Search for heavy Majorana neutrinos in μ^±μ^± + jets events in proton-proton collisions at s=8 TeV

A search is performed for heavy Majorana neutrinos (N) using an event signature defined by two muons of the same charge and two jets (μ^±μ^±jj). The data correspond to an integrated luminosity of 19.7 fb^-1 of proton-proton collisions at a center-of-mass energy of 8 TeV, collected with the CMS detector at the CERN LHC. No excess of events is observed beyond the expected standard model background and upper limits are set on |V_μN|² as a function of Majorana neutrino mass m_N for masses in the range of 40-500 GeV, where V_μN is the mixing element of the heavy neutrino with the standard model muon neutrino. The limits obtained are |V_μN|²<0.00470 for m_N=90 GeV, |V_μN|²<0.0123 for m_N=200 GeV, and |V_μN|²<0.583 for m_N=500 GeV. These results extend considerably the regions excluded by previous direct searches.