False-Vacuum Decay Lifetime When the Decay Integral Has an Upper Temperature Cutoff

The bounce actions span from 208 in the shallow case to 8527 in the deep case, and the lifetimes vary correspondingly over an enormous range because the action sits in an exponential. The intermediate case gives a decay probability of 10^-279 per Hubble four-volume at its reference epoch, corresponding to a lifetime of 10^279 Hubble times, comfortably stable. In all three cases the epochs that dominate the decay probability lie at or below the scale set by the potential itself, far below the ceiling temperature. Removing the formal history above the ceiling therefore changes the survival conclusion in none of the three cases: potentials that are stable remain stable, and the shallow case, which decays promptly, does so at low temperature where the truncation is irrelevant. This study is simulated and computed from stated assumptions; it is not a measurement.