{"@context":"http://schema.org","@id":"https://doi.org/10.17182/hepdata.167367.v1","@reverse":{"isBasedOn":[{"@type":"ScholarlyArticle","identifier":{"@type":"PropertyValue","propertyID":"URL","value":"https://inspirehep.net/literature/2964565"}},{"@id":"https://doi.org/10.1140/epjc/s10052-025-15191-w","@type":"JournalArticle"}]},"@type":"Dataset","additionalType":"Collection","author":{"@type":"Organization","name":"ATLAS Collaboration"},"creator":{"@type":"Organization","name":"ATLAS Collaboration"},"datePublished":"2025","description":"The existence of right-handed neutrinos with Majorana masses below the electroweak scale could help address the origins of neutrino masses, the matter-antimatter asymmetry, and dark matter. In this paper, leptonic decays of $W$ bosons from 140 fb$^{-1}$ of 13 TeV proton-proton collisions at the LHC, reconstructed in the ATLAS experiment, are used to search for heavy neutral leptons produced through their mixing with muon or electron neutrinos in a scenario with lepton number violation. The search is conducted using prompt leptonic decay signatures. The considered final states require two same-charge leptons or three leptons, while vetoing three-lepton same-flavour topologies. No significant excess over the expected Standard Model backgrounds is found, leading to constraints on the heavy neutral lepton's mixing with muon and electron neutrinos for heavy-neutral-lepton masses. The analysis excludes $|U_{e}|^2$ values above $8\\times 10^{-5}$ and $|U_{\\mu}|^2$ values above $5.0 \\times 10^{-5}$ in the full mass range of 8-65 GeV. The strongest constraints are placed on heavy-neutral-lepton masses in the range 15-30 GeV of $|U_{e}|^2 < 1.1 \\times 10^{-5}$ and $|U_{\\mu}|^2 < 5 \\times 10^{-6}$.","hasPart":[{"@id":"https://doi.org/10.17182/hepdata.167367.v1/t1","@type":"Dataset","description":"Comparison between the data and estimated background at preselection level. Events entering the SRs defined in Section 5 are vetoed. The...","name":"Figure 2"},{"@id":"https://doi.org/10.17182/hepdata.167367.v1/t2","@type":"Dataset","description":"Comparison between the data and estimated background in the validation regions. The hatched band represents the total uncertainty in the...","name":"Figure 3"},{"@id":"https://doi.org/10.17182/hepdata.167367.v1/t3","@type":"Dataset","description":"Observed 95% confidence level (CL) exclusion limits for the (a) |Ue|2 and (b) |Uμ|2 mixing parameters versus the HNL mass. The expected...","name":"Figure 4a"},{"@id":"https://doi.org/10.17182/hepdata.167367.v1/t4","@type":"Dataset","description":"Observed 95% confidence level (CL) exclusion limits for the (a) |Ue|2 and (b) |Uμ|2 mixing parameters versus the HNL mass. The expected...","name":"Figure 4b"},{"@id":"https://doi.org/10.17182/hepdata.167367.v1/t5","@type":"Dataset","description":"Data and estimated background comparison in the three lepton SRs defined for the e±e±μ∓ decay mode. The hatched band represents...","name":"Figure 2 from Auxiliary material"},{"@id":"https://doi.org/10.17182/hepdata.167367.v1/t6","@type":"Dataset","description":"Data and estimated background comparison in the three lepton SRs defined for the μ±μ±e∓ decay mode. The hatched band represents...","name":"Figure 3 from Auxiliary material"},{"@id":"https://doi.org/10.17182/hepdata.167367.v1/t7","@type":"Dataset","description":"Data and estimated background comparison in the two lepton SRs defined for the μ±μ±e∓ decay mode. The hatched band represents...","name":"Figure 4 from Auxiliary material"},{"@id":"https://doi.org/10.17182/hepdata.167367.v1/t8","@type":"Dataset","description":"Data and estimated background comparison in a region enriched in WZ SM processes, defined with Nleptsignal =3, mT >80 GeV and...","name":"Figure 5 from Auxiliary material"},{"@id":"https://doi.org/10.17182/hepdata.167367.v1/t9","@type":"Dataset","description":"Identification of the three lepton signal region chosen to set the limits for the e±e±μ∓ decay mode. The observed (continuous...","name":"Figure 6 from Auxiliary material"},{"@id":"https://doi.org/10.17182/hepdata.167367.v1/t10","@type":"Dataset","description":"Identification of the three lepton signal region chosen to set the limits for the μ±μ±e∓ decay mode. The observed (continuous...","name":"Figure 7 from Auxiliary material"},{"@id":"https://doi.org/10.17182/hepdata.167367.v1/t11","@type":"Dataset","description":"Identification of the two lepton signal region chosen to set the limits for the μ±μ±e∓ decay mode. The observed (continuous...","name":"Figure 8 from Auxiliary material"},{"@id":"https://doi.org/10.17182/hepdata.167367.v1/t12","@type":"Dataset","description":"Observed 95% confidence-level exclusion in |Uμ|2 versus the HNL mass, as obtained with the two lepton and three lepton signal...","name":"Figure 9 from Auxiliary material"},{"@id":"https://doi.org/10.17182/hepdata.167367.v1/t13","@type":"Dataset","description":"Observed 95% confidence-level exclusion in |Uμ|2 versus the HNL mass, as obtained with the two lepton (blue) and three lepton...","name":"Figure 10 from Auxiliary material"},{"@id":"https://doi.org/10.17182/hepdata.167367.v1/t14","@type":"Dataset","description":"Observed 95% confidence-level exclusion in |Uμ|2 versus the HNL mass, as obtained with the three lepton only signal regions. The...","name":"Figure 11 from Auxiliary material"},{"@id":"https://doi.org/10.17182/hepdata.167367.v1/t15","@type":"Dataset","description":"Observed 95% confidence-level exclusion in |Uμ|2 versus the HNL mass, as obtained with the two lepton only signal regions. The...","name":"Figure 12 from Auxiliary material"}],"identifier":[{"@type":"PropertyValue","propertyID":"HEPDataRecord","value":"https://www.hepdata.net/record/ins2964565?version=1"},{"@type":"PropertyValue","propertyID":"HEPDataRecordAlt","value":"https://www.hepdata.net/record/167367"}],"inLanguage":"en","name":"Search for heavy neutral leptons in decays of W bosons produced in 13 TeV $pp$ collisions using prompt signatures in the ATLAS detector","provider":{"@type":"Organization","name":"HEPData"},"publisher":{"@type":"Organization","name":"HEPData"},"url":"https://www.hepdata.net/record/ins2964565?version=1","version":1}