$θ_{13}$, $δ$ and the neutrino mass hierarchy at a $γ=350$ double baseline Li/B $β$-Beam

Abstract

We consider a $β$-Beam facility where $^8$Li and $^8$B ions are accelerated at $γ= 350$, accumulated in a 10 Km storage ring and let decay, so as to produce intense $\bar ν_e$ and $ν_e$ beams. These beams illuminate two iron detectors located at $L \simeq 2000$ Km and $L \simeq 7000$ Km, respectively. The physics potential of this setup is analysed in full detail as a function of the flux. We find that, for the highest flux ($10 \times 10^{18}$ ion decays per year per baseline), the sensitivity to $θ_{13}$ reaches $\sin^2 2 θ_{13} \geq 2 \times10^{-4}$; the sign of the atmospheric mass difference can be identified, regardless of the true hierarchy, for $\sin^2 2 θ_{13} \geq 4\times10^{-4}$; and, CP-violation can be discovered in 70% of the $δ$-parameter space for $\sin^2 2 θ_{13} \geq 10^{-3}$, having some sensitivity to CP-violation down to $\sin^2 2 θ_{13} \geq 10^{-4}$ for $|δ| \sim 90^\circ$.