134,986 research outputs found

    Non-Gaussian statistics, maxwellian derivation and stellar polytropes

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    In this letter we discuss the Non-gaussian statistics considering two aspects. In the first, we show that the Maxwell's first derivation of the stationary distribution function for a dilute gas can be extended in the context of Kaniadakis statistics. The second one, by investigating the stellar system, we study the Kaniadakis analytical relation between the entropic parameter κ\kappa and stellar polytrope index nn. We compare also the Kaniadakis relation n=n(κ)n=n(\kappa) with n=n(q)n=n(q) proposed in the Tsallis framework.Comment: 10 pages, 1 figur

    Tree-level metastability bounds for the most general two Higgs doublet model

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    Within two Higgs doublet models, it is possible that the current vacuum is not the global minimum, in which case it could possibly decay at a later stage. We discuss the tree-level conditions which must be obeyed by the most general scalar potential in order to preclude that possibility. We propose a new procedure which is not only more general but also easier to implement than the previously published one, including CP conserving as well as CP violating scalar sectors. We illustrate these conditions within the context of the Z2 model, softly broken by a complex, CP violating parameter.Comment: RevTex, 13 pages, 3 figure

    Generalized CP Invariance and the Yukawa sector of Two-Higgs Models

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    We analyze generalized CP symmetries of two-Higgs doublet models, extending them from the scalar to the fermion sector of the theory. We show that, with a single exception, those symmetries imply massless fermions. The single model which accommodates a fermionic mass spectrum compatible with experimental data possesses a remarkable feature. It displays a new type of spontaneous CP violation, which occurs not in the scalar sector responsible for the symmetry breaking mechanism but, rather, in the fermion sector.Comment: RevTex, 4 pages, no figures Version2: Remarkable additional conclusion => title & text changes; section adde