Browsing by Subject "Extra dimensions"

Now showing 1 - 3 of 3
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    Beyond the Standard Model applications of holography
    (2020-07) Buyukdag, Yusuf
    In this thesis, we explore beyond the Standard Model of particle physics by taking advantage of the holography approach. First of all, we consider a supersymmetric model that uses partial compositeness to explain the fermion mass hierarchy and predict the sfermion mass spectrum. Linear mixing between elementary superfields and supersymmetric operators with large anomalous dimensions is responsible for simultaneously generating the fermion and sfermion mass hierarchies. After supersymmetry is broken by the strong dynamics, partial compositeness causes the first- and second-generation sfermions to be split from the much lighter gauginos and third-generation sfermions. The sfermion mass scale is constrained by the observed 125 GeV Higgs boson, leading to stop masses and gauginos around 10--100 TeV and the first two generation sfermion masses around 100--1000 TeV. This gives rise to a splitlike supersymmetric model that explains the fermion mass hierarchy while simultaneously predicting an inverted sfermion mass spectrum consistent with the Large Hadron Collider and flavor constraints. The lightest supersymmetric particle is a gravitino in the keV to TeV range, which can play the role of dark matter. This brings us to the second topic that we consider, a novel realization of the Dynamical Dark Matter (DDM) framework in which the ensemble of particles collectively constitute dark matter and they are the composite states of a strongly-coupled conformal field theory. Cosmological abundances for these states are then generated through mixing with an additional, elementary state. As a result, the physical fields of the DDM dark sector at low energies are partially composite. We calculate the masses, lifetimes, and abundances of these states --- along with the effective equation of state of the entire ensemble. Our results suggest the existence of a potentially rich cosmology associated with partially composite DDM.
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    Soft walls and heavy sleptons in a warped extra dimension.
    (2011-01) Sword, Daniel Gregory
    Extensions of the warped extra dimension framework originally proposed by Randall and Sundrum are discussed, including soft-wall models and aspects of supersymmetry breaking. In particular, the standard model in a soft-wall background is covered in detail, including electroweak physics and an extensive treatment of fermions in arbitrary warped backgrounds. Additionally, aspects of lepton flavor violation in models of supersymmetry breaking with hierarchical soft-terms and Dirac gauginos are discussed, as these can occur naturally when supersymmetry is broken near the infrared boundary.
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    Warped Compactification on General Manifolds
    (2023-08) Hendrickson, KyraElayne
    If extra dimensions exist, what effects from these dimensions manifest in our 4-dimensional spacetime? We will study these effects by performing dimensional reductions on Lagrangians. This process is called compactification. Compactification reveals a new spectrum of masses and a collection of fields called Kaluza-Klein Towers. In this thesis, we attain the spectra in closed form and consider a more general class of spacetimes that are "warped product manifolds." We will show that the Kaluza-Klein spectrum for the free warped scalar field is the same as if the full product space were a direct product manifold (un-warped). In this process, we will derive the warped scalar Laplacian. We will also present a proof showing that there are no warped solutions for a graviton with a zero cosmological constant. This project expands on previous work to derive Kaluza-Klein spectra on general manifolds that are direct product manifolds.