Sensitivity to sterile neutrino mixings and the discovery channel at a neutrino factory

TL;DR

This paper investigates the sensitivity of a neutrino factory to sterile neutrino mixings across various oscillation channels, highlighting the importance of the $ u_ o u_ au$ channel for unitarity and CP violation studies beyond the standard model.

Contribution

It provides a detailed analysis of sterile neutrino mixing sensitivities at a neutrino factory, emphasizing the role of the $ u_ o u_ au$ channel in unitarity and CP phase measurements.

Findings

The $ u_ o u_ au$ channel is crucial for testing unitarity.

Standard channels have limited sensitivity to sterile neutrino mixings.

The $ u_ o u_ au$ channel can probe new CP phases.

Abstract

Sensitivity of a neutrino factory to various mixing angles in a scheme with one sterile neutrino is studied using $\nu_e\to\nu_\mu$, $\nu_\mu\to\nu_\mu$, $\nu_e\to\nu_\tau$ and $\nu_\mu\to\nu_\tau$. While the "discovery-channel" $\nu_\mu\to\nu_\tau$ is neither useful in the standard three flavor scheme nor very powerful in the sensitivity study of sterile neutrino mixings, this channel is important to check unitarity and to probe the new CP phase in the scheme beyond the standard neutrino mixing framework.