Long-lived heavy neutral leptons at the LHC: four-fermion single-NR operators

Rebeca Beltrán, Giovanna Cottin, Juan Carlos Helo, Martin Hirsch, Arsenii Titov, Zeren Simon Wang

Research output: Contribution to journalArticlepeer-review

10 Scopus citations


Interest in searches for heavy neutral leptons (HNLs) at the LHC has increased considerably in the past few years. In the minimal scenario, HNLs are produced and decay via their mixing with active neutrinos in the Standard Model (SM) spectrum. However, many SM extensions with HNLs have been discussed in the literature, which sometimes change expectations for LHC sensitivities drastically. In the NRSMEFT, one extends the SM effective field theory with operators including SM singlet fermions, which allows to study HNL phenomenology in a “model independent” way. In this paper, we study the sensitivity of ATLAS to HNLs in the NRSMEFT for four-fermion operators with a single HNL. These operators might dominate both production and decay of HNLs, and we find that new physics scales in excess of 20 TeV could be probed at the high-luminosity LHC.

Original languageEnglish
Article number44
JournalJournal of High Energy Physics
Issue number1
StatePublished - Jan 2022
Externally publishedYes


  • Beyond Standard Model
  • Effective Field Theories
  • Neutrino Physics


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