5,095 research outputs found

    Lepton flavor violating liljγγl_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

    Exact Solutions in Five-Dimensional Axi-dilaton Gravity with Euler-Poincare Term

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    We examine the effective field equations that are obtained from the axi-dilaton gravity action with a second order Euler-Poincare term and a cosmological constant in all higher dimensions. We solve these equations for five-dimensional spacetimes possessing homogeneity and isotropy in their three-dimensional subspaces. For a number of interesting special cases we show that the solutions fall into two main classes: The first class consists of time-dependent solutions with spherical or hyperboloidal symmetry which require certain fine-tuning relations between the coupling constants of the model and the cosmological constant. Solutions in the second class are locally static and prove the validity of Birkhoff's staticity theorem in the axi-dilaton gravity. We also give a special class of static solutions, among them the well-known black hole solutions in which the usual electric charge is superseded by an axion charge.Comment: New formulas and references adde

    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

    Dynamical systems of M\"obius transformation: real, pp-adic and complex variables

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    In this paper we consider function f(x)=x+abx+cf(x)={x+a\over bx+c}, (where b0b\ne 0, cabc\ne ab, xcbx\ne -{c\over b}) on three fields: the set of real, pp-adic and complex numbers. We study dynamical systems generated by this function on each field separately and give some comparison remarks. For real variable case we show that the real dynamical system of the function depends on the parameters (a,b,c)R3(a,b,c)\in \mathbb R^3. Namely, we classify the parameters to three sets and prove that: for the parameters from first class each point, for which the trajectory is well defined, is a periodic point of ff; for the parameters from second class any trajectory (under ff) converges to one of fixed points (there may be up to two fixed points); for the parameters from third class any trajectory is dense in R\mathbb R. For the pp-adic variable we give a review of known results about dynamical systems of function ff. Then using a recently developed method we give simple new proofs of these results and prove some new ones related to trajectories which do not converge. For the complex variables we give a review of known results.Comment: 13 page

    Investigation of heavy-heavy pseudoscalar mesons in thermal QCD Sum Rules

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    We investigate the mass and decay constant of the heavy-heavy pseudoscalar, BcB_c, ηc\eta_c and ηb\eta_b mesons in the framework of finite temperature QCD sum rules. The annihilation and scattering parts of spectral density are calculated in the lowest order of perturbation theory. Taking into account the additional operators arising at finite temperature, the nonperturbative corrections are also evaluated. The masses and decay constants remain unchanged under T100 MeVT\cong 100 ~MeV, but after this point, they start to diminish with increasing the temperature. At critical or deconfinement temperature, the decay constants reach approximately to 35% of their values in the vacuum, while the masses are decreased about 7%, 12% and 2% for BcB_c, ηc\eta_c and ηb\eta_b states, respectively. The results at zero temperature are in a good consistency with the existing experimental values as well as predictions of the other nonperturbative approaches.Comment: 11 Pages, 2 Tables and 6 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

    Vacuum Fluctuations of a massless spin-1/2 field around multiple cosmic strings

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    We study the interaction of a massless quantized spinor field with the gravitational filed of N parallel static cosmic strings by using a perturbative approach. We show that the presence of more than one cosmic string gives rise to an additional contribution to the energy density of vacuum fluctuations, thereby leading to a vacuum force attraction between two parallel cosmic strings.Comment: Class. Quantum Grav. 14(1997) 321

    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

    Topologically massive magnetic monopoles

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    We show that in the Maxwell-Chern-Simons theory of topologically massive electrodynamics the Dirac string of a monopole becomes a cone in anti-de Sitter space with the opening angle of the cone determined by the topological mass which in turn is related to the square root of the cosmological constant. This proves to be an example of a physical system, {\it a priory} completely unrelated to gravity, which nevertheless requires curved spacetime for its very existence. We extend this result to topologically massive gravity coupled to topologically massive electrodynamics in the framework of the theory of Deser, Jackiw and Templeton. These are homogeneous spaces with conical deficit. Pure Einstein gravity coupled to Maxwell-Chern-Simons field does not admit such a monopole solution
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