CP violation in top quark production at the LHC and two-Higgs-doublet models

Abstract

We discuss CP violation in top–antitop production at the LHC, induced by gluon fusion and final-state Higgs exchange. Results by Bernreuther and Brandenburg are confirmed and further reduced. The lepton energy asymmetry is studied in detail in explicit two-Higgs-doublet models with near-maximal mixing in the neutral Higgs sector. Unless there is only one light Higgs particle, and unless (in “model II”) tan β≲1, the CP-violating effects are very small, possibly too small to be seen at the LHC.