Evidence for t\bartt\bart production in the multilepton final state in proton–proton collisions at \sqrts=13 \text TeV with the ATLAS detector

Laura Franconi, Sigve Haug, Michele Weber, John Kenneth Anders, Armin Fehr, Hans Peter Beck, Antonio Ereditato, Meghranjana Chatterjee, Niklaus Lehmann, Antonio Miucci, Thomas Daniel Weston
A search is presented for four-top-quark production using an integrated luminosity of 139 fb−1 of proton–proton collision data at a centre-of-mass energy of 13 TeV collected by the ATLAS detector at the LHC. Events are selected if they contain a same-sign lepton pair or at least three leptons (electrons or muons). Jet multiplicity, jet flavour and event kinematics are used to separate signal from the background through a multivariate discriminant, and dedicated control regions are used to
more » ... ain the dominant backgrounds. The four-top-quark production cross section is measured to be 24+7−6 fb. This corresponds to an observed (expected) significance with respect to the background-only hypothesis of 4.3 (2.4) standard deviations and provides evidence for this process.
doi:10.48350/155545 fatcat:23rjlzhs3jeapjzl2dqkaauwwm