How to detect possible ΔB = 2 processes

According to the grand unified theories the baryon (B) and lepton (L) number conservation laws are only approximate; so the search for breakdown of B conservation is one of their most effective experimental tests. If B is not conserved every proton, as well as every neutron bound in nuclei, must eventually decay into lighter particles. Conservation of energy, angular momentum and electric charge require that any change in the sum of baryon and lepton number - Δ(B + L) - be an even number, in any possible decay mode. The processes with ΔB = 2, ΔL = 0 appear particularly interesting among the large class of possible baryonic decays. They may induce neutron-antineutron mixing and consequently neutron-antineutron oscillations which would occur as a first-order process. In this lecture the neutron oscillation phenomenology is considered, the experimental methods for neutron oscillation detection are discussed and some features of the Grenoble experiment are presented. 12 refs.; 1 figure; 2 tabs