Distinction of atmospheric $\nu_{\mu} - \nu_{\tau}$ and $\nu_{\mu} - \nu_{sterile}$ oscillations using short or intermediate baseline experiments

The current case for atmospheric $\nu_\mu$ oscillations into active or sterile neutrinos is reviewed. It is argued that neither the study of neutral current events at Super-Kamiokande, nor the information obtained from future long baseline experiments might be sufficient to unambigously decide between these two scenarios. However, a combination of these results with the results from future short or intermediate baseline $\tau$ appearance experiments would clearly resolve most of the remaining ambiguities. This conclusion does not strongly depend on whether the results from LSND will be confirmed or not. In the case that LSND would be confirmed, a negative result in such a short or intermediate baseline experiment would also unambigously exclude the interpretation of LSND as indirect $\nu_\mu-\nu_\tau-\nu_e$ oscillations.