A relation between the electric dipole moments of the neutron and the electron in two-Higgs-doublet models

We study a possible relation between the neutron and electron electric dipole moments (EDM) in the framework of the Two-Higgs-Doublet Model which has been proposed to explain why the t-quark is much heavier than all other known quarks and leptons. If there is no especial fine-tuning between the CP-violating parameters of the model, the experimental limit on the neutron EDM, dnEXP ≤ 1.1 · 10−25 e·cm, implies de ≤ 2 · 10−28 e·cm for the electron EDM.