19,363 research outputs found

    Improving bounds on flavor changing vertices in the two Higgs doublet model from BBˉB-\bar{B} mixing

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    We find some constraints on the flavor changing vertices of the two Higgs doublet model, from the \Delta M_{B_{d}} measurement. Although bounds from this observable have already been considered, this paper takes into account the role of a new operator not included previously, as well as the vertices \xi_{bb}, \xi_{tc} and \xi_{sb}. Using the Cheng-Sher parametrization, we found that for a relatively light charged Higgs boson (200-300 GeV), we get that \lambda _{tt}<1, while the parameter \lambda_{bb} could have values up to about 50. In addition, we use bounds for \lambda_{tt} and \lambda_{bb} obtained from B^{0}->X_{s}\gamma at next to leading order, and studied the case where the only vanishing vertex factors are the ones involving quarks from the first family. We obtained that \Delta M_{B_{d}} is not sensitive to the change of the parameter \lambda_{sb}, while \lambda_{tc}<1Comment: 4 pages, 1 figure, LaTeX2

    Conserved quantities for a charged rotating black holes in 5D Einstein-Maxwell-Chern-Simons theory

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    Indexación: Scopus.In this work, we compute the conserved quantities of a charged rotating black hole which appears as the solution of Einstein-Maxwell action in five dimensions coupled to a Chern-Simons term for U(1) field. The addition of the Chern-Simons term will modify the Maxwell equations and the definition of charge but not the Einstein field equations. Upon the addition of suitable boundary terms for the pure gravity sector of the theory, which depend on the extrinsic and intrinsic curvatures (Kounterterms), we obtain the correct conserved quantities of the solution. © Published under licence by IOP Publishing Ltd.We thank Giorgos Anastasiou and David Rivera-Betancour for insightful discussions. This work was funded in part by FONDECYT Grant 1131075, UNAB Grant DI-1336-16/RG and CONICYT Grant DPI 20140115.https://iopscience.iop.org/article/10.1088/1742-6596/1043/1/01202

    The process μνeeνˉμ\mu \to \nu_{e}e\bar{\nu}_{\mu} in the 2HDM with flavor changing neutral currents

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    We consider the process μνeeνˉμ\mu \to \nu_{e}e\bar{\nu}_{\mu} in the framework of a two Higgs doublet model with flavor changing neutral currents (FCNC). Since FCNC generates in turn flavor changing charged currents in the lepton sector, this process appears at tree level mediated by a charged Higgs boson exchange. From the experimental upper limit for this decay, we obtain the bound ξμe/mH±3.8×103| \xi_{\mu e}/m_{H^{\pm}}| \leq 3.8\times 10^{-3} whereξμe \xi_{\mu e} refers to the mixing between the first and second lepton generations, and mH±m_{H^{\pm}} denotes the mass of the charged Higgs boson. This bound is independent on the other free parameters of the model. In particular, for mH±100m_{H^{\pm}}\simeq 100GeV we get ξeμ| \xi_{e\mu}| 0.38\lesssim 0.38Comment: 2 pages, no figure
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