Aad, G.Abbott, B.Abbott, D.C.Abed Abud, A.Abeling, K.Abhayasinghe, D.K.Abidi, S.H.AbouZeid, O.S.Abraham, N.L.Abramowicz, H.Abreu, H.Abulaiti, Y.Acharya, B.S.Achkar, B.Adam, L.Adam Bourdarios, C.Adamczyk, L.Adamek, L.Adelman, J.Adiguzel, A.Adorni, S.Adye, T.Affolder, A.A.2021-05-182021-05-182021-04Journal of High Energy Physics, Volume 2021, Issue 4, April 2021, Article number 16510298479http://repositorio.unab.cl/xmlui/handle/ria/18882Indexación ScopusThe results of a search for direct pair production of top squarks and for dark matter in events with two opposite-charge leptons (electrons or muons), jets and missing transverse momentum are reported, using 139 fb−1 of integrated luminosity from proton-proton collisions at s = 13 TeV, collected by the ATLAS detector at the Large Hadron Collider during Run 2 (2015–2018). This search considers the pair production of top squarks and is sensitive across a wide range of mass differences between the top squark and the lightest neutralino. Additionally, spin-0 mediator dark-matter models are considered, in which the mediator is produced in association with a pair of top quarks. The mediator subsequently decays to a pair of dark-matter particles. No significant excess of events is observed above the Standard Model background, and limits are set at 95% confidence level. The results exclude top squark masses up to about 1 TeV, and masses of the lightest neutralino up to about 500 GeV. Limits on dark-matter production are set for scalar (pseudoscalar) mediator masses up to about 250 (300) GeV. [Figure not available: see fulltext.] © 2021, The Author(s).enTop QuarkPartonsHiggs BosonsArtículo10.1007/JHEP04(2021)165