Precision measurements and tau neutrino physics in a future accelerator neutrino experiment

TL;DR

This paper explores the design and physics potential of a future accelerator-based neutrino experiment in China, focusing on beam optimization, site selection, and measurements of CP violation, non-unitary mixing, and non-standard interactions.

Contribution

It proposes specific beam setups and site choices, demonstrating the experiment's capability to measure CP phase and probe new physics with high precision.

Findings

Muon-decay-based beam can measure CP phase to 14.2° precision.

Non-unitarity can be constrained to |α_ij| ≲ 0.37.

Non-standard interactions can be limited to |ε^m_{ℓℓ'}| ≲ 0.11.

Abstract

We investigate prospects of building a future accelerator-based neutrino oscillation experiment in China, including site selection, beam optimization and tau neutrino physics aspects. CP violation, non-unitary mixing and non-standard neutrino interactions are discussed. We simulate neutrino beam setups based on muon and beta decay techniques and compare Chinese laboratory sites by their expected sensitivities. A case study on Super Proton-Proton Collider and China JinPing Laboratory is also presented. It is shown that the muon-decay-based beam setup can measure the Dirac CP phase by about 14.2$^\circ$ precision at 1$\,\sigma$ CL, whereas non-unitarity can be probed down to $|\alpha_{i j}| \lesssim$ 0.37 ($i \neq j =$ 1, 2, 3) and non-standard interactions to $|\epsilon^m_{\ell \ell'}| \lesssim$ 0.11 ($\ell \neq \ell' = e$, $\mu$, $\tau$) at 90% CL, respectively.