4,856 research outputs found

    Shedding light on the ttˉt \bar t asymmetry: the photon handle

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    We investigate a charge asymmetry in ttˉγt \bar t \gamma production at the LHC that provides complementary information to the measured asymmetries in ttˉt \bar t production. We estimate the experimental uncertainty in its measurement at the LHC with 8 and 14 TeV. For new physics models that simultaneously reproduce the asymmetry excess in ttˉt \bar t at the Tevatron and the SM-like asymmetry at the LHC, the measurement in ttˉγt \bar t \gamma at the LHC could exhibit significant deviations with respect to the SM prediction.Comment: LaTeX 15 page

    Asymmetries in top quark pair production at hadron colliders

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    We review the asymmetries in top quark pair production at the Tevatron and the LHC. We summarize the experimental measurements and the interpretations of a possible excess in terms of new physics. We also review other top quark properties-emphasizing effects related to the ttˉt \bar t asymmetries-as well as other collider signals.Comment: RevTeX 40 pages. Final version to be published in Reviews of Modern Physics, with several addition

    El Derecho Internacional Público en la Constitución Española de 1978

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    Boosting the t tbar charge asymmetry

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    We propose a kinematical enhancement of the t tbar charge asymmetry at the LHC by selecting events with the t tbar centre of mass frame highly boosted along the beam axis. This kinematical selection increases the asymmetries and their significance up to a factor of two in a rather model-independent fashion. Hence, it can be a perfect complement to enhance model discrimination at the LHC.Comment: LaTeX 15 pages. Enlarged discussions and several plots added. Final version to appear in PL

    Air radon concentration decrease in a waste water treatment plant

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    Rn-222 is a naturally occurring gas created from the decay of Ra-226. The long-term health risk of breathing radon is lung cancer. One particular place where indoor radon concentrations can exceed national guidelines is in wastewater treatment plants (WWTPs) where treatment processes may contribute to ambient airborne concentrations. The aim of this paper was to study the radon concentration decrease after the application of corrective measures in a Spanish WWTP. According to first measures, air radon concentration exceeded International Commission Radiologica1 Protection (ICRP) normative (recommends intervention between 400 and 1000 Bq m(-3)). Therefore, the WWTP improved mechanical forced ventilation to lower occupational exposure. This measure allowed to increase the administrative controls, since the limitation of workers access to the plant changed from 2 h d(-1) (considering a maximum permissible dose of 20 mSv y(-1) averaged over 5 y) to 7 h d(-1).Juste Vidal, BJ.; Ortiz Moragón, J.; Verdú Martín, GJ.; Martorell Alsina, SS. (2015). Air radon concentration decrease in a waste water treatment plant. Oxford University Press. doi:10.1093/RPD/NCV329

    Functional barriers to the adoption of electronic banking: The moderating effect of gender

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    The adoption of electronic banking in Spain is lower compared to other countries. This study analyzes the barriers that prevent its adoption, with the conceptual framework of the theory of resistance to innovation. In addition, it analyzes the moderating effect of gender on these barriers. Using structural equations, through PLS and multi-group analysis, the results confirm consumer resistance to electronic banking adoption by functional barriers. It highlights the importance of the value barrier, being this aspect of particular relevance for men, while women are more affected by the complexity in the use of electronic banking. These results have implications for management in overcoming non-adopters’ resistance to the innovation. La adopción de la banca electrónica en España es menor en comparación con otros países. Este estudio analiza las barreras que impiden su adopción, con el marco conceptual de la teoría de la resistencia a la innovación. Además, analiza el efecto moderador del género sobre estas barreras. Utilizando ecuaciones estructurales, a través de PLS y análisis multi-grupo, los resultados confirman la resistencia del consumidor a la adopción de la banca electrónica por barreras funcionales. Destaca la importancia de la barrera de valor, siendo este aspecto de especial relevancia para los hombres, mientras que a las mujeres les impacta más la complejidad en el uso de la banca electrónica. Estos resultados tienen implicaciones para la gestión para superar la resistencia de los no adoptantes a la innovación

    Collider-independent t tbar forward-backward asymmetries

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    We introduce the forward-backward asymmetries A_u, A_d corresponding to u ubar, d dbar -> t tbar production, respectively, at hadron colliders. These are collider- and center-of-mass-independent observables, directly related to the forward-backward and charge asymmetries measured at the Tevatron and the LHC, respectively. We discuss how to extract these asymmetries from data. Because these asymmetries are collider-independent, their measurement at these two colliders could elucidate the nature of the anomalous forward-backward asymmetry measured at the Tevatron. Our framework also shows in a model-independent fashion that a positive Tevatron asymmetry exceeding the standard model expectation is compatible with the small asymmetry measured at the LHC.Comment: RevTeX 5 pages. Extended discussion about A_FB vs A_C, several clarifications, references added. Version to appear in PR

    Socioeconomic and Ethnobotanical Importance of the Breadfruit Tree (Artocarpus Communis J. G & G. Forster) in Benin

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    This study aims to evaluate ethnobotanical knowledge that populations hold and income from the exploitation of the breadfruit (Artocarpus communis) in southern Benin. The data collected by interview and focus group are related to the uses of Artocarpus communis, harvest methods and the habitat of specie. The results show that A. communis is used for: food, trade, artisanal, energetic, cultural and medicinal. Local populations know the species with unequal distribution among gender (Men ID = 0.75 and IE = 0.08) and Women (ID = 0.48 and IE = 0.06); and when it comes to age (Young ID = 0.56 and IE = 0.07; Adult ID = 0.606 and IE = 0.08; Old ID = 0.75 and IE = 0.1) suggesting that people make various uses of the species. The most used plant part was the fruit (VUT=11, 87). These organs (Fruits, Flowers, Leaf), are collected either by picking or collecting, (bark) by debarking and (root) by digging. 50.51% of people surveyed collected those organs on breadfruit trees present at homes, 14.65% on those present in fields, 11.62% in the dregs and 23.23% in fallow lands. The average fruit yield of an orchard is estimated at 17 tonnes/ha, which represents an average income of about 2817 USD/individual/year
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