4,435 research outputs found

    hZγh \rightarrow Z \gamma in the complex two Higgs doublet model

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    The latest LHC data confirmed the existence of a Higgs-like particle and made interesting measurements on its decays into γγ\gamma \gamma, ZZZ Z^\ast, WWW W^\ast, τ+τ\tau^+ \tau^-, and bbˉb \bar{b}. It is expected that a decay into ZγZ \gamma might be measured at the next LHC round, for which there already exists an upper bound. The Higgs-like particle could be a mixture of scalar with a relatively large component of pseudoscalar. We compute the decay of such a mixed state into ZγZ \gamma, and we study its properties in the context of the complex two Higgs doublet model, analysing the effect of the current measurements on the four versions of this model. We show that a measurement of the hZγh \rightarrow Z \gamma rate at a level consistent with the SM can be used to place interesting constraints on the pseudoscalar component. We also comment on the issue of a wrong sign Yukawa coupling for the bottom in Type II models.Comment: 31 pages, 15 figure

    A reappraisal of the wrong-sign hbbhb\overline{b} coupling and the study of hZγh \rightarrow Z \gamma

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    It has been pointed out recently that current experiments still allow for a two Higgs doublet model where the hbbˉh b \bar{b} coupling (kDmb/vk_D m_b/v) is negative; a sign opposite to that of the Standard Model. Due to the importance of delayed decoupling in the hH+Hh H^+ H^- coupling, hγγh \rightarrow \gamma \gamma improved measurements will have a strong impact on this issue. For the same reason, measurements or even bounds on hZγh \rightarrow Z \gamma are potentially interesting. In this article, we revisit this problem, highlighting the crucial importance of hVVh \rightarrow VV, which can be understood with simple arguments. We show that the impacts on kD<0k_D<0 models of both hbbˉh \rightarrow b \bar{b} and hτ+τh \rightarrow \tau^+ \tau^- are very sensitive to input values for the gluon fusion production mechanism; in contrast, hγγh \rightarrow \gamma \gamma and hZγh \rightarrow Z \gamma are not. We also inquire if the search for hZγh \rightarrow Z \gamma and its interplay with hγγh \rightarrow \gamma \gamma will impact the sign of the hbbˉh b \bar{b} coupling. Finally, we study these issues in the context of the Flipped two Higgs doublet model.Comment: 13 pages, pdf figure

    Discrete and continuous symmetries in multi-Higgs-doublet models

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    We consider the Higgs sector of multi-Higgs-doublet models in the presence of simple symmetries relating the various fields. We construct basis invariant observables which may in principle be used to detect these symmetries for any number of doublets. A categorization of the symmetries into classes is required, which we perform in detail for the case of two and three Higgs doublets.Comment: 13 pages, RevTex, references adde

    Large pseudoscalar Yukawa couplings in the complex 2HDM

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    We start by presenting the current status of a complex flavour conserving two-Higgs doublet model. We will focus on some very interesting scenarios where unexpectedly the light Higgs couplings to leptons and to b-quarks can have a large pseudoscalar component with a vanishing scalar component. Predictions for the allowed parameter space at end of the next run with a total collected luminosity of 300fb1300 \, fb^{-1} and 3000fb13000 \, fb^{-1} are also discussed. These scenarios are not excluded by present data and most probably will survive the next LHC run. However, a measurement of the mixing angle ϕτ\phi_\tau, between the scalar and pseudoscalar component of the 125 GeV Higgs, in the decay hτ+τh \to \tau^+ \tau^- will be able to probe many of these scenarios, even with low luminosity. Similarly, a measurement of ϕt\phi_t in the vertex tˉth\bar t t h could help to constrain the low tanβ\tan \beta region in the Type I model.Comment: 21 pages, 10 figure

    Time or state dependent price setting rules? Evidence from Portuguese micro data

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    In this paper we analyse the ability of time and state dependent price setting rules to explain durations of price spells or the probability of changing prices. Our results suggest that simple time dependent models cannot be seen as providing a reasonable approximation to the data and that state dependent models are required to fully characterise the price setting behaviour of Portuguese firms. Inflation, the level of economic activity and the magnitude of the last price change emerge as relevant variables affecting the probability of changing prices. Moreover, it is seen that the impact differs for negative and positive values of these covariates. JEL Classification: C41, D40, E31CPI data, Hazard functions, inflation

    Measuring the importance of the uniform nonsynchronization hypothesis

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    In this paper we critically reappraise some measures of the importance of time-dependent price setting rules and propose an alternative way to gauge the significance of this type of price setting behaviour. The merits of the proposed measure are highlighted in an application using micro-data. Our results suggest that a large proportion of price trajectories may be compatible with simple time-dependent price setting mechanisms but the strength of this evidence very much depends on the way that is used to evaluate the importance of this type of behaviour. JEL Classification: D40, E31, L11perfect synchronization, Time-dependent price setting models, uniform staggering
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