Monte Carlo simulation of GRB data to test Lorentz-invariance violation

Lorentz-invariance violation (LV) at energy scales approaching the Planck regime serves as a critical probe for understanding quantum gravity phenomenology. Astrophysical observations of gamma-ray bursts (GRBs) present a promising avenue for testing LV-induced spectral lag phenomena; however, interpretations are complicated by degeneracies between LV effects and intrinsic emission delays. This study systematically investigates three competing time delay models: model A (LV delay combined with a constant intrinsic delay), model B (energy-dependent intrinsic delay without LV), and model C (LV delay combined with energy-dependent intrinsic delay). We utilize mock GRB datasets generated under distinct delay mechanisms and employ Bayesian parameter estimation on simulated observations of 10 GRBs. Our findings demonstrate that model C consistently recovers input parameters across all datasets, including those designed to mimic LV-dominated (model A) and intrinsic delay-dominated (model B) scenarios. In contrast, models A and B struggle to reconcile data generated under alternative mechanisms, particularly when confronted with high-energy TeV photons from GRB 190114C and GRB 221009A. Our analysis confirms that the incorporation of energy-dependent intrinsic delays in model C is essential for establishing robust LV constraints, effectively resolving prior ambiguities in the interpretation of multi-GeV and TeV photon emissions. The results validate model C as a generalized framework for future LV searches, yielding a subluminal LV scale of <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:msub><a:mrow><a:mi>E</a:mi></a:mrow><a:mrow><a:mi>LV</a:mi></a:mrow></a:msub><a:mo>≃</a:mo><a:mn>3</a:mn><a:mo>×</a:mo><a:msup><a:mrow><a:mn>10</a:mn></a:mrow><a:mrow><a:mn>17</a:mn></a:mrow></a:msup><a:mtext> </a:mtext><a:mtext> </a:mtext><a:mi>GeV</a:mi></a:mrow></a:math> based on realistic datasets, including 14 Fermi-LAT multi-GeV photons from eight GRBs, a 99.3 GeV photon from GRB 221009A observed by Fermi-LAT, a TeV photon from GRB 190114C detected by MAGIC, and a multi-TeV photon from GRB 221009A recorded by LHAASO. These findings are consistent with earlier constraints derived from Fermi-LAT datasets. This work underscores the necessity for joint modeling of LV and astrophysical emission processes in next-generation LV studies utilizing observatories such as LHAASO and CTA.