Electron and neutron electric dipole moments in the constrained MSSM

We analyze the effects of $\mathrm{CP}$-violating phases on the electric dipole moment (EDM) of the electron and neutron in the constrained minimal supersymmetric model. We find that the phases ${\phi }_{\mu }$ and ${\phi }_{A_0}$ have to be strongly correlated, in particular for small values of the SUSY mass parameters. We calculate the neutron EDM in two different models, the quark-parton model and the chiral quark model. It turns out that the predictions are quite sensitive to the model used. We show parameter regions in the $M_0-M_{1/2}$ plane which are excluded by considering simultaneously the experimental bounds of both electron and neutron EDM, assuming specific values for the phases ${\phi }_{\mu }$ and ${\phi }_{A_0}$.