Isolating CP-violating \gamma ZZ coupling in e+e- \to \gamma Z with transverse beam polarizations

We revisit the process $e^+e^- \to \gamma Z$ at the ILC with transverse beam polarization in the presence of anomalous CP-violating $\gamma Z Z$ coupling $\lambda_1$ and $\gamma \gamma Z$ coupling $\lambda_2$. We point out that if the final-state spins are resolved, then it becomes possible to fingerprint the anomalous coupling {\rm Re}$\lambda_1$.90% confidence level limit on {\rm Re}$\lambda_1$ achievable at ILC with center-of-mass energy of 500 GeV or 800 GeV with realistic initial beam polarization and integrated luminosity is of the order of few times of $10^{-2}$ when the helicity of $Z$ is used and $10^{-3}$ when the helicity of $\gamma$ is used. The resulting corrections at quadratic order to the cross section and its influence on these limits are also evaluated and are shown to be small. The benefits of such polarization programmes at the ILC are compared and contrasted for the process at hand. We also discuss possible methods by which one can isolate events with a definite helicity for one of the final-state particles.Comment: 13 pages, 9 figures, using RevTex; v2 is a significantly revised version of v1, and corresponds to the version that has been published in Physical Review

Radiative processes in external gravitational fields

Kinematically forbidden processes may be allowed in the presence of external gravitational fields. These ca be taken into account by introducing generalized particle momenta. The corresponding transition probabilities can then be calculated to all orders in the metric deviation from the field-free expressions by simply replacing the particle momenta with their generalized counterparts. The procedure applies to particles of any spin and to any gravitational fields. transition probabilities, emission power, and spectra are, to leading order, linear in the metric deviation. It is also shown how a small dissipation term in the particle wave equations can trigger a strong backreaction that introduces resonances in the radiative process and deeply affects the resulting gravitational background.Comment: 5 pages, 1 figur

Needle stick injuries among dental students: risk factors and recommendations for prevention

Aim: To evaluate the risk factors of needle stick injuries (NSIs) sustained by undergraduate dental students and nurse students at the King’s College London (KCL) Dental Institute.Materials and methods: A retrospective study evaluated the incident reports relating to NSIs reported over a period of 2 years. Factors including the dental department, study year, and when the injury took place during administration of local anaesthesia (LA) and recapping conventional syringe or clearing work surface or during disposal.Results: This report showed that students are at the highest risk of NSIs at the fourth year of their 5-year BDS course. About one-third of injuries were reported among this group of students followed by year 5 students (25%). Oral surgery clinics were the major source of incident reporting when compared with other specialised dental clinics within the institute. The left hands of the students were the most frequently affected by such injuries and then the right hands of student dental nurses. The attempt of needle recapping of conventional syringes was the least reported mechanism of injuries and constituted only 15% of the total injuries and mainly occurred in third year students. The most frequent injuries among student nurses were during disposal of the needle.Conclusion: Less NSIs occur when using safety syringes. A non-recapping policy with immediate disposal of either the conventional or safety syringe systems after injection would prevent all clearance-related NSIs sustained by nurses. To avoid NSIs, education plays a vital role particularly with effective implementation of the change to safety syringes with appropriate training.Keywords: needle stick injuries; local anaesthetic syringes; safety syringes; dental students; occupational hazards; dental anaesthetic syringe

Fitting Precision Electroweak Data with Exotic Heavy Quarks

The 1999 precision electroweak data from LEP and SLC persist in showing some slight discrepancies from the assumed standard model, mostly regarding $b$ and $c$ quarks. We show how their mixing with exotic heavy quarks could result in a more consistent fit of all the data, including two unconventional interpretations of the top quark.Comment: 7 pages, no figure, 2 typos corrected, 1 reference update

Solutions to the R_b, R_c and alpha_s puzzles by Vector Fermions

We propose two minimal extensions of Standard Model, both of which can easily accommodate the recent puzzling observations about the excess in $R_b$, the deficit in $R_c$ and the discrepancy in the low energy and high energy determinations of $\alpha_{s}$. Each model requires three additional heavy vectorial fermions in order to resolve the puzzles. The current phenomenological constraints and the new potential phenomena are also discussed.Comment: 12 pages, in LaTeX, postscript file also appear http://www.uic.edu/~keung/pub/rbrc.p

Neutrino Masses and Leptogenesis with Heavy Higgs Triplets

A simple and economical extension of the minimal standard electroweak gauge model (without right-handed neutrinos) by the addition of two heavy Higgs scalar triplets would have two significant advantages. \underline {Naturally} small Majorana neutrino masses would become possible, as well as leptogenesis in the early universe which gets converted at the electroweak phase transition into the present observed baryon asymmetry.Comment: 12 pages including one figur

Calibration of centre-of-mass energies at LEP 2 for a precise measurement of the W boson mass

The determination of the centre-of-mass energies for all LEP 2 running is presented. Accurate knowledge of these energies is of primary importance to set the absolute energy scale for the measurement of the W boson mass. The beam energy between 80 and 104 GeV is derived from continuous measurements of the magnetic bending field by 16 NMR probes situated in a number of the LEP dipoles. The relationship between the fields measured by the probes and the beam energy is defined in the NMR model, which is calibrated against precise measurements of the average beam energy between 41 and 61 GeV made using the resonant depolarisation technique. The validity of the NMR model is verified by three independent methods: the flux-loop, which is sensitive to the bending field of all the dipoles of LEP; the spectrometer, which determines the energy through measurements of the deflection of the beam in a magnet of known integrated field; and an analysis of the variation of the synchrotron tune with the total RF voltage. To obtain the centre-of-mass energies, corrections are then applied to account for sources of bending field external to the dipoles, and variations in the local beam energy at each interaction point. The relative error on the centre-of-mass energy determination for the majority of LEP 2 running is 1.2 x 10^{-4}, which is sufficiently precise so as not to introduce a dominant uncertainty on the W mass measurement.Comment: 79 pages, 45 figures, submitted to EPJ

Shine 2014 Final Report: Social Prescribing: integrating GP and Community Assets for Health

Commissioned by City and Hackney Clinical Commissioning Group, in partnership with the University of East London and Queen Mary University of London

Precision Electroweak Tests of the Standard Model

The present status of precision electroweak data is reviewed. These data include measurements of e+e- -> f+fbar, taken at the Z resonance at LEP, which are used to determine the mass and width of the Z boson. In addition, measurements have also been made of the forward-backward asymmetries for leptons and heavy quarks, and also the final state polarisation of the tau-lepton. At SLAC, where the electron beam was polarised, measurements were made of the left-right polarised asymmetry, A_LR, and the left-right forward-backward asymmetries for b and c quarks. The mass, MW, and width, GW, of the W boson have been measured at the Tevatron and at LEP, and the mass of the top quark, Mt, has been measured at the Tevatron. These data, plus other electroweak data, are used in global electroweak fits in which various Standard Model parameters are determined. A comparison is made between the results of the direct measurements of MW and Mt with the indirect results coming from electroweak radiative corrections. Using all precision electroweak data fits are also made to determine limits on the mass of the Higgs boson. The influence on these limits of specific measurements, particularly those which are somewhat inconsistent with the Standard Model, is explored. The data are also analysed in terms of the quasi model-independent epsilon variables. Finally, the impact on the electroweak fits of the improvements in the determination of the W-boson and top-quark masses, expected from the Tevatron Run 2, is examined.Comment: 80 pages, 36 Figures, Late

Stiffest Elastic Networks

The rigidity of a network of elastic beams crucially depends on the specific details of its structure. We show both numerically and theoretically that there is a class of isotropic networks which are stiffer than any other isotropic network with same density. The elastic moduli of these \textit{stiffest elastic networks} are explicitly given. They constitute upper-bounds which compete or improve the well-known Hashin-Shtrikman bounds. We provide a convenient set of criteria (necessary and sufficient conditions) to identify these networks, and show that their displacement field under uniform loading conditions is affine down to the microscopic scale. Finally, examples of such networks with periodic arrangement are presented, in both two and three dimensions