The difference between baryon- and lepton number, $B-L$, is a conserved charge in the Standard model. However, its violation is needed in order to explain the dynamical origin of the matter-antimatter asymmetry, and possibly also neutrino masses. One way to search for $B-L$ violation is via proton decays, such as in the upcoming experiments at DUNE, JUNO, and Hyper-K. However, only proton...
If a beam of slow neutrons ($n$) (with kinetic energies less than a few meV) is produced and allowed to propagate through a magnetically shielded vacuum (~nT) before letting it hit a target, then in the presence of baryon number violating interactions some $n$'s can oscillate into $\bar{n}$'s. The produced $\bar{n}$'s can annihilate with the target material producing detectable final state...
