Reconstructing a Heavy Neutral Lepton at the LHC De la Torre Domínguez, Pablo Masip Mellado, Manuel Vilches, Fuensanta Specific BSM Phenomenology Vector-Like Fermions Electroweak Precision Physics Heavy lepton singlets N slightly mixed with a standard neutrino νℓ are usually searched for at the LHC in the trilepton plus p miss T channel: pp → W+ → ℓ +N with N → ℓ −W+ → ℓ −ℓ ′+ ν. We show that, although the longitudinal momentum of the final ν escapes detection, the mass of the heavy lepton can be reconstructed. While this possibility has not been considered in recent LHC searches, we find that the search for a mass peak could improve the current collider bounds on the mixing |VℓN | 2 for any mass mN ≥ MW . 2025-11-26T12:27:07Z 2025-11-26T12:27:07Z 2025-06-12 journal article de la Torre, P., Masip, M. & Vilches, F. Reconstructing a Heavy Neutral Lepton at the LHC. J. High Energ. Phys. 2025, 129 (2025). https://doi.org/10.1007/JHEP06(2025)129 https://hdl.handle.net/10481/108365 10.1007/JHEP06(2025)129 eng info:eu-repo/grantAgreement/EU/PRTR/AST22_6.5 info:eu-repo/grantAgreement/EU/PRTR/AST22_8.4 http://creativecommons.org/licenses/by/4.0/ open access Atribución 4.0 Internacional Springer