A mechanism of unexpected temperature dependence of muonic catalysis in solid deuterium

It is shown that, at sufficiently low temperatures, the elastic scattering of $d\mu$ mesic atoms (as well as slow neutrons) in solid deuterium proceeds on the whole crystal lattice without energy loss, whereas inelastic scattering with excitation of phonons is weak. For this reason, the resonant formation of $dd\mu$ mesic molecules in solid deuterium occurs before the thermalization of $d\mu$ mesic atoms, which explains the observed temperature independence of the $dd\mu$-molecule formation rate and muonic catalysis.