Anomalous nuclear effects in solids (“cold fusion”): questions still remain

The results are discussed of recent experiments to detect the nuclear products of “cold fusion” (neutrons, tritium, and helium) and their possible theoretical interpretation. Apparently low-level neutron emission has been established rather reliably and can be understood without adducing exotic models. The results on tritium and helium require further refinement and as yet have not received a satisfactory theoretical explanation.