{"@context":"http://schema.org","@id":"https://doi.org/10.17182/hepdata.155342.v1","@reverse":{"isBasedOn":[{"@type":"ScholarlyArticle","identifier":{"@type":"PropertyValue","propertyID":"URL","value":"https://inspirehep.net/literature/2816994"}},{"@id":"https://doi.org/10.1103/PhysRevD.110.112004","@type":"JournalArticle"}]},"@type":"Dataset","additionalType":"Collection","author":{"@type":"Organization","name":"ATLAS Collaboration"},"creator":{"@type":"Organization","name":"ATLAS Collaboration"},"datePublished":"2024","description":"A search for heavy right-handed Majorana neutrinos is performed with the ATLAS detector at the CERN Large Hadron Collider, using the 140 $\\mathrm{fb}^{-1}$ of proton-proton collision data at $\\sqrt{s}$ = 13 TeV collected during Run 2. This search targets $t\\bar{t}$ production, in which both top quarks decay into a bottom quark and a $W$ boson, where one of the $W$ bosons decays hadronically and the other decays into an electron or muon and a heavy neutral lepton. The heavy neutral lepton is identified through a decay into an electron or muon and another $W$ boson, resulting in a pair of same-charge same-flavor leptons in the final state. This paper presents the first search for heavy neutral leptons in the mass range of 15-75 GeV using $t\\bar{t}$ events. No significant excess is observed over the background expectation, and upper limits are placed on the signal cross-sections. Assuming a benchmark scenario of the phenomenological type-I seesaw model, these cross-section limits are then translated into upper limits on the mixing parameters of the heavy Majorana neutrino with Standard Model neutrinos.","hasPart":[{"@id":"https://doi.org/10.17182/hepdata.155342.v1/t1","@type":"Dataset","description":"Definitions of different signal and control regions. The control regions are enriched in events from the following processes. ttW, heavy-flavor...","name":"Table 1"},{"@id":"https://doi.org/10.17182/hepdata.155342.v1/t2","@type":"Dataset","description":"Post-fit event yields for the different background processes in the signal regions, as obtained from the background-only fit in the...","name":"Table 2"},{"@id":"https://doi.org/10.17182/hepdata.155342.v1/t3","@type":"Dataset","description":"Expected and observed upper limits on the signal cross-sections at 95% CL.","name":"Table 3"},{"@id":"https://doi.org/10.17182/hepdata.155342.v1/t4","@type":"Dataset","description":"The cutflow table for $N1$ and $N2$ signal samples for different mass points. The samples consist of both $ee$ and...","name":"Table 4 (Auxiliary material)"},{"@id":"https://doi.org/10.17182/hepdata.155342.v1/t5","@type":"Dataset","description":"The cutflow table for $N3$ signal samples for different mass points. The samples consist of both $ee$ and $\\mu\\mu$ final...","name":"Table 5 (Auxiliary material)"},{"@id":"https://doi.org/10.17182/hepdata.155342.v1/t6","@type":"Dataset","description":"Expected and observed upper limits on the strength of HNL mixing with electron neutrinos","name":"Figure 6 ee"},{"@id":"https://doi.org/10.17182/hepdata.155342.v1/t7","@type":"Dataset","description":"Expected and observed upper limits on the strength of HNL mixing with muon neutrinos","name":"Figure 6 mumu"},{"@id":"https://doi.org/10.17182/hepdata.155342.v1/t8","@type":"Dataset","description":"Expected and observed upper limits on the strength of HNL mixing with tau neutrinos","name":"Figure 6 tautau"}],"identifier":[{"@type":"PropertyValue","propertyID":"HEPDataRecord","value":"https://www.hepdata.net/record/ins2816994?version=1"},{"@type":"PropertyValue","propertyID":"HEPDataRecordAlt","value":"https://www.hepdata.net/record/155342"}],"inLanguage":"en","name":"Search for heavy right-handed Majorana neutrinos in the decay of top quarks produced in proton$-$proton collisions at $\\sqrt{s}$ = 13 TeV with the ATLAS detector","provider":{"@type":"Organization","name":"HEPData"},"publisher":{"@type":"Organization","name":"HEPData"},"url":"https://www.hepdata.net/record/ins2816994?version=1","version":1}