  We plan to add high precision tracking- and timing-detectors at z = +/- 240 m
to CMS to study exclusive processes p + p -- p + X + p at high luminosity. This
enables the LHC to be used as a tagged photon-photon collider, with X = l+l-
and W+W-, and as a "tagged" gluon-gluon collider (with a spectator gluon) for
QCD studies with jets. A second stage at z = 240 m would allow observations of
exclusive Higgs boson production.
