CPT violation in long baseline neutrino experiments: a three flavor analysis

TL;DR

This paper analyzes potential CPT violation signals in three-flavor neutrino oscillations, identifying key parameter combinations and establishing bounds for long baseline experiments like NOvA and neutrino factories.

Contribution

It provides a systematic analytical framework to estimate CPT violation effects in three-flavor neutrino oscillations and identifies experimentally relevant parameter combinations.

Findings

CPT violating contributions are small but can be constrained.

Relevant parameter combinations can be bounded below 10^{-23} GeV.

Bounds can be derived from existing and future long baseline experiments.

Abstract

We explore possible signals of CPT violation in neutrinos in the complete three-flavor framework. Employing a systematic expansion in small parameters, we analytically estimate the CPT violating contributions to the survival probabilities of $\nu_\mu, \bar{\nu}_\mu, \nu_e$ and $\bar{\nu}_e$. The results indicate that, in spite of the large number of CPT violating parameters, only a small number of combinations are relevant for oscillation experiments. We identify the combinations that can be constrained at the long baseline experiments, and show that their contribution to the neutrino Hamiltonian can be bounded to $< 10^{-23}$ GeV, by considering the NOvA experiment for the muon sector, and neutrino factories for the electron sector.This formalism also allows us to translate the bounds on the parameters describing non-standard interactions of neutrinos into the bounds on CPT violating quantities.