Triple-pomeron dynamics: valence vs. glue

Abstract

Three pomerons are known to couple via the gluon loop and interactions of this kind which are responsible for high-mass diffraction are described in terms of the gluonic structure function of the QCD pomeron. We show that the triple-pomeron coupling via the light quark loop associated with the ``valence'' in the pomeron is of the same strength as the purely gluonic coupling. The large $Q^2$ behavior of this new contribution is described by the DLLA evolution from the non-perturbative $f\bar{f}$ valence state of the pomeron. Numerical estimates of the high-mass diffraction structure functions based on the consistent account of both couplings are in good agreement with experimental data.

Comments: 4 pages, 1 Postscript figure, To appear in Proc. of DIFFRACTION 2004, Int. Workshop on Diffraction in High-Energy Physics, Cala Gonone, Sardinia, Italy, Sept. 18-23, 2004