Renormalization Group for Multiparticle Production in (2+1) Dimensions Around the Threshold

Abstract

Multiparticle production in (2+1) dimensions is investigated. We show that in a small region around the threshold the perturbation theory becomes unapplicable due to infrared divergencies in a class of Feynman graphs with rescattering in final state. We develop a technique based on renormalization group for summing up leading logarithms and apply it to the ${\varphi }^4$ models with and without symmetry breaking and to the $O(N)$ ${\varphi }^4$ theory.

based on talk at International Seminar Quarks-94, 11-18 May 1994, Vladimir, Russia, REVTEX 3.0, 13pp, 3 figures included (use bezier.sty)