Ultra-Peripheral Collisons in CMS

Abstract

Coherent peripheral collisions of atomic nuclei involve electromagnetic or long range hadronic interactions at impact parameters, where both nuclei survive intact. Recently such ultra-peripheral collisions were observed at RHIC. The effect of the electromagnetic field can be interpreted as a photon-photon collision with an effective center of mass energy up to a few GeV at RHIC. At the Large Hadron Collider the effective center of mass energy will be increased by more than an order of magnitude. This opens new opportunities, ranging from the study of non-perturbative QCD to the search for new physics.