Search for gluonic bound states in high energy proton-proton collisions

The Double Pomeron Exchange process is studied as a potential source for the production of gluonic bound states utilizing the Intersecting Storage Rings at the European Organization for Nuclear Research in Geneva, Switzerland. Three different triggers are studied, which differ in the requirements placed on the slow central system produced by the Pomeron-Pomeron interaction. Exclusive four and six prong events are studied. A spin-parity analysis is performed on the π+π- system in the exclusive channel pp → ppπ+π- for two of the triggers. The large enhancement previously seen in DPE reactions in the region of the f0 meson is confirmed to be a spin-two object. No other resonant states are observed in the π+π- system. The exclusive channels pp → ppK+K- and pp → ppp anti p are examined, but due to limited statistics no strong conclusions can be drawn from these samples. The exclusive channel pp → ppπ+π+π-π- is analyzed for the subprocesses pp → pprho0 π+π- and pp → pp rho0rho0. No enhancement is seen for the rho0rho0 channel. This result is quite different from that obtained for the topologically similar γγ interaction in e+e- collisions. A simple spin-parity analysis of the π+π+π-π- system reveals no structure as a function of the four pion mass. The exclusive process pp → ppK/sub s/0K+-π-+ is studied and the K0Kπ mass spectrum is examined. An enhancement is seen in the region of 1500 MeV, but it appears to originate from events which have missing tracks, rather than from the exclusive final state. While this does not preclude its interpretation as a genuine resonant state, it does mean that a definite statement cannot be made on the basis of this analysis