Properties of the neutron

The basic observables of the free neutron which are known at present and the precision of these determinations are tabulated. From these figures it is seen that the weak properties of the neutron, deduced from its lifetime and the asymmetries of the decay, are known with great precision and that the magnetic moment of the neutron is known to a precision far beyond that which is theoretically achievable. The quantities whose measurement is of greatest immediate interest are the electric dipole moment dsub(ne), the electric polarisability αsub(n) and the (ne) scattering length bsub(ne) of which only the last one is quantitatively measured. Such measurements are considered. In addition the examination of the doubly radiative np capture (n + p → D + γ) +γ is also discussed. (U.K.)