Search for CP violating top quark couplings in pp collisions at $\sqrt{s}$ = 13 TeV

Results are presented from a search for CP violation in top quark pair production, using proton-proton collisions at a center-of-mass energy of 13 TeV. The data used for this analysis consist of final states with two charged leptons collected by the CMS experiment, and correspond to an integrated luminosity of 35.9 fb −1. The search uses two observables, $O$ 1 and $O$ 3, which are Lorentz scalars. The observable $O$ 1 is constructed from the four-momenta of the charged leptons and the reconstructed top quarks, while $O$ 3 consists of the four-momenta of the charged leptons and the b quarks originating from the top quarks. Asymmetries in these observables are sensitive to CP violation, and their measurement is used to determine the chromoelectric dipole moment of the top quark. The results are consistent with the expectation from the standard model.