Number 47 (Story #3), September 13, 1991 by Phillip F. Schewe and Ben Stein THE LARGE HADRON COLLIDER , Europe's version of the SSC, has not been officially approved by CERN's constituent nations, but plans for the machine proceed. Like the SSC, the LHC would provide proton-proton collisions rather than proton-antiproton collisions (it takes 300,000 protons to produce one antiproton). LHC's maximum collision energy, 15 TeV, would be less than SSC's 40 TeV, but CERN's Director General Carlo Rubbia believes that their emphasis on high luminosity will enable them to harvest much of the new physics that may be waiting at TeV energies. Besides p-p interactions at 15 TeV, LHC may also be linked with the electron-positron machine LEP (in whose 27-km tunnel LHC would be built) to provide electron-proton collisions at energies up to 1.7 TeV, five times higher than will be available at the nearly completed HERA machine in Hamburg. Also, heavy-ion reactions with total energies up to 1250 TeV, will be possible. (LHC News, supplement to Aug. CERN Courier.)