The general realistic effective field theory for Lorentz violation is called the Standard-Model Extension (SME). It includes the Standard Model coupled to General Relativity along with all possible operators for Lorentz violation. Each operator for Lorentz violation is controlled by a coefficient. In practice, testing Lorentz symmetry means experimentally measuring these coefficients. This large coefficient space has been the subject of numerous precision experiments in recent years. The work listed below is a tabulation of these results.
"Data Tables for Lorentz and CPT
Violation,"
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