5,713 research outputs found

    Light, long-lived and secluded: can gluinos be driven out from LEP1 data ?

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    We briefly report about a possible settlement of the still ongoing dispute concerning the existence of SUSY signals in 4jet events at LEP1. We base our arguments on a simple selection strategy exploiting secondary vertex tagging and kinematical constraints, which could allow one to access or exclude gluino events for a broad range of masses and lifetimes.Comment: 10 pages, LaTeX, 3 PostScript figures embedded with epsfig. Complete ps paper and figures available also at ftp://ftae3.ugr.es/pub/rmt/ugrft70.p

    Possible manifestation of heavy stable colored particles in cosmology and cosmic rays

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    We discuss the cosmological implications as well as possible observability of massive, stable, colored particles which often appear in the discussion of physics beyond the standard model. We argue that if their masses are more than a few hundred GeV and if they saturate the halo density and/or occur with closure density of the universe, they are ruled out by the present WIMP search experiments as well as the searches for anomalous heavy isotopes of ordinary nuclei. We then comment on the possibility that these particles as well as the monopoles could be responsible for the ultra high energy cosmic rays with energy ≄1020\geq 10^{20} eV and point out that their low inelasticity argues against this.Comment: 9 pages; UMD-PP-98-1

    Hamara Healthy Living Centre - an evaluation

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    Hamara is a Healthy Living Centre which aims to improve health and well-being through providing a range of culturally appropriate activities and services. Hamara has a vision of 'bringing communities together' and since it was established in 2004, the Centre has provided a valuable community resource in South Leeds. Partnership work between Hamara and Leeds Met goes back to 2002. In 2007, the Centre for Health Promotion Research carried out an evaluation of Hamara in partnership with Hamara staff and Leeds Met Community Partnerships and Volunteering. This was followed by a highly successful community cohesion conference 'One Community' which was held at Hamara on 10th October 2008, and was supported through a Leeds Met public engagement grant. The event attracted over a hundred people from diverse communities and organisations across Leeds. A packed audience heard Hilary Benn, local MP and Patron of Hamara, talk about the importance of working in collaboration around community cohesion. Jane South, Centre for Health Promotion Research, presented the main evaluation results and set out the some challenges for the future. The proceedings concluded with the presentation of awards to a number of for local community champions who work to bring people together and make a real difference in the city of Leeds

    Phenomenology of light gauginos; 1, motivation, masses, lifetimes and limits

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    I explore an economical variant on supersymmetric standard models which may be indicated on cosmological grounds and is shown to have no SUSY-CP problem. Demanding radiative electroweak symmetry breaking suggests that the Higgs is light; other scalar masses may be ~ 100-200 GeV or less. In this case the gluino and photino, while massless at tree level, have 1-loop masses m(gluino) ~ 100 - 600 MeV and m(photino) ~ 100 - 1000 MeV. New hadrons with mass ~ 1 - 3 GeV are predicted and their lifetimes estimated. Existing experimental limits are discussed

    Where do "red and dead" early-type void galaxies come from?

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    Void regions of the Universe offer a special environment for studying cosmology and galaxy formation, which may expose weaknesses in our understanding of these phenomena. Although galaxies in voids are observed to be predominately gas rich, star forming and blue, a sub-population of bright red void galaxies can also be found, whose star formation was shut down long ago. Are the same processes that quench star formation in denser regions of the Universe also at work in voids? We compare the luminosity function of void galaxies in the 2dF Galaxy Redshift Survey, to those from a galaxy formation model built on the Millennium Simulation. We show that a global star formation suppression mechanism in the form of low luminosity "radio mode" AGN heating is sufficient to reproduce the observed population of void early-types. Radio mode heating is environment independent other than its dependence on dark matter halo mass, where, above a critical mass threshold of approximately M_vir~10^12.5 M_sun, gas cooling onto the galaxy is suppressed and star formation subsequently fades. In the Millennium Simulation, the void halo mass function is shifted with respect to denser environments, but still maintains a high mass tail above this critical threshold. In such void halos, radio mode heating remains efficient and red galaxies are found; collectively these galaxies match the observed space density without any modification to the model. Consequently, galaxies living in vastly different large-scale environments but hosted by halos of similar mass are predicted to have similar properties, consistent with observations.Comment: 6 pages, 3 figures, accepted MNRA
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