9,513 research outputs found

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

    Full text link
    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

    Full text link
    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

    Large pseudoscalar Yukawa couplings in the complex 2HDM

    Get PDF
    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

    CP violation in 2HDM and EFT: the ZZZ vertex

    Full text link
    We study the CP violating ZZZ vertex in the two-Higgs doublet model, which is a probe of a Jarlskog-type invariant in the extended Higgs sector. The form factor f4Zf_4^Z is evaluated at one loop in a general RξR_\xi gauge and its magnitude is estimated in the realistic parameter space. Then we turn to the decoupling limit of the two-Higgs doublet model, where the extra scalars are heavy and the physics can be described by the Standard Model supplemented by higher-dimensional operators. The leading operator contributing to f4Zf_4^Z at one loop is identified. The CP violating ZZZ vertex is not generated in the effective theory by dimension-8 operators, but instead arises only at the dimension-12 level, which implies an additional suppression by powers of the heavy Higgs mass scale.Comment: 21 pages; v2: added references and comments, appendix A on method of regions, and appendix B on derivation of CP-violating effective Lagrangian. Corrected discussion of dimension-12 operators contributing to ZZZ vertex. Final JHEP versio

    As novas tecnologias de informação no ensino da biologia: um estudo sobre fotossíntese com alunos do 10º ano de escolaridade

    Get PDF
    Ao longo das duas últimas décadas, investigações desenvolvidas no domínio do ensino da Biologia revelaram que muitos alunos possuíam concepções alternativas. Este facto conduziu ao incremento de uma linha de investigação centrada em estratégias de ensino que pudessem facilitar o desenvolvimento/ reestruturação dessas concepções. Algumas dessas estratégias incluem o recurso às Tecnologias de Informação, nomeadamente, ao Sistema de Aquisição e Tratamento de Dados (SATD), uma vez que este equipamento, ao permitir reduzir o tempo gasto no tratamento de dados, disponibiliza um maior período de tempo para os alunos preverem resultados, reflectirem e discutirem resultados obtidos, bem como compararem resultados discrepantes. Tendo como referência estas investigações, realizou-se um estudo, no tema "Fotossíntese", que incluiu 41 alunos do 10.0 ano de escolaridade, distribuídos por duas turmas - uma experimental e outra de controlo. As duas desenvolveram actividades laboratoriais, com recurso, respectivamente, ao SATD (turma experimental) e a equipamento tradicional (turma de controlo). A análise de resultados mostrou que os alunos da primeira revelaram, relativamente aos alunos da segunda, uma evolução conceptual mais extensa no tópico "Fotossíntese". Estes resultados parecem indicar que o SATD constitui um factor facilitador da aprendizagem dos alunos.During the last two decades, research studies carried out within the domain of biology educacion have shown that many students' hold alternative conceptions. This fact led to the development of another area of research that focuses on teaching strategies aiming at developing/restructuring those conceptions. Some of those strategies are based on information technology, namely on datalloging. Several researchers have argued that datalogging reduces the time usually spent with data handling and therefore releases a longer time interval (that can be used) for prevision of results, reflection upon both discussion of data collected and discrepant results. In order to evaluate the efficacy of datalogging to promote students' conceptual development a research study focusing on photosynthesis was canied out. The research was undertaken with 41 tenth graders that were allocated to a control class and to an experimental class. Both classes carried out the sarne laboratory activities but the former used traditional lab equipment whilst the latter utilised datalogging. The analysis of the results shows that students in the experimental class experienced a deeper conceptual change than their control class counterparts. These results seem to indicare that datalogging facilitares students’ learning on photosynthesis.Des recherches dans le domaine de l'enseignement de la Biologie ont révélé que bien des d'éleves possedent des conceptions alternatives. Ce fait a conduit au développement d'une autre ligne de recherche centrée sur des sLratégies d'enseignement qui facilitem le développement/restructuration de ces conceptions. Certaines de ces stratégies incluent des Technologies de l'Information, notamment "l'expérimentation assistée par ordinateur" (ExAO), vu qu'il permet de réduire le temps gaspillé avec le traitement des données, offre plus de temps pour que les éleves prévoient des résultats, réfléchissent sur les résultats obtenus et en discutent, et qu'ils comparent les résultats discordants. Ayant pour référence ces lignes de recherche, on a réalisé une étude, sur la photosynthese, qui a indu 41 éleves de la lüe année de scolarité, distribués dans deux classes - une expérimentale et une autre de contrôle. Les deux classes ont développé des activités de laboratoire en recourant respectivement au ExAO et à un équipement traditionnel. L'analyse des résultats a montré que les éleves de la classe expérimentale ont révélé, relativement aux éleves de la classe de contôle, une évolution conceptuelle plus large dans la photosynthese. Ces résultats semblent indiquer que le ExAO constitue un facteur qui facilite l'apprentissage des éleves

    The role of environmental concern and technology show-off on electric vehicles adoption: the case of Macau

    Get PDF
    Purpose: Research on battery electric vehicles (BEVs) has typically considered environmental concern a key determinant of behavioral intention that leads individuals to prefer electric vehicles. This paper challenges this assumption and argues that technology frameworks may require new variables to capture consumers' preferences. A UTAUT2-based study has been developed to assess the role of environmental concern in the BEVs context and put forward the technology show-off (TS) concept to explain the technology's acceptance. Design/methodology/approach: A quantitative and cross-sectional look at behavioral intention is adopted. The study uses structural equation modeling to analyze a sample of 236 Macau residents to determine the relevance of the factors behind the choice to adopt BEVs. Findings: The findings indicate that environmental concern and price may be relevant to explain behavioral intention to adopt the BEVs technology. Furthermore, the UTAUT2 framework seems to benefit from adding new variables, with TS playing a pertinent role in explaining technology acceptance. Social implications: The findings show that environmental concern fails to build an argument for the shift to full electric mobility and promote the desired behavioral change toward adopting BEVs. Herein lies the necessity to consider new variables that can better describe the characteristics of modern society.Originality/value: This paper proposes the TS construct, combining visibility and trialability as significant determinants of behavioral intention to use technology. The study also stresses the need to reconsider the role of environmental concerns' impact on consumer decision-making.info:eu-repo/semantics/acceptedVersio

    Does cultural background influence the dissemination and severity of the COVID-19 pandemic?

    Get PDF
    The COVID-19 pandemic has spread throughout the globe affecting countries worldwide. However, several differences have been observed in the number of daily new cases, the COVID-19 reproduction rate, and the severity of the disease in different countries. Previous studies have mostly highlighted government restriction policies to mitigate the pandemic effects as reasons for such differences. This study focuses on 101 countries and proposes that each country’s cultural background is also accountable for such differences. We considered the six Hofstede’s cultural dimensions (power distance, individualism, masculinity, uncertainty avoidance, long term orientation, and indulgence) and statistically analyzed their correlation with several COVID-19 impact metrics in comparison to several restriction policies. Our results support our claim that national culture influences both acceptance and subsequent adoption of restriction policies and the implementation by each government of those policies. We highlight that the attitudes towards and trust in political institutions, policies and governance is influenced by the cultural background, which is reflected in the pandemic numbers. As a main takeaway from this study, we conclude that data-driven models which aim at predicting the pandemic impact evolution at a global scale should also include variables that reflect the cultural background of each nation.info:eu-repo/semantics/publishedVersio
    corecore