Minimal Neutrino Beta Beam for Large θ 13

We discuss the minimum requirements for a neutrino beta beam if θ13 is discovered by an upcoming reactor experiment, such as Double Chooz or Daya Bay. We require that both neutrino mass hierarchy and leptonic CP violation can be measured to competitive precisions with a single-baseline experiment in the entire remaining θ13 range. We find that for very high isotope production rates, such as they might be possible using a production ring, a (B,Li) beta beam with a γ as low as 60 could already be sufficient to perform all of these measurements. If only the often used nominal source luminosities can be achieved, for example, a (Ne, He) beta beam from Fermilab to a possibly existing water Cherenkov detector at Homestake with γ ∼ 190− 350 (depending on the Double Chooz best-fit) could outperform practically any other beam technology including wide-band beam and neutrino factory. aEmail: [email protected]