Muonic-molecule formation in a high-density D-T system: Application to a solid phase.

Abstract

We discuss the resonant formation mechanism of muonic molecular ions in a high-density D-T system, putting emphasis on a condensed-matter effect. After generally formulating the problem, we apply the formulation to a solid phase of an admixture of ${\mathrm{D}}_{2}$, DT, and ${\mathrm{T}}_{2}$. The spectral intensity distribution of a whole system proves to be essential in understanding the above-mentioned effect. Namely the numerically calculated distribution exhibits the presence not only of a Lorentzian peak centered at a conventional, slightly shifted resonance energy but also of a broad peak lying over an energy domain that extends from the resonance energy with a scope comparable to the bandwidth of the elementary excitation spectra of the solid. The profile of the spectral distribution suggests the possibility that the condensed matter should take part in the quasiresonant reaction as an absorber of excess energy in the initial state. In fact, the formation rate at low temperatures turns out to be enhanced dramatically in the presence of subthreshold resonance levels, as compared with Vesman's mechanism [Sov. Phys. JETP Lett. 5, 91 (1967)], i.e., molecular formation in a free space. The numerical calculation of formation rates is carried out for a target system involving ortho-, para-${\mathrm{D}}_{2}$, or their thermal admixture.