Search for heavy majorana neutrinos in μ[superscript ±]μ[superscript ±] + jets events in proton–proton collisions at √s = 8 TeV

Apyan, Aram ; Barbieri, Richard Alexander ; Bierwagen, Katharina ; Busza, Wit ; Cali, Ivan Amos ; Di Matteo, Leonardo ; Gomez-Ceballos, Guillelmo ; Goncharov, Maxim ; Gulhan, Doga Can ; Klute, Markus ; Lai, Yue Shi ; Lee, Yen-Jie ; Levin, Andrew Michael ; Luckey, P. David, Jr. ; Paus, Christoph M. E. ; Ralph, Duncan Kelley ; Roland, Christof E. ; Roland, Gunther M. ; Stephans, George S. F. ; Sumorok, Konstanty C. ; Velicanu, Dragos Alexandru ; Veverka, Jan ; Wyslouch, Boleslaw ; Yang, Mingming ; Zanetti, Marco ; Zhukova, Victoria

Elsevier

Others  :  http://dspace.mit.edu/openaccess-disseminate/1721.1/98210

美国|英语

来源: MIT Theses in DSpace@MIT

【 摘 要 】

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[superscript ±]μ[superscript ±]jj). The data correspond to an integrated luminosity of 19.7 fb[superscript −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[subscript μN]|[superscript 2] as a function of Majorana neutrino mass m[subscript N] for masses in the range of 40–500 GeV, where V[subscript μN] is the mixing element of the heavy neutrino with the standard model muon neutrino. The limits obtained are |V[subscript μN]|[superscript 2]<0.00470 for m[subscript N]=90 GeV, |V[subscript μN]|[superscript 2]<0.0123 for m[subscript N]=200 GeV, and |V[subscript μN]|[superscript 2]<0.583 for m[subscript N]=500 GeV. These results extend considerably the regions excluded by previous direct searches.