CP violation, Higgs couplings, and supersymmetry

Supersymmetric extensions of the standard model genetically contain additional sources of CP violation. We discuss how at one loop a potentially large CP violating coupling of the lightest Higgs boson h⁰ to leptons is induced in the minimal supersymmetric standard model (MSSM). The CP violating couplings of h⁰ in extensions of the MSSM, such as the next-to-minimal supersymmetric standard model (NMSSM) are also considered. We indicate how this CP violation might be observed; in particular a polarization-dependent production asymmetry, in the context of a muon collider, provides a means to access this coupling cleanly. In the MSSM, existing limits on the electric dipole moment of the electron, coupled with standard universality assumptions, severely constrains any such signal. Nevertheless, extensions of the MSSM, such as the NMSSM, allow CP-violating signals as large as 100%.