Search for heavy Majorana or Dirac neutrinos and right-handed W gauge bosons in final states with charged leptons and jets in pp collisions at $\sqrt{s}=13$ TeV with the ATLAS detector

A search for heavy right-handed Majorana or Dirac neutrinos ${N}_{\text{R}}$ and heavy right-handed gauge bosons ${W}_{\text{R}}$ is performed in events with energetic electrons or muons, with the same or opposite electric charge, and energetic jets. The search is carried out separately for topologies of clearly separated final-state products ("resolved" channel) and topologies with boosted final states with hadronic and/or leptonic products partially overlapping and reconstructed as a large-radius jet ("boosted" channel). The events are selected from pp collision data at the LHC with an integrated luminosity of 139 fb ${}^{-1}$ collected by the ATLAS detector at $\sqrt{s}=13$ TeV. No significant deviations from the Standard Model predictions are observed. The results are interpreted within the theoretical framework of a left-right symmetric model, and lower limits are set on masses in the heavy right-handed ${W}_{\text{R}}$ boson and ${N}_{\text{R}}$ plane. The excluded region extends to about $m\left({W}_{\text{R}}\right)=6.4$ TeV for both Majorana and Dirac ${N}_{\text{R}}$ neutrinos at $m\left({N}_{\text{R}}\right)<1$ TeV. ${N}_{\text{R}}$ with masses of less than 3.5 (3.6) TeV are excluded in the electron (muon) channel at $m\left({W}_{\text{R}}\right)=4.8$ TeV for the Majorana neutrinos, and limits of $m\left({N}_{\text{R}}\right)$ up to 3.6 TeV for $m\left({W}_{\text{R}}\right)=5.2$ (5.0) TeV in the electron (muon) channel are set for the Dirac neutrinos. These constitute the most stringent exclusion limits to date for the model considered.