Neutrino oscillation physics with a higher-γ β-beam

The precision measurement and discovery potential of a neutrino factory based on boosted radioactive ions in a storage ring ("beta-beam") is re-examined. In contrast with past designs, which assume ion gamma factors of similar to100 and baselines of L = 130 km, we emphasize the advantages of boosting the ions to higher gamma and increasing the baseline proportionally. In particular, we consider a "medium-gamma" scenario (gamma similar to 500, L similar to 730 km) and a "high-gamma" scenario (gamma similar to 2000, L similar to 3000 km). The increase in statistics, which grow linearly with the average beam energy, the ability to exploit the energy dependence of the signal and the sizable matter effects at this longer baseline all increase the discovery potential of such a machine very significantly. (C) 2004 Elsevier B.V. All rights reserved.