L. Taylor

Post implantation, a thin TiO2 film protects Ti-6Al-4V in vivo. Mechanically and chemically destructive conditions may disrupt this oxide film and promote corrosion at the device interface. While tribocorrosion has been explored in vitro, pre-clinical tests fail to fully reproduce the damage documented on retrievals. A gap persists in our fundamental knowledge of the oxide film and its response to adverse electrochemical events. In this study, we first characterized the TiO2 oxide film structure after inducing β phase selective dissolution. Next, we used electrochemical impedance spectroscopy and Mott-Schottky analysis to investigate the oxide film on freshly prepared surfaces following negative potential excursions. We systematically increased electrode potential from -1 V vs. Ag/AgCl in 0.1 V steps to +0.5 V. Various H2O2 concentrations (0.1 M to 0.001 M) in phosphate buffered saline and temperatures ranging from 24 °C to 55 °C were investigated. Atomic force microscopy showed morphological changes to oxide domes over the α phase following β phase selective dissolution. Below the Ti-6Al-4V open circuit potential (ca. -0.3 V), we identified systematic variations in polarization resistance (Rp) and capacitance (C) with potential, solution chemistry, and temperature. The combined effect of cathodic activation and H2O2 solution concentration synergistically and systematically decreased Rp by orders of magnitude (p = 0.000). Increased solution temperatures decreased Rp (p = 0.000). At high concentrations of ROS (0.1 M), we documented changes in constant phase element capacitance, from n-type to p-type. Finally, we developed empirical equations to predict Rp for a given concentration, temperature, and potential. In totality, these experiments help to further elucidate the complex interactions at the oxide-biology interface in vivo and provide guidance for in vitro testing methods development.

We report on measurements of correlated $$b\bar b$$ production in $$p\bar p$$ collisions at $$\sqrt s = 630GeV$$ , using dimuon data to tag both theb and $$\bar b$$ quarks. Starting from an inclusive dimuon sample we obtain improved cross-sections for single inclusive beauty production and confirm our earlier results on $$B^0 - \bar B^0$$ mixing. From a study of $$b\bar b$$ correlations we derive explicit cross-sections for semi-differential $$b\bar b$$ production. We compare the measured cross-sections and correlations to $$\mathcal{O}\left( {\alpha _s^3 } \right)$$ QCD predictions and find good quantitative agreement. From the measured angular distributions we establish a size-able contribution from higher order QCD processes with a significance of about seven standard deviations. A large nonperturbative contribution to these higher order corrections is excluded.

A Higgs particle produced in association with a Z boson and decaying into two photons is searched for in the data collected by the L3 experiment at LEP. All possible decay modes of the Z boson are investigated. No signal is observed in 447.5 pb^-1 of data recorded at centre-of-mass energies up to 209 GeV. Limits on the branching fraction of the Higgs boson decay into two photons as a function of the Higgs mass are derived. A lower limit on the mass of a fermiophobic Higgs boson is set at 105.4 GeV at 95% confidence level.

A search for multifractal structures, in analogy with multifractal theories, is performed on UA1 minimum bias events. A downward concave multifractal spectral function,f(α) (where α is the Lipschitz-Hölder exponent), indicates that there are self-similar cascading processes, governing the evolution from the quark to the hadron level, in the final states of hadronic interactions.f(α) is an accurate measure of the bin to bin fluctuations of any observable. It is shown that the most sensitive comparison between data and the Monte Carlo models, GENCL and PYTHIA 4.8 can be made usingf(α). It is found that these models do not fully reproduce the behaviour of the data.

iSpy is a general-purpose event data and detector visualization program that was developed as an event display for the CMS experiment at the LHC and has seen use by the general public and teachers and students in the context of education and outreach. Central to the iSpy design philosophy is ease of installation, use, and extensibility.

The L3 central tracking detector has been in operation since the start-up of LEP (Large Electron Positron collider) in 1989. This detector consists of a Time Expansion Chamber (TEC), a layer of Plastic Scintillating Fibers and a Z-chamber. The TEC gives a high spatial resolution and an excellent multi-track reconstruction capability. The fibers are designed to calibrate the drift velocity with high precision. The Z-Chamber provides TEC with accurate information about the z-coordinates of the tracks. A description of the design and the infrastructure of these three detectors, including the readout and data acquisition system, is given. The performance of the detectors during the 1990 and 1991 LEP running periods is presented.

The CMS Experiment at the LHC is establishing a global network of inter-connected "CMS Centres" for controls, operations and monitoring. These support: (1) CMS data quality monitoring, detector calibrations, and analysis; and (2) computing operations for the processing, storage and distribution of CMS data. We describe the infrastructure, computing, software, and communications systems required to create an effective and affordable CMS Centre. We present our highly successful operations experiences with the major CMS Centres at CERN, Fermilab, and DESY during the LHC first beam data-taking and cosmic ray commissioning work. The status of the various centres already operating or under construction in Asia, Europe, Russia, South America, and the USA is also described. We emphasise the collaborative communications aspects. For example, virtual co-location of experts in CMS Centres Worldwide is achieved using high-quality permanently-running "telepresence" video links. Generic Web-based tools have been developed and deployed for monitoring, control, display management and outreach.

The UA1 Collaboration has recently improved its measurement of the beauty production cross-section by including explicit measurements of bb correlations. Using these data we have determined the strong coupling constant αs. The comparison of the measured cross-section for 2-body final states with O(αs3) QCD predictions yields a measurement of αs(20 GeV) = 0.145−0.010 exp −0.016 th+0.012 +0.013, corresponding to αs(Mz) = 0.113−0.006 exp −0.009 th+0.007 +0.008. This is the first theoretically well-defined measurement of αs from a purely hadronic production process. Evaluating αs from cross-sections at different Q2-values we find that the running of αs is needed for internal consistency of the UA1 data.

We have measured the probability, n(g->cc~), of a gluon splitting into a charm-quark pair using 1.7 million hadronic Z decays collected by the L3 detector. Two independent methods have been applied to events with a three-jet topology. One method relies on tagging charmed hadrons by identifying a lepton in the lowest energy jet. The other method uses a neural network based on global event shape parameters. Combining both methods, we measure n(g->cc~)= [2.45 +/- 0.29 +/- 0.53]%.

The CMS experiment is currently developing a computing system capable of serving, processing and archiving the large number of events that will be generated when the CMS detector starts taking data. During 2004 CMS undertook a large scale data challenge to demonstrate the ability of the CMS computing system to cope with a sustained data-taking rate equivalent to 25% of startup rate. Its goals were: to run CMS event reconstruction at CERN for a sustained period at 25 Hz input rate; to distribute the data to several regional centers; and enable data access at those centers for analysis. Grid middleware was utilized to help complete all aspects of the challenge. To continue to provide scalable access from anywhere in the world to the data, CMS is developing a layer of software that uses Grid tools to gain access to data and resources, and that aims to provide physicists with a user friendly interface for submitting their analysis jobs. This paper describes the data challenge experience with Grid infrastructure and the current development of the CMS analysis system.

Abstract The IGUANA project has developed visualisation tools for multiple high-energy experiments. At the core of IGUANA is a generic, high-performance visualisation system based on OpenInventor and OpenGL. This paper describes the back-end and a feature-rich 3D visualisation system built on it, as well as a new 2D visualisation system that can automatically generate 2D views from 3D data, for example to produce R/Z or X/Y detector displays from existing 3D display with little effort. IGUANA has collaborated with the open-source gl2ps project to create a high-quality vector postscript output that can produce true vector graphics output from any OpenGL 2D or 3D display, complete with surface shading and culling of invisible surfaces. We describe how it works. We also describe how one can measure the memory and performance costs of various OpenInventor constructs and how to test scene graphs. We present good patterns to follow and bad patterns to avoid. We have added more advanced tools such as per-object clipping, slicing, lighting or animation, as well as multiple linked views with OpenInventor, and describe them in this paper. We give details on how to edit object appearance efficiently and easily, and even dynamically as a function of object properties, with instant visual feedback to the user.

We calculate the squared matrix element for the process e+e− → τ+τ−γ allowing for anomalous magnetic and electric dipole moments at the ττγ vertex. No interferences are neglected and no approximations of light fermion masses are made. We show that anomalous moments affect not only the cross section, but also the shape of the photon energy and angular distributions. We also demonstrate that in the case of the anomalous magnetic dipole moment, the contribution from interference involving Standard Model and anomalous amplitudes is significant compared to the contribution from anomalous amplitudes alone. A program to perform the calculation is available and it may be employed as a Monte Carlo generator.

This paper reviews the theoretical predictions for and the experimental measurements of the anomalous magnetic and electric dipole moments of the tau lepton. In particular, recent analyses of the e+e− → τ+τ−γ process from the L3 and OPAL collaborations are described. The most precise results, from L3, for the anomalous magnetic and electric dipole moments respectively are: aτ = 0.004 ± 0.027 ± 0.023 and dτ = (0.0 ± 1.5 ± 1.3) × 10−16e·cm.

We present the development and use of a novel distributed geohazard modeling environment for the analysis and interpretation of large scale earthquake data sets. Our work demonstrates, for the first time, how earthquake-related surface deformation measured from satellite images using imageodesy algorithms is coupled with analysis and simulation using finite-element numerical models. Our work realises a real time distributed analytical environment where analysis and simulation are closely coupled; integrating high performance implementations of image mining components executing on dedicated Discovery Net servers at Imperial College London, UK and high performance implementations of finiteelement models executing at specialised servers at the University of Oklahoma, USA. Novel scientific results produced using our data sets provide a valuable insight into earthquake analysis. In addition, our informatics work provides a novel high performance computing framework and methods for the application of complex knowledge discovery methods to understanding earthquake dynamics. Furthermore, the realisation of our distributed computing platform is based on the implementation of a set of open standards, making its results accessible over the Grid to the wider scientific community.

We present a new method for the determination of the Cabibbo-Kobayashi-Maskawa quark mixing matrix element $|{V}_{\mathrm{tb}}|$ from electroweak loop corrections, in particular those affecting the process $\stackrel{\ensuremath{\rightarrow}}{Z}b\overline{b}.$ From a combined analysis of results from the CERN LEP, SLC, Fermilab Tevatron, and neutrino scattering experiments we determine $|{V}_{\mathrm{tb}}|{=0.77}_{\ensuremath{-}0.24}^{+0.18}.$

The age and size of the CMS collaboration at the LHC means it now has many hundreds of inhomogeneous web sites and services, and hundreds of thousands of documents. We describe a major initiative to create a single coherent CMS internal and public web site. This uses the Drupal web Content Management System (now supported by CERN/IT) on top of a standard LAMP stack (Linux, Apache, MySQL, and php/perl). The new navigation, content and search services are coherently integrated with numerous existing CERN services (CDS, EDMS, Indico, phonebook, Twiki) as well as many CMS internal Web services. We describe the information architecture; the system design, implementation and monitoring; the document and content database; security aspects; and our deployment strategy, which ensured continual smooth operation of all systems at all times.

IGUANA is a generic interactive visualisation framework based on a C++ component model. It provides powerful user interface and visualisation primitives in a way that is not tied to any particular physics experiment or detector design. The article describes interactive visualisation tools built using IGUANA for the CMS and D0 experiments, as well as generic GEANT4 and GEANT3 applications. It covers features of the graphical user interfaces, 3D and 2D graphics, high-quality vector graphics output for print media, various textual, tabular and hierarchical data views, and integration with the application through control panels, a command line and different multi-threading models.

We use recent experimental measurements of tau branching fractions to determine the weak charged current magnetic and electric dipole moments of the tau and the Michel parameter $\eta$ with unprecedented precision. These results are then used to constrain the tau compositeness scale and the allowed parameter space for Higgs doublet models. We also present new constraints on the mass of the tau neutrino and its mixing with a fourth generation neutrino.

In order to prepare the Physics Technical Design Report, due by end of 2005, the CMS experiment needs to simulate, reconstruct and analyse about 100 million events, corresponding to more than 200 TB of data. The data will be distributed to several Computing Centres. In order to provide access to the whole data sample to all the world-wide dispersed physicists, CMS is developing a layer of software that uses the Grid tools provided by the LCG project to gain access to data and resources and that aims to provide a user friendly interface to the physicists submitting the analysis jobs. To achieve these aims CMS will use Grid tools from both the LCG-2 release and those being developed in the framework of the ARDA project. This work describes the current status and the future developments of the CMS analysis system.

On 30 March 2010 the first high-energy collisions brought the LHC experiments into the era of research and discovery. Millions of viewers worldwide tuned in to the webcasts and followed the news via Web 2.0 tools, such as blogs, Twitter, and Facebook, with 205,000 unique visitors to CERN's Web site. Media coverage at the experiments and in institutes all over the world yielded more than 2,200 news items including 800 TV broadcasts. We describe the new multimedia communications challenges, due to the massive public interest in the LHC programme, and the corresponding responses of the ATLAS and CMS experiments, in the areas of Web 2.0 tools, multimedia, webcasting, videoconferencing, and collaborative tools. We discuss the strategic convergence of the two experiments' communications services, information systems and public database of outreach material.

The leptonic branching fractions of the tau lepton are sensitive to anomalous charged current interactions. We use recent experimental measurements to determine the weak charged current magnetic and electric dipole moments and the Michel parameter $\eta$ with unprecedented precision. These results are then used to constrain the tau compositeness scale and the allowed parameter space for Higgs doublet models.

The standard method for the propagation of errors, based on a Taylor series expansion, is approximate and frequently inadequate for realistic problems. A simple and generic technique is described in which the likelihood is constructed numerically, thereby greatly facilitating the propagation of errors.

We present a composite 1 framework 2 which exploits the advantages of the CMS data model and uses a novel approach for building CMS simulation, reconstruction, testbeam visualisation and future analysis applications. The framework exploits LCG SEAL [1] and CMS COBRA [2] plug-ins and extends the COBRA framework to pass communications between the GUI and event threads, using SEAL callbacks to navigate through the metadata and event data interactively in a distributed environment. We give examples of current applications based on the framework, including CMS test-beams, geometry description debugging, Geant4 [3] simulation, event reconstruction, and the verification of reconstruction and higher level trigger algorithms.

The CMS experiment is about to embark on its first physics run at the LHC. To maximize the effectiveness of physicists and technical experts at CERN and worldwide and to facilitate their communications, CMS has established several dedicated and inter-connected operations and monitoring centres. These include a traditional 'Control Room' at the CMS site in France, a 'CMS Centre' for up to fifty people on the CERN main site in Switzerland, and remote operations centres, such as the 'LHC@FNAL' centre at Fermilab. We describe how this system of centres coherently supports the following activities: (1) CMS data quality monitoring, prompt sub-detector calibrations, and time-critical data analysis of express-line and calibration streams; and (2) operation of the CMS computing systems for processing, storage and distribution of real CMS data and simulated data, both at CERN and at offsite centres. We describe the physical infrastructure that has been established, the computing and software systems, the operations model, and the communications systems that are necessary to make such a distributed system coherent and effective.

We have derived constraints on the \ensuremath{\tau} neutrino mass and fourth generation mixing from an analysis of the partial widths of \ensuremath{\tau} lepton decays, in particular, ${\ensuremath{\tau}}^{\ensuremath{-}}\ensuremath{\rightarrow}{e}^{\ensuremath{-}}{\overline{\ensuremath{\nu}}}_{e}{\ensuremath{\nu}}_{\ensuremath{\tau}},$ ${\ensuremath{\tau}}^{\ensuremath{-}}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{\ensuremath{-}}{\overline{\ensuremath{\nu}}}_{\ensuremath{\mu}}{\ensuremath{\nu}}_{\ensuremath{\tau}},$ $\ensuremath{\tau}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\nu}}_{\ensuremath{\tau}},$ and $\ensuremath{\tau}\ensuremath{\rightarrow}{K}^{\ensuremath{-}}{\ensuremath{\nu}}_{\ensuremath{\tau}}.$ We present predictions for the \ensuremath{\tau} decay widths, allowing for a nonzero \ensuremath{\tau} neutrino mass ${m}_{{\ensuremath{\nu}}_{\ensuremath{\tau}}}$ and for mixing with a neutrino of mass ${m}_{{\ensuremath{\nu}}_{L}}>{M}_{Z}/2$, which is parametrized using a Cabibbo-like mixing angle ${\ensuremath{\theta}}_{L}.$ By comparison of these theoretical predictions with the experimental measurements, we obtain the following bounds at the 90% confidence level: ${m}_{{\ensuremath{\nu}}_{\ensuremath{\tau}}}<42$ MeV and ${\mathrm{sin}}^{2}{\ensuremath{\theta}}_{L}<0.014$.

We present a detailed simulation of the performance of water Čerenkov detectors suitable for use in the Pierre Auger Observatory. Using geant4, a flexible object-oriented simulation program, including all known physics processes, has been developed. The program also allows interactive visualization, and can easily be modified for any experimental setup.

The L3 vertex detector is comprised of the time expansion chamber (TEC), the Z-chamber and a layer of plastic scintillating fibers. The TEC has shown a high spatial resolution and an excellent multi-track reconstruction capability at LEP luminosity. The Z-chamber provides information about the z-coordinates of the tracks and the fibers are used for calibrating the drift velocity with a high precision. A description of the L3 vertex detector, its readout and data acquisition and its performance during the 1990 LEP running period is presented in this paper.

The data collected by the LHC experiments are unique and present an opportunity and a challenge for a long-term preservation and re-use. The CMS experiment has defined a policy for the data preservation and access to its data and is starting its implementation. This note describes the driving principles of the policy and summarises the actions and activities which are planned in the starting phase of the project.

Geneva, 10 September 2008. The first beam in the Large Hadron Collider at CERN was successfully steered around the full 27 kilometers of the world's most powerful particle accelerator at 10h 28 this morning. This historic event marks a key moment in the transition from over two decades of preparation to a new era of scientific discovery2. From 9:44 am CET attention of the CMS physicists in the control room is drawn to the CMS event display -the "eyes" of the detector. We observe the tell-tale splash events (see figure 1 and 2), the beam gas and beam halo muons. We see in real time how the beam events become more and more clean as the beam is corrected.

We analyse the process $\tau^-\to\nu_\tau\pi^-\pi^0$ allowing for anomalous weak charged current magnetic and electric dipole moment interactions and determine the effects on the differential and total decay rates. Using recent experimental data we determine the following values for the anomalous magnetic and electric dipole moment parameters, respectively: $\kappa = 0.16 \pm 0.08; and |\tilde\kappa| = 0.88^{+0.25}_{-0.35}.$

The event display and data quality monitoring visualisation systems are especially crucial for commissioning CMS in the imminent CMS physics run at the LHC. They have already proved invaluable for the CMS magnet test and cosmic challenge. We describe how these systems are used to navigate and filter the immense amounts of complex event data from the CMS detector and prepare clear and flexible views of the salient features to the shift crews and offline users. These allow shift staff and experts to navigate from a top-level general view to very specific monitoring elements in real time to help validate data quality and ascertain causes of problems. We describe how events may be accessed in the higher level trigger filter farm, at the CERN Tier-0 centre, and in offsite centres to help ensure good data quality at all points in the data processing workflow. Emphasis has been placed on deployment issues in order to ensure that experts and general users may use the visualization systems at CERN, in remote operations and monitoring centres offsite, and from their own desktops.

We have analysed radiative e + e − → ττ(γ) events using 84 pb −1 of data collected by the L3 experiment during the 1992–1994 LEP runs at the Z resonance. The energy spectrum of the photons is compared to the predictions of QED including additional magnetic and electric dipole terms. No deviations from the standard model are observed so upper limits are set on the magnetic and electric dipole form factors of the tau.

The design, construction and operation of a five-layer silicon microstrip detector is described. The detector consisted of silicon microstrip wafers bonded to the RAL Microplex MX2 readout chip. The readout chip provided amplification with double-correlated sampling for each microstrip channel and multiplexing of 128 signals. The circuitry controlling the chip, the readout electronics, the stage holding the microstrip wafers and their alignment, are also described. A single-layer resolution of 10±0.6 μm was obtained in a test beam. This work is part of a program to design a microvertex detector for UA1 at the CERN pp collider.

CMS has developed approximately one million lines of C++ code and uses many more from HEP, Grid and public domain projects. We describe a suite of tools which help to manage this complexity by measuring software dependencies, quality metrics, and CPU and memory performance. This coherent environment integrates and extends existing open-source tools where possible and provides new in-house components where a suitable solution does not already exist. This is a freely available environment with graphical user interface which can be run on any software without the need to recompile or instrument it. We have developed ignominy which performs software dependency analysis of source code, binary products and external software. CPU profiling is provided based on oprofile, with added features such as profile snapshots, distributed profiling and aggregate profiles for farm systems including server-side tools for collecting profile data. Finally, we have developed a low-overhead performance and memory profiling tool, MemProf, which can perform (gprof-style) hierarchical performance profiling, in a way that works with multiple threads and dynamically loaded libraries (unlike gprof). It also gathers exact memory allocation profiles including which code allocates most, in what sizes of chunks, for how long, where the memory is getting freed and where it is getting leaked. We describe this tool suite and how it has been used to enhance the quality of CMS software.

The L3 plastic scintillating fibre system is used to calibrate the central tracker by providing an external measurement of the track position in the bending plane. We describe the performance of the system during the LEP runs of 1989–1995 on the Z and the results of the calibration using the PSF system.

The CMS Experiment at the LHC has established a network of more than fifty inter-connected "CMS Centres" at CERN and in institutes in the Americas, Asia, Australasia, and Europe. These facilities are used by people doing CMS detector and computing grid operations, remote shifts, data quality monitoring and analysis, as well as education and outreach. We present the computing, software, and collaborative tools and videoconferencing systems. These include permanently running "telepresence" video links (hardware-based H.323, EVO and Vidyo), Webcasts, and generic Web tools such as CMS-TV for broadcasting live monitoring and outreach information. Being Web-based and experiment-independent, these systems could easily be extended to other organizations. We describe the experiences of using CMS Centres Worldwide in the CMS data-taking operations as well as for major media events with several hundred TV channels, radio stations, and many more press journalists simultaneously around the world.

The properties of the W boson are reviewed. Particular emphasis is placed on recent measurements from the LEP2 and Tevatron experiments.

The CMS collaboration is undertaking a big effort to define the analysis model and to develop software tools with the purpose of analysing several millions of simulated and real data events by a large number of people in many geographically distributed sites. From the computing point of view, one of the most complex issues when doing remote analysis is the data discovery and access. Some software tools were developed in order to move data, make them available to the full international community and validate them for the subsequent analysis. The batch analysis processing is performed with workload management tools developed on purpose, which are mainly responsible for the job preparation and the job submission. The job monitoring and the output management are implemented as the last part of the analysis chain. Grid tools provided by the LCG project are evaluated to gain access to the data and the resources by providing a user friendly interface to the physicists submitting the analysis jobs. An overview of the current implementation and of the interactions between the previous components of the CMS analysis system is presented in this work.

LaunchMON is a tool infrastructure that allows a HPC tool to deploy tool daemons into the right remote nodes. It makes use of a target resource manager (RM)'s Automatic Process Acquisition Interface (APAI) to identify the remote nodes and processes of a parallel program, and also exploits the same RM's efficient MPI job launching capability on co-locating daemons with the job. To support a wide range of HPC tools that are inherently distributed software, LaunchMON provides the tool with distributed application programming interface sets: the front end (FE) API, the back end (BE) API and the middleware (MW) API. They each support a tool's front end, back end daemons and middleware communication daemons, respectively. Using those API sets, the tool can launch and initialize their remote daemons scalably.

This paper assesses the feasibility of exploiting commercial satellite television technologies to broadcast video signals and data from major High Energy Physics facilities to collaborating institutes throughout the world.

We present new constraints on the mass $m_{ν_τ}$ of the tau neutrino and its mixing with a fourth generation neutrino. From an analysis of the partial widths of tau lepton decays we obtain the following bounds at the 90% confidence level: $m_{ν_τ} < 32$ MeV and $\sin^2θ< 0.007$, where $θ$ describes the Cabibbo-like mixing of the third and fourth generation neutrinos.

The magnitudes of the CKM matrix elements $V_{td}$, $V_{ts}$, and $V_{tb}$ are determined for the first time without any assumptions of unitarity. The implications for the unitarity of the CKM matrix as a whole are discussed.

We estimate the branching ratios of the weak gauge bosons Z0 and W± into two and three pion final states using vector meson dominance. On the basis of the upper bounds obtained, it is unlikely that any of these decay modes for the weak gauge bosons will be observed with present experiments.

We have derived constraints on the tau neutrino mass and fourth generation mixing from an analysis of the tau lifetime and the partial widths of tau lepton decays : τ→e¯v¯evτ, τ→u¯v¯uvτ, τ → π−ντ, and τ → K−ντ. We present predictions for the tau decay widths, allowing for a non-zero tau neutrino mass, mντ, and for mixing with a neutrino of mass mνL > Mz/2, which is parametrised using a Cabibbo-like mixing angle, θL. By comparison of these theoretical predictions with the experimental measurements, we obtain the following bounds at the 90% confidence level: mντ < 42 MeV and sin2 θL < 0.014

Abstract The ability to visualise the LHC detectors and their response to physics events is of great importance, both in the design, construction, and data analysis phases of the experiments. We discuss the visualisation requirements for the LHC and the current and future visualisation software, emphasising the difficulties faced compared to the LEP era.

We analyse the sensitivities of exclusive one-prong tau branching fractions to: the tau neutrino mass; its mixing with a fourth generation neutrino; the weak charged current magnetic and electric dipole moments of the tau; and the Michel parameter $η$. Quantitative constraints are derived from current experimental data and the future constraints derivable from tau-charm factory measurements are estimated. The anomalous coupling constraints are used to constrain the tau compositeness scale and the allowed parameter space for Higgs doublet models.

We analyse the sensitivities of exclusive one-prong tau branching fractions to: the tau neutrino mass; its mixing with a fourth generation neutrino; the weak charged current magnetic and electric dipole moments of the tau; and the Michel parameter �. Quantitative constraints are derived from current experimental data and the future constraints derivable from tau-charm factory measurements are estimated. The anomalous coupling constraints are used to constrain the tau compositeness scale and the allowed parameter space for Higgs doublet models.

Abstract We use recent experimental measurements of tau branching fractions to determine the weak charged current magnetic and electric dipole moments of the tau and the Michel parameter η with unprecedented precision. These results are then used to constrain the tau compositeness scale and the allowed parameter space for Higgs doublet models. We also present new constraints on the mass of the tau neutrino and its mixing with a fourth generation neutrino.

The properties of the W boson are reviewed. Particular emphasis is placed on recent measurements from the LEP2 and Tevatron experiments.

We have derived constraints on the tau neutrino mass and fourth generation mixing from an analysis of the partial widths of tau lepton decays, in particular: tau -&gt; e nu nu_tau, tau -&gt; mu nu nu_tau, tau -&gt; pi nu_tau, tau -&gt; K nu_tau. We present predictions for the tau decay widths, allowing for a non-zero tau neutrino mass, m(nu_tau), and for mixing with a neutrino of mass m(nu_L) &gt; M_Z/2, which is parametrised using a Cabibbo-like mixing angle, theta_L. By comparison of these theoretical predictions with the experimental measurements, we obtain the following bounds at the 90% confidence level: m(nu_tau) &lt; 42 MeV and sin^2(theta_L) &lt; 0.014.

Experiments being planned by the Neutral Beam Technology Group of the Accelerator Technology Division will require the tracking of a monochromatic light source in space. Some general optical tracking problems are analyzed with an eye toward their application in the proposed Beam Experiments Aboard Rockets (BEAR) Program. This paper reports on a demonstration project intended as an initial step in fulfilling this requirement.