  We propose to add high precision track detectors 55m downstream on both (E&W)
sides of CDF, to measure high Feynman-x protons and antiprotons in association
with central states. A primary motivation is to search for the Higgs boson, and
if it is seen to measure its mass precisely. The track detectors will be
silicon strip telescopes backed up by high resolution time-of-flight counters.
The addition of these small detectors effectively converts the Tevatron into a
gluon-gluon collider with sqrt{s} from 0 to ~ 200 GeV.
  This experiment will also measure millions/year clean high-|t| elastic
scattering events and produce millions of pure gluon jets. Besides a wealth of
unique QCD studies we will search for signs of exotic physics such as SUSY and
Large Extra Dimensions.
