Constraining the Quantum Gravity Energy Scale via Gamma-Ray Burst Spectral Lag Data

Lorentz invariance violation (LIV) can alter the group velocity of photons by modifying their dispersion relation, manifesting as differences in the arrival times of photons with different energies. This effect can accumulate over long propagation distances, making gamma-ray bursts (GRBs) a key tool for probing Lorentz invariance violation. By analyzing spectral lag data from 360 measurements across 90 GRBs using Markov Chain Monte Carlo (MCMC) sampling, and under the assumption that all GRBs share a common intrinsic time delay function, we report a maximum a posteriori value of the energy scale of quantum gravity at linear order EQG=8.96×1014 GeV, though the data are also compatible with Lorentz invariance (EQG=∞) to within 2.8σ. Furthermore, we are 95% confident that EQG≥6.67×1014 GeV.