216,877 research outputs found

    Generalized Gauge Theories and Weinberg-Salam Model with Dirac-K\"ahler Fermions

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    We extend previously proposed generalized gauge theory formulation of Chern-Simons type and topological Yang-Mills type actions into Yang-Mills type actions. We formulate gauge fields and Dirac-K\"ahler matter fermions by all degrees of differential forms. The simplest version of the model which includes only zero and one form gauge fields accommodated with the graded Lie algebra of SU(2∣1)SU(2|1) supergroup leads Weinberg-Salam model. Thus the Weinberg-Salam model formulated by noncommutative geometry is a particular example of the present formulation.Comment: 33 pages, LaTe

    Pati-Salam explanations of the B-meson anomalies

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    We provide a combined explanation of the increasingly tantalizing BB-meson anomalies, both in RK(∗)R_{K^{(*)}} and RD(∗)R_{D^{(*)}}, in the Pati-Salam model with minimal matter content. This well-known model, based on the gauge group SU(4)LC×SU(2)L×SU(2)RSU(4)_{LC} \times SU(2)_L \times SU(2)_R, naturally contains a variety of scalar leptoquarks with related and restricted couplings. In particular we show that the seesaw-motivated scalar leptoquark within the representation (10‾,3,1)(\overline{10}, 3, 1) and its right-handed parity partner (10‾,1,3)(\overline{10}, 1, 3) can solve both anomalies while making testable predictions for related observables such as B→KννB \to K\nu\nu and B→KμτB \to K \mu\tau. The solution of the RK(∗)R_{K^{(*)}} anomaly alone can be related to a type-II seesaw neutrino mass structure. Explaining also RD(∗)R_{D^{(*)}} requires the existence of a light right-handed neutrino, which constrains the UV structure of the model.Comment: 26 pages, includes discussion of RGEs; to appear in JHE

    On the q

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    Recently Al-Salam and Verma discussed two polynomial sets {Zn(α)(x,k|q)} and {Yn(α)(x,k|q)} which are biorthogonal on (0,∞) with respect to a continuous or discrete distribution function. For the polynomials Yn(α)(x,k|q) the operational formula is derived

    Exophobic Quasi-Realistic Heterotic String Vacua

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    We demonstrate the existence of heterotic-string vacua that are free of massless exotic fields. The need to break the non-Abelian GUT symmetries in k=1 heterotic-string models by Wilson lines, while preserving the GUT embedding of the weak-hypercharge and the GUT prediction sin^2\theta_w(M(GUT))=3/8, necessarily implies that the models contain states with fractional electric charge. Such states are severely restricted by observations, and must be confined or sufficiently massive and diluted. We construct the first quasi-realistic heterotic-string models in which the exotic states do not appear in the massless spectrum, and only exist, as they must, in the massive spectrum. The SO(10) GUT symmetry is broken to the Pati-Salam subgroup. Our PS heterotic-string models contain adequate Higgs representations to break the GUT and electroweak symmetry, as well as colour Higgs triplets that can be used for the missing partner mechanism. By statistically sampling the space of Pati-Salam vacua we demonstrate the abundance of quasi--realistic three generation models that are completely free of massless exotics, rendering it plausible that obtaining realistic Yukawa couplings may be possible in this space of models.Comment: 14 pages. Standard LaTex. 1 figure. 2 tables. Typos correcte

    Graviton Propagation in an Asymmetric Warped Background: Lorentz Violation and the Null Energy Condition

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    The graviton propagation in an asymmetric background is studied. The background is a configuration in the six-dimensional Salam-Sezgin model, in which a 3-form H-field turned on [JHEP 0910(2009)086]. The compact dimensions form a cylindrical space with branes as boundaries. The background gets asymmetry due to the H-field and violates the Lorentz symmetry. We derive the graviton equation in this background and show that it gets massless mode traveling with superluminal speed. A tower of K-K modes exists with a mass gap. On the other hand, it is known that breaking the Lorentz symmetry on an asymmetric background is constrained by the null energy condition. This no-go theorem doesn't work well in six-dimensional space-times and by this model we provide a counterexample for which the null energy condition is satisfied while the Lorentz symmetry is gravitationally violated.Comment: 20 pages, 1 figure. v2: published version, more phenomenological discussions added, references added, numerical error fixe
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