201 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

    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

    CP Asymmetry of B→Xsl+l−B\to X_sl^+l^- in Low Invariant Mass Region

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    I analyzed the CP asymmetry of B→Xsl+l−B\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

    Possible Supersymmetric Effects on Angular Distributions in B→K∗(→Kπ)ℓ+ℓ−B \to K^* (\to K \pi) \ell^+ \ell^- Decays

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    We investigate the angular distributions of the rare B decay, B→K∗(→Kπ)ℓ+ℓ−B \to K^* (\to K \pi) \ell^+ \ell^-, in general supersymmetric extensions of the standard model. We consider the new physics contributions from the operators O7,8,9,10O_{7,8,9,10} in small invariant mass region of lepton pair. We show that the azimuthal angle distribution of the decay can tell us the new physics effects clearly from the behavior of the distribution, even if new physics does not change the decay rate substantially from the standard model prediction

    New Physics Effects in B→K(∗)ννB \to K^(*) \nu \nu Decays

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    We present a model-independent analysis of rare B decays, B→K(∗)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 B→K(∗)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

    A Systematic Analysis of the Lepton Polarization Asymmetries in the Rare B Decay, B -> X_s\tau^+\tau^-

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    The most general model-independent analysis of the lepton polarization asymmetries in the rare B decay, \Bstt, is presented. We present the longitudinal, normal and transverse polarization asymmetries for the τ+\tau^+ and τ−\tau^-, and combinations of them, as functions of the Wilson coefficients of twelve independent four-Fermi interactions, ten of them local and two nonlocal. These procedures will tell us which type of operators contributes to the process. And it will be very useful to pin down new physics systematically, once we have the experimental data with high statistics and a deviation from the Standard Model is found.Comment: 24 pages, 8 figures, LaTe

    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

    Lepton Polarization Asymmetry in B\to\ell^{+}\ell^{-} decay Beyond the Standard Model

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    The lepton polarization asymmetry in the B\to\ell^{+}\ell^{-} decay, when one of the leptons is polarized, is investigated using the most general form of the effective Hamiltonian. The sensitivity of the asymmetry to the new Wilson coefficients is studied.Moreover, correlations between the lepton polarization asymmetry and the branching ratio is studied. It is observed that, there are not exist such regions of new Wilson coefficients, which the value of branching ratio coincides with SM result while the lepton polarization does not, i.e new physics effects can be established by studying lepton polarization only.Comment: 9 pages,4 figure

    Exclusive semileptonic rare decays B−>(B ->_ (K,K^*) \ell^+ \ell^- in supersymmetric theories

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    The invariant mass spectrum, forward-backward asymmetry, and lepton polarizations of the exclusive processes B→K(K∗)ℓ+ℓ−,ℓ=μ,τB\to K(K^*)\ell^+ \ell^-, \ell=\mu, \tau are analyzed under supersymmetric context. Special attention is paid to the effects of neutral Higgs bosons (NHBs). Our analysis shows that the branching ratio of the process \bkm can be quite largely modified by the effects of neutral Higgs bosons and the forward-backward asymmetry would not vanish. For the process \bksm, the lepton transverse polarization is quite sensitive to the effects of NHBs, while the invariant mass spectrum, forward-backward asymmetry, and lepton longitudinal polarization are not. For both \bkt and \bkst, the effects of NHBs are quite significant. The partial decay widths of these processes are also analyzed, and our analysis manifest that even taking into account the theoretical uncertainties in calculating weak form factors, the effects of NHBs could make SUSY shown up.Comment: Several references are added, typo are correcte

    General analysis of the rare Bc->D^*_s l^+ l^- decay beyond the standard model

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    The general analysis of the rare Bc->D^*_s l^+ l^- decay is presented by using the most general, model independent effective Hamiltonian. The dependencies of the branching ratios, longitudinal, normal and transversal polarization asymmetries for l^- and the combined asymmetries for l^- and l^+ on the new Wilson coefficients are investigated. 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: 27 Pages, 14 Figure
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