Semiclassical Approach to Heterogeneous Vacuum Decay

TL;DR

This paper develops a semiclassical framework to calculate how impurities like baryonic matter influence vacuum decay rates, applying it to the Standard Model Higgs vacuum and exploring potential effects of new physics.

Contribution

It introduces a formalism for heterogeneous vacuum decay considering impurities and applies it to the SM Higgs vacuum, highlighting conditions for decay rate enhancement or suppression.

Findings

Heterogeneous decay is generally suppressed compared to homogeneous decay.

Baryonic matter does not significantly alter the decay probability in the SM.

New physics at certain scales can enhance the vacuum decay rate.

Abstract

We derive the decay rate of an unstable phase of a quantum field theory in the presence of an impurity in the thin-wall approximation. This derivation is based on the how the impurity changes the (flat spacetime) geometry relative to case of pure false vacuum. Two examples are given that show how to estimate some of the additional parameters that enter into this heterogeneous decay rate. This formalism is then applied to the Higgs vacuum of the Standard Model (SM), where baryonic matter acts as an impurity in the electroweak Higgs vacuum. We find that the probability for heterogeneous vacuum decay to occur is suppressed with respect to the homogeneous case. That is to say, the conclusions drawn from the homogeneous case are not modified by the inclusion of baryonic matter in the calculation. On the other hand, we show that Beyond the Standard Model physics with a characteristic scale comparable to the scale that governs the homogeneous decay rate in the SM, can in principle lead to an enhanced decay rate.