Electroweak Fits and Constraints on the Higgs Mass

The current status of the quantities entering into the global electroweak fits is reviewed, highlighting changes since Summer 2003. These data include the precision electroweak properties of the Z and W bosons, the top-quark mass and the value of the electromagnetic coupling constant, at the scale of the Z boson mass. Using these Z and W (high Q^2) data, the value of the Higss mass is extracted, within the context of the Standard Model (SM). The consistency of the data, and the overall agreement with the SM, are discussed.Comment: 8 pages, 5 postscript figure

Are there anomalous Z fermion couplings ?

The couplings of the fermions to the Z boson are of great importance in establishing the validity of the Standard Model and in looking for physics beyond it. The couplings of the b-quark to the Z boson have been the subject of much experimental study and theoretical interpretation. The apparent excess in the value of \Rbbz, the ratio of the partial width of the Z boson to \bbbar to its total hadronic width, above the Standard Model expectation reported a few years ago has now become much less significant. However, the measurements of the pole forward-backward asymmetry \Afbzb for b-quarks at the Z pole and of the {\it polarisation parameter} \Ab, obtained using a polarised electron beam, have improved considerably in accuracy. The latest data are examined and values of the vector and axial-vector b-quark and c-quark couplings to the Z are extracted. The left and right handed couplings are also extracted. It is found that whereas the c-quark couplings are compatible with the Standard Model, those of the b-quark data are only compatible with the Standard Model at about the 1% level. In addition, the individual lepton couplings are extracted and the hypothesis of {\it lepton universality} is examined. The sensitivity of the limits from electroweak fits to the Higgs boson mass to these data is examined.Comment: 16 pages, 6 figures. Figure captions correcte

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

Practicalities of HCR-20 implementation within secure psychiatric services

The HCR-20 is established as the de-facto tool for the assessment of violence risk within forensic psychiatric services. Although much has been written about the value of the tool, less has been written about the practicalities of achieving meaningful completion of HCR-20 assessments at a service level. The present paper seeks to review recommendations within the literature and also those based upon the authors’ own experiences in HCR-20 implementation, reviewing a number of the common issues and barriers encountered within the development of a strategic, service-level, approach to completion of the HCR-20. Possible solutions to these problems are also considered. We conclude that although there is not necessarily a single approach that is right for every service, certain principles need to be followed to ensure high quality assessments. Further, we develop a number of ‘good practice points’ which will be useful for services considering this issue on a strategic level, as well as commissioners evaluating the quality of HCR-20 completion within services

Precise bounds on the Higgs boson mass

We study the renormalization group evolution of the Higgs quartic coupling $\lambda_{H}$ and the Higgs mass $m_{H}$ in the Standard Model. The one loop equation for $\lambda_{H}$ is non linear and it is of the Riccati type which we numerically and analytically solve in the energy range $[m_{t},E_{GU}]$ where $m_{t}$ is the mass of the top quark and $E_{GU}=10^{14}$ GeV. We find that depending on the value of $\lambda_{H}(m_{t})$ the solution for $\lambda_{H}(E)$ may have singularities or zeros and become negative in the former energy range so the ultra violet cut off of the standard model should be below the energy where the zero or singularity of $\lambda_{H}$ occurs. We find that for $0.369\leq\lambda_{H}(m_{t})\leq0.613$ the Standard Model is valid in the whole range $[m_{t},E_{GU}]$. We consider two cases of the Higgs mass relation to the parameters of the standard model: (a) the effective potential method and (b) the tree level mass relations. The limits for $\lambda_{H}(m_{t})$ correspond to the following Higgs mass relation $150\leq m_{H}\lessapprox 193$ GeV. We also plot the dependence of the ultra violet cut off on the value of the Higgs mass. We analyze the evolution of the vacuum expectation value of the Higgs field and show that it depends on the value of the Higgs mass. The pattern of the energy behavior of the VEV is different for the cases (a) and (b). The behavior of $\lambda_{H}(E)$, $m_{H}(E)$ and $v(E)$ indicates the existence of a phase transition in the standard model. For the effective potential this phase transition occurs at the mass range $m_{H}\approx 180$ GeV and for the tree level mass relations at $m_{H}\approx 168$ GeV.Comment: 14 pages, 7 figures. Expanded the discussion of the Higgs mass relation between the parameters of the Standard Model. Included the method of the Higgs effective potentia

Intraligamentary local anaesthesia for posterior mandibular extractions

This article reviews research and author experience behind Intraligamentary Local Anaesthesia (ILA) and Infiltration Local Anaesthesia (IFA) with Inferior Alveolar Nerve Block (IANB). In particular, the use of ILA with 4% articaine is discussed as an effective anaesthetic technique to replace both IANB and IFA for the purpose of tooth extraction in the posterior mandible. ILA also avoids the possible complications associated with IANB. Other advantages and some shortfalls of the ILA technique are described in relation to primary dental care. The technique for achieving ILA is described. CPD/Clinical Relevance: The ILA technique with articaine is a simple, swift and effective alternative to IANB and IFA for extraction of posterior teeth in the mandible in primary dental care. ILA has fewer potential debilitating complications than IANB and is likely to be more effective than IFA

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