7,781 research outputs found

    INFLATION AND ITS CONTROL

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    Financial Economics,

    D Branes and Textures

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    We examine the flavor structure of the trilinear superpotential couplings which can result from embedding the Standard Model within D brane sectors in Type IIB orientifold models, which are examples within the Type I string framework. We find in general that the allowed flavor structures of the Yukawa coupling matrices to leading order are given by basic variations on the "democratic" texture ansatz. In certain interesting cases, the Yukawa couplings have a novel structure in which a single right-handed fermion couples democratically at leading order to three left-handed fermions. We discuss the viability of such a ``single right-handed democracy'' in detail; remarkably, even though there are large mixing angles in the u,d sectors separately, the CKM mixing angles are small. The analysis demonstrates the ways in which the Type I superstring framework can provide a rich setting for investigating novel resolutions to the flavor puzzle.Comment: 23 pages, references adde

    Limits on violations of Lorentz Symmetry from Gravity Probe B

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    Generic violations of Lorentz symmetry can be described by an effective field theory framework that contains both general relativity and the standard model of particle physics called the Standard-Model Extension (SME). We obtain new constraints on the gravitational sector of the SME using recently published final results from Gravity Probe B. These include for the first time an upper limit at the 10^(-3) level on the time-time component of the new tensor field responsible for inducing local Lorentz violation in the theory, and an independent limit at the 10^(-7) level on a combination of components of this tensor field.Comment: 8 pages, 1 figur

    Toward understanding the Soviet Union

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    Thesis (M.A.)--Boston University, 1947. This item was digitized by the Internet Archive

    Evaluation of the suitability of Skylab data for the purpose of petroleum exploration

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    There are no author-identified significant results in this report

    Phenomenological Implications of Supersymmetric Family Non-universal U(1)-prime Models

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    We construct a class of anomaly-free supersymmetric U(1)' models that are characterized by family non-universal U(1)' charges motivated from E_6 embeddings. The family non-universality arises from an interchange of the standard roles of the two SU(5) 5* representations within the 27 of E_6 for the third generation. We analyze U(1)' and electroweak symmetry breaking and present the particle mass spectrum. The models, which include additional Higgs multiplets and exotic quarks at the TeV scale, result in specific patterns of flavor-changing neutral currents in the b to s transitions that can accommodate the presently observed deviations inthis sector from the SM predictions.Comment: 25 pages, 3 figure
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