Inclusive Pomeron-Pomeron interactions at the CERN ISR

Data are presented for the first time on inclusive Pomeron-Pomeron interactions which produce a central system X (composed mainly of multimeson states) in proton-proton collisions at √s=62 GeV at the CERN ISR. The system X has a Feynman-x distribution which is sharply peaked at xf=0, is inconsistent with any significant contributions from Reggeon exchange processes, and has an invariant mass dependence on good agreement with the predicted form MX-2. Kaon production is about 15% of pion production, nearly independent of MX, while proton-antiproton production averages about 5% of pion production and increases with MX. The structure of the central system X develops into a jetlike shape, as MX increases, as would be expected from a model of Pomeron fragmentation. The shape of the xf(π) distribution in the center of mass of the X system (although not proving existence) is consistent with a soft partonic substructure of the Pomeron. (orig.)