New Experimental Results on Muon Catalyzed Fusion in Low Density Deuterium-Tritium Gas

Abstract

The general theoretical ideas for resonant formation of muonic hydrogen molecules have been discussed by G. Fiorentini at this school. Let us now take a closer look at this remarkable process, which is the starting point for the renewed interest in the field of muon catalyzed fusion. As an example Figure 1 presents the level scheme of the dμt formation process

$$\mu t + D_2 \to \left[ {\left( {d\mu t} \right)dee} \right]*$$

(1)

One should notice the different energy scales involved in this transition: some hundred eV on the muonic side (the extraordinary weakly bound djjt state, responsible for resonant formation, has a binding energy of only −640 meV), some hundred meV for the energy spacing between vibrational levels on the electronic side. Resonant molecule formation is only possible if the value of the thermal kinetic energy of the initial μt atoms (dashed region in Figure 1) allows a transition between the indicated levels. As this thermal energy is of the order of some meV (at low temperatures) experimental physics has a precise method of determining the energies for resonant formation by observing the rate of mesomolecule formation as a function of temperature. Due to the high accuracy reached, tiny energy splittings, which usually are completely negligible on the muonic energy scale, become important (see Figure 1). On the muonic side these small energy splittings are dominated by the hyperfine structure of muonic atoms and molecules. The sensitivity of resonant molecular formation to these splittings is particularly interesting, because hyperfine effects in muonic hydrogen have not been accessible to direct experimental observation before.