Lorentz-violating matter-gravity couplings in small-eccentricity binary pulsars

TL;DR

This paper uses precise pulsar timing of neutron star-white dwarf binaries to set new constraints on Lorentz-violating matter-gravity couplings within the Standard-Model Extension, complementing other experimental limits.

Contribution

It extends previous analyses by focusing on Lorentz-violating matter-gravity couplings in small-eccentricity binaries, providing new bounds on SME coefficients for neutrons, protons, and electrons.

Findings

Tight constraints on SME coefficients for matter-gravity couplings.

Complementary to lunar laser ranging and clock experiment limits.

Improved limits using pulsar timing data.

Abstract

Lorentz symmetry is an important concept in modern physics. Precision pulsar timing was used to put tight constraints on the coefficients for Lorentz violation in the pure-gravity sector of the Standard-Model Extension (SME). We extend the analysis to Lorentz-violating matter-gravity couplings, utilizing three small-eccentricity relativistic neutron star (NS) -- white dwarf (WD) binaries. We obtain compelling limits on various SME coefficients related to the neutron, the proton, and the electron. These results are complementary to limits obtained from lunar laser ranging and clock experiments.