Grant: Subatomic Physics Envelope - Individual

85% of the matter in the Universe is missing: astronomical observations show beyond any doubt that some form of Dark Matter (DM) is exerting a strong gravitational influence, but its nature remains unknown. Astroparticle physics links the study of subatomic physics with data from astrophysics and cosmology. The objective of our research program is to investigate three promising streams which have received comparatively little attention in the search for DM. These are: 1) the effect of particle DM in the life and death of stars in our galaxy; 2) the connection between DM and neutrinos, the ghostly particles behind the 2015 Nobel Prize awarded to Arthur B. McDonald (Queen's), and 3) the intriguing possibility of extra dimensions of space, which can lead to the production of small black holes in the early Universe and may constitute a fraction of the Universe's missing matter. These black holes can evaporate rather quickly: this disappearing act can provide further clues about the nature of the dark sector. Methods: This grant will train a team of students and postdoctoral researchers to investigate each of these streams. The first will involve theoretical calculations of DM's effect in stars, followed by detailed supercomputer simulations of possible effects on the Sun and other stars. These will be tested against the latest data, including the 1 billion stars surveyed by the Gaia satellite. Stream two will require a combination of theoretical physics calculations, phenomenology (the connection of theory with experiment), and state-of-the-art statistical techniques to try and decipher what experiments, including neutrino telescopes such as the South Pole IceCube Neutrino Observatory, and a new neutrino telescope in Canada called P-ONE, could tell us about the dark sector and new dark forces. Stream three will involve a combination of analytical and numerical calculations to determine how extra dimensions affect cosmology, including the production of the light elements during the Big Bang, and the distribution of galaxies throughout the Universe, and the link with future successors to the Large Hadron Collider. Impacts: the main impact of our work will be to bring us closer to understanding the nature of dark matter itself. Our work should lead to new insights into stellar evolution, neutrino physics, and potentially find answers to the "hierarchy problem": why is gravity so much weaker than the other fundamental forces? Personnel will be trained in competitive skillsets that include advanced research computing, machine learning, Bayesian data analysis, writing and presentation, in addition to acquiring core knowledge in particle physics and astronomy.