Pseudo-bounces vs. new instantons

Abstract Some false vacua do not decay via bounces. This usually happens when a flat direction of the tunneling action due to scale invariance is lifted sloping valley by breaking perturbation, pushing bounce off infinity. We compare two types alternative configurations that have been proposed recently describe in such cases: pseudo-bounces and new instantons. Although both field are quite similar, we find pseudo-bounce lower than instanton one describes more faithfully bottom valley. In addition, cover range space wider instantons and, as result, lead rate can be orders magnitude.