The top quark, being exceptionally heavy with respect to the other standard model particles, plays a special role as the only particle whose coupling to the Higgs boson is of order unity, and therefore we suspect it has a special connection with physics beyond the standard model. Our research is concentrated on studying interactions that contain top quarks, aimed to search for deviations with respect to standard model predictions and to improve the modeling of its production and decay since the top quark is an important background in searches beyond the standard model.
Our group has measured the associated production of top quarks plus b-quark jets (ttbb) in the challenging all-jets signature. Good knowledge of the ttbb topology is needed in order to gain insight into other processes like ttH and tttt. The cross-section was measured for the visible, as well as for the full phase space. The measured cross-sections were compared with predictions of several event generators and are found to be generally higher than the theoretical predictions [TOP, TOPpub]. Currently, our group is working on differential measurements of this process and including the single lepton final state.