Classical Nonminimal Lagrangians and Kinematic Tests of Special Relativity

TL;DR

This paper reviews recent classical lagrangians for nonminimal fermion sectors in the SME, applying them to interpret kinematic tests of Special Relativity and deriving new constraints on Lorentz-violating coefficients.

Contribution

It provides explicit classical lagrangians for nonminimal SME coefficients and demonstrates their use in analyzing classical tests of Lorentz invariance.

Findings

New constraints on nonminimal SME coefficients

Classical lagrangians effectively interpret kinematic tests

Experimental sensitivities remain far from Planck scale

Abstract

This article gives a brief summary on recently obtained classical lagrangians for the nonminimal fermion sector of the Standard-Model Extension (SME). Such lagrangians are adequate descriptions of classical particles that are subject to a Lorentz-violating background field based on the SME. Explicitly, lagrangians were obtained for the leading nonminimal contributions of the m, a, c, e, and f coefficients. These results were then used to interpret classical, kinematic tests of Special Relativity in the framework of the nonminimal SME. This led to new constraints on certain nonminimal controlling coefficients. Although the experiments were very sophisticated in the era when they were carried out, their sensitivities for detecting Lorentz violation were still far away from the Planck scale. Obtaining the novel constraints can be considered as a proof-of-principle demonstrating the applicability of the classical lagrangians computed.