Selection Dynamics in Reproductive Vacuum Landscapes with Temporal Extension

This manuscript develops a selection framework for cosmological vacuum structure based on vacuum decay dynamics and temporal extension. The central hypothesis explored is that vacuum tunneling events may be interpreted as universe-generating transitions within a multiverse landscape. Under this assumption, the rate and timing of vacuum decay become selection-relevant variables. In particular, vacua that permit extended cosmic expansion before decay may disproportionately contribute to the genealogical structure of the multiverse. We analyse simplified landscape models (smooth, rugged, and clustered topologies) using branching-process dynamics to study how decay rates, expansion duration, and landscape structure affect cumulative multiverse contribution. The results show a long-tail amplification effect: even modest extensions in vacuum longevity can significantly increase total genealogical weight across many generations. The framework does not assume that intelligent life directly causes vacuum transitions. Instead, it explores the possibility that stability-enhancing processes within a light cone indirectly influence multiverse structure by delaying tunneling events and allowing further expansion prior to decay. This work is exploratory and model-dependent. It aims to clarify how selection effects may arise from vacuum dynamics alone, and to distinguish these effects from anthropic reasoning or black-hole–based cosmological natural selection proposals. The manuscript is released as a preprint for open access and archival purposes.