Left-right asymmetry in polarized neutron scattering

In the paper the two principal origins of the appearance of LRA in the polarised neutron scattering are discussed, the space (P) and the time (T) parity violations. The first takes place for instance, in crystals without a centre of symmetry, or in the presence of an electric field. The second occurs in a ferromagnet, or in other magnetic structures under applied magnetic fields. Several examples of P- and T- symmetry breaking are discussed using results from polarised neutron scattering experiments on helical magnetic structures, critical spin fluctuations and spin waves. A short review of experimental work involving the static and the dynamical chirality is given. (authors)