Search for heavy neutrinos and third-generation leptoquarks in hadronic states of two τ leptons and two jets in proton-proton collisions at √s=13 TeV


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Sirunyan A., Tumasyan A., Adam W., Ambrogi F., Asilar E., Bergauer T., ...More

Journal of High Energy Physics, vol.2019, no.3, 2019 (SCI-Expanded, Scopus) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 2019 Issue: 3
  • Publication Date: 2019
  • Doi Number: 10.1007/jhep03(2019)170
  • Journal Name: Journal of High Energy Physics
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Keywords: Beyond Standard Model, Dark matter, Hadron-Hadron scattering (experiments)
  • Open Archive Collection: AVESIS Open Access Collection
  • Yıldız Technical University Affiliated: Yes

Abstract

A search for new particles has been conducted using events with two high transverse momentum τ leptons that decay hadronically and at least two energetic jets. The analysis is performed using data from proton-proton collisions at s=13 TeV, collected by the CMS experiment at the LHC in 2016 and corresponding to an integrated luminosity of 35.9 fb −1 . The observed data are consistent with standard model expectations. The results are interpreted in the context of two physics models. The first model involves right-handed charged bosons, W R , that decay to heavy right-handed Majorana neutrinos, N ℓ (ℓ = e, μ, τ), arising in a left-right symmetric extension of the standard model. The model considers that N e and N μ are too heavy to be detected at the LHC. Assuming that the N τ mass is half of the W R mass, masses of the W R boson below 3.50 TeV are excluded at 95% confidence level. Exclusion limits are also presented considering different scenarios for the mass ratio between N τ and W R , as a function of W R mass. In the second model, pair production of third-generation scalar leptoquarks that decay into ττbb is considered, resulting in an observed exclusion region with leptoquark masses below 1.02 TeV, assuming a 100% branching fraction for the leptoquark decay to a τ lepton and a bottom quark. These results represent the most stringent limits to date on these models.[Figure not available: see fulltext.].