Eikonalization and unitarity constraints

An extensive generalization of the ordinary and quasi-eikonal methods is presented for the pp and elastic scattering amplitudes, which takes into account in a phenomenological way all intermediate multiparticle states involving the crossing even and crossing odd combinations of Reggeons. The formalism in this version involves a maximum of three parameters corresponding to the intermediate states which are possible in this configuration. The unitarity restriction is investigated and particular cases are discussed. An interesting result that emerges concerns the Odderon trajectory intercept: we find that unitarity dictates that this quantity must be below or equal unity unless a very peculiar equality exists between the coupling of the particles to the Pomeron and the Odderon. Received: 3 September 1999 / Revised version: 21 February 2000 / Published online: 8 May 2000 2000