Conclusions

The use of our non-parametric procedure using the maximum likelihood method permits the effective solution of problems in $\mu SR$ experiments. In our view it is especially helpful when analytical form of solution is unknown and it is a subject of research itself.

We have demonstrated that the direct reconstruction of the muonium formation rate function proves the lack of a scaling law for muon depolarization in superfluid helium with changing temperature, which results from the change of the radial distribution function W(r) in a velocity relaxation process.