A realistic formulation of approximate CP Original Research Article

CP violation in the SM is naturally implemented as a small imaginary perturbation to real Yukawa couplings. For example, a large CP asymmetry in Bd decays can arise if the imaginary parts of quark mass matrices are of order 10−3mt,b or smaller. Applying the principle of “additive CP violation” to soft SUSY-breaking terms, the electric dipole moments of the neutron and mercury atom are predicted near current experimental limits; for nonuniversal A-terms, EDM bounds can be satisfied given certain flavour structures. The proposal may be formulated in a democratic basis, with Yukawas and soft terms of the form const·(1+ϵ+iζ) where |ϵ|⪡1, |ζ|≲10−3, motivated by approximate permutation × CP symmetry.