ar X iv : h ep - p h / 99 03 27 9 v 1 7 M ar 1 99 9 Pomeron Fusion and Central η and η ′ Meson Production

The contribution of pomeron fusion to the cross section of η and η productions in double-diffractive scattering has been calculated within the Donnachie-Landshoff model of pomeron. It is shown that the double pomeron exchange mechanism does not explain the full set of the recent data of WA102 Collaboration, though it might not be inconsistent with η productions. On leave of absence from Institute of Physics and Technology, Almaty, 480082, Kazakhstan The structure of the pomeron is now widely under discussion [1]. One of the interesting ways to investigate this structure is the double diffractive process(DDP). Recently, the precise experimental data on central productions of pseudoscalar mesons, π, η and η, have been published by WA102 Collaboration [2]. The most spread wisdom is that the main contribution to the DDP cross section should be related with the double pomeron exchange (DPE)[3]. The kinematics of DDP corresponds to a small momentum transfer region and in this region the contribution from other processes such as photon-photon and vector meson-vector meson fusion is also possible [4]. However, the experimental data give the value of the cross section of pseudoscalar meson productions which are several orders of magnitude larger than one can expect, for example, from γγ fusion [2]. One of the interesting feature of the data is unusual azimuthal angle dependence of the cross section. Different mechanisms, which may responsible for an enhancement of the production cross section in the kinematical region where the azimuthal angle between the pT vectors of two final protons is 90 degrees, have been discussed in recent papers [4],[5], [6]. The subject of our paper is to estimate the DPE contribution to the cross section of central η, η productions in WA102 kinematics. A DPE diagram contributing to central η, η productions, is presented in Fig.1. In order to