218 research outputs found

    Direct CP violation in D+K0(Kˉ0)π+D^+ \to K^0(\bar K^0) \pi^+ decays as a probe for new physics

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    In this paper we investigate CP violation in charged decays of DD meson. Particularly, we study the direct CP asymmetry of the Cabibbo favored non-leptonic D+Kˉ0π+D^+ \rightarrow \bar K^0 \pi^+ and the doubly Cabibbo-suppressed decay mode D+K0π+D^+ \rightarrow K^0 \pi^+ within standard model, two Higgs doublet model with generic Yukawa structure and left right symmetric models. In the standard model, we first derive the contributions from box and di-penguin diagrams contributing to their amplitudes which are relevant to the generation of the weak phases essential for non-vanishing direct CP violation. Then, we show that these phases are so tiny leading to a direct CP asymmetry of order 101110^{-11} in both decay modes. Regarding the two Higgs doublet model with generic Yukawa structure and after taking into account all constraints on the parameter space of the model, we show that the enhanced direct CP asymmetries can be 6 and 7 orders of magnitudes larger than the standard model prediction for D+Kˉ0π+D^+ \rightarrow \bar K^0 \pi^+ and D+K0π+D^+ \rightarrow K^0 \pi^+ respectively. Finally, within left right symmetric models, we find that sizable direct CP asymmetry of O(103){\mathcal O } (10^{-3}) can be obtained for the decay mode D+Kˉ0π+D^+ \rightarrow \bar K^0 \pi^+ after respecting all relevant constraints.Comment: 20 pages, 2 figures. arXiv admin note: text overlap with arXiv:1710.0041

    A new strategy for probing the Majorana neutrino CP violating phases and masses

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    We propose a new strategy for detecting the CP-violating phases and the effective mass of muon Majorana neutrinos by measuring observables associated with neutrino-antineutrino oscillations in π±\pi^{\pm} decays. Within the generic framework of quantum field theory, we compute the non-factorizable probability for producing a pair of same-charged muons in π±\pi^{\pm} decays as a distinctive signature of νμνμˉ\nu_{\mu}-\bar{\nu_{\mu}} oscillations. We show that an intense neutrino beam through a long baseline experiment is favored for probing the Majorana phases. Using the neutrino-antineutrino oscillation probability reported by MINOS collaboration, a new stringent bound on the effective muon-neutrino mass is derived.Comment: 4 pages, 1 figur

    Supersymmetric contribution to B to rho K and B to pi K^* decays in SCET

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    We analyze the supersymmetric contributions to the direct CP asymmetries of the decays BπKB \to \pi K^* and BρKB\to\rho K within Soft Collinear Effective Theory. We extend the Standard Model analysis of these asymmetries to include the next leading order QCD corrections. We find that, even with QCD correction, the Standard Model predictions can not accommodate the direct CP asymmetries in these decay modes. Using Mass Insertion Approach, we show that non-minimal flavor SUSY contributions mediated by gluino exchange can enhance the CP asymmetries significantly and thus can accommodate the experimental results.Comment: 12 pages, 5 figures, version to appear in PL

    Complex Hybrid Inflation and Baryogenesis

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    We propose a hybrid inflation model with a complex waterfall field which contains an interaction term that breaks the U(1) global symmetry associated to the waterfall field charge. We show that the asymmetric evolution of the real and imaginary parts of the complex field during the phase transition at the end of inflation translates into a charge asymmetry. The latter strongly depends on the vev of the waterfall field, which is well constrained by diverse cosmological observations.Comment: 4 RevTex pages, no figures. Changes made in response to referee's comments; matches version published in Phys.Rev.Let

    Neutrino Mixing and the Pattern of Supersymmetry Breaking

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    We study the implications of a large νμντ\nu_\mu - \nu_\tau mixing angle on lepton flavour violating radiative transitions in supersymmetric extensions of the standard model. The transition rates are calculated to leading order in ϵ\epsilon, the parameter which characterizes the flavour mixing. The uncertainty of the predicted rates is discussed in detail. For models with modular invariance the branching ratio BR(μeγ)BR(\mu \to e \gamma) mostly exceeds the experimental upper limit. In models with radiatively induced flavour mixing the predicted range includes the upper limit, if the Yukawa couplings in the lepton sector are large, as favoured by Yukawa coupling unification.Comment: 12 pages, 2 figures, used axodraw.sty, to be published in Physics Letters