3,716 research outputs found

    Implications for BηKB \to \eta K and BGlueball+KB \to Glueball + K Modes from Observed Large BηK+XB\to \eta' K+X

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    The unexpectedly large branching ratios for BηK(ηXs)B\to \eta' K (\eta' X_s) decays could be of gluonic origin. We study the implications for BηK(ηXs)B\to \eta K (\eta X_s) and PK(PXs)P K (PX_s), where PP is the pseudoscalar glueball. In the mechanism proposed by Fritzsch, large branching ratios are predicted for these modes. The BηKB\to \eta K rate is barely within the experimental limit, and BPKB\to P K, PXsPX_s could be at the 0.1% and 1% level, respectively. Smaller but less definite results are found for the mechanism of gηgg^* \to \eta' g via the gluon anomaly.Comment: 11 pages, revtex, no fig

    Bounds on charged higgs boson in the 2HDM type III from Tevatron

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    We consider the Two Higgs Doublet Model (2HDM) of type III which leads to Flavour Changing Neutral Currents (FCNC) at tree level. In the framework of this model we can use an appropriate form of the Yukawa Lagrangian that makes the type II model limit of the general type III couplings apparent. This way is useful in order to compare with the experimental data which is model dependent. The analytical expressions of the partial width Γ(tH+b)\Gamma (t \to H^+ b) are derived and we compare with the data available at this energy range. We examine the limits on the new parameters λij\lambda_{ij} from the validness of perturbation theory.Comment: 14 pages, 4 figures, Universidad Nacional de Colombia. typos correcte

    CP Nonconservation in ppˉtbˉXp\bar p\to t\bar b X at the Tevatron

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    The reaction ppˉtbˉXp\bar p\to t\bar bX is found to be rather rich in exhibiting several different types of CP asymmetries. The spin of the top quark plays an important role. Asymmetries are related to form factors arising from radiative corrections of the tbWtbW production vertex due to non-standard physics. As illustrations, effects are studied in two Higgs Doublet Models and in Supersymmetric Models; asymmetries up to a few percent may be possible.Comment: 14 pages, 3 figures. Note: replaced due to minor problems that appeared on some postscript previewers. No change in conten

    Implications of a W^+W^- (ZZ) - Higgs - t c-bar$ Interaction for e^+e^- -> t c-bar \nu_e \nu_e-bar, t c-bar e^+ e^-, t c-bar Z and for t -> cW^+W^-, cZZ in a Two Higgs Doublet Model

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    The Standard Model with one extra Higgs doublet may give rise to enhanced TREE-LEVEL flavor-changing-scalar coupling of a neutral Higgs to a pair of top-charm quarks. This coupling may drive a large TREE-LEVEL effective W^+W^-(ZZ) - Higgs - t c-bar interaction. As a result we find that the reactions e^+e^- -> t c-bar \nu_e \nu_e-bar, t c-bar e^+ e^-, t c-bar Z and the two rare top decays t -> cW^+W^-, t -> cZZ become very sensitive probes of such an effective interaction. The most promising ones, e^+e^- -> t c-bar \nu_e \nu_e-bar, t c-bar e^+ e^-, may yield several hundreds and up to thousands of such events at the Next Linear Collider with a center of mass energy of \sqrt{s}=0.5 - 2 TeV if the mass of the lightest neutral Higgs is a few hundred GeV. The rare decays t -> cW^+W^- and t -> cZZ may be accessible at the LHC if the mass of the lightest neutral Higgs lies in the narrow window 150 GeV < m_h < 200 GeV.Comment: 18 pages, plain latex, 12 figures embadded in the text using epsfi

    Putting a Squeeze on PubMed

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    How do you squeeze a 13-hour professional development class on PubMed into a 1-hour staff development workshop? This was the challenge that we, the workshop organizers, faced after completing the PubMed for Trainers class in the summer of 2013. Although the University hosted the class, there were several UVM librarians who could not attend. The issue facing us was how to effectively pass along the valuable information from the workshop to those absent colleagues. Our solution was to distill the most essential information from the class into a series of micro-presentations and deliver them using a modified Pecha Kucha format. This poster outlines that process

    Discrete Ambiguities in the Measurement of the Weak Phase Gamma

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    Several time-independent methods have been devised for measuring the phase gamma of the Cabibbo-Kobayashi-Maskawa unitarity triangle. It is shown that such measurements generally suffer from discrete ambiguity which is at least 8-fold, not 4-fold as commonly stated. This has serious experimental implications, which are explored in methods involving B->DK decays. The measurement sensitivity and new physics discovery potential are estimated using a full Monte Carlo detector simulation with realistic background estimates.Comment: 15 pages, 2 figures, fixed typ

    Lepton Flavor Violation in the Two Higgs Doublet Model type III

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    We consider the Two Higgs Doublet Model (2HDM) of type III which leads to Flavour Changing Neutral Currents (FCNC) at tree level in the leptonic sector. In the framework of this model we can have, in principle, two situations: the case (a) when both doublets acquire a vacuum expectation value different from zero and the case (b) when only one of them is not zero. In addition, we show that we can make two types of rotations for the flavor mixing matrices which generates four types of lagrangians, with the rotation of type I we recover the case (b) from the case (a) in the limit tanβ\tan \beta \to \infty , and with the rotation of type II we obtain the case (b) from (a) in the limit tanβ0.\tan \beta \to 0. Moreover, two of the four possible lagrangians correspond to the models of types I and II plus Flavor Changing (FC) interactions. The analitical expressions of the partial lepton number violating widths Γ(μeee)\Gamma (\mu \to eee) and Γ(μeγ)\Gamma (\mu \to e\gamma) are derived for the cases (a) and (b) and both types of rotations. In all cases these widths go asymptotically to zero in the decoupling limit for all Higgses. We present from our analysis upper bounds for the flavour changing transition μe,\mu \to e, and we show that such bounds are sensitive to the VEV structure and the type of rotation utilized.Comment: 7 pages RevTeX4, 4 figures postscript, new section added and some new reference

    Texture of Yukawa coupling matrices in general two-Higgs-doublet model

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    We discuss possible parallel textures of the Yukawa coupling matrices in the generaltwo-Higgs-doublet model (2HDM). In those textures the flavor changing neutral currentsare naturally suppressed. Motivated by a phenomenologically successful texturewith four texture zeros in the standard model, we propose a predictive ansatz for the Yukawa coupling matrices with the same texture in the general 2HDM. Compared with the six texture-zero based ansatz proposed by Cheng and Sher, it is in a better agreement with the data of quark mixings and CP violation. The four texture-zero based ansatz predicts a different hierarchy in the Yukawa coupling matrix elements. As a consequence, in the lepton sector, the related Yukawa couplings are less constrained by the experimental upper bound of μeγ\mu\to e\gamma, which allows significantly larger predictions for other processes. The contributions from neutral scalar interactions to the lepton number violation decay modes 123\ell\to \ell_{1}\ell_{2}\ell_{3} are calculated in both ansatz. It is shown that the predictions from the four texture-zero based ansatz could be two order of magnitude greater than that from the six texture-zero based one. The branching ratio of μ3e\mu\to 3e and τ3μ\tau\to 3\mu can reach 7.5×10177.5 \times 10^{-17} and 1.3\tiems 10^{-10} respectively. The predicted ratio of Br(μ3e)/Br(τ3e)Br(\mu\to 3e)/Br(\tau\to 3e) is also larger and almost parameter independent. Those differences make the two ansatz to be easily distinguished by the future experiments.Comment: 12 pages, 2 figure

    Time dependent CP asymmetry in B0ρ0γB^0 \to \rho^0 \gamma decay to probe the origin of CP violation

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    Since the CP violation in the BB system has been investigated up to now only through processes related to the BB--Bˉ\bar{B} mixing, urgently required is new way of study for the CP violation and establishing its origin in the BB system independent of the mixing process. In this work, we explore the exclusive B0ρ0γ B^0 \to \rho^0 \gamma decay to obtain the time-dependent CP asymmetry in bdb \to d decay process in the standard model and the supersymmetric model. We find that the complex RL and RR mass insertion to the squark sector in the MSSM can lead to a large CP asymmetry in bdγb \to d \gamma decay through the gluino-squark diagrams, which is not predicted in the Standard Model induced by the BB--Bˉ\bar{B} mixing.Comment: 10 pages, 4 eps figure

    Polarized Single Top Production at Leptonic Colliders from Broken R Parity Interactions Incorporating CP Violation

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    The contribution from the R parity violating interactions in the associated production of a top quark with a charm antiquark is examined for high energy leptonic colliders. We concentrate on the reactions associated with the semileptonic top decay. A set of characteristic dynamical distributions for the signal events is evaluated and the results contrasted against those from the standard model W-boson pair production background. Next, we turn to a study of a CP-odd observable, associated with the top spin, which leads to an asymmetry in the energy distribution of the emitted charged leptons for the pair of CP-conjugate final states, blˉνcˉb \bar l \nu \bar c and bˉlνˉc \bar b l \bar \nu c . A non vanishing asymmetry arises from a CP-odd phase, embedded in the R parity violating coupling constants, through interference terms between the R parity violating amplitudes at both the tree and loop levels.Comment: revtex file. 17 pages. 7 postscript figures. 1 table. The revised version includes an estimate of experimental uncertainties. Submitted to Phys. Rev.
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