10,489 research outputs found

    Ternary numbers and algebras. Reflexive numbers and Berger graphs

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    The Calabi-Yau spaces with SU(m) holonomy can be studied by the algebraic way through the integer lattice where one can construct the Newton reflexive polyhedra or the Berger graphs. Our conjecture is that the Berger graphs can be directly related with the nn-ary algebras. To find such algebras we study the n-ary generalization of the well-known binary norm division algebras, R{\mathbb R}, C{\mathbb C}, H{\mathbb H}, O{\mathbb O}, which helped to discover the most important "minimal" binary simple Lie groups, U(1), SU(2) and G(2). As the most important example, we consider the case n=3n=3, which gives the ternary generalization of quaternions and octonions, 3p3^p, p=2,3p=2,3, respectively. The ternary generalization of quaternions is directly related to the new ternary algebra and group which are related to the natural extensions of the binary su(3)su(3) algebra and SU(3) group. Using this ternary algebra we found the solution for the Berger graph: a tetrahedron.Comment: Revised version with minor correction

    The Fermion Generations Problem in the Gust in the Free World-Sheet Fermion Formulation

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    In the framework of the four dimensional heterotic superstring with free fermions we present a revised version of the rank eight Grand Unified String Theories (GUST) which contain the SU(3)HSU(3)_H-gauge family symmetry. We also develop some methods for building of corresponding string models. We explicitly construct GUST with gauge symmetry G=SU(5)×U(1)×(SU(3)×U(1))H G = SU(5) \times U(1)\times (SU(3) \times U(1))_H and G=SO(10)×(SU(3)×U(1))HG = SO(10)\times (SU(3) \times U(1))_H or E(6)×SU(3)HE(6)\times SU(3)_H E(8)\subset E(8) and consider the full massless spectrum for our string models. We consider for the observable gauge symmetry the diagonal subgroup GsymmG^{symm} of the rank 16 group G×GG \times G SO(16)×SO(16)\subset SO(16) \times SO(16) or E(8)×E(8)\subset E(8) \times E(8). We discuss the possible fermion matter and Higgs sectors in these theories. We study renormalizable and nonrenormolizable contributions to the superpotential. There has to exist "superweak" light chiral matter (mHf<MWm_H^f < M_W) in GUST under consideration. The understanding of quark and lepton mass spectra and family mixing leaves a possibility for the existence of an unusually low mass breaking scale of the SU(3)HSU(3)_H family gauge symmetry (some TeV).Comment: 68 page

    Transition between ordinary and topological insulator regimes in two-dimensional resonant magnetotransport

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    In the two-dimensional case the transition between ordinary and topological insulator states can be described by a massive Dirac model with the mass term changing its sign at the transition point. We theoretically investigate how such a transition manifests itself in resonant transport via localized helical edge states. The resonance occurs in the middle of the band gap due to a zero edge-state mode which is protected by the time-reversal symmetry, also when coupled to the conducting leads. We obtain the explicit dependence of the resonant conductance on the mass parameter and an external magnetic field. The proposal may be of practical use, allowing one to determine the orbital g-factor of helical edge states in two-dimensional topological insulators.Comment: 7 pages, 3 eps figures, Phys. Rev. B (in press

    Pion Polarizability in the NJL model and Possibilities of its Experimental Studies in Coulomb Nuclear Scattering

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    The charge pion polarizability is calculated in the Nambu-Jona-Lasinio model, where the quark loops (in the mean field approximation) and the meson loops (in the 1/Nc1/N_c approximation) are taken into account. We show that quark loop contribution dominates, because the meson loops strongly conceal each other. The sigma-pole contribution (mσ2t)1(m^2_\sigma-t)^{-1} plays the main role and contains strong t-dependence of the effective pion polarizability at the region t4Mπ2|t|\geq 4M_\pi^2. Possibilities of experimental test of this sigma-pole effect in the reaction of Coulomb Nuclear Scattering are estimated for the COMPASS experiment.Comment: 11 pages, 8 figure

    The processes e+eππ(π)e^{+}e^{-} \to \pi\pi(\pi') in the extended NJL model

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    The process e+eπ+πe^{+}e^{-} \to \pi^{+}\pi^{-} is described in the framework of the extended NJL model. Intermediate vector mesons ρ0(770)\rho^0(770), ω(782)\omega(782) and \rho'(1450)aretakenintoaccount.Ourresultsareinsatisfactoryagreementwithexperimentaldata.Thepredictionfortheprocess are taken into account. Our results are in satisfactory agreement with experimental data. The prediction for the process e^{+}e^{-} \to \pi\pi'(1300)isgiven.Herethemaincontributionisgivenbythediagramwithintermediate is given. Here the main contribution is given by the diagram with intermediate \rho'(1450)$ meson.Comment: 7 pages, 5 figure
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