Examples of Semiclassical Instanton-Like Scattering: Massless ${\varphi }^4$ and SU(2) Gauge Theories

Abstract

Two-parameter sets of solutions to the classical field equations in the massless ${\varphi }^4$ model and SU(2) gauge theory are found, each solution presumably describing a multi-particle instanton-like transition at high energy. In the limit of small number of initial particles, the probability of the transition is suppressed by $\exp (-2S_0)$, where $S_0$ is the instanton action.

Comments: 18pp., LaTeX, to be published in Nucl. Phys. B