Search for Down-Type Fourth Generation Quarks with the ATLAS Detector in Events with One Lepton and Hadronically Decaying W Bosons


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Aad G., Abbott B., Abdallah J., Abdelalim A. A., Abdesselam A., Abdinov O., ...More

PHYSICAL REVIEW LETTERS, vol.109, no.3, 2012 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 109 Issue: 3
  • Publication Date: 2012
  • Doi Number: 10.1103/physrevlett.109.032001
  • Journal Name: PHYSICAL REVIEW LETTERS
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Middle East Technical University Affiliated: Yes

Abstract

This Letter presents a search for pair production of heavy down-type quarks decaying via b' -> Wt in the lepton + jets channel, as b'(b) over bar' -> W(-)tW(+)(t) over bar -> b (b) over barW(+)W(-)W(+)W- -> l(+/-) nu b (b) over barq (q) over barq (q) over barq ($) over barq. In addition to requiring exactly one lepton, large missing transverse momentum, and at least six jets, the invariant mass of nearby jet pairs is used to identify high transverse momentum W bosons. In data corresponding to an integrated luminosity of 1.04 fb(-1) from pp collisions at root s = 7 TeV recorded with the ATLAS detector, a heavy down-type quark with mass less than 480 GeV can be excluded at the 95% confidence level.