Magnitude of Higgs-boson-exchange CP violation in two-doublet models with large tan beta.

Abstract

CP violation in neutral Higgs-boson exchange is studied in two-doublet models in an expansion in (1/${\mathrm{tan}}^{2}$\ensuremath{\beta}). The typical magnitude of various CP-violating quantities is found for large tan\ensuremath{\beta}. In particular the electric dipole moment (EDM) of the electron and the coefficient ${\mathit{c}}_{\mathit{S}}$ of the CP-violating electron-nucleon scalar-pseudoscalar operator are examined and it is found that in a simple class of two-doublet models ${\mathit{c}}_{\mathit{S}}$/${\mathit{d}}_{\mathit{e}}$ is typically O(${\mathrm{tan}}^{2}$\ensuremath{\beta}). Therefore ${\mathit{c}}_{\mathit{S}}$ is more important than ${\mathit{d}}_{\mathit{e}}$ for the EDM's of diamagnetic atoms and molecules (Hg, Xe, TlF) typically if tan\ensuremath{\beta}\ensuremath{\gtrsim}5, and for paramagnetic atoms (Cs, Tl) if tan\ensuremath{\beta}\ensuremath{\gtrsim}15. The dependence on tan\ensuremath{\beta} of the various contributions to the neutron EDM including the Weinberg three-gluon operator, and the dependence on tan\ensuremath{\beta} of the top-quark EDM are also discussed. Supersymmetric and three-doublet models are also considered.