DOI 10.1007/s1005298000905
Triple pomeron vertex in the limit

M. Braun1,2 - G.P. Vacca1
1 Department of Physics,
University of Bologna and INFN, Italy
2 Department of High Energy Physics, University of S.Petersburg, Russia
Received: 11 December 1997 / Revised version: 6 February 1998 / Published online: 7 August 1998
Abstract
In the hard pomeron theory with the number of colours
the diffractive amplitude obtained in [3] is compared with the results
found for Nc=3 in [1] and in the dipole approach in [5]. It is shown
that the double pomeron exchange contribution can be substituted by
an equivalent triple pomeron interaction term. After such a
substitution
the triple pomeron vertices in [1,3,5] essentially coincide. It is
demonstrated that, in any form, the triple pomeron vertex is conformal
invariant. It is also shown that higher order densities in the
dipole approach do not involve 1 to k pomeron verteces with k>2 but
are rather given by a set of pomeron fan diagrams with only a triple
pomeron coupling.
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