4,352 research outputs found

    Lepton flavor violating li→ljγγl_i\to l_j \gamma\gamma decays induced by scalar unparticle

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    We study the radiative lepton flavor violating l_i -> l_j \gamma\gamma decays in the case that the lepton flavor violation is induced by the scalar unparticle mediation. We restrict the scaling dimension d_u and the scalar unparticle-photon-photon coupling by using the experimental upper limit of the branching ratio of the decay \mu -> e \gamma\gamma. Furthermore, we predict the BRs of the other radiative decays by using the restrictions we get. We observe that the measurements of upper limits of BRs of these decays ensure considerable information for testing the possible signals coming from unparticle physicsComment: 10 pages, 5 figures, 1 tabl

    B_s ---> \gamma \gamma decay in the model III and 3HDM(O_2) with CP violating effects

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    We analyse the CP asymmetry for B_{s} -->\gamma\gamma in the two Higgs doublet model with tree level flavor changing currents (model III) and three Higgs doublet model with O_2 symmetry in the Higgs sector, including O_{7} type long distance effects. Further, we study the dependencies of the branching ratio Br(B_{s} --> \gamma\gamma)$ and the ratio of CP-even and CP-odd amplitude squares, R=|A^{+}|^2/|A^{-}|^2, on the CP parameter sin \theta. We found that, there is a weak CP asymmetry, at the order of 10^{-4}. Besides, the branching ratio Br(B_{s} --> \gamma\gamma), and also R ratio, is not sensitive to the CP parameter for |\frac{\bar{\xi}^{U}_{N,tt}}{\bar{\xi}^{D}_{N,bb}}|<1.Comment: 17 pages, 11 figure

    The (gamma gamma -> H^0 H^0) process in noncommutative quantum electrodynamics

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    We study the possibility of detecting noncommutative QED through neutral Higgs boson pair production at (gamma--gamma) collider. This is based on the assumption that H^0 interacts directly with photon as suggested by symmetry considerations. The sensitivity of the cross-section to the noncommutative scale (Lambda_{NC}) and Higgs mass is investigated.Comment: 13 pages, 10 figures, LaTeX formatte

    The scalar unparticle effect on the charged lepton electric dipole moment

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    We study the charged lepton electric dipole moment which is induced by the scalar unparticle mediation and we predict the appropriate range for the free parameters appearing in the effective lagrangian which drives the unparticle-standard model lepton interactions. We observe that the charged lepton electric dipole moment is strongly sensitive to the scaling dimension d_u of the unparticle and the new couplings in the effective interaction. Furthermore, we see that the current experimental limits of charged lepton electric dipole moments can ensure an appropriate range for these free parameters.Comment: 19 pages, 13 Figure

    The CP asymmetry for B--> K^* l^+ l^- decay in the general two Higgs doublet model

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    We study CP asymmetry for the exclusive decay B --> K^* l^+ l^- in the two Higgs doublet model with three level flavor changing neutral currents (model III). We analyse the dependency of this quantity to the new phase coming from the complex Yukawa couplings in the theory and we find that there exist a considerable CP violation for the relevant process. Further, we see that the sign of the Wilson coefficient C_7^{eff} can be determined by fixing dilepton mass. Therefore, the future measurements of CP asymmetry for B --> K^* l^+ l^- decay will give a powerful information about the sign of Wilson coefficient C_{7}^{eff} and the new physics beyond the SM.Comment: 22 pages, 8 figure

    Analysis of \Lambda_b \rar \Lambda \ell^+ \ell^- transition in SM4 using form factors from Full QCD

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    Using the responsible form factors calculated via full QCD, we analyze the Λb→Λℓ+ℓ−\Lambda_{b}\rightarrow \Lambda \ell^{+}\ell^{-} transition in the standard model containing fourth generation quarks (SM4). We discuss effects of the presence of t′t' fourth family quark on related observables like branching ratio, forward-backward asymmetry, baryon polarization as well as double lepton polarization asymmetries. We also compare our results with those obtained in the SM as well as with predictions of the SM4 but using form factors calculated within heavy quark effective theory. The obtained results on branching ratio indicate that the Λb→Λℓ+ℓ−\Lambda_{b}\rightarrow \Lambda \ell^{+}\ell^{-} transition is more probable in full QCD comparing to the heavy quark effective theory. It is also shown that the results on all considered observables in SM4 deviate considerably from the SM predictions when mt′≥400GeVm_{t'}\geq 400 GeV.Comment: 22 Pages and 21 Figure

    B --> K^* \tau^+ \tau^- decay in the general two Higgs doublet model including the neutral Higgs boson effects

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    We study the CP violating asymmetry, the forward-backward asymmetry of the lepton pair and the CP asymmetry in the forward backward asymmetry for the exclusive decay $B --> K^* \tau^+ \tau^- in the general two Higgs doublet model including the neutral Higgs boson effects. We analyse the dependencies of these quantities on the model III parameters. We found that the physical parameters studied above are at the order of the magnitude 1% and neutral Higgs boson effects are detectable for large values of the coupling \bar{\xi}_{N,\tau\tau}^D.Comment: 20 pages, 11 Figure

    Exclusive B --> K^* l^+ l^-$ decay in the three Higgs doublet model

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    We study the differential Branching ratio and CP asymmetry for the exclusive decay B --> K^* l^+ l^- in the three Higgs doublet model with additional global O(2) symmetry in the Higgs sector. We analyse dilepton mass square q^2 dependency of the these quantities. Further, we study the effect of new parameter of the global symmetry in the Higgs sector on the differential branching ratio and CP asymmetry. We see that there exist an enhancement in the branching ratio and a considerable CP violation for the relevant process. In addition to this, we realize that fixing dilepton mass gives information about the sign of the Wilson coefficient C_7^{eff}.Therefore, the future measurements of the CP asymmetry for B\to K^* l^+ l^- decay will give a powerful information about the sign of Wilson coefficient C_{7}^{eff} and new physics beyond the SM.Comment: 19 pages, 6 figure
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