Jacob Julian Kempster (Royal Holloway, University of London)
Top pair events provide a source of b-bbar pairs, which can be used to probe CP violation in heavy-flavour mixing and decay. In events where one of the W bosons decays leptonically to an electron or muon, the charge of the W boson can be used to determine unambiguously the flavour charge of the accompanying b quark at the time of its production. In cases where the b also decays semileptonically to a muon, this sample allows to probe two CP asymmetries constructed with the charge signs of the W and the soft muon. The first measurement of the CP asymmetries in b-bar from top pair decays is hence presented using the data collected with the ATLAS detector during the 8 TeV run of the LHC.
ATLAS Collaboration (CERN)