Optimizing the greenfield Beta-beam

TL;DR

This paper compares the physics potential of Beta-beam neutrino experiments using two different ion pairs, optimizing parameters like baseline and boost factor to enhance sensitivity to neutrino properties.

Contribution

It provides a detailed analysis of optimal experimental configurations for Beta-beam sources, identifying specific baselines and ion pairs for different neutrino measurements.

Findings

Two optimal baselines identified for each ion pair.

Different ion pairs are best suited for CP violation and mass hierarchy detection.

Optimal configurations depend on boost factor and luminosity.

Abstract

We perform a comprehensive and detailed comparison of the physics reach of Beta-beam neutrino experiments between two pairs of plausible source ions, (8B, 8Li) and (18Ne, 6He). We study the optimal choices for the baseline, boost factor, and luminosity. We take a 50 kton iron calorimeter, a la ICAL@INO, as the far detector. We follow two complementary approaches for our study: (i) Fixing the number of useful ion decays and boost factor of the beam, and optimizing for the sensitivity reach between the two pairs of ions as a function of the baseline. (ii) Matching the shape of the spectrum between the two pairs of ions, and studying the requirements for baseline, boost factor, and luminosity. We find that for each pair of ions there are two baselines with very good sensitivity reaches: a short baseline with $L [km]/ \gamma \simeq 2.6$ (8B+8Li) and $L [km]/\gamma \simeq 0.8$ (18Ne+6He), and a long ``magic'' baseline. For $\gamma \sim 500$, one would optimally use 18Ne and 6He at the short baseline for CP violation, 8B and 8Li at the magic baseline for the mass hierarchy, and either 18Ne and 6He at the short baseline or 8B and 8Li at the magic baseline for the $\sin^22\theta_{13}$ discovery.