. Rodning, P. M. Watkins, A. Rooke, J. E. Pilcher, Gabriella Pasztor, Claudio Grandi, J. Grunhaus, D. C. Imrie, P. R. Hobson, J. G. Layter, I. Nakamura, A. K. Honma, R. Van Kooten, F. G. Oakham, D. Eatough, B. Schmitt, E. L. Barberio, R. Bartoldus, D. Lui, B. Nellen, A. M. Smith, A. Oh, Paolo Capiluppi, J-P. Meyer, John Allison, Richard Keeler, R. J. Hemingway, H. O. Ogren, L. Levinson, G. D. Long, M. Schumacher, K. Stephens, G. A. Snow, C. P. Ward, E. Lefebvre, R. L. Coxe, Christoph Geich-Gimbel, J. R. Carter, Georges Azuelos, C. R. Jones, G. Mikenberg, T. Kawamoto, Stefan Schmitt, A. Macpherson, B. W. Kennedy, P. Jovanovic, R. Lahmann, Austin Ball, S. Söldner-Rembold, F. Odorici, A. Hocker, G. N. Patrick, Peter Krieger, R. G. Kellogg, P. E.L. Clarke, Alessandro Montanari, R. Davis, Silvia Arcelli, Hans-Christian Schultz-Coulon, Csaba Hajdu, D. Chrisman, R. Perez-Ochoa, G. D. Lafferty, M. Verzocchi, K. W. Bell, Otmar Biebel, H. G. Evans, M. J. Goodrick, P. Igo-Kemenes, N. I. Geddes, Michael Hildreth, P. Gagnon, M. K. Jones, J. P. Martin, J. Letts, Christoph Rembser, E. Tsur, S. Komamiya, V. Gibson, J. S. White, Stefano Marcellini, C. Hartmann, D. G. Fong, J. Gascon, D. E. Plane, S. Dado, J. Pinfold, J. C. Hill, D. Lazic, T. J. McMahon, C. Couyoumtzelis, P. Mättig, S. Asai, Vakhtang Kartvelishvili, G. P. Siroli, S. De Jong, Christoph Schwick, K. Ackerstaff, F. Fiedler, F. Wäckerle, L. Brigliadori, S. Baumann, H. Jeremie, Stephen Lloyd, Stephen Hillier, R. K. Carnegie, E. Gross, Dave Charlton, B. Poli, F. Scharf, German Martinez, I. J. Bloodworth, Peter Schleper, K. Kawagoe, J. E. Conboy, A. Fürtjes, K. Sachs, J. Goldberg, E. A. Mckigney, S. Tarem, B. C. Shen, G. M. Dallavalle, T. R. Junk, J. M. Roney, M. Fierro, J. E.G. Edwards, R. Bürgin, H. M. Fischer, A. N. Bell, D. M. Gingrich, M. Herndon, B. Dienes, I. Trigger, A. Joly, J. W. Gary, W. P. Lai, D. S. Koetke, Marcello Mannelli, Guenter Duckeck, Lutz Feld, R. Mir, M. Bobinski, Norbert Wermes, Sherry Towers, Paolo Giacomelli, J. A. Wilson, M. Hansroul, D. R. Ward, M. Jimack, Siegfried Bethke, T. Kress, W. G. Scott, A. Michelini, H. Mes, O. Schaile, P. W. Jeffreys, M. Foucher, I. P. Duerdoth, S. D. Bird, G. G. Hanson, A. M. Lee, G. Alexander, M. Boutemeur, F. S. Merritt, Richard Teuscher, S. Braibant, S. Yamashita, R. Rylko, B. Stockhausen, Paul Kyberd, F. K. Loebinger, D. I. Futyan, A. S. Turcot, C. Burgard, I. Cohen, Ivor Fleck, G. Giacomelli, S. W. O'Neale, A. Jawahery, Joleen Pater, M. F. Turner-Watson, R. W. Springer, R. J. Homer, D. Karlen, T. Saeki, P. I. Kayal, S. F. Ashby, R. Giacomelli, Sven Menke, Daniele Bonacorsi, Z. Trácsanyi, Peter Sherwood, S. Mihara, S. M. Gascon-Shotkin, M. A. Thomson, S. Robertson, D. Glenzinski, Dezso Horvath, M. J. Losty, R. Sobie, M. S. Dixit, Frans Meijers, P. S. Wells, J. Bechtluft, K. J. Anderson, M. Fanti, D. Zer-Zion, V. Blobel, J. A. McKenna, J. Ludwig, Reda Tafirout, Klaus Kurt Desch, S. A. Robins, R. Hawkings, K. Runge, P. Bock, E. Torrence, S. Petzold, Matthew Evans, A. M. Rossi, M. Kolrep, M. Sproston, Terry Richard Wyatt, C. Y. Chang, P. Vikas, D. Lanske, T. Mori, J. von Krogh, D. Lellouch, W. R. Gibson, J. E. Bloomer, D. Axen, K. R. Hossain, S. B. Anderson, J. Pálinkás, J. Kirk, P. Szymanski, P. Taras, Michael Kobel, R. M. Brown, E. von Tärne, Theodoros Geralis, A. Skillman, O. C. Cooke, P. Pfeifenschneider, A. T. Watson, L. A. del Pozo, Stan Bentvelsen, Allen Mincer, T. P. Kokott, T. Mashimo, Alessandra Fanfani, J. Patt, André Schöning, Robert McPherson, C. Sbarra, P. Huntemeyer, A. A. Carter, Ron Folman, T. Kobayashi, Mathieu Doucet, R. D. Heuer, P. Utzat, A. A. Faust, Fabrizio Fabbri, J. Schieck, D. M. Strom, E. Duchovni, W. Mohr, A. Posthaus, K. Nagai, D. R. Rust, J. Kanzaki, S. Tanaka, Tara Shears, P. A. Hart, P. Poffenberger, K. Ishii, Claire Shepherd-Themistocleous, A. Wagner, Matthias Schröder, T. Behnke, J. Steuerer, M. Thiergen, A. Macchiolo, M. Gruwé, C. M. Hawkes, Richard Nisius, Marco Cuffiani, U. Müller, A. J. Martin, C. K. Hargrove, K. Stoll, Andris Skuja, and Y. Rozen

Subjects
Physics, Particle physics, Missing energy, Physics and Astronomy (miscellaneous), Electron–positron annihilation, Physics beyond the Standard Model, Standard Model, Nuclear physics, Pair production, Neutralino, High Energy Physics::Experiment, Production (computer science), Engineering (miscellaneous), Energy (signal processing)
Abstract

Photonic events with large missing energy have been observed in \(\mathrm{e^+e^-}\) collisions at centre-of-mass energies of 130, 136, 161 and 172 GeV using the OPAL detector at LEP. Results are presented based on search topologies designed to select events with a single photon and missing transverse energy or events with a pair of acoplanar photons. In both search topologies, cross-section measurements are performed within the kinematic acceptance of the selection. These results are compared with the expectations from the Standard Model processes \({\rm e^+e^-}\to \nu\overline\nu \gamma (\gamma )\) (single-photon) and \({\rm e^+e^-}\to \nu\overline\nu \gamma \gamma (\gamma )\) (acoplanar-photons). No evidence is observed for new physics contributions to these final states. Upper limits on \(\sigma({\rm e^+e^- \to XY)\cdot BR(X\to Y\gamma })\) and \(\sigma({\rm e^+e^- \to XX)\cdot BR^2(X\to Y\gamma })\) are derived for the case of stable and invisible Y. These limits apply to single and pair production of excited neutrinos (\({\rm X}= \nu^*,{\rm Y}= \nu\)), to neutralino production (\({\rm X}=\tilde\chi^0_2, {\rm Y}=\tilde\chi^0_1\)), and to supersymmetric models in which \({\rm X}= \tilde\chi^0_1\) and \({\rm Y}=\tilde{\rm G}\) is a light gravitino. For the latter scenario, the results of the acoplanar-photons search are used to provide mode l-dependent lower limits on the mass of the lightest neutralino.

Published
1998

50. Multi-photon final states in e+e− collisions at ∝s =130-172 GeV

Author

S. Petzold, G. D. Long, Tetsuro Mashimo, J. M. Roney, Anna Macchiolo, W. Gorn, Gabriella Pasztor, S. D. Bird, P. E. L. Clarke, W. Mohr, A. Posthaus, Matthias Schröder, G. A. Snow, S. R. Lautenschlager, H. A. Neal, M. Jimack, C. P. Ward, John Allison, B. Schmitt, K. Nagai, Eduardo Ros, N. K. Watson, S. M. Gascon-Shotkin, M. Thiergen, D. L. Rees, S. Söldner-Rembold, Kiyotomo Kawagoe, S. J. De Jong, Satoshi Mihara, Daniel Lellouch, Hildreth, P. Scharff-Hansen, C.J. Beeston, A. P. Wagner, Frank Fiedler, D. Axen, S. Komamiya, A. Jawahery, David G. Charlton, Gideon Bella, BT Bouwens, Rick J. Van Kooten, Eugene P. Gross, F. Wäckerle, Paolo Giacomelli, Takehiko Mori, H. J. Burckhart, Jacqueline Batley, M. Hansroul, Georges Azuelos, E. Tsur, C. M. Hawkes, S. H. Robertson, J. Goldberg, B. Nellen, N. J. Oldershaw, E. Lefebvre, J. Steuerer, A. M. Rossi, Isabel Marian Trigger, K. W. Bell, F. Scharf, German Martinez, Gideon Alexander, Otmar Biebel, Marco Verzocchi, R. Bartoldus, J. W. Gary, J. Palinkas, K. Sachs, F. Odorici, R. G. Kellogg, C. H. Shepherd-Themistocleous, R. J. Homer, D. S. Koetke, Csaba Hajdu, Stefano Marcellini, James Letts, A. D. Schaile, A. S. Turcot, P. Igo-Kemenes, Gy. Wolf, Shigenori Tanaka, Shlomo Dado, K. Ishii, K. R. Hossain, Paolo Capiluppi, P.A. Hart, H. Jeremie, H. O. Ogren, J. C. Hill, R. J. Teuscher, A. M. Smith, A. Michelini, V. Kartvelishvili, S. A. Robins, D. Rigby, R. J. Hemingway, Christoph Geich-Gimbel, D. R. Rust, J. Ludwig, B. C. Shen, K. Runge, P. Bock, J. R. Carter, P. I. Kayal, T. Behnke, Siegfried Bethke, G. Duckeck, W. G. Scott, P. G. Estabrooks, V. Gibson, H. G. Evans, P. Szymanski, M. J. Goodrick, Doug Gingrich, J. A. McKenna, I. Cohen, P. Jovanovic, I. J. Bloodworth, James Pinfold, I. Nakamura, R. Perez-Ochoa, E. do Couto e Silva, Ehud Duchovni, E. von Törne, C. R. Jones, Richard Nisius, U. Müller, T. Kress, Peter Krieger, D. G. Fong, Carla Sbarra, J. Gascon, P. Gagnon, Dezso Horvath, M. J. Losty, Sven Menke, Alessandro Montanari, A. J. Martin, K. Ackerstaff, P. M. Watkins, Takayuki Saeki, Jean-Arcady Meyer, Sherry Towers, T. Kawamoto, Marco Cuffiani, N. L. Rodning, A. Skillman, D. E. Hutchcroft, C. Dallapiccola, M. Kolrep, D. Karlen, Carsten Daniel Burgard, B. Poli, G. Mikenberg, O. Schaile, I. P. Duerdoth, Yoram Rozen, V. Zacek, A. Sittler, S. Orito, A. K. Honma, N. Altekamp, M. Foucher, Claudio Grandi, Peter Schleper, C. K. Hargrove, Zoltan Laszlo Trocsanyi, S. J. Hillier, Tara Shears, Robert McPherson, B. Stockhausen, P. Kyberd, P. Hüntemeyer, S. B. Anderson, F. K. Loebinger, D. J. Miller, A. H. Ball, Silvia Arcelli, M. F. Turner-Watson, Meirin Oan Evans, D. C. Imrie, Mathieu Doucet, M. Hapke, R. Bürgin, Marcello Mannelli, D. M. Strom, Matthew Herndon, Fabrizio Fabbri, M. Morii, Markus Schumacher, E.K.G. Sarkisian, H. Voss, G. W. Wilson, Peter R Hobson, Ivor Fleck, G. P. Siroli, S. Baumann, M. J. Pearce, U. Jost, R. Mir, Stan Bentvelsen, Christoph Schwick, J.A. Lauber, M. J. Oreglia, H. Mes, D Chrisman, E. A. Mckigney, S. Braibant, J. E. Conboy, S. D. Talbot, M. Sproston, Joleen Pater, Peter Sherwood, D. Zer-Zion, W. P. Lai, A. Fürtjes, Stefan Kluth, T. Geralis, R. D. Heuer, Shlomit Tarem, F. G. Oakham, Stefan Schmitt, Norbert Wermes, G. N. Patrick, E. L. Barberio, A. Klier, D. Eatough, R. Giacomelli, G. D. Lafferty, D. I. Futyan, Volker Blobel, P. Routenburg, T. R. Wyatt, Jochen Schieck, T. R. Junk, M. Gruwe, Hans-Christian Schultz-Coulon, Thomson, M. J. Kobel, P. Mättig, Shoji Asai, Stephen Lloyd, A. A. Faust, D. Glenzinski, Satoru Yamashita, Robert M Brown, Gregor Herten, R. Rylko, Robert Wayne Springer, M. Boutemeur, M. Fierro, J. E.G. Edwards, F. S. Merritt, T. P. Kokott, Dixit, P. W. Jeffreys, P. S. Wells, David E. Plane, B. Wilkens, J. E. Bloomer, T. Kobayashi, A. M. Lee, A. Macpherson, Richard Keeler, P. Vikas, R. J. Sobie, Robert Lahmann, R. Howard, J. S. White, Alexander Oh, J. E. Pilcher, D. Lanske, J. Bechtluft, M. Hauschild, C. Markus, G. T. Jones, E. H. Vokurka, P R Poffenberger, J. Grunhaus, C. Hartmann, H. Fischer, O. Runolfsson, Alan Watson, Matthew Jones, Reda Tafirout, Klaus Kurt Desch, W. R. Gibson, A. Joly, Lorne Levinson, B. W. Kennedy, N. I. Geddes, Roger Barlow, K. Stephens, W.John McDonald, D. Lazic, D. R. Ward, U. Ruppel, M. R. Ingram, C. Y. Chang, P. Taras, G. Yekutieli, Allen Mincer, Marcello Fanti, Julie Kirk, P. Pfeifenschneider, A. A. Carter, Ron Folman, J. Patt, André Schöning, G. G. Hanson, G.Marco Dallavalle, P. Utzat, Beatrix Dienes, L. Brigliadori, G. Giacomelli, Daniele Bonacorsi, O. C. Cooke, S. W. O'Neale, R. Davies, P. Schenk, K. J. Anderson, J. von Krogh, Frans Meijers, R. J. Hawkings, L. A. del Pozo, A. Biguzzi, A. Rooke, J. G. Layter, T. J. McMahon, R. K. Carnegie, M. Bobinski, J. A. Wilson, J.P. Martin, A. N. Bell, K. Stoll, and Andris Skuja

Subjects
Nuclear physics, Physics, Particle physics, Angular distribution, Physics and Astronomy (miscellaneous), Electron–positron annihilation, Engineering (miscellaneous)
Published
1998

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