Extracting the Pomeron-Pomeron Cross Section from Diffractive Mass Spectra

We have calculated the mass distribution ($d\sigma/dM_X$) as observed by UA8 Collaboration in the inclusive reaction $p \bar p \to p X \bar p$ at $\sqrt s = 630 GeV$, using the Interacting Gluon Model (IGM) with Double Pomeron Exchange included. The only new parameter is the $IP IP$ cross section, which we can extract from fitting experimental data. We compare our results with the values obtained in the UA8 study. Assuming a constant Pomeron-Pomeron total cross section ($\sigma_{IP IP} = 1 mb$), we make predictions for $d\sigma/dM_X$ at Tevatron and LHC energies.