CP-odd A0 production at e+e- colliders in the minimal supersymmetric standard model with CP violating phases

We study the production of a heavy CP-odd A⁰ boson in association with a photon e⁺e^-→A⁰γ and a Z boson e⁺e^-→A⁰Z as well as the single production of A⁰ via e⁺e^- →ν_eν¯_eA⁰ in the minimal supersymmetric standard model (MSSM) with CP violating phases. In the case of e⁺e^-→A⁰γ/A⁰Z, we show that the squark contribution, which vanishes in the MSSM with real parameters, turns out to be sizable in the presence of CP violating phases in the soft supersymmetric parameters. For e⁺e^- →ν_eν¯_eA⁰ in both the two Higgs doublet model and the MSSM with real parameters, the cross section does not reach observable rates at a Next Linear Collider. It is found that, with a large CP violating phase for A_t, cross sections of the order of 0.08 fb are attainable for all the processes e⁺e^-→A⁰γ, e⁺e^-→A⁰Z, and e⁺e^- →ν_eν¯_eA⁰.