Searches for Physics Beyond the Standard Model: From Colliders to Dark Matter Plasmas
Abstract
In this dissertation, we provide a collection of works dedicated to various searches for physics beyond the Standard Model of particle physics. For Earth-based searches, we perform dedicated analyses of future beam dump and pion decay experiments with special emphasis on probing heavy neutral leptons. We find that these experiments show great promise in their discovery capabilities and provide exciting new opportunities to probe a variety of models. In the astrophysical context, we extend the typical single particle interaction paradigm of dark matter to incorporate collective modes generated from plasma instabilities. With the use of dedicated particle-in-cell simulations of the Bullet Cluster and semi-analytic models of the Jeans instability, we rule out large regions of parameter space for dark matter with a secluded U(1)D gauge group previously inaccessible.