Bridging high and low energies in search of quantum gravity - 2025 Cost Action CA23130 First Annual Conference

New constraints on Lorentz invariance violations from H.E.S.S. observations of the blazar PKS 2155-304 flaring period of July 2006

8 Jul 2025, 14:40

20m

Amphithéâtre Charpak (LPNHE)

Oral contribution WG2 High Energy QG Experiments

Speaker

Ugo Pensec

Description

Lorentz invariance is a cornerstone of modern physics. However, certain quantum gravity models suggest potential violations of Lorentz symmetry (LIV) at high energy scales. Blazars, such as PKS 2155-304, are powerful, variable sources of very high-energy gamma rays and provide an ideal setting for testing such phenomena. We analyze the temporal and spectral properties of the July 29, 2006 PKS 2155-304 flare recorded by the H.E.S.S. experiment. A likelihood technique is used to measure energy-dependent time delays in the arrival times of gamma-ray photons that could indicate LIV effects. No significant LIV effect is observed and a stringent constraint on the energy scale of the tested model E_{QG} is set.