Tale of two hard Pomerons

Two mechanisms are examined for hard double "pomeron" exchange dijet production, the factorized model of Ingelman-Schlein, and the nonfactorized model of lossless jet production which exhibits the Collins-Frankfurt-Strikman mechanism. Comparisons between these two mechanisms are made of the total cross section, E spectra, and mean rapidity spectra. For both mechanisms, several specific models are examined with the cuts of the collider detector at Fermilab (CDF), DØ, and representative cuts of CERN LHC. Distinct qualitative differences are predicted by the two mechanisms for the CDF y spectra and for the E spectra for all three experimental cuts. The preliminary CDF and DØ experimental data for this process are interpreted in terms of these two mechanisms. The y spectra of the CDF data are suggestive of domination by the factorized Ingelman-Schlein mechanism, whereas the DØ data show no greater preference for either mechanism. An inconsistency is found among all the theoretical models in attempting to explain the ratio of the cross sections given by the data from these two experiments. ©2000 The American Physical Society.