Minimal Neutrino Beta Beam for Large theta_13

TL;DR

This paper explores the minimal neutrino beta beam configurations needed to measure neutrino mass hierarchy and CP violation effectively, considering different isotope production rates and detector setups, to optimize future neutrino experiments.

Contribution

It identifies the minimal beam parameters and isotope production requirements for effective neutrino measurements post theta_13 discovery, proposing feasible configurations for future experiments.

Findings

High isotope production rates enable low gamma beta beams to perform all measurements.

Nominal source luminosities with specific configurations outperform other beam technologies.

A (Ne,He) beta beam from Fermilab can achieve competitive results with existing detectors.

Abstract

We discuss the minimum requirements for a neutrino beta beam if theta_13 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 theta_13 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 gamma 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 gamma \sim 190-350 (depending on the Double Chooz best-fit) could outperform practically any other beam technology including wide-band beam and neutrino factory.