Conventional Beams or Neutrino Factories: The Next Generation of Accelerator-Based Neutrino Experiments

The purpose of this paper is to provoke a discussion about the right next step in accelerator-based neutrino physics. In the next five years many experiments will be done to determine the neutrino mixing parameters. However, the small parameters theta{sub 13}, Delta-m{sub 21}{sup 2}, and the CP violating phase are unlikely to be well determined. Here, the author looks at the potential of high-intensity, low-energy, narrow-band conventional neutrino beams to determine these parameters. He finds, after roughly estimating the possible intensity and purity of conventional neutrino and anti-neutrino beam, that sin2 theta13 can be measured if greater than a few parts in ten thousand, Delta-m{sub 21}{sup 2} can be measured if it is greater than 4 x 10{sup {minus}5} (eV){sup 2}, and the CP violating phase can be measured if it is greater than 20{degree} and the other parameters are not at their lower bounds. If these conclusions stand up to more detailed analysis, these experiments can be done long before a muon storage ring source could be built and at much less cost.