Resonance in the rate of production of dd. mu. mesic molecules in gaseous deuterium

A deuterium-gas target was used in the muon beam of the 680-MeV synchrocyclotron at the Laboratory for Nuclear Problems of the Joint Institute for Nuclear Research to determine the rate of production of dd..mu.. mesic molecules (lambda/sub d/d..mu..) as a function of the energy epsilon/sub d/..mu.. of the d..mu.. atom in the range 0.015--0.050 eV (deuterium temperature 120--380/sup 0/ K). Experimental results confirm the theoretically predicted resonance mechanism of production of dd..mu.. mesic molecules. Analysis of the experimental data shows that the resonance occurs at epsilon/sup 0//sub d/..mu..=0.050 +- 0.003 eV and that the value of lambda/sub d/d..mu.. at the peak of the curve is lambda/sub d/d..mu..(epsilon/sup 0//sub d/d..mu..) = (0.85 +- 0.11) x 10/sup 6/ sec/sup -1/. This has been used to determine, with high precision, the binding energy of the dd..mu.. molecule in the state with quantum numbers L=1, v=1, which is responsible for the resonance: epsilon/sub d/d..mu.. (L=1, v=1) =-2.196 +- 0.003 eV.