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

Abstract

CP violating asymmetries in both the production and the decays of $s$-channel neutral Higgs bosons at $μ^+μ^-$ colliders can be large. If the CP violation occurs in the muon-Higgs coupling, one observes a production asymmetry with transversely polarized $μ^+μ^-$ beams. Likewise if the CP violation occurs in the top-Higgs or $τ$-Higgs coupling, one observes an azimuthal decay asymmetry in $μ^+μ-\to t\bar t$ (or $τ^+τ^-$). 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.