261 research outputs found

    The Effects of Non-Local Interactions in Rare B Decays, B -> X_s l^+l^-

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    The effects of non-local interactions in rare B decays, \Bsll, are investigated. We show the correlation between the branching ratio and the forward-backward asymmetry via two coefficients of the non-local interactions. This will certainly help us find any deviations from the standard model through the non-local interactions.Comment: 16 pages, 5 figures, LaTeX, Accepted for IJMP

    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

    CP Asymmetry of BXsl+lB\to X_sl^+l^- in Low Invariant Mass Region

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    I analyzed the CP asymmetry of BXsl+lB\to X_sl^+l^- based on model-independent analysis which includes twelve independent four Fermi operators. The CP asymmetry is suppressed in the Standard Model, however, if some new physics make it much larger, the present or the next generation B factories may catch the CP violation in this decay mode. In this paper, we studied the correlation of the asymmetry and the branching ratio, and then we will find only a type of interactions can be enlarge the asymmetry. Therefore, in comparison with experiments, we have possibility that we can constrain models beyond the standard model.Comment: 12 pages, 5 figures, LaTeX, Accepted for Physical Review

    Lepton polarization and CP-violating effects in "B -> K^* tau^+ tau^-" decay in standard and two Higgs doublet models

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    The most general model independent expressions for the CP-violating asymmetry, longitudinal, transversal and normal polarizations of leptons are derived. Application of these general results to the concrete models such as Standard model and three different types of two Higgs doublet model is discussed.Comment: 18 pages, 8 postscripted figure

    New Physics Effects in BK()ννB \to K^(*) \nu \nu Decays

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    We present a model-independent analysis of rare B decays, BK()ννB \to K^{(*)} \nu \nu. The effect of possible new physics is written in terms of dimension-6 four-fermi interactions. The lepton number violating scalar- and tensor-type interactions are included, and they induce BK()νν(νˉνˉ)B \to K^{(*)} \nu \nu ({\bar \nu} {\bar \nu}) decays. We show systematically how the branching ratios and missing mass-squared spectrum depend on the coefficients of the four-fermi interactions.Comment: 20 pages with 7 figure

    Longitudinal polarization asymmetry of leptons in the pure leptonic B decays

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    Longitudinal lepton polarization asymmetry in B_q -> l l (q = d, s$ and l = e, mu, tau) decays is investigated. The analysis is done in a general manner by using the effective operators approach. It is shown that the longitudinal lepton polarization asymmetry would provide a direct search for the scalar and pseudoscalar type interactions, which are induced in all variants of Higgs-doublet models.Comment: 7 page

    Lepton Polarization and Forward-Backward Asymmetries in b -> s tau+ tau-

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    We study the spin polarizations of both tau leptons in the decay b -> s tau+ tau-. In addition to the polarization asymmetries involving a single tau, we construct asymmetries for the case where both polarizations are simultaneously measured. We also study forward-backward asymmetries with polarized tau's. We find that a large number of asymmetries are predicted to be large, >~ 10%. This permits the measurement of all Wilson coefficients and the b-quark mass, thus allowing the standard model (SM) to be exhaustively tested. Furthermore, there are many unique signals for the presence of new physics. For example, asymmetries involving triple-product correlations are predicted to be tiny within the SM, O(10^{-2}). Their observation would be a clear signal of new physics.Comment: 21 pages, LaTeX, 4 figures (included). Paper somewhat reorganized, references greatly expanded, conclusions unchange

    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

    General analysis of lepton polarizations in rare B -> K^* l^+ l^- decay beyond the standard model

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    The general analysis of lepton polarization asymmetries in rare B -> K^* l^+ l^- decay is investigated. Using the most general, model independent effective Hamiltonian, the general expressions of the longitudinal, normal and transversal polarization asymmetries for l^- and l^+ and combinations of them are presented. The dependence of lepton polarizations and their combinations on new Wilson coefficients are studied in detail. Our analysis shows that the lepton polarization asymmetries are very sensitive to the scalar and tensor type interactions, which will be very useful in looking for new physics beyond the standard model.Comment: 29 pp, 15 figure

    New physics effects to the lepton polarizations in the B -> K l^+ l^- decay

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    Using the general, model independent form of the effective Hamiltonian, the general expressions of the longitudinal, normal and transversal polarization asymmetries for (l^-) and (l^+) and combinations of them for the exclusive (B -> K l^+ l^-) decay are found. The sensitivity of lepton polarizations and their combinations on new Wilson coefficients are studied. It is found that there exist regions of Wilson coefficients for which the branching ratio coincides with the Standard Model result while the lepton polarizations differ substantially from the standard model prediction. Hence, studying lepton polarization in these regions of new Wilson coefficients can serve as a promising tool for establishing new physics beyond the Standard Model.Comment: 18 pp, 14 figures (postscript formatted), LaTex formatte
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