2540 km: Bimagic baseline for neutrino oscillation parameters

TL;DR

A 2540 km baseline for neutrino experiments offers advantages in identifying neutrino mass hierarchy independently of CP violation and θ13, while also enabling measurements of CP phase and θ13.

Contribution

This study demonstrates that a 2540 km baseline provides a robust method for neutrino hierarchy determination and parameter sensitivity in a low energy neutrino factory.

Findings

Wrong-sign muon signal is hierarchy-independent in certain energy ranges.

The setup can probe CP violation and θ13 simultaneously.

Reduced uncertainties in hierarchy identification.

Abstract

We show that a source-to-detector distance of 2540 km offers multiple advantages for a low energy neutrino factory with a detector that can identify muon charge. At this baseline, for any neutrino hierarchy, the wrong-sign muon signal is almost independent of CP violation and $\theta_{13}$ in certain energy ranges. This reduces the uncertainties due to these parameters and allows the identification of the hierarchy in a clean way. In addition, part of the muon spectrum is also sensitive to the CP violating phase and $\theta_{13}$, so that the same setup can be used to probe these parameters as well.