Neutral Higgs CP Violation at μ^+μ^- colliders

CP violating asymmetries in both the production and the decays of $s$-channel neutral Higgs bosons at $\mu^+\mu^-$ colliders can be large. If the CP violation occurs in the muon-Higgs coupling, one observes a production asymmetry with transversely polarized $\mu^+\mu^-$ beams. Likewise if the CP violation occurs in the top-Higgs or $\tau$-Higgs coupling, one observes an azimuthal decay asymmetry in $\mu^+\mu-\to t\bar t$ (or $\tau^+\tau^-$). CP studies at such colliders allow a uniquely clean way of deducing the underlying CP phases; in turn these parameters would significantly improve our understanding of baryogenesis.