First observation of spin flip in dμ-atoms via formation and back decay of ddμ molecules

Abstract

We present the results of precision measurements of dμ spin-flip rates in pure D₂, in pure HD gas, and in the non-equilibrium and equilibrium H₂+D₂ gas mixtures. The experiments were performed at PSI in 1994-1996 using the high pressure ionization chamber from Gatchina as a 100% efficient detector of the charged fusion products. The measurements have been carried out in the temperature range 28-300 K, at gas density of 5% of LHD. In pure deuterium, the measured temperature dependence of the spin-flip rate allowed us to separate the two components (resonant and non-resonant) of the spin-flip processes. From the experiments in H/D mixtures we have measured the non-resonant spin-flip rate in collisions of dμ-atoms with HD molecules. Comparison with the theory revealed considerable disagreement in the case of non-resonant spin-flip in collisions of the dμ-atoms with D₂ molecules.