Future short baseline neutrino oscillation experiments

A neutrino mass that would make a significant contribution to the hidden mass of the universe and thus contribute to the solving of the dark matter puzzle is still the most valuable prize in neutrino physics. This would presumably be through a mixed dark matter scenario and would involve a neutrino mass of 1-2 eV. Assuming the Delta m/sup 2/ observed in neutrino oscillations is the difference between this mass and a negligible mass of a second neutrino, CHORUS and NOMAD would only have a sensitivity of sin/sup 2/ 2 theta ~10/sup -3/ in this domain. The aim of future nu /sub mu /- nu /sub tau / oscillation searches is therefore to improve the sensitivity of the search by about an order of magnitude. NOMAD has a number of events looking exactly like a nu /sub tau / interaction should but, in spite of the good kinematical capabilities of the experiment, the number of such events is consistent with the number of expected background events. Therefore to improve on this situation it is imperative to be able to determine whether the tau decay daughter candidate originates from a secondary vertex located at a distance ~1 mm from the primary vertex. In short the topology capabilities of CHORUS must be combined with the kinematical capabilities of NOMAD. This is the strategy of TOSCA and, until it was withdrawn earlier this year, of COSMOS. (13 refs).