874 research outputs found

    {\Large{\bf Higgs or Neutral Vector Boson Production with a WW Pair in {\LARGE γγ\gamma \gamma} Collisions}}

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    Exploiting the fact that WW pair production in high-energy γγ\gamma \gamma collisions is very large, we use this process to trigger Higgs, ZZ or photon radiation. We find that there are sizeable rising cross-sections for triple bosons production. At energies about 1TeV1TeV the new mechanism for Higgs production becomes very competitive with the dominant Higgs production processes in e+e−e^+e^- and eγe \gamma reactions. The effect of different polarized photon spectra obtained through back-scattered laser light on the electron beam of a linear collider is investigated . We give a special attention to the search of the intermediate mass Higgs in WWHWWH production and discuss how to effectively suppress the backgrounds.Comment: ENSLAPP-A-430/93, 14 pages, plus 6 figures available through mail or fax upon reques

    New Physics with three-photon events at LEP

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    The effect of the most general \z3gt vertex in the reaction e^+e^- \ra 3\gamma is studied with a particular attention to LEP searches. We give exact analytical expressions including realistic cuts for the signal and present a detailed analysis based on a Monte Carlo that includes the effect of the irreducible 3γ3\gamma QED cross section. As special applications we discuss the effect of heavy scalars, fermions and gauge bosons and comment on the ``monopole" connection.Comment: No changes made from previous version, 34 pages, LateX, uses epsf, 11 .eps figs., full paper (including figs) is also available via WWW at http://lapphp0.in2p3.fr/preplapp/psth/lastee3g.ps.gz or via anonymous ftp at ftp:///lapphp0.in2p3.fr/pub/preprints-theorie/ftpee3g.u

    Minimal Ten-parameter Hermitian Texture Zeroes Mass Matrices and the CKM Matrix

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    Hermitian mass matrices for the up and down quarks with texture zeroes but with the minimum number of parameters, ten, are investigated. We show how these {\em minimum parameter} forms can be obtained from a general set of hermitian matrices through weak basis transformations. For the most simple forms we show that one can derive exact and compact parametrizations of the CKM mixing matrix in terms of the elements of these mass matrices (and the quark masses).Comment: 14 pages.Talk given by M.B. at the MRST 98, ``Towards the Theory of Everything", Montr\'eal, 13-15 May 199

    Semi-leptonic four-fermion final states in polarised \gamma\gamma reactions: Exact results vs an improved narrow width approximation

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    We calculate the process γγ→e−νˉeudˉ\gamma \gamma \rightarrow e^- \bar{\nu}_e u \bar{d} with the full set of Feynman diagrams. We consider different implementations of the WW width and different combinations of the photon polarisations. The results of an improved narrow width approximation based on γγ→W+W−\gamma \gamma \rightarrow W^+ W^- with full spin-correlations that takes into account different angular cuts as well as cuts on the invariant masses are compared to those of the complete calculation.Comment: paper in LATEX, 19 pages, 3 figures. Complete psfile available via anonymous ftp at ftp://lapphp0.in2p3.fr/pub/preprints-theorie/enslapp635.uu or at http://lapphp0.in2p3.fr/preplapp/psth/enslapp635.ps.g

    Lowland tundra plant stoichiometry is somewhat resilient decades following fire despite substantial and sustained shifts in community structure

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    The Arctic is experiencing the greatest increase in average surface temperature globally, which is projected to amplify wildfire frequency and severity. Wildfire alters the biogeochemical characteristics of arctic ecosystems. However, the extent of these changes over time-particularly with regard to plant stoichiometries relative to community structure-is not well documented. Four years after the Yukon-Kuskokwim Delta, Alaska, experienced its largest fire season, aboveground plant and lichen biomass was harvested across a gradient of burn history: unburned ("reference"), 2015 burn ("recent burn"), and 1972 burn ("historic burn") to assess the resilience of tundra plant communities to fire disturbance. Fire reduced aboveground biomass in the recent burn; early recovery was characterized by evergreen shrub and graminoid dominance. In the historic burn, aboveground biomass approached reference conditions despite a sustained reduction of lichen biomass. Although total plant and lichen carbon (C) and nitrogen (N) were reduced immediately following fire, N stocks recovered to a greater degree-reducing community-level C:N. Notably, at the species level, N enrichment was observed only in the recent burn. Yet, community restructuring persisted for decades following fire, reflecting a sustained reduction in N-poor lichens relative to more N-rich vascular plant species

    Quartic Anomalous Couplings in γγ\gamma\gamma Colliders

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    We study the constraints on the vertices W+W−ZγW^+W^- Z\gamma, W+W−γγW^+W^-\gamma\gamma, and ZZγγZZ\gamma\gamma that can be obtained from triple-gauge-boson production at the next generation of linear e+e−e^+e^- colliders operating in the γγ\gamma\gamma mode. We analyze the processes γγ→W+W−V\gamma\gamma \to W^+W^-V (V=ZV=Z, or γ\gamma) and show that these reactions increase the potential of e+e−e^+e^- machines to search for anomalous four-gauge-boson interactions.Comment: 15 pages, Latex file using ReVteX, 4 uufiled figures include

    Contribution of Scalar Loops to the Three-Photon Decay of the Z

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    I corrected 3 mistakes from the first version: that were an omitted Feynman integration in the function f^3_{ij}, a factor of 2 in front of log f^3_{ij} in eq.2 and an overall factor of 2 in Fig.1 c). The final result is changed drastically. Doing an expansion in the Higgs mass I show that the matrix element is identically 0 in the order (MZ/MH)^2, which is due to gauge invariance. Left with an amplitude of the order (MZ/MH)^4 the final result is that the scalar contribution to this decay rate is several orders of magnitude smaller than those of the W boson and fermions.Comment: 6 pages, plain Tex, 1 figure available under request via fax or mail, OCIP/C-93-5, UQAM-PHE-93/0

    Did female prisoners with mental disorders receive psychiatric treatment before imprisonment?

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    © 2015 Mundt et al.; licensee BioMed Central. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.BackgroundThroughout the world, high prevalence rates of mental disorders have been found in prison populations, especially in females. It has been suggested that these populations do not access psychiatric treatment. The aim of this study was to establish rates of psychiatric in- and outpatient treatments prior to imprisonment in female prisoners and to explore reasons for discontinuation of such treatments.Methods150 consecutively admitted female prisoners were interviewed in Berlin, Germany. Socio-demographic characteristics, mental disorders, and previous psychiatric in- and outpatient treatments were assessed by trained researchers. Open questions were used to explore reasons for ending previous psychiatric treatment.ResultsA vast majority of 99 prisoners (66%; 95% CI: 58¿73) of the total sample reported that they had previously been in psychiatric treatment, 80 (53%; 95 CI: 45¿61) in inpatient treatment, 62 (41%; 95 CI: 34¿49) in outpatient treatment and 42 (29%; 21¿39) in both in- and outpatient treatments. All prisoners with psychosis and 72% of the ones with any lifetime mental health disorder had been in previous treatment. The number of inpatient treatments and imprisonments were positively correlated (rho¿=¿0.27; p¿<¿0.01). Inpatient treatment was described as successfully completed by 56% (N¿=¿41) of those having given reasons for ending such treatment, whilst various reasons were reported for prematurely ending outpatient treatments.ConclusionThe data do not support the notion of a general `mental health treatment gap¿ in female prisoners. Although inpatient care is often successfully completed, repeated inpatient treatments are not linked with fewer imprisonments. Improved transition from inpatient to outpatient treatment and services that engage female prisoners to sustained outpatient treatments are needed
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