Formation of metastable dt mu molecules in t mu(2s)-D-2 collision

The formation process of metastable dt mu molecules in D-2-T-2 mixtures is investigated. The dt mu molecule exhibits a series of three-body resonances embedded in the t mu+d scattering continuum just below the t mu(2s)+d threshold, These states can-be formed in collisions of excited t mu(2s) atoms with D-2 molecules, whereby the excess of binding energy is absorbed by the rovibrational degrees of freedom of D-2. We present a scattering-theoretic model for this process, and perform a numerical calculation of its cross section. The essential transition amplitudes are obtained from three-body wave functions for the dt mu subcluster, and adiabatic wave functions for the entire hybrid system in the final channel. It is found that the effective formation rate is limited by the Auger-transition rates of the molecular complex formed. The calculated cross sections exhibit broad ''peaks,'' with magnitudes large enough for the formation process to favorably compete with deexcitation of t mu(n=2) atoms via radiative and collisional processes. The formation of metastable dt mu can therefore be one of the fastest processes depleting the n=2 levels of the t mu atom in hydrogen mixtures, of importance for low-energy muon science, electroweak physics, and muon catalyzed fusion.