Study of multiparticle production in Reggeon field theory

Abstract

The concept of Reggeon field theory (RFT) is applied to particle production in the multi-Regge region. For processes with repeated Pomeron ($\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{P}$) exchange we calculate the high-energy behavior of the production cross sections ${\ensuremath{\sigma}}_{n}(s)$ and find that ${\ensuremath{\sigma}}_{n}(s)\ensuremath{\sim}{\ensuremath{\sigma}}_{\mathrm{el}}(s)\ensuremath{\sim}{(\mathrm{ln}s)}^{\ensuremath{-}\frac{5}{6}}$ for every $n$. It is then shown that $s$-channel unitarity constraints are respected: in the absence of $\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{P}$ cuts these processes are known to violate the Froissart bound (Finkelstein-Kajantie problem). We show that the inclusion of $\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{P}$ cuts in our RFT model solves this problem, provided the $\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{P}$-particle-$\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{P}$ vertex is not large. Furthermore, we demonstrate that the way in which $s$-channel unitarity is restored does not lead to decoupling problems. Finally, particle production with a secondary Reggeon exchange is considered. We find that the ${\ensuremath{\sigma}}_{n}(s)$ have qualitatively the same behavior as in the absence of $\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{P}$ cuts.