@article{OPUS4-17247,
  title     = {Search for pair production of heavy vector-like quarks decaying to high-\(p_T\) \(W\) bosons and \(b\) quarks in the lepton-plus-jets final state in \(pp\) collisions at \(\sqrt{s}=13\) TeV with the ATLAS detector},
  series = {Journal of High Energy Physics},
  volume    = {2017},
  journal   = {Journal of High Energy Physics},
  number    = {141},
  organization    = {The ATLAS Collaboration},
  doi       = {10.1007/JHEP10(2017)141},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-172472},
  year      = {2017},
  abstract  = {A search is presented for the pair production of heavy vector-like \(T\) quarks, primarily targeting the \(T\) quark decays to a \(W\) boson and a \(b\)-quark. The search is based on 36.1 fb\(^{-1}\) of \(pp\) collisions at \(\sqrt{s}=13\) TeV recorded in 2015 and 2016 with the ATLAS detector at the CERN Large Hadron Collider. Data are analysed in the lepton-plus-jets final state, including at least one \(b\)-tagged jet and a large-radius jet identified as originating from the hadronic decay of a high-momentum \(W\) boson. No significant deviation from the Standard Model expectation is observed in the reconstructed \(T\) mass distribution. The observed 95\% confidence level lower limit on the \(T\) mass are 1350 GeV assuming 100\% branching ratio to \(Wb\). In the SU(2) singlet scenario, the lower mass limit is 1170 GeV. This search is also sensitive to a heavy vector-like \(B\) quark decaying to \(Wt\) and other final states. The results are thus reinterpreted to provide a 95\% confidence level lower limit on the \(B\) quark mass at 1250 GeV assuming 100\% branching ratio to \(Wt\); in the SU(2) singlet scenario, the limit is 1080 GeV. Mass limits on both \(T\) and \(B\) production are also set as a function of the decay branching ratios. The 100\% branching ratio limits are found to be applicable to heavy vector-like \(Y\) and \(X\) production that decay to \(Wb\) and \(Wt\), respectively.},
  language  = {en}
}
@phdthesis{Tam2014,
  author    = {Tam, Jason},
  title     = {Search for Second Generation Scalar Leptoquarks using the ATLAS Detector},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-103451},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2014},
  abstract  = {Leptoquarks are hypothetical particles that attempt to explain the coincidental similarities between leptons and quarks included in SM. Their exact properties vary between different theoretical models, and there are no strong theoretical constraints on their possible mass values. They can possibly be produced from particle collisions, and there have already been searching efforts at previous collider experiments. Their presence have yet been observed, and this fact has been translated into lower bound exclusions on their possible mass values. The Large Hadron Collider (LHC) being the most recently constructed particle collider with the highest collision energies ever achieved experimentally, provides a new platform to continue the search for Leptoquarks at even higher mass ranges. This thesis describes a search for pair-produced second-generation Leptoquarks using 20.3 fb-1 of data recorded by the ATLAS detector of LHC at √s = 8 TeV. Events with two oppositely charged muons and two or more jets in the final state were used. Candidate leptoquark events were selected with the help of four observables: the di-muon invariant mass (Mμμ ), the sum of the pT of the two muons (LT ), the sum of the pT of the two leading jets (HT ) and the average Leptoquark mass (MLQ ). Monte Carlo simulations of SM background processes have shown to be in good agreement with data, both in the region constructed using selection requirements for candiate leptoquark events and in the designated control regions. Since no significant excess of events was observed in data, a exclusion limit was set as a function of the Leptoquark mass.},
  subject      = {Leptoquark},
  language  = {en}
}