A neutrino apparatus with improved capabilities for a short baseline nu(mu)(nu(e))<->nu(tau) search

We propose the conceptual design of a Neutrino ApparatUS with Improved CApAbilities (NAUSICAA). This detector could be used for a new, short-baseline, high sensitivity nu(mu)(nu(e)) left-right arrow nu(tau) oscillation search experiment at the CERN-SPS neutrino beam, as well as at the future Fermilab Main Injector neutrino beam. The heart of the detector is a finely instrumented target, made of a sandwich of a light Z material and high resolution tracking detectors. Downstream of the target there are tracking detectors for momentum measurement, followed by a compensating calorimeter. All these systems are contained within magnet providing a magnetic field of about 1 T. Following the magnet there is a muon detector. Unlike previous experiments, NAUSICAA would be capable of searching for the tau signature using both kinematical and vertex criteria simultaneously. Detailed Monte Carlo calculations show that NAUSICAA could improve the sensitivity of the on-going experiments, CHORUS and NOMAD by an order of magnitude in a four-year neutrino run at CERN. Further improvement on the sensitivity (by a factor of two to five) could be achieved in a four-year sun at Fermilab.