Electric Dipole Moments as Probes of CPT Invariance

Electric dipole moments (EDMs) of elementary particles and atoms probe violations of T and P symmetries and consequently of CP if CPT is an exact symmetry. We point out that EDMs can also serve as sensitive probes of CPT-odd, CP-even interactions, that are not constrained by any other existing experiments. Analyzing models with spontaneously broken Lorentz invariance, we calculate EDMs in terms of the leading CPT-odd operators to show that experimental sensitivity probes the scale of CPT breaking as high as 10^{12}GeV.