Neutron electric dipole moment

There are many different theories of CP violation, all of which can fit the experimental information available from K decays. There have been many attempts to compute the neutron electric dipole moment in these theories, which have all concentrated on one particular mechanism for the generation of the neutron edm. Here we consider both quark level and hadronic level processors, and argue that there is no double counting in simply adding these terms. We then survey the results obtained in the standard model, in the Weinberg Model and in the Left Right symmetric model. The present upper bound is 2.6 x 10-25 e cm, we show that the Weinberg Model would give a dipole moment greater than 1 x 10-25 e cm, and the L-R symmetric model gives a value in the range 1.9 x 10-26 e cm to 1.9 x 10-27 e cm - the range being fixed by the recently observed value of ε'/ε = (3.3 +- 1.1) x 10-3. The standard model gives much smaller values - of the order 10-32 e cm