Optimization of the Two-Baseline Beta-Beam

TL;DR

This paper designs an optimized two-baseline beta-beam experiment with four source ions and variable boost factors to enhance sensitivity to neutrino properties like $ heta_{13}$, CP violation, and mass hierarchy, while addressing engineering challenges.

Contribution

It introduces a novel configuration with adjustable boost factors and dual baselines to improve experimental sensitivity and feasibility in neutrino oscillation studies.

Findings

Enhanced sensitivity to neutrino parameters compared to previous setups.

Feasibility of increasing boost factors to compensate for geometric constraints.

Comparable or improved performance relative to other proposed facilities.

Abstract

We propose a $\beta$-Beam experiment with four source ions and two baselines for the best possible sensitivity to $\theta_{13}$, CP violation and mass hierarchy. Neutrinos from $^{18}$Ne and $^6$He with Lorentz boost $\gamma=350$ are detected in a 500 kton water \chr detector at a distance L=650 km from the source. Neutrinos from $^8$B and $^8$Li are detected in a 50 kton magnetized iron detector at a distance L=7000 km from the source. Since a tilt angle $\vartheta=34.5^\circ$ is required to send the beam to the magic baseline, the far end of the ring has a maximum depth of $d=2132$ m. We alleviate this problem by proposing to trade reduction of the decay ring with the increase in the boost factor of the $^8$Li and $^8$B ions up to $\gamma_{^8\mathrm{Li}}=390$ and $\gamma_{^8\mathrm{Li}}=650$, such that the number of events at the detector remains almost the same. We study the sensitivity reach of this two-baseline two-storage ring $\beta$-Beam experiment, and compare it with the corresponding reach of the other proposed facilities.