19,121 research outputs found

    A Next-to-Minimal Supersymmetric Model of Hybrid Inflation

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    We propose a model of inflation based on a simple variant of the NMSSM, called ϕ\phiNMSSM, where the additional singlet ϕ\phi plays the role of the inflaton in hybrid (or inverted hybrid) type models. As in the original NMSSM, the ϕ\phiNMSSM solves the μ\mu problem of the MSSM via the VEV of a gauge singlet NN, but unlike the NMSSM does not suffer from domain wall problems since the offending Z3Z_3 symmetry is replaced by an approximate Peccei-Quinn symmetry which also solves the strong CP problem, and leads to an invisible axion with interesting cosmological consequences. The PQ symmetry may arise from a superstring model with an exact discrete Z3×Z5Z_3 \times Z_5 symmetry after compactification. The model predicts a spectral index n=1n=1 to one part in 101210^{12}.Comment: 17 pages, Latex; note added, accepted for Phys. Lett.

    Dynamical light vector mesons in low-energy scattering of Goldstone bosons

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    We present a study of Goldstone boson scattering based on the flavor SU(3) chiral Lagrangian formulated with vector mesons in the tensor field representation. A coupled-channel channel computation is confronted with the empirical s- and p-wave phase shifts, where good agreement with the data set is obtained up to about 1.2 GeV. There are two relevant free parameters only, the chiral limit value of the pion decay constant and the coupling constant characterizing the decay of the rho meson into a pair of pions. We apply a recently suggested approach that implements constraints from micro- causality and coupled-channel unitarity. Generalized potentials are obtained from the chiral Lagrangian and are expanded in terms of suitably constructed conformal variables. The partial-wave scattering amplitudes are defined as solutions of non-linear integral equations that are solved by means of an N/D ansatz.Comment: 15 pages, 8 figures, typos corrected, accepted for publication in Physics Letters

    Selective Transparence of Single-Mode Waveguides with Surface Scattering

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    A random surface scattering in a one-mode waveguide is studied in the case when the surface profile has long-range correlations along the waveguide. Analytical treatment of this problem shows that with a proper choice of the surface, one can arrange any desired combination of transparent and non-transparent frequency windows. We suggest a method to find such profiles, and demonstrate its effectiveness by making use of direct numerical simulations.Comment: RevTex, 3 pages including 2 ps-figure

    The first confirmation of V-type asteroids among the Mars crosser population

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    The Mars crossing region constitutes a path to deliver asteroids from the Inner Main Belt to the Earth crossing space. While both the Inner Main Belt and the population of Earth crossing asteroids contains a significant fraction of asteroids belonging to the V taxonomic class, only two of such V-type asteroids has been detected in the Mars crossing region up to now. In this work, we searched for asteroids belonging to the V class among the population of Mars crossing asteroids, in order to support alternative paths to the delivery of this bodies into the Earth crossing region. We selected 18 candidate V-type asteroids in the Mars crossing region using observations contained in the Sloan Digital Sky Survey Moving Objects Catalog. Then, we observed 4 of these candidates to take their visible spectra using the Southern Astrophysical Research Telescope (SOAR). We also performed the numerical simulation of the orbital evolution of the observed asteroids. We confirmed that 3 of the observed asteroids belong to the V class, and one of these may follow a path that drives it to an Earth collision in some tens of million years

    F-term Hybrid Inflation in Effective Supergravity Theories

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    We show that the effective low energy supergravity theories which result from a generic string theory can provide a promising framework for models of hybrid inflation in which the potential energy which drives inflation originates from the F-term of the effective supergravity theory. In the class of models considered the inflaton is protected from receiving mass during inflation by a Heisenberg symmetry and the potential during inflation takes the positive definite form V∼∣F∣2V \sim |F|^2, which allows the possibility that V≪m3/22MP2V\ll m_{3/2}^2 M_P^2. We discuss a toy example where this is realised, then describe the application of this result to realistic models focusing on a particular example in which the μ\mu problem and the strong CP-problem are addressed

    Onset of Delocalization in Quasi-1D Waveguides with Correlated Surface Disorder

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    We present first analytical results on transport properties of many-mode waveguides with rough surfaces having long-range correlations. We show that propagation of waves through such waveguides reveals a quite unexpected phenomena of a complete transparency for a subset of propagating modes. These modes do not interact with each other and effectively can be described by the theory of 1D transport with correlated disorder. We also found that with a proper choice of model parameters one can arrange a perfect transparency of waveguides inside a given window of energy of incoming waves. The results may be important in view of experimental realizations of a selective transport in application to both waveguides and electron/optic nanodevices.Comment: RevTex, 4 pages, no figures, few references are adde
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