Virtual research and learning communities in Latin America : The CEVALE2VE case

New strategies for the adaptation of higher scientific education to the requirements of the network society are briefly discussed, in particular the pivotal role played by virtual research and learning communities in the Latin American region. The Centro Virtual de Altos Estudios de Altas Energias (CEVALE2VE) is singled out in reference to the virtual graduate course on particle physics that was given at several Venezuelan and Colombian national universities and research institutions during the semesters September 2014 - February 2015 and March 2016 - July 2016. Different course implementation aspects are reviewed to encourage and facilitate similar regional initiatives in the near future.Peer reviewe

Study of ordered hadron chains with the ATLAS detector

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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