Testing CP in the Bjorken process Original Research Article

In a more general electroweak theory, there could be Higgs particles that are odd under CP, and also Higgs-like particles which are not eigenstates of CP. We discuss distributions which for the Bjorken process are sensitive to the CP parity. Correlations among momenta of the initial electron and final-state fermions yield this kind of information. We discuss also observables which may demonstrate the presence of CP violation and identify a phase shift δ which is a measure of the strength of CP violation in the Higgs-vector-vector coupling, and which can be measured directly in the decay distribution. In the context of discriminating between CP eigenstates, we present Monte Carlo data on the expected efficiency, and conclude that at a future linear collider it will be relatively easy to determine whether the candidate Higgs particle is even or odd under CP. This does not appear possible at LEP2.