Theses, Captstones, and Dissertations
An approximation for the fractional neutron abundance in the 1 MeV to .1 MeV range in the early universe is derived. This is then computed and plotted using the Mathematica software. It is compared with and found in agreement with similar plots and acts as an upper limit on $^4$He during Big bang nucleosynthesis. The approximation falls short at around 0.1 MeV due the onset of neutron decay and D production, changing effective degrees of relativistic freedom, and the increasing consequence of the mass of the electron as the universe cooled.
An extension of the Standard Model of particle physics is proposed that is motivated primarily by the hierarchy problem. The model expands the gauge group of quantum chromodynamics in an attempt to provide a viable model of dark matter and a reason for the unexpected nature of the Higgs vacuum expectation value. These changes introduce new fermion and boson fields to the Standard Model, as well as interesting new collider phenomenology.
Large collider facilities such as the Large Hadron Collider (LHC) employ a variety of search methods in hopes of finding new particles. It may be that new physics beyond the SM is waiting to be discovered at energies accessible to the LHC. Quirks are particles charged under a new confining gauge group with masses much larger than their confinement scale. This project details the dynamics of quirks, as well as the production and decay of electrically charged bound states of scalar quirks. The cross section for these states is compared to existing Wγ resonance searches at the LHC. Such a state is above the most sensitive LHC search up to an invariant mass of about M ≲ 640 GeV.
Twin Higgs models have the potential to explain phenomena outside of the Standard Model and provide an natural explanation of the Higgs mass. Here I explore a new realization of the twin Higgs concept with an SU(4)c symmetry that is spontaneously broken in the Standard Model sector, but remains unbroken in the Twin sector. I detail the phenomenological results produced by this model. I show that this construction leads to a qualitatively new behavior regarding the fine-tuning of the Higgs mass due to the top-quark sector.
Magnetic monopoles, or particles that emit radial magnetic fields, are as yet undiscovered. However, quantum field theory makes many predictions about them. The prediction most relevant to this paper is that the strength of the interaction between magnetic monopoles and other particles depends on the interaction’s energy scale. This phenomenon is well understood for electrically charged particles and is known as the “running of the electric coupling.” In this paper, we show a formalism for determining how the magnetic coupling would run and how it could affect the running of the electric coupling as well. We hope to be able to extend these methods to other types of theories.
We present an alternative method for writing the Einstein-Maxwell equations as a set of five divergence-free, two-dimensional vector fields. These fields have close ties to the conserved quantities of a black hole. This formulation has the potential to provide new understanding of black hole uniqueness, based upon a black hole's conserved quantities.