76 research outputs found

    Polarized lepton pair forward-backward asymmetries in (B -> K^* l^+ l^-) decay beyond the standard model

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    We study the polarized lepton pair forward-backward asymmetries in (B -> K^* l^+ l^-) decay using a general, model independent form of the effective Hamiltonian. We present the general expression for nine double-polarization forward-backward asymmetries. It is shown that, the study of the forward-backward asymmetries of the doubly-polarized lepton pair is a very useful tool for establishing new physics beyond the standard model.Comment: 29 pages, 18 figures, LaTeX formatte

    General analysis of CP violation in polarized (b -> d l^+ l^-) decay

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    The CP violating asymmetries in the (b -> d l^+ l^-) decay, when one of the leptons is polarized, is investigated using the most general form of the effective Hamiltonian. The sensitivity of the CP violating asymmetries on the new Wilson coefficients is studied.Comment: 25 pages, 20 figures, LaTeX formatte

    Light vector meson octet-decuplet baryon vertices in QCD

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    The strong coupling constants between light vector mesons and octet-decuplet baryons are calculated in framework of the light cone QCD sum rules, taking into account SU(3) flavor symmetry breaking effects. It is shown that all strong coupling constants can be represented in terms of a single universal function. Size of the SU(3) symmetry breaking effects are estimated.Comment: 27 pages, 6 figures, LaTeX formatte

    Vector meson dominance and radiative decays of heavy spin-3/2 baryons to heavy spin--1/2 baryons

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    Using the calculated values of the strong coupling constants of the heavy sextet spin-3/2 baryons to sextet and antitriplet heavy spin-1/2 baryons with light mesons within the light cone QCD sum rules method, and vector meson dominance assumption, the radiative decay widths are calculated. These widths are compared with the "direct" radiative decay widths predicted in the framework of the light cone QCD sum rules.Comment: 8 pages, no figures, LaTeX formatte

    Double-lepton polarization asymmetries in the Exclusive (B -> rho l^+ l^-) decay beyond the Standard Model

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    The double-lepton polarization asymmetries in (B -> rho l^+ l^-) decay is analyzed in a model independent framework. The general expressions for nine double-polarization asymmetries are calculated. It is shown that the study of the double-lepton polarization asymmetries proves to be very useful tool in looking for new physics beyond the standard model.Comment: 28 pages, 16 figures, LaTeX formatte

    Pseudoscalar--meson decuplet--baryon coupling constants in light cone QCD

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    Taking into account the SU(3)fSU(3)_f breaking effects, the strong coupling constants of the π\pi, KK and η\eta mesons with decuplet baryons are calculated within light cone QCD sum rules method. It is shown that all coupling constants, even in the case of SU(3)fSU(3)_f breaking, are described in terms of only one universal function. It is shown that for Ξ0Ξ0η\Xi^{\ast 0} \to \Xi^{\ast 0} \eta transition violation of SU(3)fSU(3)_f symmetry is very large and for other channels when SU(3)fSU(3)_f symmetry is violated, its maximum value constitutes 1010%\div15%.Comment: 17 Pages, one Figure and 3 Table

    Vector meson-baryon strong coupling contants in light cone QCD sum rules

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    Using the most general form of the interpolating current of the baryons, the strong coupling constants of the light vector mesons with the octet baryons are calculated within the light cone QCD sum rules. The SU(3)_f symmetry breaking effects are taken into account in the calculations. It is shown that each of the electric and magnetic coupling constants can be described in terms of three universal functions. A detailed comparison of the results of this work on aforementioned couplings with the existing theoretical results is presented.Comment: 25 pages, 4 figures, LaTeX formatte

    Involvement of the histaminergic system in the resuscitating effect of centrally acting leptin in haemorrhagic shock in rats

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    Leptin, acting centrally as a neuromodulator, induces the activation of the sympathetic nervous system, which may lead to a pressor action in normotensive animals. In haemorrhagic shock, leptin administered intracerebroventricularly (icv.) evokes the resuscitating effect, with long-lasting rises in mean arterial pressure (MAP) and heart rate (HR), subsequent increase in peripheral blood flows, and a 100% survival at 2 h. Since leptin is able to activate histaminergic neurons, and centrally acting histamine also induces the resuscitating effect with the activation of the sympathetic nervous system, in the present study, we investigated an involvement of the histaminergic system in leptin-evoked cardiovascular effects in haemorrhagic shock. The model of irreversible haemorrhagic shock, with MAP decreased to and stabilised at 20 - 25 mmHg, has been used. Leptin (20 μg) given icv. at 5 min of critical hypotension evoked 181.5% increase in extracellular hypothalamic histamine concentration during the first 10 min after injection. Rises in MAP, HR and renal, mesenteric and hindquarters blood flows induced by leptin were inhibited by icv. pre-treatment with histamine H1 receptor antagonist chlorpheniramine (50 nmol). In contrast, there was no effect of H2, H3 and H4 receptor antagonists ranitidine (25 nmol), VUF 5681 (25 nmol) and JNJ 10191584 (25 nmol), respectively. In conclusion, the histaminergic system is involved in centrally-acting leptin-induced resuscitating effect in haemorrhagic shock in rats

    The "radiative Delta -> N gamma" decay in light cone QCD

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    The "g_{Delta N gamma}" coupling for the "Delta -> N gamma" decay is calculated in framework of the light cone QCD sum rules and is found to be g_{Delta N gamma} = (1.6 pm 0.2) GeV^(-1). Using this value of g_{Delta N gamma} we estimate the branching ratio of the Delta^+ -> N gamma decay, which is in a very good agreement with the experimental result.Comment: 9 pages, 1figures, LaTeX formatte

    Exclusive Lambda_b -> Lambda l^+ l^- decay in two Higgs doublet model

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    Rare Lambda_b -> Lambda l^+ l^- decay is investigated in framework of general two Higgs doublet model, in which a new source of CP violation exists (model III). The polarization parameter, CP asymmetry and decay width are calculated. It is shown that CP asymmetry is a very sensitive tool for establishing model III.Comment: 16 pages, 3 figures, LaTeX formatte
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