  For a bound state internal wave function respecting parity symmetry, it can
be rigorously argued that the mean electric dipole moment must be strictly
zero. Thus, both the neutron, viewed as a bound state of three quarks, and the
water molecule, viewed as a bound state of ten electrons two protons and an
oxygen nucleus, both have zero mean electric dipole moments. Yet, the water
molecule is said to have a nonzero dipole moment strength $d=e\Lambda $ with
$\Lambda_{H_2O} \approx 0.385\ \dot{A}$. The neutron may also be said to have
an electric dipole moment strength with $\Lambda_{neutron} \approx 0.612\ fm$.
The neutron analysis can be made experimentally consistent, if one employs a
quark-diquark model of neutron structure.
