RUI: Studies of Lorentz Violation

California Polytechnic State University Foundation, San Luis Obispo CA

Investigators

Abstract

This award funds the research activities of Professor Matthew Mewes at California Polytechnic State University. Lorentz invariance is the basis of Special Relativity and is thought to be an exact symmetry of nature. It is a feature of both the Standard Model of particle physics and General Relativity. Consequently, any violation of this basic principle would be a signal of new physics. Moreover, attempts to unify the Standard Model and General Relativity suggest Lorentz invariance might be slightly broken at low energies. The research of Professor Mewes focuses on the theoretical description of Lorentz-symmetry breaking and the identification of possible experimental signatures. The goal of this project is to extend existing theory to include a very broad class of Lorentz-invariance violations. To date, most studies of Lorentz violation have focused on the simplest minimal violations. This project aims to understand the theoretical and experimental significance of more general nonminimal violations. Research in this area advances the national interest by promoting the progress of science in one of its most fundamental directions: the discovery and understanding of new physical law. Moreover, parts of this work will be accessible to undergraduates and will provide research opportunities for physics majors at Cal Poly, a primarily undergraduate institution. Students involved in this research will gain valuable exposure to theoretical physics. In more technical terms, this project seeks to fill in several major gaps in the theoretical framework known as the Standard-Model-Extension (SME). The SME aims to provide a general description of Lorentz violation in any system. The generality of the approach implies that the full SME contains an infinite number of violations. To keep the problem tractable, most studies have focused on the minimal SME, which restricts attention to operators of renormalizable mass dimension. However, there are reasons to suspect that nonrenormalizable violations may dominate. Recent studies have systematically examined nonrenormalizable violations in photons and free fermions. This project will build on this work by studying violations in gauge interactions between photons and fermions. It will also extend our understanding of potential violations in gravity by considering higher-order nonminimal violations in General Relativity.