In view of the recent diffractive dijet data from CDF run II, we critically
re-evaluate the standard approach to the calculation of central production of
dijets in quasi-elastic hadronic collisions. We find that the process is
dominated by the non-perturbative region, and that even perturbative
ingredients, such as the Sudakov form factor, are not under theoretical
control. Comparison with data allows us to fix some of the uncertainties.
Although we focus on dijets, our arguments apply to other high-mass central
systems, such as the Higgs boson.Comment: 37 pages, 18 figures. Two new appendices, and a discussion of the
upper scale of the Sudakov form factor are introduced. The text about the
calculation of the uncertainties has been rewritte