Combination of CDF and D0 measurements of the W boson helicity in top quark decays

We report the combination of recent measurements of the helicity of the W boson from top quark decay by the CDF and D0 collaborations, based on data samples corresponding to integrated luminosities of 2.7-5.4fb -1 of pp̄ collisions collected during Run II of the Fermilab Tevatron collider. Combining measurements that simultaneously determine the fractions of W bosons with longitudinal (f 0) and right-handed (f +) helicities, we find f 0=0.722±0.081[±0.062(stat)±0.052(syst)] and f +=-0.033±0.046[±0.034(stat)±0.031(syst)]. Combining measurements where one of the helicity fractions is fixed to the value expected in the standard model, we find f 0=0.682±0. 057[±0.035(stat)±0.046(syst)] for fixed f + and f +=-0.015±0.035[±0.018(stat)±0.030(syst)] for fixed f 0. The results are consistent with standard model expectations. © 2012 American Physical Society.

Combination of the top-quark mass measurements from the Tevatron collider

The top quark is the heaviest known elementary particle, with a mass about 40 times larger than the mass of its isospin partner, the bottom quark. It decays almost 100% of the time to a W boson and a bottom quark. Using top-antitop pairs at the Tevatron proton-antiproton collider, the CDF and D0 Collaborations have measured the top quark's mass in different final states for integrated luminosities of up to 5.8fb -1. This paper reports on a combination of these measurements that results in a more precise value of the mass than any individual decay channel can provide. It describes the treatment of the systematic uncertainties and their correlations. The mass value determined is 173.18±0.56(stat)±0.75(syst)GeV or 173.18±0.94GeV, which has a precision of ±0.54%, making this the most precise determination of the top-quark mass. © 2012 American Physical Society.

Deus abençoe a América: religião, política e relações internacionais dos Estados Unidos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Documentação de fé: reflexões sobre os ex-votos e a sala das promessas do Santuário Nacional de Aparecida

This article brings to light a reflection about the possibility to enlarge the notion about document. Beyond the French school explanation, and taking up again important author of Information Science campus, the debates exposes within the Brazilian Catholic dimensions is possible to extrapolate the revision about the document’s idea, which is generally restrict to informational spaces. The National Sanctuary of Aparecida protects in a specific room the votive offerings – objects leaved there whether to pay a promise or to thank for any miracle that someone believes receive it. It is mediation’ space and it is can be thought as an environment, because there are possibilities to establish mediations inside it. Although, the room of the promises is a sacred and profane place, it involves a Cathequesis mission, expositive, informational, in spite of this last characteristic does not be explicit. First of all, the article reflects about the room of the promises and follows analyzing the document’s comprehension; in a second moment we finish purposing to understand the votive offering as a faith’s document, because they assume the position as proof of miracles and received graces, and these special objects brings with them a materiality positive and a documental value which the room fo the promises give to them.