3,936 research outputs found

    Kahler Independence of the G2-MSSM

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    The G2-MSSM is a model of particle physics coupled to moduli fields with interesting phenomenology both for colliders and astrophysical experiments. In this paper we consider a more general model - whose moduli Kahler potential is a completely arbitrary G2-holonomy Kahler potential and whose matter Kahler potential is also more general. We prove that the vacuum structure and spectrum of BSM particles is largely unchanged in this much more general class of theories. In particular, gaugino masses are still supressed relative to the gravitino mass and moduli masses. We also consider the effects of higher order corrections to the matter Kahler potential and find a connection between the nature of the LSP and flavor effects.Comment: Final version, matches the version published in JHE

    Stabilizing All Kahler Moduli in Type IIB Orientifolds

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    We describe a simple and robust mechanism that stabilizes all Kahler moduli in Type IIB orientifold compactifications. This is shown to be possible with just one non-perturbative contribution to the superpotential coming from either a D3-instanton or D7-branes wrapped on an ample divisor. This moduli-stabilization mechanism is similar to and motivated by the one used in the fluxless G_2 compactifications of M-theory. After explaining the general idea, explicit examples of Calabi-Yau orientifolds with one and three Kahler moduli are worked out. We find that the stabilized volumes of all two- and four-cycles as well as the volume of the Calabi-Yau manifold are controlled by a single parameter, namely, the volume of the ample divisor. This feature would dramatically constrain any realistic models of particle physics embedded into such compactifications. Broad consequences for phenomenology are discussed, in particular the dynamical solution to the strong CP-problem within the framework.Comment: RevTeX, 24 pages, 2 tables, 1 figure

    A Comparison of Supersymmetry Breaking and Mediation Mechanisms

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    We give a unified treatment of different models of supersymmetry breaking and mediation from a four dimensional effective field theory standpoint. In particular a comparison between GMSB and various gravity mediated versions of SUSY breaking shows that, once the former is embedded within a SUGRA framework, there is no particular advantage to that mechanism from the point of view of FCNC suppression. We point out the difficulties of all these scenarios - in particular the cosmological modulus problem. We end with a discussion of possible string theory realizations.Comment: Added clarifications and references, 20 page

    Larval and Post-Larval Stages of Pacific Oyster (Crassostrea gigas) Are Resistant to Elevated CO2

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    Growth of quantum dot coated core-shell anisotropic nanowires for improved thermal and electronic transport

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    Anisotropic nanowires are promising candidates for electronic thermal management due to their unique electrical and thermal properties.However, eco-friendly solution-processed nanomaterials with an elaborate morphology and microstructure for modulating thermal andcharge transfer are still a considerable challenge. Herein, we present a simple but effective approach for synthesizing pseudo core-shell nano-wires through quantum dot (QD)-like nanostructure coating (p-NW@QD) to generate exceptional electron-phonon transport properties.With the assistance of diphenyl ether as a coordination solvent, high crystallinity lead sulfide NWs can be fabricated with a large aspect ratiotogether with uniform QD coating. Thisp-NW@QD exhibits high electronic mobility (30.65 cm2/Vs) as well as a diameter independent lowthermal conductivity (1.5361 W/m K). Direct charge/heat carrier flow measurements and computational simulations demonstrate that theunusual electrical and thermal transport phenomenon is strongly dependent on the fast charge transport through the QD shell, and a slowphonon migration across the Umklapp process dominated NW cores. These findings indicate a significant step toward colloidal synthesisnanostructures for future high-performance nanoelectronics and thermal energy devices

    Mammalian Stem Cells Reprogramming in Response to Terahertz Radiation

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    We report that extended exposure to broad-spectrum terahertz radiation results in specific changes in cellular functions that are closely related to DNA-directed gene transcription. Our gene chip survey of gene expression shows that whereas 89% of the protein coding genes in mouse stem cells do not respond to the applied terahertz radiation, certain genes are activated, while other are repressed. RT-PCR experiments with selected gene probes corresponding to transcripts in the three groups of genes detail the gene specific effect. The response was not only gene specific but also irradiation conditions dependent. Our findings suggest that the applied terahertz irradiation accelerates cell differentiation toward adipose phenotype by activating the transcription factor peroxisome proliferator-activated receptor gamma (PPARG). Finally, our molecular dynamics computer simulations indicate that the local breathing dynamics of the PPARG promoter DNA coincides with the gene specific response to the THz radiation. We propose that THz radiation is a potential tool for cellular reprogramming

    Study of B -> \rho \pi decays at Belle

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    This paper describes a study of B meson decays to the pseudoscalar-vector final state \rho\pi using 31.9\times 10^6 B\bar{B} events collected with the Belle detector at KEKB. The branching fractions B(B^+ \to \rho^0\pi^+) = (8.0^{+2.3+0.7}_{-2.0-0.7}) \times 10^{-6} and B(B^0 -> \rho^{+-} \pi^{-+}) = (20.8^{+6.0+2.8}_{-6.3-3.1}) \times 10^{-6} are obtained. In addition, a 90% confidence level upper limit of B(B^0 \to \rho^0\pi^0) < 5.3 \times 10^{-6}is reported.Comment: 14 pages, 3 figures, to be submitted to Phys. Lett.

    Light hadron, Charmonium(-like) and Bottomonium(-like) states

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    Hadron physics represents the study of strongly interacting matter in all its manifestations and the understanding of its properties and interactions. The interest on this field has been revitalized by the discovery of new light hadrons, charmonium- and bottomonium-like states. I review the most recent experimental results from different experiments.Comment: Presented at Lepton-Photon 2011, Mumbai, India; 21 pages, 18 figures; add more references; some correctio

    Multiple infarcted regenerative nodules in liver cirrhosis after decompensation of cirrhosis: a case series

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    These patients showed focal liver lesions, to be considered in the differential diagnosis of cirrhotic livers. Infarcted regenerative nodules may be underdiagnosed in patients with decompensation of cirrhosis. In order to differentiate these lesions from malignant tumors, serial imaging seems to be helpful. However, the main differential diagnosis should be an abscess. It is important to know the wide spectrum of image appearances of these lesions. Hypotension can lead to a reduction of portal and arterial liver flow. Since variceal bleeding or septic shock can induce hypotension - as observed in our patients - we conclude that this leads to infarction of such nodules
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