7,715 research outputs found

    Gravitational field equations in a braneworld with Euler-Poincare term

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    We present the effective gravitational field equations in a 3-brane world with Euler-Poincare term and a cosmological constant in the bulk spacetime. The similar equations on a 3-brane with Z2\mathbb{Z}_2 symmetry embedded in a five dimensional bulk spacetime were obtained earlier by Maeda and Torii using the Gauss-Coddazzi projective approach in the framework of the Gaussian normal coordinates. We recover these equations on the brane in terms of differential forms and using a more general coordinate setting in the spirit of Arnowitt, Deser and Misner (ADM). The latter allows for acceleration of the normals to the brane surface through the lapse function and the shift vector. We show that the gravitational effects of the bulk space are transmitted to the brane through the projected ``electric'' 1-form field constructed from the conformal Weyl curvature 2-form of the bulk space. We also derive the evolution equations into the bulk space for the electric 1-form field, as well as for the ``magnetic'' 2-form field part of the bulk Weyl curvature 2-form. As expected, unlike on-brane equations, the evolution equations involve terms determined by the nonvanishing acceleration of the normals in the ADM-type slicing of spacetime

    Exclusive B -> K^* l^+ l^- decay with polarized K^* and new physics effects

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    Using the most general, model independent effective Hamiltonian, the branching ratio of the (B -> K^* l^+ l^-) decay, when K^* meson is longitudinally or transversally polarized, is presented. The dependence of the branching ratio on the new Wilson coefficients, when K^* meson is polarized, is studied. It is observed that the branching ratio is very sensitive to the vector and tensor type interactions, which will be useful in search of new physics beyond the Standard Model.Comment: 13 pp, 6 figures (postscript formatted), LaTex formatte

    Exact metric around a wiggly cosmic string

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    The exact metric around a wiggly cosmic string is found by modifying the energy momentum-tensor of a straight infinitely thin cosmic string to include an electric current along the symmetry axis.Comment: 5 page

    Semileptonic decays of pseudoscalar mesons to scalar "f_0" meson

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    The transition form factors of (D_s -> f_0 l nu), (D -> f_0 l nu) and (B_u -> f_0 l nu) decays are calculated in 3-point QCD sum rule method, assuming that "f_0" is a quark-antiquark state with a mixture of strange and light quarks. The branching ratios of these decays are calculated in terms of the mixing angle.Comment: 12 pages, 4 figures, LaTeX formatte

    General analysis of time evolution of decay spectrum in B^0 -> pi^+ pi^- l^+ l^-

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    Using the general, model independent form of effective Hamiltonian, the decay spectrum of B^0 -> pi^+ pi^- l^+ l^- decay is studied. The sensitivity of experimentally measurable asymmetries to the new Wilson coefficients and time is studied. It is observed that different asymmetries are sensitive to the new Wilson coefficients and they can serve as an efficient tool for establishing new physics beyond SM.Comment: 15 pp, 4 figures (postscript formatted), LaTex formatte

    T violation in (Lambda_b -> Lambda l^+ l^-) decay beyond standard model

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    Using the most general, model independent form of effective Hamiltonian, the transverse polarization P_T of Lambda in Lambda_b -> Lambda l^+ l^- decay is studied. It is observed that the averaged is very sensitive to the existence of new physics and can attain large values, which can be measured at future colliders.Comment: 12 pages, 7 figures, LaTeX formatte
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