Observation of unexpected density effects in muon-catalyzed d-t fusion

New experimental results on muon-catalyzed d-t fusion are reported. Unexpected target-density effects have been discovered both in dt{μ} molecular formation in t{μ}+D₂ collisions and in the effective sticking probability. The dt{μ} formation rate is significantly enhanced at high density, presumably because of a strong three-body contribution. The origin of the observed reduction of the sticking probability at high density remains unclear. Both effects increase the number of fusions per muon that can be achieved; 150±{}4(stat.)±{}20(syst.) fusions per muon have been observed.