Expanding the Reach of Laboratory SME Searches Using Higher-Precision Boost Transformations

TL;DR

This paper develops a framework to expand Lorentz-violation searches in the fermion sector by using higher-precision boost transformations between the Sun-centered and laboratory frames. By expressing the observable tilde coefficients $\tilde{b}_j$ in terms of Sun-centered SME coefficients via a transformation $\mathbf{A} = \mathbf{R} \Lambda_L \Lambda_\oplus$ and performing Fourier decompositions, the authors show that new signals arise not only at the sidereal frequency $\omega$ but also at boosted frequencies and their combinations. Through simple toy limits, they demonstrate that existing high-precision data can constrain additional coefficients such as $\tilde{d}_X$ and $\tilde{g}_{TX}$, and that joint fits (Coefficient-Separation) or maximum-reach analyses can reveal hidden sensitivity to multiple SME parameters. The results indicate that higher-precision boost analyses greatly broaden the reach of laboratory SME searches, enabling access to previously unprobed parts of the 44-dimensional fermion-coefficient space and suggesting new experimental directions and reinterpretations of published results.

Abstract

Additional sensitivities to Lorentz violation can be obtained from existing experiments by considering additional boost-suppressed effects. The additional Lorentz-violating signals arise as variations in experimental observables at the commonly-used sidereal frequency as well as more novel frequencies. In this work we provide some examples that serve to illustrate how interesting signals arise from the structure of the relevant boost transformations.