Search for heavy neutrinos or third-generation leptoquarks in final states with two hadronically decaying tau leptons and two jets in proton-proton collisions at sqrt(s) = 13 TeV

摘要

A search for new particles has been conducted using events with two hightransverse momentum (pt) tau leptons that decay hadronically, at least twohigh-pt jets, and missing transverse energy from the tau lepton decays. Theanalysis is performed using data from proton-proton collisions, collected bythe CMS experiment in 2015 at sqrt(s) = 13 TeV, corresponding to an integratedluminosity of 2.1 inverse femtobarns. The results are interpreted in twophysics models. The first model involves heavy right-handed neutrinos, N[l] (l= e, mu, tau), and right-handed charged bosons, W[R], arising in a left-rightsymmetric extension of the standard model. Masses of the W[R] boson below 2.35(1.63) TeV are excluded at 95% confidence level, assuming the N[tau] mass is0.8 (0.2) times the mass of the W[R] boson and that only the N[tau] flavorcontributes to the W[R] decay width. In the second model, pair production ofthird-generation scalar leptoquarks that decay into tau tau bb is considered.Third-generation scalar leptoquarks with masses below 740 GeV are excluded,assuming a 100% branching fraction for the leptoquark decay to a tau lepton anda bottom quark. This is the first search at hadron colliders for thethird-generation Majorana neutrino, as well as the first search forthird-generation leptoquarks in the final state with a pair of hadronicallydecaying tau leptons and jets.