A study of inclusive Double-${\cal P}$omeron-Exchange in $p \bar{p} \to p X \bar{p}$ at $\sqrt{s} = 630$ GeV

Abstract. We report measurements of the inclusive reaction, $p \bar p \to p X \bar p$, in events where either or both the beam-like final-state baryons were detected in Roman-pot spectrometers and the central system was detected in the UA2 calorimeter. A Double-${\cal P}$omeron-Exchange (DPE) analysis of these data and single diffractive data from the same experiment demonstrates that, for central masses of a few GeV, the extracted ${\cal P}$omeron-${\cal P}$omeron total cross section, $\sigma^{tot}_{\cal PP}$ exhibits an enhancement which exceeds factorization expectations by an order-of-magnitude. This may be a signature for glueball production. The enhancement is shown to be independent of uncertainties connected with possible non-universality of the ${\cal P}$omeron flux factor. Based on our analysis, we present DPE cross section predictions, for unit (1 mb) ${\cal P}$omeron-${\cal P}$omeron total cross section, at the Tevatron, LHC and the 920 GeV fixed-target experiment, HERA-B.