CMS collaboration (2218 authors)Nayak, ArunaBargassa, PedrameBeirão Da Cruz E Silva, CristóvãoCalpas, BettyDi Francesco, AgostinoFaccioli, PietroGallinaro, MicheleHollar, JonathanLeonardo, NunoLloret Iglesias, LaraSeixas, JoaoToldaiev, OleksiiVadruccio, DanieleVarela, JoaoVischia, PietroDavid Tinoco Mendes, AndreSilva, PedroMusella, PasqualePela, Joao2019-02-042019-02-042017-12-10http://dx.doi.org/10.1016/j.physletb.2017.11.001http://hdl.handle.net/10400.26/27371A search for physics beyond the standard model in the final state with two same-flavour leptons (electrons or muons) and two quarks produced in proton–proton collisions at s=13TeV is presented. The data were recorded by the CMS experiment at the CERN LHC and correspond to an integrated luminosity of 2.3fb−1 . The observed data are in good agreement with the standard model background prediction. The results of the measurement are interpreted in the framework of a recently proposed model in which a heavy Majorana neutrino, Nℓ , stems from a composite-fermion scenario. Exclusion limits are set for the first time on the mass of the heavy composite Majorana neutrino, mNℓ , and the compositeness scale Λ. For the case mNℓ=Λ , the existence of Ne ( Nμ ) is excluded for masses up to 4.60 (4.70) TeV at 95% confidence level.engjournal article2019-02-04