Forward Physics with Rapidity Gaps at the LHC

A rapidity gap physics program with great potential can be realized at the LHC by adding a few simple forward shower counters (FSCs) along the beam line on both sides of the CMS detector. Measurement of single diffractive cross sections down to the lowest diffractive masses can be made with an efficient level-one trigger. Exceptionally, the detectors also make feasible the study of Central Exclusive Diffraction, and in particular the interaction g g -> g g, in the colour-singlet channel, effectively becoming a "gluon-collider".