Big Bang Nucleosynthesis as a Probe of New Physics

TL;DR

Big Bang Nucleosynthesis (BBN) serves as a crucial observational tool to test the hot big bang model and explore new physics scenarios, including exotic particles, varying constants, and non-thermal processes.

Contribution

This paper provides a comprehensive overview of how BBN can be used to probe various non-standard physics beyond the standard cosmological model.

Findings

BBN constraints limit properties of new particles and interactions.

Non-thermal processes from decaying particles affect light element abundances.

Charged relics can catalyze nuclear reactions during BBN.

Abstract

Big bang nucleosynthesis (BBN), an epoch of primordial nuclear transformations in the expanding Universe, has left an observable imprint in the abundances of light elements. Precision observations of such abundances, combined with high-accuracy predictions, provide a nontrivial test of the hot big bang and probe non-standard cosmological and particle physics scenarios. We give an overview of BBN sensitivity to different classes of new physics: new particle or field degrees of freedom, time-varying couplings, decaying or annihilating massive particles leading to non-thermal processes, and catalysis of BBN by charged relics.