Search for third-generation scalar leptoquarks and heavy right-handed neutrinos in final states with two tau leptons and two jets in proton-proton collisions at √s=13 TeV

• Main Authors: Sirunyan, A. M., Tumasyan, A. R., Adam, Wolfgang, Asilar, Ece, Bergauer, Thomas, Md. Ali, Mohd. Adli
• Format: Article
• Language: English; English
• Published: Springer Verlag 2017
• Subjects: Q Science (General); QC Physics
• Online Access: http://irep.iium.edu.my/63126/1/63126_Search%20for%20third-generation%20scalar_article.pdf; http://irep.iium.edu.my/63126/2/63126_Search%20for%20third-generation%20scalar_scopus.pdf; http://irep.iium.edu.my/63126/; https://link.springer.com/content/pdf/10.1007%2FJHEP07%282017%29121.pdf

A search is performed for third-generation scalar leptoquarks and heavy righthanded neutrinos in events containing one electron or muon, one hadronically decaying τ lepton, and at least two jets, using a √ 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, NR, and right-handed W bosons, WR, arising in a left-right symmetric extension of the standard model. In this search, WR bosons are assumed to decay to a tau lepton and NR followed by the decay of the NR to a tau lepton and an off-shell WR boson. Assuming the mass of the right-handed neutrino to be half of the mass of the right-handed W boson, WR 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.