A 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=13 TeVis presented. The data were recorded by the CMS experiment at the CERN LHC and correspond to an integrated luminosity of 2.3 fb−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, N , stems from a composite-fermion scenario. Exclusion limits are set for the first time on the mass of the heavy composite Majorana neutrino, mN , and the compositeness scale . For the case mN = , the existence of Ne(Nμ) is excluded for masses up to 4.60 (4.70)TeV at 95% confidence level.
Sirunyan, A. M., Tumasyan, A., Adam, W., Ambrogi, F., Asilar, E., Bergauer, T., ... & Flechl, M. (2017). Search for a heavy composite Majorana neutrino in the final state with two leptons and two quarks at s= 13TeV. Physics letters B, 775, 315-337.