Resonant Formation of $d\mu t$ Molecules in Deuterium: An Atomic Beam Measurement of Muon Catalyzed dt Fusion

Resonant formation of $d\mu t$ molecules in collisions of muonic tritium ($\mu t$) on D${}_2$ was investigated using a beam of $\mu t$ atoms, demonstrating a new direct approach in muon catalyzed fusion studies. Strong epithermal resonances in $d\mu t$ formation were directly revealed for the first time. From the time-of-flight analysis of $2036\pm 116$ $dt$ fusion events, a formation rate consistent with $0.73\pm (0.16){meas} \pm (0.09){model}$ times the theoretical prediction was obtained. For the largest peak at a resonance energy of $0.423\pm 0.037$ eV, this corresponds to a rate of $(7.1\pm 1.8)\times {10}^9$ s${}^{-1}$, more than an order of magnitude larger than those at low energies.