Exploratory study of shrinkage of the diffraction cone for the generalized BFKL pomeron

Abstract

In color dipole gBFKL dynamics, we describe the emerging gBFKL phenomenology of a subasymptotic energy dependence of the diffraction slope and discuss possibilities of testing the gBFKL predictions in exclusive photo- and electroproduction of vector mesons $V$ at HERA. A substantial shrinkage of the diffraction cone ${\gamma }^{\ast }p\to Vp$ processes from the CERN/FNAL to HERA range of energy $W$ is predicted. This subasymptotic shrinkage is faster than expected from the small slope of pomeron's Regge trajectory ${\alpha }_{\text{Pom}}^{\prime }$. We point out that the diffraction slope is a scaling function of $(m_V^2+Q^2)$, what relates production of different vector mesons.

Comments: plain LaTeX, 4 figures upon the request from kph154@zam001.zam.kfa-juelich.de