Two-component structure of the geometrical pomeron

Abstract

Phenomenological observations at FNAL and CERN-ISR not only confirm the dominance of the short range correlation (SRC) over the long-range correlation (LRC) in multihadronie production (1), but also suggest geometrical scaling (2) and two-component structure (3) of the pomeronic amplitude. Moreover, it has long been recognized that the absorptive mechanism is crucial for the possible stabilization of the pomeron under direct-channel unitarization (~-8). Consequently, it will be of physical importance to investigate the theoretical features of central and peripheral components of the geometrical pomeron within the framework of an absorptive multiperipheral unitarization. By the use of the absorptive procedure of CAN]~SCHI and SCrtwI~R (5), in fact, the first-step unitarization of the dipole pomeron (DPP) has already been studied along this line in a recent paper of two of us (s), which gives a successful description of the SRC component. In this short note, therefore, let us perform the second-step unitarization of the DPP by the self-consistent introduction of the LRC component and examine the possible stability of the two-component structure under absorption. First of all, let us summarize the typical features of the singularity structure of the first-step unitarization of the Dt)P (*). First Crtot(~Y), ~el(:Y) and a~,l(iY ) are described by the colliding-cut pomeron (CCP) of the Finkelstein-Zaeh ariasen type (~), which coalesces into a triple pole at l- 1 for t 0. Secondly az~(:Y) is effectively described by the multiperipheral exchange of the nonlcading colliding-cut pomeron (NLCP), which turns out to be a hard branch cut at 1 1 --gO~2 for t : 0 (**). Thirdly, the NLCP is legitimately approximated by the input DPP near t : 0 so long as go~ln In s/ln s. Finally