A study of heavy flavor quarks produced in association with top quark pairs at sqrt(s) = 7 TeV using the ATLAS detector

Understand

Using a sample of dilepton top-quark pair (ttbar) candidate events, a study is performed of the production of top-quark pairs together with heavy-flavor (HF) quarks, ttbar+b+X or ttbar+c+X, collectively referred to as ttbar+HF.

• The dataset used corresponds to an integrated luminosity of 4.7 fb-1 of proton--proton collisions at a center-of-mass energy of 7 TeV recorded by the ATLAS detector at the CERN Large Hadron Collider.
• The presence of additional HF quarks in the ttbar sample is inferred by looking for events with at least three b-tagged jets, where two are attributed to the b-quarks from the ttbar decays and the third to additional HF production.
• The dominant background to ttbar+HF in this sample is ttbar+jet events in which a light-flavor jet is misidentified as a heavy-flavor jet.