The Signals of Doomsday I: False Higgs vacuum decay signatures

TL;DR

This paper explores potential observable signals from false Higgs vacuum decay, focusing on neutrino and photon emissions caused by bubble dynamics, which could be detected by current or future observatories.

Contribution

It introduces a novel calculation of Higgs particle spectra from vacuum bubbles and identifies detectable long-range signals as potential evidence of vacuum decay.

Findings

Thermal Higgs production leads to large bursts of high-energy neutrinos and photons.

Signals from bubble decay could be detectable with existing or upcoming multi-messenger facilities.

Frictional effects influence the propagation and observable signatures of vacuum bubbles.

Abstract

The measured standard model parameters indicate that we might live in a false Higgs vacuum, though with a very long lifetime. However, small black holes can serve as catalysers and significantly speed up the phase transition. In fact, bubbles of true vacuum might already exist in our universe. If the propagation of the bubble walls slows down due to interaction with the surrounding matter and plasma, these signals can reach us before the bubble wall hits us. Using the vacuum mismatch method, we calculate the spectrum of the Higgs particles produced by such a bubble until the terminal velocity is reached. In addition, we show that frictional dissipation at the terminal wall velocity generates a large population of thermally produced Higgs particles, which continues even after the mismatch channel shuts off. Since the Higgs is neutral, a good part of the final decay products (after hadronization, annihilation and decay of unstable particles) will be photons and neutrinos, which will then act as a long-range signature. For the conservative set of parameters used here, the thermal channel produces a macroscopically large burst of high energy neutrinos and photons from Higgs decays, which could be detectable from sufficiently nearby bubbles with current or upcoming multi messenger facilities.