Proton-proton intersecting storage accelerator facility ISABELLE at the Brookhaven National Laboratory

The intersecting storage accelerator facility ISABELLE proposed for construction at the Brookhaven National Laboratory is reviewed. ISABELLE would permit the exploration of proton-proton collisions at center-of-mass energies continuously variable from 60 to 400 GeV and with luminosities of ${10}^{32}$-${10}^{33}$ ${\mathrm{cm}}^{-2\mathrm{}}$${\mathrm{s}}^{-1\mathrm{}}$ over the entire energy range. The facility would consist of two interlaced rings of superconducting magnets, operating at 40 kG, in a common tunnel about 2.6 km in circumference. The proton beams would collide at six intersection regions where particle detecting systems would be located. Protons of about 30 GeV from the AGS will be accumulated in each ring to obtain the design current of 10 A prior to their acceleration to the final energy. In this paper the design philosophy underlying the principal design choices, as well as a brief description of the major accelerator systems and the conventional structures, is presented. An overview of the physics potential provided by ISABELLE is then given. The large extension of the center-of-mass energy range combined with the very high luminosity would provide unique possibilities for the investigation of the questions of greatest current interest in particle physics. Arguments, based on the available data and reasonable theoretical concepts, are presented that suggest strongly that the intermediate vector bosons required for a unified weak and electromagnetic field theory should be discovered. They should be studied in detail. The hadron production at high transverse momentum, the energy dependence of the strong interactions, and the possible search for new, massive particles are also discussed. The paper concludes with a detailed beam analysis, the various limitations on beam current, the procedures followed in optimizing the luminosity, and a justification of the projected performance levels.