Theses, Captstones, and Dissertations
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.
Squirks are theoretical particles predicted in many realizations of neutral naturalness, a framework which extends the Standard Model to address the electroweak hierarchy problem. For a two-squirk bound state with net electric charge, the annihilation branching ratios depend on the mass difference $\Delta$ between the squirks. In this work, I show that as $\Delta$ increases, the $\Delta$-dependent branching ratios weaken experimental bounds on squirk masses. In particular, I find that some squirk masses less than 1 TeV have not yet been excluded by searches at the Large Hadron Collider (LHC). These masses are accessible at the LHC's current energy levels, so with a new strategy, we can search for squirks more effectively, increasing the discovery power of the LHC while maintaining its current collision energy. In this paper, I present one such new strategy, which is to search for events where the collision produces a pair of squirks with a glueball. The squirks annihilate into a pair of bosons, and the glueball creates a displaced vertex when it decays in the detector. I also present our simulations of searching for this combination of a bosonic resonance and a displaced vertex. I find that this strategy complements and extends current methods, probing a larger region of squirk mass parameter space than the region excluded by current search strategies, especially for large $\Delta$.
We derive the Unruh effect using the method of Bogoliubov transformations. We begin by constructing the Bogoliubov transformations which relate different sets of QFT operators to each other. We then consider the specific case of comparing an inertial reference frame to an accelerating reference frame. We calculate the Bogoliubov coefficients for this situation and use these to show that the state which is a vacuum from the perspective of the inertial observer contains particles from the perspective of the accelerating observer. The particle density has the form of a thermal bath with a temperature proportional to the acceleration. We discuss the interpretation of this result and possible other applications of the techniques used in this derivation.
Early universe measurements of the Hubble constant usually find the best-fit value for H0 given a specific data set and a particular cosmological model. Planck’s all-sky survey of the Cosmic Microwave Background is a common choice for this data, and is often supplemented with additional constraints from other measurements of cosmological phenomena. For example, the SH0ES collaboration’s measurement of H0 from local type Ia supernovae is a common constraint to include, in the hope of reconciling the tension between late and early universe measurements. We attempt to quantify the effect of this constraint on early universe measurements of H0. We obtain values for H0 from several cosmological models—ΛCDM, CPL dark energy, and exponential acoustic dark energy—under two sets of constraints: only CMB data, and CMB data as well as the SH0ES measurement. We compare these results to each other and find that, for these models, constraining the H0 measurement with SH0ES’ measurement generally reduces the Hubble tension by ~0.5σ. Given the limited scope of this study, our results are probably not generalizable to models other than the ones we examined.