Title: “Evidence for light-by-light scattering in heavy-ion collisions with the ATLAS detector at the LHC”
Author: ATLAS Collaboration
Reference: doi:10.1038/nphys4208
(Originally published on Particle Bites)
According to classical wave theory, two electromagnetic waves that happen to cross each other in space will not interfere. In fact, this is a crucial feature of the conventional definition of a wave, in contrast to a corpuscle or particle: when two waves meet, they briefly occupy the same space at the same time, each without “knowing” about the other’s existence.