The Early Universe as a Probe of New Physics

TL;DR

This paper explores how the early Universe can be used to detect new physics beyond the Standard Model, focusing on dark matter, charged particles, and extra dimensions through cosmological effects.

Contribution

It introduces methods to probe new physics by analyzing early Universe phenomena, extending beyond terrestrial experimental limitations.

Findings

Constraints on dark matter models from Big Bang Nucleosynthesis

Potential signatures of higher dimensions in cosmological observations

Limits on charged massive particles from early Universe data

Abstract

The Standard Model of Particle Physics has been verified to unprecedented precision in the last few decades. However there are still phenomena in nature which cannot be explained, and as such new theories will be required. Since terrestrial experiments are limited in both the energy and precision that can be probed, new methods are required to search for signs of physics beyond the Standard Model. In this dissertation, I demonstrate how these theories can be probed by searching for remnants of their effects in the early Universe. In particular I focus on three possible extensions of the Standard Model: the addition of massive neutral particles as dark matter (through the use of several minimal models of dark matter), the addition of charged massive particles (through catalyzed Big Bang Nucleosynthesis), and the existence of higher dimensions (through its effects on BBN and galactic positron production). For each new model, I review the existing experimental bounds and the potential for discovering new physics in the next generation of experiments.