CPT and Lorentz-invariance violation

TL;DR

This paper reviews the theoretical motivations and experimental tests for Lorentz and CPT symmetry violations, focusing on their potential as signals of quantum gravity effects, especially in antimatter experiments.

Contribution

It provides an overview of the SME framework, mechanisms for symmetry breakdown, and recent experimental efforts to detect Lorentz and CPT violations.

Findings

Ultrahigh-precision tests can detect minuscule symmetry violations.

Antimatter experiments offer promising avenues for observing CPT violation.

The SME framework guides experimental searches for Lorentz and CPT symmetry breakdown.

Abstract

The largest gap in our understanding of nature at the fundamental level is perhaps a unified description of gravity and quantum theory. Although there are currently a variety of theoretical approaches to this question, experimental research in this field is inhibited by the expected Planck-scale suppression of quantum-gravity effects. However, the breakdown of spacetime symmetries has recently been identified as a promising signal in this context: a number of models for underlying physics can accommodate minuscule Lorentz and CPT violation, and such effects are amenable to ultrahigh-precision tests. This presentation will give an overview of the subject. Topics such as motivations, the SME test framework, mechanisms for relativity breakdown, and experimental tests will be reviewed. Emphasis is given to observations involving antimatter.