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 |VμN|2 as a function of Majorana neutrino mass mN for masses in the range of 40-500 GeV, where VμN is the mixing element of the heavy neutrino with the standard model muon neutrino. The limits obtained are |VμN|2<0.00470 for mN=90 GeV, |VμN|2<0.0123 for mN=200 GeV, and |VμN|2<0.583 for mN=500 GeV. These results extend considerably the regions excluded by previous direct searches.