V.G.Gurzadyan and A.Margarian, Physica Scripta,53,513-515,1996.pdf

The importance of probing of the accuracy of basic physical principles, the Lorentz invariance, the light speed isotropy, has always been among goals of physical studies since the classic Michelson-Morley experiment.

In this paper an original method was proposed to test those fundamental physical principles based on the continuous measuring of the Compton Edge (the highest energy of the scattered photons) at the scattering of high energy accelerator electrons and laser monochromatic photons in the absolute reference frame of cosmic background radiation.

This program was performed at the GRAAL experiment at the European Synchrotron Radiation Facility (ESRF) in Grenoble for 6 GeV electron energy, first with available facility, then with upgraded and dedicated experiment; the results are in:

V.G.Gurzadyan, et al, Probing the Light Speed Anisotropy with respect to the Cosmic Microwave Background Radiation Dipole, Mod. Phys. Lett. A20 (2005) 19; J.-P. Bocquet, et al, Limits on light-speed anisotropies from Compton scattering of high-energy electrons, Phys.Rev.Lett. 104, 241601, 2010. 515; V.G.Gurzadyan, et al, A new limit on the light speed isotropy from the GRAAL experiment at the ESRF, Proceed. MG12 meeting on General Relativity, vol.B, p. 1495, World Scientific, 2012.

The obtained limit of unprecedented accuracy, 1.6  10^(-14), became a reference value for a number of models of extensions of the Special Relativity.