The Standard-Model Extension and Gravitational Tests

TL;DR

This paper reviews the Standard-Model Extension's role in testing CPT and Lorentz symmetry through gravitational experiments, summarizing recent results and proposing new constraints and experimental approaches.

Contribution

It provides a comprehensive review of SME-based gravitational tests and introduces new symmetry violation examples and constraints on additional operators.

Findings

LIGO gravitational wave data constrains SME parameters

Short-range gravity experiments set sensitivity limits

Cosmic-ray data provides first constraints on 81 SME operators

Abstract

The Standard-Model Extension (SME) provides a comprehensive effective field-theory framework for the study of CPT and Lorentz symmetry. This work reviews the structure and philosophy of the SME and provides some intuitive examples of symmetry violation. The results of recent gravitational tests performed within the SME are summarized including analysis of results from the Laser Interferometer Gravitational-Wave Observatory (LIGO), sensitivities achieved in short-range gravity experiments, constraints from cosmic-ray data, and results achieved by studying planetary ephemerids. Some proposals and ongoing efforts will also be considered including gravimeter tests, tests of the Weak Equivalence Principle, and antimatter experiments. Our review of the above topics is augmented by several original extensions of the relevant work. We present new examples of symmetry violation in the SME and use the cosmic-ray analysis to place first-ever constraints on 81 additional operators.