Lorentz Violation in Deep Inelastic Electron-Proton Scattering

Lorentz violation in the quark sector induces a sidereal time dependence in electron-proton, proton-antiproton and proton-proton cross sections. At high energies nonperturbative effects are buried in universal nucleon parton distribution functions and Lorentz violating effects are calculable in perturbation theory. We focus on deep inelastic electron-proton scattering data collected from ZEUS and H1 at HERA and show that a sideral time analysis of these events is able to set strong constraints on most of the coefficients we consider.