45,812 research outputs found

    Complementarity of LHC and EDMs for Exploring Higgs CP Violation

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    We analyze the constraints on a CP-violating, flavor conserving, two Higgs doublet model from the measurements of Higgs properties and from the search for heavy Higgs bosons at LHC, and show that the stronger limits typically come from the heavy Higgs search channels. The limits on CP violation arising from the Higgs sector measurements are complementary to those from EDM measurements. Combining all current constraints from low energy to colliders, we set generic upper bounds on the CP violating angle which parametrizes the CP odd component in the 126 GeV Higgs boson.Comment: 34 pages, 17 figures, 2 tables; references added, constraints from Higgs decay into tau updated, version accepted for publication in JHE

    Symmetry of superconducting states with two orbitals on a tetragonal lattice: application to LaO1xFxFeAsLaO_{1-x}F_{x}FeAs

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    We use group theory to classify the superconducting states of systems with two orbitals on a tetragonal lattice. The orbital part of the superconducting gap function can be either symmetric or anti-symmetric. For the orbital symmetric state, the parity is even for spin singlet and odd for spin triplet; for the orbital anti-symmetric state, the parity is odd for spin singlet and even for spin triplet. The gap basis functions are obtained with the use of the group chain scheme by taking into account the spin-orbit coupling. In the weak pairing limit, the orbital anti-symmetric state is only stable for the degenerate orbitals. Possible application to iron-based superconductivity is discussed.Comment: published versio

    Electroweak Effective Operators and Higgs Physics

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    We derive bounds from oblique parameters on the dimension-6 operators of an effective field theory of electroweak gauge bosons and the Higgs doublet. The loop- induced contributions to the S, T, and U oblique parameters are sensitive to these contributions and we pay particular attention to the role of renormalization when computing loop corrections in the effective theory. Limits on the coefficients of the effective theory from loop contributions to oblique parameters yield complementary information to direct Higgs production measurements.Comment: 33 pages, 6 figures; additional scalar operator included and references adde

    Higgs CP Violation from Vectorlike Quarks

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    We explore CP violating aspects in the Higgs sector of models where new vectorlike quarks carry Yukawa couplings mainly to the third generation quarks of the Standard Model. We point out that in the simplest model, Higgs CP violating interactions only exist in the hWW channel. At low energy, we find that rare B decays can place similarly strong constraints as those from electric dipole moments on the source of CP violation. These observations offer a new handle to discriminate from other Higgs CP violating scenarios such as scalar sector extensions of the Standard Model, and imply an interesting future interplay among limits from different experiments.Comment: 19 pages, 5 figure

    Quantum Robot: Structure, Algorithms and Applications

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    A kind of brand-new robot, quantum robot, is proposed through fusing quantum theory with robot technology. Quantum robot is essentially a complex quantum system and it is generally composed of three fundamental parts: MQCU (multi quantum computing units), quantum controller/actuator, and information acquisition units. Corresponding to the system structure, several learning control algorithms including quantum searching algorithm and quantum reinforcement learning are presented for quantum robot. The theoretic results show that quantum robot can reduce the complexity of O(N^2) in traditional robot to O(N^(3/2)) using quantum searching algorithm, and the simulation results demonstrate that quantum robot is also superior to traditional robot in efficient learning by novel quantum reinforcement learning algorithm. Considering the advantages of quantum robot, its some potential important applications are also analyzed and prospected.Comment: 19 pages, 4 figures, 2 table

    Invisible Higgs Decay at the LHeC

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    The possibility that the 125 GeV Higgs boson may decay into invisible non-standard-model (non-SM) particles is theoretically and phenomenologically intriguing. In this letter we investigate the sensitivity of the Large Hadron Electron Collider (LHeC) to an invisibly decaying Higgs, in its proposed high luminosity running mode. We focus on the neutral current Higgs production channel which offers more kinematical handles than its charged current counterpart. The signal contains one electron, one jet and large missing energy. With a cut-based parton level analysis, we estimate that if the hZZhZZ coupling is at its standard model (SM) value, then assuming an integrated luminosity of 1\,\mbox{ab}^{-1} the LHeC with the proposed 60 GeV electron beam (with 0.9-0.9 polarization) and 7 TeV proton beam is capable of probing Br(hE ⁣ ⁣ ⁣ ⁣/T)=6%\mathrm{Br}(h\rightarrow E\!\!\!\!/_T)=6\% at 2σ2\sigma level. Good lepton veto performance (especially hadronic τ\tau veto) in the forward region is crucial to the suppression of the dominant WjeWje background. We also explicitly point out the important role that may be played by the LHeC in probing a wide class of exotic Higgs decay processes and emphasize the general function of lepton-hadron colliders in precision study of new resonances after their discovery in hadron-hadron collisions.Comment: 6 pages, 3 figures. Description of the backgrounds, analysis and results is simplified. Results unchanged with respect to v2. References update