913 research outputs found

    Proposal for Higgs and Superpartner Searches at the LHCb Experiment

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    The spectrum of supersymmetric theories with R-parity violation are much more weakly constrained than that of supersymmetric theories with a stable neutralino. We investigate the signatures of supersymmetry at the LHCb experiment in the region of parameter space where the neutralino decay leaves a displaced vertex. We find sensitivity to squark production up to squark masses of order 1 TeV. We note that if the Higgs decays to neutralinos in this scenario, LHCb should see the lightest Higgs boson before ATLAS and CMS.Comment: 7 pages, 5 figure

    A Geometry of the Generations

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    We propose a geometric theory of flavor based on the discrete group (S3)3(S_3)^3, in the context of the minimal supersymmetric standard model. The group treats three objects symmetrically, while making fundamental distinctions between the generations. The top quark is the only heavy quark in the symmetry limit, and the first and second generation squarks are degenerate. The hierarchical nature of Yukawa matrices is a consequence of a sequential breaking of (S3)3(S_3)^3.Comment: 10 pages, 1 EPS figure as uuencoded tar-compressed file, uses psfig.st

    Detecting Determinism in High Dimensional Chaotic Systems

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    A method based upon the statistical evaluation of the differentiability of the measure along the trajectory is used to identify in high dimensional systems. The results show that the method is suitable for discriminating stochastic from deterministic systems even if the dimension of the latter is as high as 13. The method is shown to succeed in identifying determinism in electro-encephalogram signals simulated by means of a high dimensional system.Comment: 8 pages (RevTeX 3 style), 5 EPS figures, submitted to Phys. Rev. E (25 apr 2001

    Towards a Sustainable Governance of Information Systems: Devising a Maturity Assessment Tool of Eco-Responsibility Inspired by the Balanced Scorecard

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    Part 3: Section 2: Sustainable and Responsible InnovationInternational audienceThe assessment of the maturity of Information System (IS) regarding its contribution to corporate social responsibility policy is considered as a stake for organizations. However, few research efforts have been dedicated to this evaluation and even less to the elaboration of a management tool. This paper adopts an engineering perspective to develop a performance assessment approach in this field. Theoretically, this communication (1) mobilizes the methodology of engineering research to build a measurement system of the IS maturity in relation to the economic, social and environmental performance, (2) extends the researches about the sustainable balanced scorecard (SBSC) to the field of IS governance. Practically, this study provides organizations with a global approach to this complex phenomenon as well as a guide to assess it. The originality of this research lies in the application of the conceptual framework of the SBSC to a new research domain

    Scherk-Schwarz Supersymmetry Breaking for Quasi-localized Matter Fields and Supersymmetry Flavor Violation

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    We examine the soft supersymmetry breaking parameters induced by the Scherk-Schwarz (SS) boundary condition in 5-dimensional orbifold field theory in which the quark and lepton zero modes are quasi-localized at the orbifold fixed points to generate the hierarchical Yukawa couplings. In such theories, the radion corresponds to a flavon to generate the flavor hierarchy and at the same time plays the role of the messenger of supersymmetry breaking. As a consequence, the resulting soft scalar masses and trilinear AA-parameters of matter zero modes at the compactification scale are highly flavor-dependent, thereby can lead to dangerous flavor violations at low energy scales. We analyze in detail the low energy flavor violations in SS-dominated supersymmetry breaking scenario under the assumption that the compactification scale is close to the grand unification scale and the 4-dimensional effective theory below the compactification scale is given by the minimal supersymmetric standard model. Our analysis can be applied to any supersymmetry breaking mechanism giving a sizable FF-component of the radion superfield, e.g. the hidden gaugino condensation model.Comment: revtex4, 22 pages, some numerical errors are corrected in phenomenological analysis, main conclusion does not chang

    Axion-photon Couplings in Invisible Axion Models

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    We reexamine the axion-photon couplings in various invisible axion models motivated by the recent proposal of using optical interferometry at the ASST facility in the SSCL to search for axion. We illustrate that the assignment of U(1)PQU(1)_{PQ} charges for the fermion fields plays an important role in determining the couplings. Several simple non-minimal invisible axion models with suppressed and enhanced axion-photon couplings are constructed, respectively. We also discuss the implications of possible new experiments to detect solar axions by conversion to XX-rays in a static magnetic apparatus tracking the sun.Comment: 14 pages, LaTeX fil

    Scales of the Extra Dimensions and their Gravitational Wave Backgrounds

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    Circumstances are described in which symmetry breaking during the formation of our three-dimensional brane within a higher-dimensional space in the early universe excites mesoscopic classical radion or brane-displacement degrees of freedom and produces a detectable stochastic background of gravitational radiation. The spectrum of the background is related to the unification energy scale and the the sizes and numbers of large extra dimensions. It is shown that properties of the background observable by gravitational-wave observatories at frequencies f104f\approx 10^{-4} Hz to 10310^3 Hz contain information about unification on energy scales from 1 to 101010^{10} TeV, gravity propagating through extra-dimension sizes from 1 mm to 101810^{-18}mm, and the dynamical history and stabilization of from one to seven extra dimensions.Comment: 6 pages, Latex, 1 figure, submitted to Phys. Re

    Naturalness and Higgs Decays in the MSSM with a Singlet

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    The simplest extension of the supersymmetric standard model - the addition of one singlet superfield - can have a profound impact on the Higgs and its decays. We perform a general operator analysis of this scenario, focusing on the phenomenologically distinct scenarios that can arise, and not restricting the scope to the narrow framework of the NMSSM. We reexamine decays to four b quarks and four tau's, finding that they are still generally viable, but at the edge of LEP limits. We find a broad set of Higgs decay modes, some new, including those with four gluon final states, as well as more general six and eight parton final states. We find the phenomenology of these scenarios is dramatically impacted by operators typically ignored, specifically those arising from D-terms in the hidden sector, and those arising from weak-scale colored fields. In addition to sensitivity of m_Z, there are potential tunings of other aspects of the spectrum. In spite of this, these models can be very natural, with light stops and a Higgs as light as 82 GeV. These scenarios motivate further analyses of LEP data as well as studies of the detection capabilities of future colliders to the new decay channels presented.Comment: 3 figures, 1 appendix; version to appear in JHEP; typos fixed and additional references and acknowledgements adde

    The price of rapid exit in venture capital-backed IPOs

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    This paper proposes an explanation for two empirical puzzles surrounding initial public offerings (IPOs). Firstly, it is well documented that IPO underpricing increases during “hot issue” periods. Secondly, venture capital (VC) backed IPOs are less underpriced than non-venture capital backed IPOs during normal periods of activity, but the reverse is true during hot issue periods: VC backed IPOs are more underpriced than non-VC backed ones. This paper shows that when IPOs are driven by the initial investor’s desire to exit from an existing investment in order to finance a new venture, both the value of the new venture and the value of the existing firm to be sold in the IPO drive the investor’s choice of price and fraction of shares sold in the IPO. When this is the case, the availability of attractive new ventures increases equilibrium underpricing, which is what we observe during hot issue periods. Moreover, I show that underpricing is affected by the severity of the moral hazard problem between an investor and the firm’s manager. In the presence of a moral hazard problem the degree of equilibrium underpricing is more sensitive to changes in the value of the new venture. This can explain why venture capitalists, who often finance firms with more severe moral hazard problems, underprice IPOs less in normal periods, but underprice more strongly during hot issue periods. Further empirical implications relating the fraction of shares sold and the degree of underpricing are presented

    Detection and Localization Sensor Assignment with Exact and Fuzzy Locations

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    Sensor networks introduce new resource allocation problems in which sensors need to be assigned to the tasks they best help. Such problems have been previously studied in simplified models in which utility from multiple sensors is assumed to combine additively. In this paper we study more complex utility models, focusing on two particular applications: event detection and target localization. We develop distributed algorithms to assign directional sensors of different types to multiple simultaneous tasks using exact location information. We extend our algorithms by introducing the concept of fuzzy location which may be desirable to reduce computational overhead and/or to preserve location privacy. We show that our schemes perform well using both exact or fuzzy location information
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