An intermediate γ beta-beam neutrino experiment with long baseline

Abstract

In order to address some fundamental questions in neutrino physics a wide, future programme of neutrino oscillation experiments is currently under discussion. Among those, long baseline experiments will play a crucial role in providing information on the value of θ13, the type of neutrino mass ordering and on the value of the CP-violating phase δ, which enters in 3-neutrino oscillations. Here, we consider a beta-beam setup with an intermediate Lorentz factor γ = 450 and a baseline of 1050 km. This could be achieved in Europe with a beta-beam sourced at CERN to a detector located at the Boulby mine in the United Kingdom. We consider a neutrino run alone and show that, by exploiting the oscillatory pattern of the signal, a very good sensitivity to CP-violation and the type of hierarchy can be reached. We analyse the physics potential of this setup in detail and study two different exposures (1 × 1021 and 5 × 1021 ions-kton-years). In both cases, we find that the type of neutrino mass hierarchy could be determined at 99% CL, for all values of δ, for sin 22θ13>0.03. In the high-exposure scenario, we find that the value of the CP-violating phase δ could be measured with a 99% CL error of ~ 20o if sin 22θ13>10−3, with some sensitivity down to values of sin 22θ13 10−4. The ability to determine the octant of θ23 is also studied, and good prospects are found for the high-statistics scenario.