An intermediate gamma beta-beam neutrino experiment with long baseline

TL;DR

This paper evaluates a proposed intermediate gamma beta-beam long-baseline neutrino experiment, demonstrating its potential to determine neutrino mass hierarchy, measure CP violation, and resolve the theta23 octant with high confidence.

Contribution

It introduces and analyzes a novel beta-beam setup with gamma=450 and 1050 km baseline, assessing its physics reach for key neutrino parameters.

Findings

Mass hierarchy can be determined at 99% CL for sin^2(2 theta13) > 0.03.

CP phase delta can be measured with ~20° precision if sin^2(2 theta13) > 10^{-3}.

Good prospects for determining the octant of theta23 in high-statistics scenario.

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 theta13, the type of neutrino mass ordering and on the value of the CP-violating phase delta, which enters in 3-neutrino oscillations. Here, we consider a beta-beam setup with an intermediate Lorentz factor gamma=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 analyse the physics potential of this setup in detail and study two different exposures (1 x 10^{21} and 5 x 10^{21} 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 delta, for sin^2(2 theta13) > 0.03. In the high-exposure scenario, we find that the value of the CP-violating phase delta could be measured with a 99% CL error of ~20 deg if sin^2 (2 theta13) > 10^{-3}, with some sensitivity down to values of sin^2(2 theta13) ~ 10^{-4}. The ability to determine the octant of theta23 is also studied, and good prospects are found for the high-statistics scenario.