44,715 research outputs found

    Copper and Barium Abundances in the Ursa Major Moving Group

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    We present Cu and Ba abundances for 7 G-K dwarf stars, members of the solar-metallicity, 0.3 Gyr old Ursa Major Moving Group. All analyzed member stars show [Ba/Fe] excesses of +0.3-plus, associated with [Cu/Fe] deficiencies of up to -0.23 dex. The present results suggest that there is an anti-correlation between the abundances of Cu and the heavy elements produced by the main component of the neutron capture s-process. Other possible anomalies are Na and C deficiencies with respect to normal solar-metallicity stars. The new data do not confirm the recent claim that the group member HR6094 is a Ba dwarf star.Comment: 8 pages, 6 figures, accepted to MNRA

    Bounds on the Simplest Little Higgs Model Mass Spectrum Through Z Leptonic Decay

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    We derive the leptonic neutral current in the simplest little Higgs model and compute the contribution of the model to the decay width Z→e+e−Z \to e^+e^-. Using the precision electroweak data we obtain a strong lower bound f≥5.6f\geq 5.6 TeV at 95% C.L. on the characteristic energy scale of the model. It results in a lower bound for the new gauge bosons W′±W^{\prime\pm} and Z′Z^{\prime} as being MW′±≥2.6M_{W^{\prime\pm}}\geq 2.6 TeV and MZ′≥3.1M_{Z^{\prime}}\geq 3.1 TeV, respectively. We also present the allowed values of the k=f1/f2k=f_1/f_2 which is the parameter relating the two vacuum expectation values of the scalar triplets in the model, and the μ\mu parameter of a quadratic term, involving the triplets, necessary to provide an acceptable mass range for the standard Higgs boson.Comment: New references added, 13 pages. Version to be publishe

    Real and complex integral closure, Lipschitz equisingularity and applications on square matrices

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    Recently the authors investigated the Lipschitz triviality of simple germs of matrices. In this work, we improve some previous results and we present an extension of an integral closure result for the real setting. These tools are applied to investigate classes of square matrices singularities classified by Bruce and Tari

    Realizing the supersymmetric inverse seesaw model in the framework of R-parity violation

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    If, on one hand, the inverse seesaw is the paradigm of TeV scale seesaw mechanism, on the other it is a challenge to find scenarios capable of realizing it. In this work we propose a scenario, based on the framework of R-parity violation, that realizes minimally the supersymmetric inverse seesaw mechanism. In it the energy scale parameters involved in the mechanism are recognized as the vacuum expectation values of the scalars that compose the singlet superfields N^C\hat N^C and S^\hat S. We develop also the scalar sector of the model and show that the Higgs mass receives a new tree-level contribution that, when combined with the standard contribution plus loop correction, is capable of attaining 125125GeV without resort to heavy stops.Comment: Minor modification of the text. Final version to be published in PL

    Zoneamento agroclimático da cultura do feijoeiro para o Estado de Alagoas.

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    Neste estudo foi utilizado o modelo SARRA (Sistema de Análise Regional dos Riscos Agroclimáticos).bitstream/CNPAF/25034/1/comt_122.pd
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