Cosmic Colliders: High Energy Physics with First-Order Phase Transitions

TL;DR

This paper explores how early Universe vacuum bubble collisions during first-order phase transitions can serve as cosmic-scale high-energy colliders, offering insights into fundamental physics and cosmology beyond current experimental capabilities.

Contribution

It reviews recent advances and challenges in understanding cosmic colliders formed by runaway bubble collisions during phase transitions and their implications for particle physics and cosmology.

Findings

Cosmic bubble collisions can reach energies near the Planck scale.

Such collisions can produce observable gravitational waves.

They have broad applications including dark matter and leptogenesis.

Abstract

Collisions of vacuum bubbles in the early Universe can act as cosmic-scale high-energy colliders with energy reach close to the Planck scale. Such "cosmic colliders" would represent the most energetic phenomena in our cosmic history, transcending any temperature or energy scale ever reached in our Universe, opening tremendous opportunities for particle physics and cosmology. Such configurations are realized during first-order phase transitions with runaway bubbles -- a topic of significant current research interest as a promising cosmological source of gravitational waves. We discuss recent developments and challenges in the physics of such cosmic colliders, as well as their broad applications for particle physics and cosmology, from dark matter to leptogenesis to gravitational waves.