Limits onCP-odd four-fermion operators containing the strange quark field

The bounds on the neutron electric dipole moment and T-odd nucleon-nucleon interaction are used to extract the limits on the effective CP-odd four-fermion operators containing a strange quark field. This completes the study of the dim=5,6 CP-odd operators built from light-quark fields. The limits are very strong and comparable to those obtained previously for operators containing up and down flavors. We also analyze the shift of the axionic vacuum, θeff, induced by four-fermion operators in the presence of the PQ mechanism and conclude that this gives subleading contributions to CP-odd observables as compared with the direct ones.