Chiral estimate of the electric dipole moment of the neutron in quantum chromodynamics

Current algebra for CP violating strong interactions is investigated. In particular, the neutron electric dipole moment D n is shown to behave as θm π 21nm π 2 for small pion mass m π and CP violating parameter θ. This logarithm is explicitly calculable: it contributes 5.2×10−16θ cm to D n. This result is somewhat larger than a previous O(m π 2) estimate based on the bag model.