Accelerator experiments check general relativity

Abstract

The deflection of gamma-rays in Earth's gravitational field is tested in laser Compton scattering at high energy accelerators. Within a formalism connecting the bending angle to the photon's momentum it follows that detected gamma-ray spectra are inconsistent with a deflection magnitude of 2.78 nrad, predicted by Einstein's gravity theory. Moreover, preliminary results for 13-28 GeV photons from two different laboratories show opposite - away from the beam line - deflection, amounting to 33.8-0.8 prad. These conclusions, however, are applicable only for gravitationally sterile high energy electrons. Much more subtle effects are expected if the gravitational deflection of the electrons is taken into account.