Unification of SU(2)xU(1) Using a Generalized Covariant Derivative and U(3)

A generalization of the Yang-Mills covariant derivative, that uses both vector and scalar fields and transforms as a 4-vector contracted with Dirac matrices, is used to simplify and unify the Glashow-Weinberg-Salam model. Since SU(3) assigns the wrong hypercharge to the Higgs boson, it is necessary to use a special representation of U(3) to obtain all the correct quantum numbers. A surplus gauge scalar boson emerges in the process, but it uncouples from all other particles.Comment: 12 pages, no figures. To be published in Int. J. Mod. Phys.

Intrinsic Charm Contribution to Double Quarkonium Hadroproduction

Double $J/\psi$ production has been observed by the NA3 collaboration in $\pi N$ and $p N$ collisions with a cross section of the order of 20-30 pb. The $\psi \psi$ pairs measured in $\pi^-$ nucleus interactions at 150 and 280 GeV$/c$ are observed to carry an anomalously large fraction of the projectile momentum in the laboratory frame, $x_{\psi \psi} \geq 0.6$ at 150 GeV$/c$ and $\geq 0.4$ at 280 GeV$/c$. We postulate that these forward $\psi \psi$ pairs are created by the materialization of Fock states in the projectile containing two pairs of intrinsic $c \overline c$ quarks. We calculate the overlap of the charmonium states with the $|\overline u d c \overline c c \overline c \rangle$ Fock state as described by the intrinsic charm model and find that the $\pi^- N \rightarrow \psi \psi$ longitudinal momentum and invariant mass distributions are both well reproduced. We also discuss double $J/\psi$ production in $pN$ interactions and the implications for other heavy quarkonium production channels in QCD.Comment: Revtex, APS style, 7 pages, 3 figures in uuencoded fil

QCD Mechanisms for Double Quarkonium and Open Heavy Meson Hadroproduction

Double $J/\psi$ production on the order of 20-30 pb has been observed by the NA3 collaboration. These $\psi \psi$ pairs, measured in $\pi^- N$ interactions at 150 and 280 GeV$/c$ and in $pN$ interactions at 400 GeV$/c$, carry a large fraction of the projectile momentum, $x_{\psi \psi} \geq 0.6$ for the 150 GeV$/c$ beam and $\geq 0.4$ at 280 GeV$/c$. We examine several sources of $\psi \psi$ pair production within QCD, including ${\cal O}(\alpha_s^4)$ $\psi \psi$ production, leading-twist $b \overline b$ production and decay, and the materialization of heavy-quark Fock states in the projectile. We estimate the production cross section and the single and double $J/\psi$ momentum and mass distributions for each, comparing the results with the NA3 data, and predict $\psi \psi$ production in $pN$ interactions at 800 GeV$/c$, accessible to current fixed-target experiments. We also discuss the observable implications of open heavy meson pair production from the intrinsic heavy quark Fock states.Comment: Revtex, APS style, 16 pages, 15 figures available as uuencoded postscript files (or ps files) from the Autho

Signals for Double Parton Scattering at the Fermilab Tevatron

Four double-parton scattering processes are examined at the Fermilab Tevatron energy. With optimized kinematical cuts and realistic parton level simulation for both signals and backgrounds, we find large samples of four-jet and three-jet+one-photon events with signal to background ratio being 20\%-30\%, and much cleaner signals from two-jet+two-photon and two-jet+$e^+e^-$ final states. The last channel may provide the first unambiguous observation of multiple parton interactions, even with the existing data sample accumulated by the Tevatron collider experiments.Comment: 7 pages, plain LaTeX, 2 tables, no figures. A compressed PS file is available by anonymous ftp at ftp://phenom.physics.wisc.edu/pub/preprints/1996/madph-96-945.ps.

Formality and informality in the summative assessment of motor vehicle apprentices: a case study

This article explores the interaction of formal and informal attributes of competence‐based assessment. Specifically, it presents evidence from a small qualitative case study of summative assessment practices for competence‐based qualifications within apprenticeships in the motor industry in England. The data are analysed through applying an adaptation of a framework for exploring the interplay of formality and informality in learning. This analysis reveals informal mentoring as a significant element which influences not only the process of assessment, but also its outcomes. We offer different possible interpretations of the data and their analysis, and conclude that, whichever interpretation is adopted, there appears to be a need for greater capacity‐building for assessors at a local level. This could acknowledge a more holistic role for assessors; recognise the importance of assessors’ informal practices in the formal retention and achievement of apprentices; and enhance awareness of inequalities that may be reinforced by both informal and formal attributes of assessment practices

Heterogeneity in reporting on urinary outcome and cure after surgical interventions for stress urinary incontinence in adult neuro-urological patients: A systematic review

Aims: To describe all outcome parameters and definitions of cure used to report on outcome of surgical interventions for stress urinary incontinence (SUI) in neuro-urological (NU) patients. Methods: This systematic review was performed and reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. The study protocol was registered and published (CRD42016033303; http://www.crd.york.ac.uk/PROSPERO). Medline, Embase, Cochrane controlled trials databases, and clinicaltrial.gov were systematically searched for relevant publications until February 2017. Result