Neutron-antineutron transition as a test-bed for dynamical CPT violations

TL;DR

This paper proposes a mechanism where CPT violation in neutrons arises dynamically via a see-saw process involving a hidden sector and exotic instantons, offering a testable prediction for future neutron-antineutron experiments.

Contribution

It introduces a CPT-violating see-saw mechanism involving a hidden sector and exotic instantons, providing a novel way to generate neutron CPT violation.

Findings

A small CPT-violating mass for the neutron can be naturally generated.

The model predicts observable effects in upcoming neutron-antineutron experiments.

It links CPT violation to non-perturbative quantum gravity effects.

Abstract

We show a simple mechanism for a dynamical CPT violation in the neutron sector. In particular, we show a {\it CPT-violating see-saw mechanism}, generating a Majorana mass and a CPT violating mass for the neutron. CPT-violating see-saw involves a sterile partner of the neutron, living in a hidden sector, in which CPT is spontaneously broken. In particular, neutrons (antineutrons) can communicate with the hidden sector through non-perturbative quantum gravity effects called {\it exotic instantons}. Exotic instantons dynamically break R-parity, generating one effective vertex between the neutron and its sterile partner. In this way, we show how a small CPT violating mass term for the neutron is naturally generated. This model can be tested in the next generation of experiments in neutron-antineutron physics. This strongly motivates researches of CPT-violating effects in neutron-antineutron physics, as a test-bed for dynamical CPT-violations in SM.