Quantum gravity signals and the CTA

The arrival of TeV-energy photons from distant galaxies is expected to be affected by their QED interaction with intergalactic radiation fields through electron-positron pair production.
In theories where high-energy photons violate Lorentz symmetry (such as some theories of quantum gravity), the kinematics of the process γ+γ→e+e- is altered and the cross-section suppressed.
Consequently, one would expect more of the highest-energy photons to arrive if QED is modified by Lorentz violation than if it is not.

I will present a calculation of the sensitivity of the Cherenkov Telescope Array (CTA) to changes in the γγ-ray horizon of the Universe due to Lorentz violation, and find that it should be competitive with other leading constraints.

            Serdecznie zapraszam,

                        Agnieszka Majczyna