Searches for the appearance of $\nu_\tau$ using neutrino beams from muon storage rings

Abstract. We study the possibilities offered by muon storage rings for $\nu_\tau$ appearance experiments in order to determine masses and mixing angles for the $\nu_\mu \rightarrow \nu_\tau$ and $\bar\nu_e \rightarrow \bar\nu_\tau$ oscillations. The dependence of tau event rates on baseline, forward peaking of decay neutrinos with increasing energies, and average fluxes intercepted by detectors of various sizes is discussed. It is found that the baseline length does not significantly affect the rates for oscillations of such magnitudes as are suggested by the current atmospheric neutrino data. Subsequently, the effects of cuts on hadronic and wrong sign leptonic modes are computed and used to plot 90% CL contours for the parameter regions that can be explored in such experiments. The results show that even for modest muon beam energies, convincing coverage and verification of the Super Kamiokande parameters is possible. In addition, a very significant enlargement of present day bounds on the mixing parameters for neutrino oscillations of all types is guaranteed by these types of searches.