Testing Lorentz Invariance Violation at the Pierre Auger Observatory

Abstract

In this work, we present the capabilities of testing Lorentz invariance violation (LIV) using data from the Pierre Auger Observatory. Two independent scenarios are treated. Firstly, LIV on the hadron sector is considered and the modified UHECR propagation obtained. An updated combined fit of the spectrum and composition data is performed for each LIV assumption. The data is better described with a low maximum rigidity at sources, which leads to a poor sensitivity to LIV effects. Secondly, subluminal LIV on the photon sector is considered and the propagation of GZK photons is modified. For one of the scenarios considered, very competitive limits on the LIV coefficient of the order of $\delta_\gamma^{(1)} \gtrsim -10^{-40} \, \text{eV}^{-1}$ and $\delta_\gamma^{(2)} \gtrsim -10^{-60} \, \text{eV}^{-2}$ are imposed. Finally, we discuss a promising possibility of testing LIV using the development of UHE air-showers.