Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

Cachimbos europeus de cerâmica branca, séculos XVI ao XIX: parâmetros básicos para análise arqueológica

O tabaco foi introduzido na Europa no final do século XV. Desde então, uma das formas mais comuns para o seu consumo foi o cachimbo, além do rapé, do tabaco de mascar, do charuto e, mais recentemente, dos cigarros. Os cachimbos de cerâmica branca, largamente produzidos e utilizados na Europa desde o século XV, são encontrados em sítios arqueológicos históricos ao redor do mundo, incluindo no Brasil, em decorrência do comércio internacional, que gradualmente se intensificou após o início da conquista europeia. Eles funcionam como excelentes elementos para datação de sítios e estratos arqueológicos, tendo sido estudados em vários países a partir dessa abordagem. Ainda, esse tipo de artefato, mais que fornecer datações, permite identificar redes comerciais entre nações e desenvolver discussões de cunho social e cultural. Contudo, eles foram pouco estudados no Brasil. Visando contribuir com os estudos nacionais dessa categoria material, este artigo oferece uma revisão da literatura internacional acerca do histórico da produção dos cachimbos europeus de caulim, incluindo apresentação dos principais centros produtores; da morfologia e decoração desses produtos, considerando a cronologia do fabrico; e dos métodos de análise dos diferentes cachimbos de caulim no âmbito da arqueologia histórica.Tobacco was introduced in Europe at the end of the 15th century. Since then, one of the most traditional means for its use has been the pipe, next to the powder version, chewing, cigars, and, more recently, cigarettes. White clay tobacco pipes, widely produced and used in Europe since the 15th century, are found in historical archaeological sites around the world, including Brazil, due to international trade, which gradually intensified with the European conquest of the New World. They are excellent guides for dating archaeological sites and layers. In addition, this type of artifact, more than a dating tool, permits identifying trading networks between nations and developing discussions of cultural and social nature. These pipes, however, have been understudied in Brazil. In order to contribute to studies of this type of artifact in our country, this paper offers a revision of the international literature on the history of clay pipe production in Europe, including the presentation of main production centers; morphology and decoration of these products, considering issues of fabrication chronology; and the methods used in Historical Archaeology for analyzing clay tobacco pipes