THE PSI EXPERIMENTS ON MUON-CATALYZED PT FUSION

The experiments on pt fusion performed at Paul Scherrer Institut, Vill igen, Switzerland, are described. Liquid triple mixtures of protium, d euterium and tritium with low concentrations on deuterium and tritium were used. Gamma rays, X-rays, neutrons and, for the first time, conve rsion muons, were measured. Preliminary results are: Rate for spin fli p from the triplet to the singlet state of tmu(1s), lambda10 = (1.0 +/ - 0.2) x 10(3) mus-1; rate for muon-catalyzed pt fusion from the (I = 1) nuclear-spin state, lambda(pt)f(I = 1) = 0.07 +/- 0.01 mus-1; and t he molecular formation rate, lambda(pt)m = (7.5 +/- 1.3)mus-1 (all nor malized to liquid hydrogen density).