6,312 research outputs found

    Spontaneous CP-violation in the Simplest Little Higgs Model

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    We proposed how spontaneous CP-violation can be generated in the simplest little Higgs model in this talk. Comparing with the original paper, both formalism and phenomenology are updated. The model is still alive facing the collider and electric dipole moment (EDM) measurements. Strictest constraint comes from LHC Z′Z' direct search, which leads to f≳8 TeVf\gtrsim8~\textrm{TeV}. Higgs measurements also set strict constraint on the scalar mixing angle, if the Higgs rare decay channel is open. EDM measurements still set weak constraints for this model, even after the recent ACME updated measurement on electron's EDM. In this talk, we also discussed the test of CP-violation in the scalar sector, through the interactions between scalars and gauge bosons.Comment: Talk given at The 39th International Conference on High Energy Physics (ICHEP2018, July 4-11, Seoul, Korea); 4 pages; references and abstract updated; submitted version to Po

    Higgs-μ\mu-τ\tau Coupling at High and Low Energy Colliders

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    There is no tree-level flavor changing neutral current (FCNC) in the standard model (SM) which contains only one Higgs doublet. If more Higgs doublets are introduced for various reasons, the tree level FCNC would be inevitable except extra symmetry was imposed. Therefore FCNC processes are the excellent probes for the physics beyond the SM (BSM). In this paper, we studied the lepton flavor violated (LFV) decay processes h→μτh\rightarrow\mu\tau and τ→μγ\tau\rightarrow\mu\gamma induced by Higgs-μ\mu-τ\tau vertex. For τ→μγ\tau\rightarrow\mu\gamma, its branching ratio is also related to the httˉht\bar{t}, hτ+τ−h\tau^+\tau^- and hW+W−hW^+W^- vertices. We categorized the BSM into two scenarios for the Higgs coupling strengths near or away from SM. For the latter scenario, we took the spontaneously broken two Higgs doublet model (Lee model) as an example. We considered the constraints by recent data from LHC and B factories, and found that the measurements gave weak constraints. At LHC Run II, h→μτh\rightarrow\mu\tau will be confirmed or set stricter limit on its branching ratio. Accordingly, Br(τ→μγ)≲O(10−10−10−8)\textrm{Br}(\tau\rightarrow\mu\gamma)\lesssim\mathcal{O}(10^{-10}-10^{-8}) for general chosen parameters. For the positive case, τ→μγ\tau\rightarrow\mu\gamma can be discovered with O(1010)\mathcal{O}(10^{10}) τ\tau pair samples at SuperB factory, Super τ\tau-charm factory and new Z-factory. The future measurements for Br(h→μτ)\textrm{Br}(h\rightarrow\mu\tau) and Br(τ→μγ)\textrm{Br}(\tau\rightarrow\mu\gamma) will be used to distinguish these two scenarios or set strict constraints on the correlations among different Higgs couplings, please see Table II in the text for details.Comment: 18 pages, 10 figures, 2 table; more references added; more discussions about cancellation in the amplitude added accoeding to the referee's suggestion

    Enhanced quantum teleportation in the background of Schwarzschild spacetime by weak measurements

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    It is commonly believed that the fidelity of quantum teleportation in the gravitational field would be degraded due to the heat up by the Hawking radiation. In this paper, we point out that the Hawking effect could be eliminated by the combined action of pre- and post-weak measurements, and thus the teleportation fidelity is almost completely protected. It is intriguing to notice that the enhancement of fidelity could not be attributed to the improvement of entanglement, but rather to the probabilistic nature of weak measurements. Our work extends the ability of weak measurements as a quantum technique to battle against gravitational decoherence in relativistic quantum information.Comment: 9 pages, 5 figures, comments are welcom
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