Existence and transitions properties of three-deuteron muonic molecule (3d 2e^- μ^-)

We calculated the energy and the size of the three-deuteron muonic molecule (3d 2e^- \mu^-) = D_3 \mu. It turns out that this system possesses two equilibrium positions, one at distances typical for muonic molecules and a second one at the usual molecular size. We show, moreover, that the fusion probability of the three deuterons is considerably enhanced due to the existence of a ^6Li^* threshold resonance. Our estimates indicate that this probability is considerably higher than the decay rate of the competing Auger transition.