671 research outputs found

    Goldstini Can Give the Higgs a Boost

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    Supersymmetric collider phenomenology depends crucially on whether the lightest observable-sector supersymmetric particle (LOSP) decays, and if so, what the LOSP decay products are. For instance, in SUSY models where the gravitino is lighter than the LOSP, the LOSP decays to its superpartner and a longitudinal gravitino via supercurrent couplings. In this paper, we show that LOSP decays can be substantially modified when there are multiple sectors that break supersymmetry, where in addition to the gravitino there are light uneaten goldstini. As a particularly striking example, a bino-like LOSP can have a near 100% branching fraction to a higgs boson and an uneaten goldstino, even if the LOSP has negligible higgsino fraction. This occurs because the uneaten goldstino is unconstrained by the supercurrent, allowing additional operators to mediate LOSP decay. These operators can be enhanced in the presence of an R symmetry, leading to copious boosted higgs production in SUSY cascade decays.Comment: 30 pages, 12 figures; v2: title change, clarifications added, version to appear in JHE

    Readability estimates for commonly used health-related quality of life surveys

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    To estimate readability of seven commonly used health-related quality of life instruments: SF-36, HUI, EQ-5D, QWB-SA, HALex, Minnesota Living with Heart Failure Questionnaire (MLHFQ), and the NEI-VFQ-25. The Flesch–Kincaid (F–K) and Flesch Reading Ease (FRE) formulae were used to estimate readability for every item in each measure. The percentage of items that require more than 5 years of formal schooling according to F–K was 50 for the EQ-5D, 53 for the SF-36, 80 for the VFQ-25, 85 for the QWB-SA, 100 for the HUI, HALex, and the MLHFQ. The percentage of items deemed harder than “easy” according to FRE was 50 for the SF-36, 67 for the EQ-5D, 79 for the QWB-SA, 80 for the VFQ-25, 100 for the HUI, HALex, and the MLHFQ. All seven surveys have a substantial number of items with high readability levels that may not be appropriate for the general population

    Four Generations: SUSY and SUSY Breaking

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    We revisit four generations within the context of supersymmetry. We compute the perturbativity limits for the fourth generation Yukawa couplings and show that if the masses of the fourth generation lie within reasonable limits of their present experimental lower bounds, it is possible to have perturbativity only up to scales around 1000 TeV. Such low scales are ideally suited to incorporate gauge mediated supersymmetry breaking, where the mediation scale can be as low as 10-20 TeV. The minimal messenger model, however, is highly constrained. While lack of electroweak symmetry breaking rules out a large part of the parameter space, a small region exists, where the fourth generation stau is tachyonic. General gauge mediation with its broader set of boundary conditions is better suited to accommodate the fourth generation.Comment: 27 pages, 5 figure

    A Stealth Supersymmetry Sampler

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    The LHC has strongly constrained models of supersymmetry with traditional missing energy signatures. We present a variety of models that realize the concept of Stealth Supersymmetry, i.e. models with R-parity in which one or more nearly-supersymmetric particles (a "stealth sector") lead to collider signatures with only a small amount of missing energy. The simplest realization involves low-scale supersymmetry breaking, with an R-odd particle decaying to its superpartner and a soft gravitino. We clarify the stealth mechanism and its differences from compressed supersymmetry and explain the requirements for stealth models with high-scale supersymmetry breaking, in which the soft invisible particle is not a gravitino. We also discuss new and distinctive classes of stealth models that couple through a baryon portal or Z' gauge interactions. Finally, we present updated limits on stealth supersymmetry in light of current LHC searches.Comment: 45 pages, 16 figure

    The Cosmology of Composite Inelastic Dark Matter

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    Composite dark matter is a natural setting for implementing inelastic dark matter - the O(100 keV) mass splitting arises from spin-spin interactions of constituent fermions. In models where the constituents are charged under an axial U(1) gauge symmetry that also couples to the Standard Model quarks, dark matter scatters inelastically off Standard Model nuclei and can explain the DAMA/LIBRA annual modulation signal. This article describes the early Universe cosmology of a minimal implementation of a composite inelastic dark matter model where the dark matter is a meson composed of a light and a heavy quark. The synthesis of the constituent quarks into dark mesons and baryons results in several qualitatively different configurations of the resulting dark matter hadrons depending on the relative mass scales in the system.Comment: 31 pages, 4 figures; references added, typos correcte

    Detection of Prion Infectivity in Fat Tissues of Scrapie-Infected Mice

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    Distribution of prion infectivity in organs and tissues is important in understanding prion disease pathogenesis and designing strategies to prevent prion infection in animals and humans. Transmission of prion disease from cattle to humans resulted in banning human consumption of ruminant nervous system and certain other tissues. In the present study, we surveyed tissue distribution of prion infectivity in mice with prion disease. We show for the first time detection of infectivity in white and brown fat. Since high amounts of ruminant fat are consumed by humans and also incorporated into animal feed, fat-containing tissues may pose a previously unappreciated hazard for spread of prion infection

    Republicanism and the political economy of democracy

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    Europe is experiencing rapidly accelerating poverty and social exclusion, following half a decade of financial crisis and austerity politics. The key problem behind Europe's malaise, in our view, is the economic disenfranchisement of large parts of its population in the winner-takes-all-society. This article proposes that we examine the contribution of republican political theory as a distinctive approach that provides us with the conceptual and normative resources to reclaim what we call the political economy of democracy, the constellation of political and economic institutions aimed at promoting broad economic sovereignty and individuals' capacities to govern their own lives. This article identifies three key ideas that together constitute a distinctively republican approach to political economy: (1) establish an economic floor; (2) impose an economic ceiling to counter excess economic inequality; and (3) democratize the governance and regulation of the main economic institutions

    How a Diverse Research Ecosystem Has Generated New Rehabilitation Technologies: Review of NIDILRR’s Rehabilitation Engineering Research Centers

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    Over 50 million United States citizens (1 in 6 people in the US) have a developmental, acquired, or degenerative disability. The average US citizen can expect to live 20% of his or her life with a disability. Rehabilitation technologies play a major role in improving the quality of life for people with a disability, yet widespread and highly challenging needs remain. Within the US, a major effort aimed at the creation and evaluation of rehabilitation technology has been the Rehabilitation Engineering Research Centers (RERCs) sponsored by the National Institute on Disability, Independent Living, and Rehabilitation Research. As envisioned at their conception by a panel of the National Academy of Science in 1970, these centers were intended to take a “total approach to rehabilitation”, combining medicine, engineering, and related science, to improve the quality of life of individuals with a disability. Here, we review the scope, achievements, and ongoing projects of an unbiased sample of 19 currently active or recently terminated RERCs. Specifically, for each center, we briefly explain the needs it targets, summarize key historical advances, identify emerging innovations, and consider future directions. Our assessment from this review is that the RERC program indeed involves a multidisciplinary approach, with 36 professional fields involved, although 70% of research and development staff are in engineering fields, 23% in clinical fields, and only 7% in basic science fields; significantly, 11% of the professional staff have a disability related to their research. We observe that the RERC program has substantially diversified the scope of its work since the 1970’s, addressing more types of disabilities using more technologies, and, in particular, often now focusing on information technologies. RERC work also now often views users as integrated into an interdependent society through technologies that both people with and without disabilities co-use (such as the internet, wireless communication, and architecture). In addition, RERC research has evolved to view users as able at improving outcomes through learning, exercise, and plasticity (rather than being static), which can be optimally timed. We provide examples of rehabilitation technology innovation produced by the RERCs that illustrate this increasingly diversifying scope and evolving perspective. We conclude by discussing growth opportunities and possible future directions of the RERC program
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