Search for Z' bosons decaying to pairs of heavy Majorana neutrinos in proton-proton collisions at $\sqrt{s}$ = 13 TeV

A search for pair production of heavy Majorana neutrinos (N) from the decays of Z' bosons is performed using the CMS detector at the LHC. The data were collected in proton-proton collisions at a center-of-mass energy of $\sqrt{s}$ = 13 TeV, with an integrated luminosity of $138 fb^{-1}$. The signature for the search is two same-flavor leptons (e or $\mu$) and at least two jets. No significant excess of events beyond the expected background is observed. Upper limits at 95\% confidence level are set on the product of cross section and branching fraction for the pair production of ${N}_{l}$, as functions of ${N}_{l}$ and Z' boson masses (${m}_{N}$ and ${m}_{Z'}$, respectively) for ${m}_{Z'}$ from $0.4$ to 4.4 TeV and ${m}_{N}$ from 0.1 TeV to ${m}_{Z'}/2$. In the theoretical framework of a left-right symmetric model, exclusion bounds on the ${m}_{N}$-${m}_{Z'}$ plane are presented in both the electron and muon channels. The observed upper limit on ${m}_{Z'}$ reaches up to 4.42 TeV.