90 research outputs found
A search for Z = -1 dark matter annihilation products in cosmic rays with AMS-01
No full textThesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 2007.Includes bibliographical references (p. 85-89).The majority of mass in the universe has not been observed optically and is termed dark matter. The supersymmetric neutralino provides an interesting dark matter candidate, which may self-annihilate in our galaxy, producing particles visible in the cosmic ray spectrum. During a ten day space shuttle flight, the AMS-01 detector recorded over 100 million cosmic ray events. This analysis searches for the products of neutralino annihilation in the AMS-01 Z=-1 spectrum, and uses the results to place limits on which supersymmetric and dark matter halo distribution models are compatible.by Gray Rybka.Ph.D
A Piezoelectrically Tuned RF-Cavity Search for Dark Matter Axions
No full textThesis (Ph.D.)--University of Washington, 2017-03The Axion is a well motivated hypothetical elementary particle that must exist in nature if the strong CP problem of QCD is explained by the spontaneous breaking of a Peccei-Quinn symmetry. Not only would the discovery of the axion solve deep issues in QCD, an axion with a mass of eV - meV could account for most or all of the missing mass in our galaxy and finally reveal the composition of dark matter. The Axion Dark Matter experiment (ADMX) seeks to resolve these two critical problems in physics by looking for the resonant conversion of dark-matter axions to microwave photons in a strong magnetic field. Utilizing state of the art electronics and dilution refrigerator cryogenics, ADMX is the world's leading haloscope search for axions - able to discover or rule out even the most pessimistically coupled QCD axions. With multi- functionality and with the commissioning of the new high-frequency Sidecar experiment, ADMX is also sensitive to a wide range of plausible axion masses. Here I motivate axions as ideal dark matter candidates, review techniques for detecting them and give a detailed description of the ADMX experiment. I discuss my contributions to the construction of the ADMX dual-channel receiver, which is the most sensitive microwave receiver on earth. I discuss the data acquisition, data taking and real-time analysis software. The primary focus of this work, however, is the ADMX Sidecar experiment which is a miniature axion haloscope that fits inside of the ADMX insert and has the capability of searching for axion masses between 16eV - 24eV on the and 26.4 - 30eV on the . I discuss analysis of the Sidecar data and exclude axion-to-two-photon coupling over a mass range of 3eV ( 708 MHz) from 21.05 - 23.98 eV for axions that compose 100 of dark matter. Over a narrow subsection of this range, 22.89 - 22.95eV (15 MHz) I set a stricter limit
Superconducting Resonator Development for the Axion Dark Matter eXperiment
No full textThesis (Ph.D.)--University of Washington, 2024The Axion Dark Matter eXperiment (ADMX) is the first axion haloscope search to reachDFSZ sensitivity in any mass range for the QCD axion. The QCD axion is a well-motivated
dark matter candidate that additionally solves the strong CP problem in nuclear physics. A
haloscope has three necessary components; a very strong external magnet, a high Q cavity
resonator embedded in this field, and an ultra-sensitive RF read-out system. This dissertation mainly reports on the future development of the resonators for ADMX, specifically superconducting RF (SRF) cavities. It starts with an overview of axions, haloscopes, and the current ADMX experiment, followed by the work done at Lawrence Livermore National Laboratory (LLNL) on SRF cavities, and finally the preliminary results of the ADMX "hybrid" superconducting-copper Sidecar cavity in run 1D
A Search for Wavelike Dark Matter with Dielectrically-loaded Multimode Cavities
No full textThesis (Ph.D.)--University of Washington, 2021Dark matter makes up 85% of the matter in the universe and 27% of its energy density, but we don’t know what comprises dark matter. There are several compelling candidates for dark matter that have wavelike properties, including axions and dark photons. Wavelike dark matter can be detected using ultra-sensitive microwave cavities. The ADMX experiment usesa cylindrical cavity operating at the fundamental mode to search for axions in the few µeV mass range. However, the ADMX search technique becomes increasingly challenging with increasing axion mass. This is because higher masses require smaller-diameter cavities, and a smaller cavity volume reduces the signal strength. Thus, there is interest in developing more sophisticated resonators to overcome this problem. The ADMX-Orpheus experiment uses a dielectric-loaded Fabry-Perot cavity to search for axions and dark photons with masses approaching 100 µeV. Orpheus maintains a large volume by operating at a higher-order mode, and the dielectrics shape the electric field so that the mode couples more strongly to the axion and dark photon. This thesis describes the development and commissioning of ADMX-Orpheus to search for dark photons with masses between 65.5 µeV and 69.3 µeV. This thesis includes• Motivation for why dielectric cavities are suitable for detecting axions and dark photons around 100 µeV.
• The design and characterization of such a cavity, including the resonant frequency, quality factor, and detection volume of the mode of interest.
• The mechanical design, electronics, and data acquisition system for the Orpheus experiment.
• The inaugural search for dark photons 65.5 µeV and 69.3 µeV and the resulting excluded parameter space.
• Plans for upgrading Orpheus to search for axions in a similar mass range
Constraining the Neutrino Mass Using Cyclotron Radiation Emission Spectroscopy
No full textThesis (Ph.D.)--University of Washington, 2020The existing prototype to demonstrate the viability of the Cyclotron Radiation Emission Spectroscopy (CRES) has been upgraded to incorporate tritium compatibility. The spectrum of the conversion electrons from has been measured with great linearity and a precision of over the energy range of 17-32 \eV. The first tritium beta-spectrum using CRES has also been measured to conclude an endpoint value of . The recorded tritium spectrum is analyzed to set the first CRES limit on the neutrino mass,
Designing, Operating and Analyzing: The Quest for Axion Dark Matter with ADMX
No full textThesis (Ph.D.)--University of Washington, 2025The Axion Dark Matter eXperiment (ADMX), located at the University of Washington, is a world-renowned experiment and is at the forefront of the hunt for the elusive QCD axion. The QCD axion, originally proposed in the late 1970s to solve a problem in particle physics, was quickly identified as a promising dark matter candidate. While it was initially thought to be impossible to detect due to its extremely weak coupling to standard model particles, over the past couple of decades major advancements in experimental technology have allowed experiments, like ADMX, to become sensitive enough to detect such a particle. In this thesis I will begin by providing context on the history of and evidence for dark matter, the origin of the axion as a theoretical particle, and what makes the axion a good dark matter candidate. Next, I will explain how experiments like ADMX search for axions today as well as situate ADMX in the landscape of existing and proposed axion searches. The remainder of the thesis will cover the details of the most recent data taking run with ADMX, Run 1D. More specifically I will detail the hardware changes made since the last run, the most thorough noise calibration campaign done with ADMX to date, the operations and procedures involved in taking data, as well as the full analysis process. I will finish by reporting results including a 90% confidence level upper limit on axion-photon coupling between 1.088-1.315 GHz, as well as a discussion about the discovery ability of this data set
Project 8: Progress Towards using Cyclotron Radiation Emission Spectroscopy on Atomic Tritium for a Neutrino Mass Measurement
No full textProject 8 has demonstrated Cyclotron Radiation Emission Spectroscopy (CRES) as a novel technique for performing electron spectroscopy. Applying this method to highest energy electrons from atomic tritium beta decay should lead to a direct neutrino mass measurement. I will present recent developments in CRES for precision electron energy measurements, performance of the Project 8 prototype, and outline outline a path toward a viable atomic tritium source
Direct detection searches for axion dark matter
No full textAbstractThe axion is both a compelling dark matter candidate and provides an elegant solution to the strong CP problem. The axion haloscope technique has the potential to detect dark matter axions. ADMX (the Axion Dark Matter eXperiment) is an implementation of the axion haloscope technique, and has undergone a series of sensitivity-improving upgrades. With the impending addition of a dilution refrigerator, ADMX is poised to search a large region of plausible dark matter axion masses. Meanwhile, a number of other axion experimental techniques are being considered to explore other axion masses relevant to dark matter
A review of the monograph The Vowels in the Dialects of Upper Silesia and in the contemporary Polish language. Comparison with the Use of Acoustic and Articulation Data by Piotr Rybka
No full textRecenzja jest poświęcona najnowszej książce Piotra Rybki "Samogłoski w gwarach Górnego Śląska i polszczyźnie ogólnej. Porównanie z wykorzystaniem danych akustycznych i artykulacyjnych" wydanej w 2018 roku w ramach Prac Instytutu Języka Polskiego Polskiej Akademii Nauk. Jest to eksperymentalna praca z zakresu fonetyki dialektalnej. Autor opracował modele akustyczne i artykulacyjne, które umożliwiają porównanie cech samogłosek w mowie mieszkańców Górnego Śląska i wymowie ogólnopolskiej.The review is devoted to the latest book written by Piotr Rybka, The Vowels in the Dialects of Upper Silesia and in the contemporary Polish language. Comparison with the Use of Acoustic and Articulation Data, published in 2018 as part of the work of the Institute of the Polish Language of the Polish Academy of Sciences. This is an experimental study in the field of dialectal phonetics. The author has developed acoustic and articulatory models that made it possible to compare features of the vowels in the speech of Upper Silesian residents with Polish standard pronunciation
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