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Analysis of events with b-jets and a pair of leptons of the same charge in pp collisions at √s = 8 TeV with the ATLAS detector

Research output: Contribution to journalJournal article

  • ATLAS Collaboration
Article number150
<mark>Journal publication date</mark>10/2015
<mark>Journal</mark>Journal of High Energy Physics
Number of pages51
Publication statusPublished
Early online date22/10/15
Original languageEnglish


An analysis is presented of events containing jets including at least one btagged
jet, sizeable missing transverse momentum, and at least two leptons including a
pair of the same electric charge, with the scalar sum of the jet and lepton transverse
momenta being large. A data sample with an integrated luminosity of 20.3 fb−1 of pp collisions
at √
s = 8 TeV recorded by the ATLAS detector at the Large Hadron Collider is used.
Standard Model processes rarely produce these final states, but there are several models
of physics beyond the Standard Model that predict an enhanced rate of production of
such events; the ones considered here are production of vector-like quarks, enhanced fourtop-quark
production, pair production of chiral b
-quarks, and production of two positively
charged top quarks. Eleven signal regions are defined; subsets of these regions are combined
when searching for each class of models. In the three signal regions primarily sensitive to
positively charged top quark pair production, the data yield is consistent with the background
expectation. There are more data events than expected from background in the set
of eight signal regions defined for searching for vector-like quarks and chiral b
-quarks, but
the significance of the discrepancy is less than two standard deviations. The discrepancy
reaches 2.5 standard deviations in the set of five signal regions defined for searching for
four-top-quark production. The results are used to set 95% CL limits on various models.