Testing non-standard CP violation in neutrino propagation

TL;DR

This paper investigates the potential to detect non-standard CP violation effects in neutrino propagation caused by effective four-fermion interactions at a neutrino factory, highlighting the risk of misinterpreting new physics as standard CP violation.

Contribution

It demonstrates that non-standard CP violation can be detectable below current bounds, emphasizing the importance of distinguishing it from standard CP violation in neutrino experiments.

Findings

Non-standard CP violation can be detected below current bounds.

Such effects may be mistaken for standard CP violation.

Detection is feasible with current neutrino factory setups.

Abstract

Non-standard physics which can be described by effective four fermion interactions may be an additional source of CP violation in the neutrino propagation. We discuss the detectability of such a CP violation at a neutrino factory. We assume the current baseline setup of the international design study of a neutrino factory (IDS-NF) for the simulation. We find that the CP violation from certain non-standard interactions is, in principle, detectable significantly below their current bounds -- even if there is no CP violation in the standard oscillation framework. Therefore, a new physics effect might be mis-interpreted as the canonical Dirac CP violation, and a possibly even more exciting effect might be missed.