Abstract
The last 50 years have seen dramatic changes in the field of theoretical physics. On the astrophysical front, the observational discovery of dark matter and dark energy, as well as advances in our understanding of our cosmological history, today described by the ΛCDM model, have led to new questions about the particle composition of the cosmos. Meanwhile, experimental particle physics confirmations of the Standard Model, and the observation that gravity cannot be renormalized to fit in this picture, along with problems such as strong-CP and neutrino masses, have led to a variety of high energy models which solve these issues. This flurry of activity has ushered in the era of particle cosmology in an attempt to solve these obser- vational issues with the aim of finding a unified theory of physics, valid at all scales.However, the lack of experimental evidence for string theory, super- symmetry, and the myriad of other high energy theories has led physicists back to observations for clues. Indeed, in the absence of any tell-tale sig- nals, it has been crucial to find new ways to discover and/or discriminate between theories. Thankfully, with our increasing understanding of nature and our observational advances come new opportunities to look for signa- tures of high energy theories, using a variety of detectors over a range of energies and scales.
In this work, we have attempted just that. By studying nuclear recoil dark matter experiments we have looked for resonant low threshold elec- tron recoil in atoms and molecules, while with precision cosmological surveys, we may search for new signatures of ultralight fields and forces be- yond the Standard Model. We have focused on repurposing current and near-future experiments to look for other signatures of new physics which had not been studied previously. Many opportunities still remain how- ever, and this work aims at encouraging further “bottom-up” (as opposed to “top-down”) searches for new physics, similar to the work we will describe in the following parts.
| Date of Award | 1 Feb 2024 |
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| Original language | English |
| Awarding Institution |
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| Supervisor | Christopher McCabe (Supervisor) |