Progress in Lorentz and CPT Violation

TL;DR

An EFT-based overview of Lorentz and CPT violation within the SME framework, linking theoretical structures (Finsler geometry, concordance, spin dynamics) to observable signatures. It leverages the analogy with Weyl semimetals to address the concordance problem and develops an extended BMT equation to model spin evolution in LV backgrounds. It also surveys charged-lepton flavor-violating processes, summarizing current experimental bounds and outlining future searches (e.g., Mu2e, COMET) to test LV and CPT-violating effects. Together, the work provides a coherent, testable program for Lorentz/CPT violation across propagation, spin, and flavor sectors with implications for high-precision experiments and cosmological rest-frame considerations.

Abstract

This talk at the CPT'25 meeting presents an overview of some recent results in Lorentz and CPT violation. Topics covered include the geometry of Finsler spaces associated with Lorentz violation, the resolution of the concordance problem in Lorentz-violating effective field theories, the relativistic evolution of a spin in background fields, and the phenomenology of searches for flavor-changing Lorentz and CPT violation in charged leptons.