Measurements of an ortho-para effect in muon-catalyzed fusion in solid deuterium

In order to investigate the dependence of the rate of muon-catalyzed fusion (mu CF) on the ortho-para state tin this case, the nuclear spin state) of deuterium molecules, the fusion protons produced in the mu CF in solid deut erium with a controlled ortho-para ratio were observed. The measurements we re carried out at a temperature of 3.5 K and ratios of ortho deuterium of 6 6.7% and 99.9%. The ortho-para effect observed in this work was small (the relative difference of fusion proton yield in the converted (ortho 99.9%) c ase to that in the normal case is -0.100(117)), suggesting evidence against a proposed solid-state effect that is strongly dependent on the ortho-para ratio (also, the rotational state) of deuterium molecules. (C) 2001 Elsevi er Science B.V. All rights reserved.