Phenomenological Effects of CPT and Lorentz Invariance Violation in Particle and Astroparticle Physics

TL;DR

This paper explores potential violations of CPT and Lorentz invariance in particle and astroparticle physics, discussing theoretical frameworks, phenomenological implications, and the significance of astrophysical and artificial neutrino observations for detecting such fundamental symmetry departures.

Contribution

It provides a comprehensive overview of CPT and Lorentz invariance violation effects, combining theoretical insights with phenomenological approaches and proposing new experimental and observational strategies.

Findings

Astrophysical messengers are crucial probes for symmetry violations.

High-energy particles can reveal effects of quantum gravity.

Current and future experiments can test CPT and Lorentz invariance.

Abstract

It is well known that a fundamental theorem of Quantum Field Theory (QFT) set in at spacetime ensures the CPT invariance of the theory. This symmetry is strictly connected to the Lorentz covariance, and consequently to the fundamental structure of spacetime. Therefore it may be interesting to investigate the possibility of departure from this fundamental symmetry, since it can furnish a window to observe possible effects of a more fundamental quantum gravity theory in a "lower energy limit". Moreover, in the past, the inquiry of symmetry violations provided a starting point for new physics discoveries. A useful physical framework for this kind of search is provided by astroparticle physics, thanks to the high energy involved and to the long path travelled by particles accelerated by an astrophysical object and then revealed on Earth. Astrophysical messengers are therefore very important probes for investigating this sector, involving high energy photons, charged particles, and neutrinos of cosmic origin. In addition, one can also study artificial neutrino beams, investigated at accelerator experiments. Here we discuss the state of art for all these topics and some interesting new proposals, both from a theoretical and phenomenological point of view.