Search for Pair Production of a New b ' Quark that Decays into a Z Boson and a Bottom Quark with the ATLAS Detector

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Aad G., Abbott B., Abdallah J., Khalek S. A. , Abdelalim A. A. , Abdesselam A., ...More

PHYSICAL REVIEW LETTERS, vol.109, no.7, 2012 (Peer-Reviewed Journal) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 109 Issue: 7
  • Publication Date: 2012
  • Doi Number: 10.1103/physrevlett.109.071801
  • Journal Indexes: Science Citation Index Expanded, Scopus


A search is reported for the pair production of a new quark b' with at least one b' decaying to a Z boson and a bottom quark. The data, corresponding to 2.0 fb(-1) of integrated luminosity, were collected from pp collisions at root s = 7 TeV with the ATLAS detector at the CERN Large Hadron Collider. Using events with a b-tagged jet and a Z boson reconstructed from opposite-charge electrons, the mass distribution of large transverse momentum b' candidates is tested for an enhancement. No evidence for a b' signal is detected in the observed mass distribution, resulting in the exclusion at a 95% confidence level of b' quarks with masses m(b)' < 400 GeV that decay entirely via b' -> Z + b. In the case of a vectorlike singlet b' mixing solely with the third standard model generation, masses m(b)' < 358 GeV are excluded.