Ultra-peripheral Collisions

Abstract

Photons in ultra-peripheral collisions of heavy ions (and protons) can be used for a variety of physics purposes - for studies of nuclear structure at low Bjorken$-x$, as probes of beyond-standard-model physics at the highest possible photon energies, and to explore new regimes of quantum mechanics via interferometry between two photon sources that share no common origin. This review will present the origins of photons in ultra-peripheral collisions and discuss the important physics that is being done with these photons, with particular emphasis on those on the energy frontier for photon physics.