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.
Highlights
Our present description of nature is based on two enormously successful theories: GeneralRelativity (GR), a classical theory describing all gravitational phenomena, and the Standard Model (SM) of particle physics, which provides a quantum description of all other interactions
The idea that physical results are unchanged under rotations and boosts of the system, and CPT symmetry, the associated invariance of the system under the combination of discrete symmetries of charge conjugation, parity, and time reversal, are pillars of both the SM and GR
While we could draw this procedure in an identical way, observer and particle transformations will be distinct when spacetime symmetries are broken, and we draw the pictures in Figure 2 for the particle transformation case somewhat differently to highlight the difference between rotating the coordinates and rotating the physical system
Summary
Our present description of nature is based on two enormously successful theories: General. The systematic search for Lorentz and CPT violation using the comprehensive effective field theory based framework of the Standard-Model Extension (SME) [3,4,5,6,7,8] provides a method of searching for Planck-suppressed effects in known physics in a complete and organized way. Throughout this work, we use natural units and metric signature +2
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