Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 19 of 19 for “"Axions"”.
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Search For Solar Axions
<p> Peccei and Quinn proposed an elegant solution for restoring CP symmetry to the QCD Lagrangian \cite{PhysRevD.16.1791}. This method includes an additional global U(1) symmetry included in the QCD Lagrangian which is spontaneously broken at a high energy scale, f<sub>a</sub>. Breaking the …
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A search for halo axions
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 1998.
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An improved RF cavity search for halo axions
… candidate. In this RF cavity experiment, halo axions entering a resonant cavity immersed in a static magnetic field convert into microwave photons, with the resulting photons detected by a low-noise receiver. I present new limits on the axion-to-photon coupling and local axion dark matter halo …
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GHz Gravitational Wave and THz Dark Matter Detectors: Analysis and Simulation
… noise and other complications. Dark matter (DM) axions can similarly be detected through the inverse Primakoff effect. Although not directly detected yet, axions are anticipated to produce stronger coherent signals and would additionally solve the strong charge-parity problem in QCD. Current …
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The First Laboratory Searches for Low-Mass Axion Dark Matter
… field interacts with the field of dark matter axions around us, inducing an effective current. This effective current is read out via a superconducting LC circuit and measured with high-sensitivity quantum sensors. The entire device must be kept only barely above absolute zero in order to …
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Search for axion-like particles in the slac beam dump
… Experimental limits were obtained for axions of mass up to ~ 200 MeV/c², and photinos of mass up to ~ 65 MeV/c².
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Dark Matter Production after Inflation and Constraints
… that the field whose angular excitations are the axions can be displaced from its minimum during inflation and later decays dominantly into ultra-relativistic, axions which contribute to the effective number of relativistic species. We finally consider the possible production of axion-like …
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Cosmic String Radiation with Adaptive Mesh Refinement
… emerge as a potential source of dark matter axions. They are also a strong source of gravitational wave (GW) emission, with the potential for detection by the Laser Interferometer Gravitational-Wave Observatory (LIGO) and other GW experiments. The nonlinear evolution of cosmic strings has …
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The instanton liquid and the axion
… to improve our understanding of the cosmology of axions. Axions couple to QCD instantons and these non-perturbative effects are modeled within the framework of the interacting instanton liquid model (IILM). The thesis describes the significant advances made within the IILM in order to study the …
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The Search for High-Frequency Gravitational Waves with a Modified Axion Detector
… introduce the first simultaneous search for both axions and gravitational waves using a lumped-element axion detector. In this thesis I will present on the high-frequency cryogenic ABRACADABRA-10cm detector, the background investigations of the detector and the design and first data from the …
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Commissioning the DIRC Detector and Searching for Axion-like Particles at GlueX
… proposed to solve the strong CP problem, axions and axion-like particles are hypothetical pseudoscalar particles found in many proposed extensions to the Standard Model of particle physics. This thesis presents a search for photoproduction of axion-like particles using data in …
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Inflationary cosmology and fundamental physics
… topics that are directly related to inflation: axions, string theory, and non-minimally coupled fields. In particular, we constrain the allowed parameter space of inflationary axion cosmology, identifying a classic window and an anthropic window; we discuss inflation in string theory, proving a …
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Exploring fundamental physics and astrophysics with gravitational-wave sources
… framework to search for ultralight bosons (e.g., axions). This search relies on the process called superradiance, in which boson clouds form around fast spinning black holes (BHs), reduce the BH spins to characteristic values, and lead to an exclusion region in the parameter space of BH mass and …
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High Power Cyclotrons: The Bridge Between Beyond the Standard Model Physics, Computation, and Medical Applications
… target create a unique opportunity to produce axions and detect monoenergetic peaks with the nearby kiloton detector. Beyond this, the high power produced by the IsoDAR cyclotron can be used for applications beyond particle physics. The lsoDAR cyclotron accelerates and extracts Ht, which …
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Frustration from Frustration: Field Tuning, Vison Crystallisation, and Disorder in Quantum Spin Ice
… strong- coupling confinement, Dirac monopoles, axions and theta terms. Excitingly, recent experiments on the Ce based pyrochlore Ce Zr O have produced compelling evidence in support of a QSI ground state – after 20 years confined to the notebooks of theorists, it would now appear that the …
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Modeling Astrophysical and Large-Scale Structure Signatures in Axion Cosmologies
… of a multitude of pseudoscalar particles called axions with logarithmically distributed masses, potentially addressing both the DM and dark energy problems simultaneously. Combining theoretical analyses with numerical simulations, we unravel the distinct signatures of FDM across intergalactic and …
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On Vacuum Structures and Quantum Corrections in String Theory
… In particular, we systematically include odd axions arising from the reduction of 2-forms (B2, C2) in Type IIB which play a central role in string cosmology. Secondly, we design and apply efficient optimisation methods to search for special vacua that may at the same time reveal hidden …
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Unveiling fundamental physics with high-resolution X-ray spectroscopy of Active Galactic Nuclei.
This doctoral thesis explores the use of high-resolution spectroscopy of active galactic nuclei (AGNs) to probe fundamental physics. It focuses on the study of axion-like particles (ALPs) and the spin of supermassive black holes (SMBHs). Chapter 1 starts with a review of black holes as mathematical …