477 research outputs found

    Matching the BPS Spectra of Heterotic - Type I - Type I' Strings

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    We give a detailed discussion of the matching of the BPS states of heterotic, type I and type I' theories in d=9 for general backgrounds. This allows us to explicitly identify these (composite) brane states in the type I' theory that lead to gauge symmetry enhancement at critical points in moduli space. An example is the enhancement of SO(16)×SO(16)SO(16)\times SO(16) to E8×E8E_8\times E_8.Comment: 11 pages; minor typos in eq. (3), (4) and on page 9 have been corrected; two footnotes taking into account additional references have been added; version to appear in Physics Letters

    Forecasting Mortality Rate Using a Neural Network with Fuzzy Inference System

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    Various methods have been developed to improve mortality forecasts. The authors proposed a neuro-fuzzy model to forecast the mortality. The forecasting of mortality is curried out by an ANFIS model which uses a first order Sugeno-type FIS. The model predicts the yearly mortality in a one step ahead prediction scheme. The method of trial and error was used in order to decide the type of membership function that describe better the model and provides the minimum error. The output of the models is the next year�s mortality. The results were presented and compared based on three different kinds of errors: RMSE, MAE, and MAPE. The ANFIS model gives good results for the case of two gbell membership functions and 500 epochs. Finally, the ANFIS model gives better results than the AR and ARMA model.ANFIS, Forecasting, Mortality, Modeling.

    The D4-D8 Brane System and Five Dimensional Fixed Points

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    We construct dual Type I' string descriptions to five dimensional supersymmetric fixed points with ENf+1E_{N_f+1} global symmetry. The background is obtained as the near horizon geometry of the D4-D8 brane system in massive Type IIA supergravity. We use the dual description to deduce some properties of the fixed points.Comment: 10 pages, LaTeX2e; improved references, corrected typo

    Implications of non-universality of soft terms in supersymmetric grand unified theories

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    Most discussions of supersymmetric grand unified theories assume universality of the soft supersymmetry breaking terms at the grand scale. We point out that the behaviour of these theories might change significantly in the presence of non--universal soft terms. Particularly in SO(10)--like models with a large value of tanβ\beta we observe a decisive change of predictions, allowing the presence of relatively light gauginos as well as small supersymmetric corrections to the b--quark mass. Some results remain rather stable, including the μ\mu--M1/2M_{1/2} correlation. Models with small tanβ\beta seem to be less affected by non--universality which mainly leads to the new possibility of small m0m_{0} (i.e. the squark and slepton soft mass parameter), excluded in the universal case.Comment: 15 pages (Latex) plus 5 figures (uuencoded postscript file). TUM-HEP 201/9

    Flavour changing neutral currents and CP violating processes in generalized supersymmetric theories

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    We consider supersymmetric extensions of the standard model with general non-universal soft breaking terms. We analyse in a model-independent way the constraints on these terms at the electroweak energy scale coming from gluino mediated flavour (F) changing neutral current and CP-violating processes. We have computed the complete ΔF=1\Delta F=1 and ΔF=2\Delta F=2 effective hamiltonian for gluino mediated processes, including for the first time the effect of box diagrams in the evaluation of ϵ/ϵ\epsilon^{\prime}/\epsilon. We present numerical results for the constraints on these non-universal soft breaking terms for different values of the parameters, extending the analysis also to the leptonic sector. A comparison with previous results in the literature is given.Comment: LaTeX, 17 pages, 3 uuencoded figure

    Predictions for Higgs and SUSY spectra from SO(10) Yukawa Unification with mu > 0

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    We use t,b,τt, b, \tau Yukawa unification to constrain SUSY parameter space. We find a narrow region survives for μ>0\mu > 0 (suggested by \bsgam and the anomalous magnetic moment of the muon) with A01.9m16A_0 \sim - 1.9 m_{16}, m101.4m16m_{10} \sim 1.4 m_{16}, m1612003000m_{16} \sim 1200 -3000 \gev and μ,M1/2100500\mu, M_{1/2} \sim 100 - 500 \gev. Demanding Yukawa unification thus makes definite predictions for Higgs and sparticle masses.Comment: 10 pages, 3 figures, revised version to be published in PR

    Phenomenological implications of moduli-dominant SUSY breaking

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    We study moduli-dominated SUSY breaking within the framework of string models. This type of SUSY breaking in general leads to non-universal soft masses, i.e. soft scalar masses and gaugino masses. Further gauginos are lighter than sfermions. This non-universality has phenomenologically important implications. We investigate radiative electroweak symmetry breaking in the mass spectrum derived from moduli-dominated SUSY breaking, where the lightest chargino and neutralino are almost gauginos. Moreover, constraints from the branching ratio of bsγb \to s \gamma and the relic abundance of the LSP are also considered. The mass spectrum of moduli-dominated SUSY breaking is favorable to the experimental bound of the bsγb \to s \gamma decay decreasing its branching ratio. We obtain an upper bound for the gravitino mass from the cosmological constraint.Comment: Version to be appeared in Nucl. Phys.

    5d quivers and their AdS(6) duals

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    We consider an infinite class of 5d supersymmetric gauge theories involving products of symplectic and unitary groups that arise from D4-branes at orbifold singularities in Type I' string theory. The theories are argued to be dual to warped AdS(6)x S4/Zn backgrounds in massive Type IIA supergravity. In particular, this demonstrates the existence of supersymmetric 5d fixed points of quiver type. We analyze the spectrum of gauge fields and charged states in the supergravity dual, and find a precise agreement with the symmetries and charged operators in the quiver theories. We also comment on other brane objects in the supergravity dual and their interpretation in the field theories.Comment: 29 pages, 15 figure

    Polydisperse Versus Monodisperse Microbubbles:A Simulation Study for Contrast-Enhanced Ultrasound Imaging

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    Objective: Contrast-enhanced ultrasound (CEUS) presents distinct advantages in diagnostic echography. Utilizing microbubbles (MBs) as conventional contrast agents enhances vascular visualization and organ perfusion, facilitating real-time, non-invasive procedures. There is a current tendency to replace traditional polydisperse MBs with novel monodisperse formulations in an attempt to optimize contrast enhancement and guarantee consistent behavior and reliable imaging outcomes. This study investigates the contrast enhancement achieved using various-sized monodisperse MBs and their influence on non-linear imaging artifacts observed in traditional CEUS. Methods: To explore the differences between monodisperse and polydisperse populations without excessive experimentation, numerical simulations are employed for delivering precise, objective and expeditious results. The iterative non-linear contrast source (INCS) method has previously demonstrated efficacy when simulating ultrasound propagation in large populations in which each bubble has individual properties and several orders of multiple scattering are significant. Therefore, this method is employed to realistically simulate both monodisperse and polydisperse MBs. Results: Our findings in CEUS imaging indicate that scattering from resonant monodisperse MBs is 11.8 dB stronger than scattering from polydisperse MBs. Furthermore, the amplitude of non-linear imaging artifacts downstream of the monodisperse population is 19.4 dB stronger compared with polydisperse suspension. Conclusion: Investigating the impact of multiple scattering on polydisperse populations compared with various monodisperse suspensions has revealed that monodisperse MBs are more effective contrast agents, especially when at resonance. Despite the strong signal-to-noise ratio of monodisperse populations, imaging artifacts caused by non-linear wave propagation are also enhanced, resulting in further mis-classification of MBs as tissue.</p

    Effects of SO(10)-inspired scalar non-universality on the MSSM parameter space at large tan beta

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    We analyze the parameter space of the (mu > 0, A_0 = 0) CMSSM at large tan beta with a small degree of non-universality originating from D-terms and Higgs-sfermion splitting inspired by SO(10) GUT models. The effects of such non-universalities on the sparticle spectrum and observables such as (g-2)_mu, B(b -> X_s gamma), the SUSY threshold corrections to the bottom mass and Omega_CDM h^2 are examined in detail and the consequences for the allowed parameter space of the model are investigated. We find that even small deviations to universality can result in large qualitative differences compared to the universal case; for certain values of the parameters, we find, even at low m_16, that radiative electroweak symmetry breaking fails as a consequence of either |mu|^2 < 0 or m_(A^0)^2 < 0. We find particularly large departures from the mSugra case for the neutralino relic density, which is sensitive to significant changes in the position and shape of the A^0 resonance and a substantial increase in the Higgsino component of the LSP. However, we find that the corrections to the bottom mass are not sufficient to allow for Yukawa unification.Comment: 53 pages, 14 figures, elsart format, some minor corrections, references adde
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