Muon catalyzed fusion in deuterium gas

We present the results of an experiment performed at PSI to investigate muo n catalyzed fusion in pure deuterium gas of 5% density (LHD) at temperature s ranging from 28 K to 350 K. Using a new high pressure ionization chamber the reactions dd --> n + He-3 and dd --> p + t were observed with 100% dete ction efficiency. The rates of d mu d formation were measured with the abso lute precision of 1% and the mu d spin-flip rates with 0.5%. The temperatur e dependence of molecular formation and spin-flip rates display pronounced resonance structures. A preliminary fit based on the Vesman mechanism of re sonant muonic molecule formation was carried out yielding a dd fusion rate of 3.5 . 10(8) s(-1) and a hfs splitting energy delta epsilon(d mu d) of 24 .3 meV, both in good agreement with the theory.