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

Abstract

A search is performed for heavy Majorana neutrinos (N) using an event signature defined by two muons of the same charge and two jets (\(\mu^{±}\mu^{±}jj\)). 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 \(|V_{\mu N}|^{2}\) as a function of Majorana neutrino mass mN for masses in the range of 40-500 GeV, where \(V_{\mu N}\) is the mixing element of the heavy neutrino with the standard model muon neutrino. The limits obtained are \(|V_{\mu N}|^{2}\) < 0.00470 for \(m_{N}\) = 90 GeV, \(|V_{\mu N}|^{2}\) < 0.0123 for \(m_{N}\) = 200 GeV, and \(|V_{\mu N}|^{2}\) < 0.583 for \(m_{N}\) = 500 GeV. These results extend considerably the regions excluded by previous direct searches.