About the structure of the Froissart limit in QCD

Abstract

The Froissart asymptotic behavior of cross-sections is usually considered in a parton picture as corresponding to the collision of two almost black disks filled with partons. In this article we mainly concentrate on the examination of the local transparency of such F-disks. We discuss how is it possible to guarantee the boost-invariance of the reciprocal transparency of two such F-disks in a process of their collision, despite the fact that the mean area of the overlapping of these F-disks at the same impact parameter is varying with the Lorentz frame. We argue that on will always have such problems, if the dominant interactions at all energies remain soft, but such a trouble can be probably avoided if the mean parton virtualities grow with energies. This last is natural in QCD, and we use the qualitative generalization of BFKL approach to estimate the distribution of hard partons with various virtualities inside a F-disk. As a result, the quasiclassical partonic wave function corresponding to the F-limit can be approximately represented by the system of enclosed parton-gluon disks with a growing virtuality and blackness. With the increase of energy the new disks with larger virtualities are created in the middle of the previous disks, and then they expand with the same transverse velocity.