Abstract
A search is performed for third-generation scalar leptoquarks and heavy right-handed neutrinos in events containing one electron or muon, one hadronically decaying τ lepton, and at least two jets, using a $\sqrt{s} = 13$ TeV pp collision data sample corresponding to an integrated luminosity of 12.9 $fb^{-1}$ collected with the CMS detector at the LHC in 2016. The number of observed events is found to be in agreement with the standard model prediction. A limit is set at 95% confidence level on the product of the leptoquark pair production cross section and $β^2$, where β is the branching fraction of leptoquark decay to a τ lepton and a bottom quark. Assuming β = 1, third-generation leptoquarks with masses below 850 GeV are excluded at 95% confidence level. An additional search based on the same event topology involves heavy right-handed neutrinos, $N_R$, and right-handed W bosons, $W_R$, arising in a left-right symmetric extension of the standard model. In this search, $W_R$ bosons are assumed to decay to a tau lepton and $N_R$ followed by the decay of the $N_R$ to a tau lepton and an off-shell $W_R$ boson. Assuming the mass of the right-handed neutrino to be half of the mass of the right-handed W boson, $W_R$ boson masses below 2.9 TeV are excluded at 95% confidence level. These results improve on the limits from previous searches for third-generation leptoquarks and heavy right-handed neutrinos with τ leptons in the final state.
CMS Collaboration