Heavy polar molecules are powerful quantum sensors for tests of fundamental symmetries and searches for physics beyond the Standard Model. Their internal electromagnetic environment can provide exceptional sensitivity to symmetry-violating effects, but they also create significant challenges for achieving high precision and accuracy in measurement. In addition, their rich internal structure significantly complicates quantum state preparation, coherent control, and readout. This thesis addresses these challenges by devising and demonstrating a general approach for engineering field-insensitive ``clock'' transitions that suppress sensitivity to external fields while preserving strong sensitivity to new physics. This approach is broadly applicable to a wide range of experimental systems, including species with complex, deformed nuclei and systems compatible with state-of-the-art cooling and trapping techniques, offering the potential to significantly improve sensitivity to various new physics while expanding the experimental design space for quantum sensing.
\r\n\r\nA central result of this work is the conceptualization and demonstration of field-insensitive clock transitions for symmetry-violation searches. Uncontrolled external electromagnetic fields are a major obstacle to precise and accurate measurements. Minimizing sensitivity to such fields is therefore essential and has played a key role in all precision experiments of this kind. Here, we devise and demonstrate clock transitions engineered to enable robust symmetry-violation searches in YbOH. Sensitivities to external electric and magnetic fields are suppressed by orders of magnitude while maintaining strong sensitivity to the electron electric dipole moment (eEDM). Using Ramsey measurements on these clock transitions, we observe suppression of electric- and magnetic-field sensitivities by at least factors of 700 and 200, respectively, and demonstrate robust spin coherence in the presence of large electromagnetic-field fluctuations. We also identify and employ selected quantum states for sensitive measurements of external magnetic and electric fields, another capability that is critical for high-accuracy experiments.
\r\n\r\nThis thesis also establishes and demonstrates the quantum-control toolkit required for symmetry violation searches in the isotopologue 173YbOH, which is of particular interest because of its large nuclear spin (I = 5/2) and quadrupole-deformed nucleus. These features make it a promising candidate for searches for hadronic symmetry-violating effects, including those arising from the nuclear magnetic quadrupole moment (MQM). Realizing an MQM measurement in 173YbOH, however, requires quantum state control within highly complex hyperfine manifolds. Here, we demonstrate state preparation, coherent control, and readout for Ramsey interferometry on MQM-sensitive transitions in 173YbOH with magnetic-field sensitivity suppressed by more than an order of magnitude. We also demonstrate a \"co-magnetometer\" protocol that disentangles a potential MQM signature from systematic backgrounds.
\r\n\r\nThese results establish the essential quantum-control toolkit for precision measurements in systems with the intricate hyperfine structure commonly encountered in searches for nuclear symmetry violation, and show that it is possible to take advantage of the suppressed field sensitivities in these complicated systems.
\r\n\r\nTogether, these results show that molecular structure can be engineered and controlled to realize robust precision measurements in complex systems and that molecular complexity can be transformed from a challenge into a resource for robust symmetry-violation measurements.
", "doi": "10.7907/jyg9-k449", "publication_date": "2026", "thesis_type": "phd", "thesis_year": "2026" }, { "id": "thesis:18732", "collection": "thesis", "collection_id": "18732", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:06012026-054619466", "primary_object_url": { "basename": "Yakov_Landau_Thesis_Final.pdf", "content": "final", "filesize": 5451261, "license": "other", "mime_type": "application/pdf", "url": "/18732/1/Yakov_Landau_Thesis_Final.pdf", "version": "v4.0.0" }, "type": "thesis", "title": "Light Rays Illuminating the Universe", "author": [ { "family_name": "Landau", "given_name": "Yakov", "orcid": "0000-0002-3744-1294", "clpid": "Landau-Yakov" } ], "thesis_advisor": [ { "family_name": "Simmons-Duffin", "given_name": "David", "orcid": "0000-0002-2937-9515", "clpid": "Simmons-Duffin-D" } ], "thesis_committee": [ { "family_name": "Cheung", "given_name": "Clifford W.", "orcid": "0000-0002-9983-9425", "clpid": "Cheung-Clifford" }, { "family_name": "Wise", "given_name": "Mark B.", "orcid": "0000-0002-9125-801X", "clpid": "Wise-M-B" }, { "family_name": "Patterson", "given_name": "Ryan B.", "orcid": "0000-0002-5787-9517", "clpid": "Patterson-R-B" }, { "family_name": "Simmons-Duffin", "given_name": "David", "orcid": "0000-0002-2937-9515", "clpid": "Simmons-Duffin-D" } ], "local_group": [ { "literal": "div_pma" } ], "abstract": "This thesis studies light ray operators in two different contexts. The first is to use light ray operators to construct spinning dispersive sum rules. These can then be used to bound corrections to Einstein's gravity in anti de Sitter space, an important step in verifying the HPPS conjecture. They can also be used to validate the known flat space limits as the functionals used in that context are shown to be flat space limits of these more rigorous constructions. The other context explored in this thesis is in the study of light ray operators as observables themselves on a rigid de Sitter background. Energy detectors can be shown to be an example of a light ray operator, and we show how they differ qualitatively from their flat space counterparts.", "doi": "10.7907/kz8m-sq03", "publication_date": "2026", "thesis_type": "phd", "thesis_year": "2026" }, { "id": "thesis:17597", "collection": "thesis", "collection_id": "17597", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:08062025-030104521", "primary_object_url": { "basename": "EthanPayneThesis2025.pdf", "content": "final", "filesize": 24013417, "license": "other", "mime_type": "application/pdf", "url": "/17597/1/EthanPayneThesis2025.pdf", "version": "v4.0.0" }, "type": "thesis", "title": "Understanding Gravitational Waves and Their Sources: Robust Inference, Tests of Gravity, and Future Prospects", "author": [ { "family_name": "Payne", "given_name": "Ethan W.", "orcid": "0000-0003-4507-8373", "clpid": "Payne-Ethan-W" } ], "thesis_advisor": [ { "family_name": "Weinstein", "given_name": "Alan Jay", "orcid": "0000-0002-0928-6784", "clpid": "Weinstein-Alan-J-Physics" } ], "thesis_committee": [ { "family_name": "Chatziioannou", "given_name": "Katerina", "orcid": "0000-0002-5833-413X", "clpid": "Chatziioannou-K" }, { "family_name": "McCuller", "given_name": "Lee P.", "orcid": "0000-0003-0851-0593", "clpid": "McCuller-Lee" }, { "family_name": "Patterson", "given_name": "Ryan B.", "orcid": "0000-0002-5787-9517", "clpid": "Patterson-R-B" }, { "family_name": "Weinstein", "given_name": "Alan Jay", "orcid": "0000-0002-0928-6784", "clpid": "Weinstein-Alan-J-Physics" } ], "local_group": [ { "literal": "LIGO" }, { "literal": "div_pma" } ], "abstract": "As gravitational-wave detectors have become increasing more sensitive since the first detection in 2015, the now routine observations of gravitational waves have provided a lens through which the field of gravitational-wave astronomy has been able to study the universe. In this thesis, I explore a substantial number of facets regarding the inference challenges associated with observations from binary compact object mergers. I demonstrate the difficulties conducting and interpreting accurate spin measurements from real observations. In addition, I then present a framework for testing general relativity from an ensemble of events without underlying statistical assumptions. This framework is then extended to incorporate theoretically motivated information into these tests. These methods were utilized to analyze observational data from the LIGO-Virgo-KAGRA Collaboration's third observing period. Additionally, I present a novel summary statistic for diagnosing model misspecification in astrophysical compact binary coalescence population studies. Finally, I conclude with a demonstration of the utility of novel detector readout schemes for future gravitational-wave interferometer designs. My thesis presents a sweeping view of a number of current research avenues with current and future gravitational-wave detectors.", "doi": "10.7907/zrzs-7b69", "publication_date": "2026", "thesis_type": "phd", "thesis_year": "2026" }, { "id": "thesis:17712", "collection": "thesis", "collection_id": "17712", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:10032025-184408800", "type": "thesis", "title": "Spin Dressing", "author": [ { "family_name": "Tat", "given_name": "Raymond H.", "orcid": "0000-0002-5648-0360", "clpid": "Tat-Raymond-H" } ], "thesis_advisor": [ { "family_name": "Filippone", "given_name": "Bradley W.", "orcid": "0000-0002-2618-2688", "clpid": "Filippone-B-W" } ], "thesis_committee": [ { "family_name": "Patterson", "given_name": "Ryan B.", "orcid": "0000-0002-5787-9517", "clpid": "Patterson-R-B" }, { "family_name": "Wise", "given_name": "Mark B.", "orcid": "0000-0002-9125-801X", "clpid": "Wise-M-B" }, { "family_name": "Hutzler", "given_name": "Nicholas R.", "orcid": "0000-0002-5203-3635", "clpid": "Hutzler-N-R" }, { "family_name": "Filippone", "given_name": "Bradley W.", "orcid": "0000-0002-2618-2688", "clpid": "Filippone-B-W" } ], "local_group": [ { "literal": "div_pma" } ], "abstract": "Measurement of a neutron electric dipole moment (nEDM) is a sensitive probe of CP-violating physics beyond the Standard Model. Such a measurement could provide clues as to the origins of the matter-antimatter asymmetry. Spin dressing is a technique where an off-resonant oscillating magnetic field is applied to a spin or ensemble of spins to modify their effective gyromagnetic ratio. This technique was proposed for use in the neutron electric dipole moment experiment at the spallation neutron source (nEDM@SNS) to increase statistical sensitivity and mitigate systematics. Here we present a comprehensive study of spin dressing in the context of EDM measurement from theoretical, computational, and experimental perspectives.", "doi": "10.7907/y463-hf16", "publication_date": "2026", "thesis_type": "phd", "thesis_year": "2026" }, { "id": "thesis:17342", "collection": "thesis", "collection_id": "17342", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:06012025-194036662", "primary_object_url": { "basename": "VarunRangaRaj_NOvA-T2K.pdf", "content": "final", "filesize": 41268063, "license": "other", "mime_type": "application/pdf", "url": "/17342/4/VarunRangaRaj_NOvA-T2K.pdf", "version": "v5.0.0" }, "type": "thesis", "title": "Measuring Neutrino Oscillations with NOvA and T2K", "author": [ { "family_name": "Raj", "given_name": "Varun Ranga", "orcid": "0000-0003-0790-4814", "clpid": "Raj-Varun-Ranga" } ], "thesis_advisor": [ { "family_name": "Patterson", "given_name": "Ryan B.", "orcid": "0000-0002-5787-9517", "clpid": "Patterson-R-B" } ], "thesis_committee": [ { "family_name": "Wise", "given_name": "Mark B.", "orcid": "0000-0002-9125-801X", "clpid": "Wise-M-B" }, { "family_name": "Porter", "given_name": "Frank C.", "orcid": "0000-0003-1948-8889", "clpid": "Porter-F-C" }, { "family_name": "Patterson", "given_name": "Ryan B.", "orcid": "0000-0002-5787-9517", "clpid": "Patterson-R-B" }, { "family_name": "Hutzler", "given_name": "Nicholas R.", "orcid": "0000-0002-5203-3635", "clpid": "Hutzler-N-R" } ], "local_group": [ { "literal": "div_pma" } ], "abstract": "The discoveries of the twentieth century proved that neutrinos have mass and can change flavor. For the past few decades, a major focus of research has been the measurement of the physical parameters which govern this flavor oscillation. These measurements remain inconclusive on a few key questions, including the ordering of the neutrino masses and whether neutrinos violate CP symmetry. NOvA and T2K are two long-baseline accelerator neutrino experiments working in this space. By placing detectors in a beam of muon (anti-)neutrinos, these experiments interrogate neutrino oscillations by measuring muon (anti-)neutrino disappearance and electron (anti-)neutrino appearance. The complementarity of NOvA's and T2K's oscillation measurements motivated the experiments to pursue a joint oscillation analysis. After bracketing the potential impacts of correlations between the two experiments' systematic uncertainties and constructing a joint likelihood function, we share in this thesis the first results from the NOvA-T2K joint oscillation analysis. We report the world's most precise measurement of Δm232 to date: +2.429+0.039-0.035 (-2.477±0.035) × 10-3 eV2 assuming the normal (inverted) mass ordering, showing a slight preference for the inverted mass ordering. The maximally CP-violating value of δCP=+π/2 is excluded by 3σ credible intervals, and if we assume neutrinos are in the inverted mass ordering, we see evidence of CP violation at 3σ.\r\nThe field of particle and fundamental physics finds itself now in a peculiar situation. The established Standard Model accurately predicts most of the observations, but several compelling reasons motivate a need for an extension of the current theory. In this thesis, I focus my research on facing the current situation of the field in a diversified threefold manner.
\r\n\r\nFirst, I develop methods based on physics-driven machine learning algorithms, with a particular focus on developing a model-independent tagger for unexpected events using artificial neural networks. This study shows how model-independent new physics triggers, possibly trained on real data, can select a low rate stream of events able to explore new physics processes up to a 10-100 pb cross section and can create a special dataset of rare unexpected events. Other important results from this body of work include the first application of the proposed anomaly detection strategy to real data, the use of graph neural networks to improve current pileup mitigation algorithms, the development of jet taggers based on the interaction network, and analysis-specific fast simulation.
\r\n\r\nSecond, I focus on the methodological and hardware development of the MIP Timing Layer that is expected to upgrade CMS in preparation for HL-LHC. My seminal study demonstrates the possibility of using time-of-flight information to perform particle identification, which has a significant impact on heavy stable charged particle searches. This work introduces how to measure time-of-flight at CMS, a strategy for particle identification, and an algorithm to locate vertices in space and time. I also participated in the sensor testing and test beam operation. In particular, I conducted a study about the design and prototype of the detector modules' thermal behavior that shows how different geometries could lead to cooling differences of a few K.
\r\n\r\nLast, I direct my attention towards CMS's first lepton flavor universality tests with B meson decays. Using a dataset acquired thanks to a custom design trigger, I independently develop the measurement of the R(D*) ratio, a parameter whose tensions between the predictions and observation have drawn remarkable attentions. I oversaw the complete mature state of the analysis, from the Monte Carlo simulation to the fitting procedure. Further collaboration-wide efforts are still required, but I demonstrate the expected sensitivity of about 15% using an Asimov dataset.
", "doi": "10.7907/bqsn-sp82", "publication_date": "2023", "thesis_type": "phd", "thesis_year": "2023" }, { "id": "thesis:15034", "collection": "thesis", "collection_id": "15034", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:09252022-195535688", "type": "thesis", "title": "Rare Higgs Processes at CMS and Precision Timing Detector Studies for HL-LHC CMS Upgrade", "author": [ { "family_name": "Dutta", "given_name": "Irene", "orcid": "0000-0003-0953-4503", "clpid": "Dutta-Irene" } ], "thesis_advisor": [ { "family_name": "Spiropulu", "given_name": "Maria", "orcid": "0000-0001-8172-7081", "clpid": "Spiropulu-M" } ], "thesis_committee": [ { "family_name": "Patterson", "given_name": "Ryan B.", "orcid": "0000-0002-5787-9517", "clpid": "Patterson-R-B" }, { "family_name": "Wise", "given_name": "Mark B.", "orcid": "0000-0002-9125-801X", "clpid": "Wise-M-B" }, { "family_name": "Hutzler", "given_name": "Nicholas R.", "orcid": "0000-0002-5203-3635", "clpid": "Hutzler-N-R" }, { "family_name": "Filippone", "given_name": "Bradley W.", "orcid": "0000-0002-2618-2688", "clpid": "Filippone-B-W" }, { "family_name": "Spiropulu", "given_name": "Maria", "orcid": "0000-0001-8172-7081", "clpid": "Spiropulu-M" } ], "local_group": [ { "literal": "div_pma" } ], "abstract": "This thesis describes the search for two rare Higgs processes. The first analysis describes the CMS Run 2 search for
The second analysis describes the CMS Run 2 search for
Finally, this thesis also discusses the planned MIP Timing Detector (MTD) upgrade for CMS at the HL-LHC. The MTD will be a time-of-flight (TOF) detector, designed to provide a precision timing information for charged particles using SiPMs + LYSO scintillating crystals, with a time resolution of ~30 ps. This thesis describes several R&D tests that have been performed for characterizing the sensor properties (time resolution, light yield, etc.) and optimizing the sensor design geometry. This thesis also contains a description of mock test setups for cooling the sensors, since it is known to be an effective way of mitigating the increased dark current rates in the sensors due to radiation damage.
", "doi": "10.7907/tmt4-nq20", "publication_date": "2023", "thesis_type": "phd", "thesis_year": "2023" }, { "id": "thesis:15199", "collection": "thesis", "collection_id": "15199", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:05212023-152144355", "primary_object_url": { "basename": "Chang_YenYung_2021.pdf", "content": "final", "filesize": 97488420, "license": "other", "mime_type": "application/pdf", "url": "/15199/1/Chang_YenYung_2021.pdf", "version": "v4.0.0" }, "type": "thesis", "title": "SuperCDMS HVeV Run 2 Low-Mass Dark Matter Search, Highly Multiplexed Phonon-Mediated Particle Detector with Kinetic Inductance Detector, and the Blackbody Radiation in Cryogenic Experiments", "author": [ { "family_name": "Chang", "given_name": "Yen-Yung", "orcid": "0000-0002-6441-980X", "clpid": "Chang-Yen-Yung" } ], "thesis_advisor": [ { "family_name": "Golwala", "given_name": "Sunil", "clpid": "Golwala-S-R" } ], "thesis_committee": [ { "family_name": "Patterson", "given_name": "Ryan B.", "orcid": "0000-0002-5787-9517", "clpid": "Patterson-R-B" }, { "family_name": "Cheung", "given_name": "Clifford W.", "orcid": "0000-0002-9983-9425", "clpid": "Cheung-Clifford" }, { "family_name": "Porter", "given_name": "Frank C.", "orcid": "0000-0003-1948-8889", "clpid": "Porter-F-C" }, { "family_name": "Golwala", "given_name": "Sunil", "orcid": "0000-0002-1098-7174", "clpid": "Golwala-S-R" } ], "local_group": [ { "literal": "div_pma" } ], "abstract": "There is ample evidence of dark matter (DM), a phenomenon responsible for \u2248 85% of the matter content of the Universe that cannot be explained by the Standard Model (SM). One of the most compelling hypotheses is that DM consists of beyond-SM particle(s) that are nonluminous and nonbaryonic. So far, numerous efforts have been made to search for particle DM, and yet none has yielded an unambiguous observation of DM particles.
\r\n\r\nWe present in Chapter 2 the SuperCDMS HVeV Run 2 experiment, where we search for DM in the mass ranges of 0.5--10\u2074 MeV/c\u00b2 for the electron-recoil DM and 1.2--50 eV/c\u00b2 for the dark photon and the Axion-like particle (ALP). SuperCDMS utilizes cryogenic crystals as detectors to search for DM interaction with the crystal atoms. The interaction is detected in the form of recoil energy mediated by phonons. In the HVeV project, we look for electron recoil, where we enhance the signal by the Neganov-Trofimov-Luke effect under high-voltage biases. The technique enabled us to detect quantized e\u207bh\u207a creation at a 3% ionization energy resolution. Our work is the first DM search analysis considering charge trapping and impact ionization effects for solid-state detectors. We report our results as upper limits for the assumed particle models as functions of DM mass. Our results exclude the DM-electron scattering cross section, the dark photon kinetic mixing parameter, and the ALP axioelectric coupling above 8.4 x 10\u207b\u00b3\u2074 cm\u00b2, 3.3 x 10\u207b\u00b9\u2074, and 1.0 x 10\u207b\u2079, respectively.
\r\n\r\nCurrently every SuperCDMS detector is equipped with a few phonon sensors based on the transition-edge sensor (TES) technology. In order to improve phonon-mediated particle detectors' background rejection performance, we are developing highly multiplexed detectors utilizing kinetic inductance detectors (KIDs) as phonon sensors. This work is detailed in chapter 3 and chapter 4. We have improved our previous KID and readout line designs, which enabled us to produce our first \u00f83\" detector with 80 phonon sensors. The detector yielded a frequency placement accuracy of 0.07%, indicating our capability of implementing hundreds of phonon sensors in a typical SuperCDMS-style detector. We detail our fabrication technique for simultaneously employing Al and Nb for the KID circuit. We explain our signal model that includes extracting the RF signal, calibrating the RF signal into pair-breaking energy, and then the pulse detection. We summarize our noise condition and develop models for different noise sources. We combine the signal and the noise models to be an energy resolution model for KID-based phonon-mediated detectors. From this model, we propose strategies to further improve future detectors' energy resolution and introduce our ongoing implementations.
\r\n\r\nBlackbody (BB) radiation is one of the plausible background sources responsible for the low-energy background currently preventing low-threshold DM experiments to search for lower DM mass ranges. In Chapter 5, we present our study for such background for cryogenic experiments. We have developed physical models and, based on the models, simulation tools for BB radiation propagation as photons or waves. We have also developed a theoretical model for BB photons' interaction with semiconductor impurities, which is one of the possible channels for generating the leakage current background in SuperCDMS-style detectors. We have planned for an experiment to calibrate our simulation and leakage current generation model. For the experiment, we have developed a specialized ``mesh TES'' photon detector inspired by cosmic microwave background experiments. We present its sensitivity model, the radiation source developed for the calibration, and the general plan of the experiment.
", "doi": "10.7907/jswx-ad33", "publication_date": "2023", "thesis_type": "phd", "thesis_year": "2023" }, { "id": "thesis:14347", "collection": "thesis", "collection_id": "14347", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:08292021-214153213", "type": "thesis", "title": "Precision Measurement of the Neutron Lifetime", "author": [ { "family_name": "Fries", "given_name": "Eric Michael", "orcid": "0000-0002-3788-8096", "clpid": "Fries-Eric-Michael" } ], "thesis_advisor": [ { "family_name": "Filippone", "given_name": "Bradley W.", "orcid": "0000-0002-2618-2688", "clpid": "Filippone-B-W" } ], "thesis_committee": [ { "family_name": "Patterson", "given_name": "Ryan B.", "orcid": "0000-0002-5787-9517", "clpid": "Patterson-R-B" }, { "family_name": "Filippone", "given_name": "Bradley W.", "orcid": "0000-0002-2618-2688", "clpid": "Filippone-B-W" }, { "family_name": "Golwala", "given_name": "Sunil", "orcid": "0000-0002-1098-7174", "clpid": "Golwala-S-R" }, { "family_name": "Vogel", "given_name": "Petr", "orcid": "0000-0003-0587-5466", "clpid": "Vogel-P" } ], "local_group": [ { "literal": "div_pma" } ], "abstract": "The neutron lifetime plays a critical role in Big Bang nucleosynthesis (BBN) calculations, and measurements of the neutron lifetime can also be used to probe the unitarity of the Cabibbo-Kobayashi-Maskawa quark weak mixing matrix. Most experiments that measure the neutron lifetime fall into two classes: \"bottle\" and \"beam\" experiments. A bottle experiment stores neutrons in a bottle and counts the number of neutrons that do not decay. A beam experiment counts the decay products of a beam of neutrons that passes through an electrostatic trap. An unresolved \u2248 4\u03c3 difference remains between the current global averages of measurements of the neutron lifetime using the bottle method and measurements using the beam method. This difference is the dominant uncertainty in BBN calculations of the helium mass fraction in the early universe. The UCN\u03c4 experiment is a bottle experiment which uses a magneto-gravitational trap to store ultra-cold neutrons (UCN) without any physical interactions between the UCN and the walls of the trap. The UCN that do not decay are counted with an in situ detector that is lowered into the trap. These two features stand in contrast to most past bottle experiments, which had to make significant corrections to the extracted lifetime to account for losses of neutrons due to material interactions with walls and losses while removing the neutrons from the bottle in order to be counted. This thesis will present an analysis of the 2017-2018 UCN\u03c4 data set that extracted a value for the neutron lifetime of 877.79 \u00b1 0.27 (stat.) +0.19-0.12 (sys.) s. This measurement has an uncertainty of roughly half of the current global average for the neutron lifetime.
", "doi": "10.7907/qr2k-7b09", "publication_date": "2022", "thesis_type": "phd", "thesis_year": "2022" }, { "id": "thesis:14440", "collection": "thesis", "collection_id": "14440", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:12032021-231746989", "primary_object_url": { "basename": "Thesis_XuanSun_December_2021_FINAL.pdf", "content": "final", "filesize": 59351230, "license": "other", "mime_type": "application/pdf", "url": "/14440/1/Thesis_XuanSun_December_2021_FINAL.pdf", "version": "v5.0.0" }, "type": "thesis", "title": "Measurements of Beyond Standard Model Interactions with the UCNA and nEDM@SNS Experiments", "author": [ { "family_name": "Sun", "given_name": "Xuan", "orcid": "0000-0001-8817-4643", "clpid": "Sun-Xuan" } ], "thesis_advisor": [ { "family_name": "Filippone", "given_name": "Bradley W.", "orcid": "0000-0002-2618-2688", "clpid": "Filippone-B-W" } ], "thesis_committee": [ { "family_name": "Patterson", "given_name": "Ryan B.", "orcid": "0000-0002-5787-9517", "clpid": "Patterson-R-B" }, { "family_name": "Vogel", "given_name": "Petr", "orcid": "0000-0003-0587-5466", "clpid": "Vogel-P" }, { "family_name": "Filippone", "given_name": "Bradley W.", "orcid": "0000-0002-2618-2688", "clpid": "Filippone-B-W" }, { "family_name": "Hutzler", "given_name": "Nicholas R.", "orcid": "0000-0002-5203-3635", "clpid": "Hutzler-N-R" } ], "local_group": [ { "literal": "div_pma" } ], "abstract": "Ultracold neutrons (UCNs) are neutrons that have been cooled such that their kinetic energy is on the order of their gravitational potential energy. Experimentally, ultracold neutrons are valuable because at these energies they are trappable and provide experimenters with long observation times. In fact, their observation times are on the order of the free neutron decay lifetime --- allowing direct observation of neutron \u03b2-decay. Many contemporary experiments measuring high-precision processes involving neutrons use UCNs. Two such experiments are UCNA and nEDM@SNS, both of which form the basis of this work.
\r\n \r\nUCNA is an experiment that took place at Los Alamos National Laboratory. In this work, we analyze the 2010-2013 UCNA datasets on neutron \u03b2-decay using UCNs. These datasets were originally designed to measure the asymmetry parameter, A, in neutron \u03b2-decay. However, there was also sensitivity to another physical parameter in the neutron \u03b2-decay rate: the Fierz interference term, b. The Fierz interference term in neutron \u03b2-decay acts as a probe of beyond Standard Model (SM) physics interactions, specifically scalar and tensor couplings in the weak interaction. Due to the vector - axial-vector nature of the weak interaction in the SM, any non-zero measurements of b would be indicative of new, beyond SM couplings. In this work, we present the extraction of the Fierz interference term as measured by neutron \u03b2-decay for the 2010, 2011-2012, and 2012-2013 UCNA datasets. We present these measurements using two methods: a direct extraction by measuring shape distortions in the \u03b2-decay electron spectrum, and an energy dependence in the asymmetry, A0. These two methods across the three datasets yield six new measurements of b from neutron \u03b2-decay data. Our final result is the weighted average of the three asymmetry-extracted b results.
\r\n \r\nThe UCNA datasets were also sensitive to another type of beyond SM interaction: neutron decaying to dark matter with an accompanying positron-electron pair (first proposed in [FG18a]. This decay channel was originally proposed in order to resolve the discrepancy between two measurement methods of the neutron lifetime: bottle experiments which measure neutron population as a function of time, and beam experiments which measure the decay protons from conventional neutron \u03b2-decay. Due to the experimental setup of the UCNA apparatus, the UCNA dataset was sensitive to such a decay channel. Using the 2012-2013 UCNA dataset which had functioning timing data, we effectively rule out this decay channel as the sole explanation for the neutron lifetime discrepancy for \u2248 84% of the available decay phase space. Furthermore, we set branching ratio limits on this decay channel as compared to the conventional weak interaction mediated decay.
\r\n \r\nThe last project in this work is the construction of a large scale magnet for the nEDM@SNS experiment. The nEDM@SNS experiment is an experiment designed to measure the neutron electric dipole moment (nEDM) and will take place at the Spallation Neutron Source (SNS) in Oak Ridge National Laboratory (ORNL). This experiment will take place in 2027 and make a leading precision measurement on the nEDM. Part of the experiment is the magnetic system and, within that system, the B0 magnet which will provide a DC holding field to UCNs within the experiment's measurement volume. The assembly procedure for constructing the B0 magnet is detailed and intermediate quality checks as well as a post-construction room temperature magnetic field map are presented. The preliminary results indicate that the completed B0 magnet satisfies the specifications and will be useable in the nEDM@SNS experiment.
", "doi": "10.7907/n87j-gh29", "publication_date": "2022", "thesis_type": "phd", "thesis_year": "2022" }, { "id": "thesis:14598", "collection": "thesis", "collection_id": "14598", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:05232022-144829107", "primary_object_url": { "basename": "Yunxuan_Li_2022_thesis.pdf", "content": "final", "filesize": 16554843, "license": "other", "mime_type": "application/pdf", "url": "/14598/1/Yunxuan_Li_2022_thesis.pdf", "version": "v4.0.0" }, "type": "thesis", "title": "Search for Beyond Standard Model Physics at BaBar", "author": [ { "family_name": "Li", "given_name": "Yunxuan", "orcid": "0000-0001-9004-2471", "clpid": "Li-Yunxuan" } ], "thesis_advisor": [ { "family_name": "Hitlin", "given_name": "David G.", "orcid": "0000-0003-4028-6982", "clpid": "Hitlin-D-G" } ], "thesis_committee": [ { "family_name": "Porter", "given_name": "Frank C.", "orcid": "0000-0003-1948-8889", "clpid": "Porter-F-C" }, { "family_name": "Hitlin", "given_name": "David G.", "orcid": "0000-0003-4028-6982", "clpid": "Hitlin-D-G" }, { "family_name": "Patterson", "given_name": "Ryan B.", "orcid": "0000-0002-5787-9517", "clpid": "Patterson-R-B" }, { "family_name": "Wise", "given_name": "Mark B.", "orcid": "0000-0002-9125-801X", "clpid": "Wise-M-B" }, { "family_name": "Echenard", "given_name": "Bertrand", "orcid": "0000-0002-3866-9370", "clpid": "Echenard-Bertrand" } ], "local_group": [ { "literal": "div_pma" } ], "abstract": "This thesis reports searches for beyond Standard Model physics in e+e\u2212 collisions in two directions.
\r\n\r\nWe report the first search for a dark matter bound state. The existence of dark matter bound states could arise in a simple dark sector model in which a dark photon (A\u2032) is light enough to generate an attractive force between dark fermions. We report herein a search for a JPC\u2004=\u20041\u2005\u2212\u2005\u2212 darkonium state, the \u03a5D, produced in the reaction e+e\u2212\u2004\u2192\u2004\u03b3\u03a5D,\u2006\u03a5D\u2004\u2192\u2004A\u2032A\u2032A\u2032, where the dark photons subsequently decay into pairs of leptons or pions, using data collected with the BaBar detector. No significant signal is observed, and we derive limits on the \u03b3\u2005\u2212\u2005A\u2032 kinetic mixing (\u03f5) as a function of the dark sector coupling constant for 0.001\u2004<\u2004mA\u2032\u2004<\u20043.16 GeV and 0.05\u2004<\u2004m\u03a5D\u2004<\u20049.5 GeV. Bounds on the mixing strength \u03f5 down to 5\u2005\u00d7\u200510\u2005\u2212\u20055\u2005\u2212\u200510\u2005\u2212\u20053 are set for a large fraction of the parameter space.
\r\n\r\nWe also report a measurement of R(D)\u2004=\u2004B(B\u2004\u2192\u2004D\u0304\u03c4\u03bd\u0304\u03c4)/B(B\u2004\u2192\u2004D\u0304\u2113\u03bd\u0304\u2113) and R(D*)\u2004=\u2004B(B\u2004\u2192\u2004D\u0304*\u03c4\u03bd\u0304\u03c4)/B(B\u2004\u2192\u2004D\u0304*\u2113\u03bd\u0304\u2113), where \u2113 refers to either an electron or muon. We select samples by reconstructing tag-side B mesons in semileptonic decays and signal-side \u03c4 in a purely leptonic decay. Using data collected with the BaBar detector, we measure R(D)\u2004=\u20040.316\u2005\u00b1\u20050.062(stat)\u2005\u00b1\u20050.019(syst) and R(D*)\u2004=\u20040.226\u2005\u00b1\u20050.022(stat)\u2005\u00b1\u20050.012(syst), which agree with the Standard Model expectations by 0.26\u03c3 and 1.10\u03c3, respectively. Taken together, the results are in agreement with the Standard Model within 1.51\u03c3 level.
", "doi": "10.7907/tz7n-d662", "publication_date": "2022", "thesis_type": "phd", "thesis_year": "2022" }, { "id": "thesis:14142", "collection": "thesis", "collection_id": "14142", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:05112021-210031085", "type": "thesis", "title": "Does Richard Feynman Dream of Electric Sheep? Topics on Quantum Field Theory, Quantum Computing, and Computer Science", "author": [ { "family_name": "Liu", "given_name": "Junyu", "orcid": "0000-0003-1669-8039", "clpid": "Liu-Junyu" } ], "thesis_advisor": [ { "family_name": "Cheung", "given_name": "Clifford W.", "orcid": "0000-0002-9983-9425", "clpid": "Cheung-Clifford" }, { "family_name": "Preskill", "given_name": "John P.", "orcid": "0000-0002-2421-4762", "clpid": "Preskill-J" }, { "family_name": "Simmons-Duffin", "given_name": "David", "orcid": "0000-0002-2937-9515", "clpid": "Simmons-Duffin-D" } ], "thesis_committee": [ { "family_name": "Patterson", "given_name": "Ryan B.", "orcid": "0000-0002-5787-9517", "clpid": "Patterson-R-B" }, { "family_name": "Cheung", "given_name": "Clifford W.", "orcid": "0000-0002-9983-9425", "clpid": "Cheung-Clifford" }, { "family_name": "Preskill", "given_name": "John P.", "orcid": "0000-0002-2421-4762", "clpid": "Preskill-J" }, { "family_name": "Simmons-Duffin", "given_name": "David", "orcid": "0000-0002-2937-9515", "clpid": "Simmons-Duffin-D" } ], "local_group": [ { "literal": "div_pma" } ], "abstract": "In this thesis, we mainly discuss three topics in theoretical physics: a proof of the weak gravity conjecture, a basic statement in the string theory landscape using the black hole entropy, solving the critical O(3) model using the conformal bootstrap method involving semidefinite programming, and numerical simulation of the false vacuum decay using tensor network methods. Those topics cover different approaches to deep understanding of quantum field theories using concepts and methods of information theory, and computer science with classical and quantum computations.
", "doi": "10.7907/adtc-ss13", "publication_date": "2021", "thesis_type": "phd", "thesis_year": "2021" }, { "id": "thesis:11264", "collection": "thesis", "collection_id": "11264", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:11042018-161928279", "type": "thesis", "title": "Fundamental Physics in the Era of Gravitational-Wave Astronomy: The Direct Measurement of Gravitational-Wave Polarizations and Other Topics", "author": [ { "family_name": "Isi Ba\u00f1ales", "given_name": "Maximiliano", "orcid": "0000-0001-8830-8672", "clpid": "Isi-Ba\u00f1ales-Maximiliano" } ], "thesis_advisor": [ { "family_name": "Weinstein", "given_name": "Alan Jay", "orcid": "0000-0002-0928-6784", "clpid": "Weinstein-Alan-J-Physics" } ], "thesis_committee": [ { "family_name": "Chen", "given_name": "Yanbei", "orcid": "0000-0002-9730-9463", "clpid": "Chen-Yanbei" }, { "family_name": "Weinstein", "given_name": "Alan Jay", "orcid": "0000-0002-0928-6784", "clpid": "Weinstein-Alan-J-Physics" }, { "family_name": "Patterson", "given_name": "Ryan B.", "orcid": "0000-0002-5787-9517", "clpid": "Patterson-R-B" }, { "family_name": "Hopkins", "given_name": "Philip F.", "orcid": "0000-0003-3729-1684", "clpid": "Hopkins-P-F" } ], "local_group": [ { "literal": "LIGO" }, { "literal": "div_pma" } ], "abstract": "In this thesis, I explore several avenues for learning about fundamental physics from gravitational-wave (GW) observations. In particular, I focus on the phenomenological study of basic properties of GWs in ways that require minimal assumptions about the underlying nature of gravity. I place a special emphasis on GW polarizations, but also consider their speed and possible dispersion. To constrain possible modifications to general relativity, I develop data-analysis frameworks to measure these properties with both transient and persistent signals detected by ground-based detectors. This includes, among other results, the analysis of two LIGO and Virgo compact-binary detections, GW170814 and GW170817, to produce the first direct observational statements about the local geometry of GW polarizations. I also present constraints on the potential amplitude of nontensorial monochromatic signals from 200 known pulsars in the Milky Way and describe in detail the methods used to obtain them. Because stochastic signals will be a great resource for studying GW properties, I also carefully review the assumptions that go into standard stochastic analyses and explore their applicability beyond general relativity, concluding that those measurements will have to be interpreted carefully to make meaningful statements about corrections to Einstein\u2019s theory. Besides the properties of the waves themselves, I also study the prospect for using GWs as a means to uncover signatures of new ultralight bosons\u2014an exciting possibility that could bring particle physics into the reach of GW astronomy. I explore the potential of current and future detectors to detect these conjectured particles, concluding that third-generation instruments are certain to place theoretically interesting constraints. Because little can be done in the absence of signals, I also propose data-analysis methods to improve LIGO and Virgo\u2019s chances of detecting both transient and continuous signals. The latter have now been used to diagnose real detection candidates on several occasions.
", "doi": "10.7907/S15R-3495", "publication_date": "2019", "thesis_type": "phd", "thesis_year": "2019" }, { "id": "thesis:11168", "collection": "thesis", "collection_id": "11168", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:09022018-124448728", "primary_object_url": { "basename": "Rankin_Jamie_2019.pdf", "content": "final", "filesize": 37042966, "license": "other", "mime_type": "application/pdf", "url": "/11168/1/Rankin_Jamie_2019.pdf", "version": "v4.0.0" }, "type": "thesis", "title": "Voyager 1 Observations of Galactic Cosmic Ray Anisotropies in the Local Interstellar Medium", "author": [ { "family_name": "Rankin", "given_name": "Jamie Sue", "orcid": "0000-0002-8111-1444", "clpid": "Rankin-Jamie-Sue" } ], "thesis_advisor": [ { "family_name": "Stone", "given_name": "Edward C.", "orcid": "0000-0002-2010-5462", "clpid": "Stone-E-C" } ], "thesis_committee": [ { "family_name": "Stone", "given_name": "Edward C.", "orcid": "0000-0002-2010-5462", "clpid": "Stone-E-C" }, { "family_name": "Hallinan", "given_name": "Gregg W.", "orcid": "0000-0002-7083-4049", "clpid": "Hallinan-G-W" }, { "family_name": "Hopkins", "given_name": "Philip F.", "orcid": "0000-0003-3729-1684", "clpid": "Hopkins-P-F" }, { "family_name": "Patterson", "given_name": "Ryan B.", "orcid": "0000-0002-5787-9517", "clpid": "Patterson-R-B" } ], "local_group": [ { "literal": "Space Radiation Laboratory" }, { "literal": "div_pma" } ], "abstract": "Since crossing the heliopause on August 25, 2012, Voyager 1 has observed reductions in galactic cosmic ray counting rates caused by a time-varying depletion of particles with pitch angles near 90-deg, while intensities of particles with other pitch angles remain unchanged. Between late 2012 and mid-2017, three large-scale, durable events occurred, lasting roughly 100 to 630 days. Omnidirectional and directional data from the Cosmic Ray Subsystem's high energy telescopes are used to report observations of the cosmic ray intensity variations. Omnidirectional (>20 MeV) proton-dominated measurements show up to a ~3.8% intensity reduction. Bi-directional (>70 MeV) and unidirectional (~18 to ~70 MeV) proton-dominated measurements are analyzed using data taken from various spacecraft orientations, including during magnetometer roll calibrations and 70-deg-offset maneuvers. The anisotropy is characterized as a \"notch\" in an otherwise uniform pitch-angle distribution of varying depth and width centered about 90-deg in pitch angle space. The notch averages ~22-deg wide and ~15% deep -- signifying a depletion region that is broad and shallow. However, electron observations reveal that there is only a weak, at most, evidence of pitch angle anisotropy in cosmic-ray electrons with energies of ~3 to ~105 MeV, indicating that the generation of the notch or its evolution differs between electrons and protons, or varies with rigidity. There are indications that the anisotropy is formed by a combination of magnetic trapping and adiabatic cooling in associated shocks or compression regions.\r\n", "doi": "10.7907/WX3S-1D86", "publication_date": "2019", "thesis_type": "phd", "thesis_year": "2019" }, { "id": "thesis:11010", "collection": "thesis", "collection_id": "11010", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:06012018-215047231", "primary_object_url": { "basename": "Pershey_measurement-appearance-disappearance.pdf", "content": "final", "filesize": 26700692, "license": "other", "mime_type": "application/pdf", "url": "/11010/1/Pershey_measurement-appearance-disappearance.pdf", "version": "v4.0.0" }, "type": "thesis", "title": "A Measurement of \u03bde Appearance and \u03bd\u03bc Disappearance Neutrino Oscillations with the NOvA Experiment", "author": [ { "family_name": "Pershey", "given_name": "Daniel Stephen", "orcid": "0000-0003-4298-0337", "clpid": "Pershey-Daniel-Stephen" } ], "thesis_advisor": [ { "family_name": "Patterson", "given_name": "Ryan B.", "orcid": "0000-0002-5787-9517", "clpid": "Patterson-R-B" } ], "thesis_committee": [ { "family_name": "Patterson", "given_name": "Ryan B.", "orcid": "0000-0002-5787-9517", "clpid": "Patterson-R-B" }, { "family_name": "Porter", "given_name": "Frank C.", "orcid": "0000-0003-1948-8889", "clpid": "Porter-F-C" }, { "family_name": "Filippone", "given_name": "Bradley W.", "orcid": "0000-0002-2618-2688", "clpid": "Filippone-B-W" }, { "family_name": "Cheung", "given_name": "Clifford W.", "orcid": "0000-0002-9983-9425", "clpid": "Cheung-Clifford" } ], "local_group": [ { "literal": "div_pma" } ], "abstract": "NOvA is a two-detector, neutrino oscillation experiment on an 810 km baseline in the NuMI beam at Fermilab. NuMI is an off-axis, narrow-band beam centered near 1.8 GeV and is configurable to send a high-purity \u03bd\u03bc or -\u03bd\u03bc neutrino flux which passes through the NOvA far detector, sensitive to \u03bd\u03bc and -\u03bd\u03bc disappearance and \u03bde and -\u03bde appearance. The NOvA near and far detectors are functionally identical, liquid scintillator trackers. They are finely segmented relative to the radiation length in the detectors allowing for the detailed reconstruction of electromagnetic shower necessary to identify \u03bde CC events.
\r\n\r\nThrough a joint analysis of the appearance and disappearance oscillation channels using neutrino and anti-neutrino data, NOvA constrains the allowed parameter space in \u03b4CP, the neutrino mass hierarchy, sin2\u03b823, and \u0394m232. We observe 58 and 18 appearance candidates on an expected background of 15.06 and 5.32 events in neutrino and anti-neutrino mode, respectively. This observation gives a 1.77\u03c3 preference for the normal mass hierarchy and 1.7\u03c3 preference for \u03b823 in the upper octant. NOvA will maintain its position as a long-baseline oscillation experiment with leading sensitivity for several more years in which time analysis will further disambiguate the fundamental neutrino parameters that determine oscillation behavior.
", "doi": "10.7907/rc0w-zg32", "publication_date": "2018", "thesis_type": "phd", "thesis_year": "2018" }, { "id": "thesis:8897", "collection": "thesis", "collection_id": "8897", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:05282015-131606315", "type": "thesis", "title": "Gauge Invariant Spectral Cauchy Characteristic Extraction of Gravitational Waves in Computational General Relativity", "author": [ { "family_name": "Handmer", "given_name": "Casey John", "clpid": "Handmer-Casey-John" } ], "thesis_advisor": [ { "family_name": "Chen", "given_name": "Yanbei", "orcid": "0000-0002-9730-9463", "clpid": "Chen-Yanbei" }, { "family_name": "Ott", "given_name": "Christian D.", "orcid": "0000-0003-4993-2055", "clpid": "Ott-C-D" } ], "thesis_committee": [ { "family_name": "Chen", "given_name": "Yanbei", "orcid": "0000-0002-9730-9463", "clpid": "Chen-Yanbei" }, { "family_name": "Szilagyi", "given_name": "Bela", "orcid": "0000-0001-7744-6180", "clpid": "Szilagyi-B" }, { "family_name": "Scheel", "given_name": "Mark", "orcid": "0000-0001-6656-9134", "clpid": "Scheel-M-A" }, { "family_name": "Weinstein", "given_name": "Alan Jay", "orcid": "0000-0002-0928-6784", "clpid": "Weinstein-Alan-J-Physics" }, { "family_name": "Phinney", "given_name": "E. Sterl", "orcid": "0000-0002-9656-4032", "clpid": "Phinney-E-S" }, { "family_name": "Patterson", "given_name": "Ryan B.", "orcid": "0000-0002-5787-9517", "clpid": "Patterson-R-B" }, { "family_name": "Ott", "given_name": "Christian D.", "orcid": "0000-0003-4993-2055", "clpid": "Ott-C-D" } ], "local_group": [ { "literal": "TAPIR" }, { "literal": "Astronomy Department" }, { "literal": "LIGO" }, { "literal": "div_pma" } ], "abstract": "We present a complete system for Spectral Cauchy characteristic extraction (Spectral CCE). Implemented in C++ within the Spectral Einstein Code (SpEC), the method employs numerous innovative algorithms to efficiently calculate the Bondi strain, news, and flux.
\r\n\r\nSpectral CCE was envisioned to ensure physically accurate gravitational wave-forms computed for the Laser Interferometer Gravitational wave Observatory (LIGO) and similar experiments, while working toward a template bank with more than a thousand waveforms to span the binary black hole (BBH) problem\u2019s seven-dimensional parameter space.
\r\n\r\nThe Bondi strain, news, and flux are physical quantities central to efforts to understand and detect astrophysical gravitational wave sources within the Simulations of eXtreme Spacetime (SXS) collaboration, with the ultimate aim of providing the first strong field probe of the Einstein field equation.
\r\n\r\nIn a series of included papers, we demonstrate stability, convergence, and gauge invariance. We also demonstrate agreement between Spectral CCE and the legacy Pitt null code, while achieving a factor of 200 improvement in computational efficiency.
\r\n\r\nSpectral CCE represents a significant computational advance. It is the foundation upon which further capability will be built, specifically enabling the complete calculation of junk-free, gauge-free, and physically valid waveform data on the fly within SpEC.
", "doi": "10.7907/Z9NP22DZ", "publication_date": "2015", "thesis_type": "phd", "thesis_year": "2015" }, { "id": "thesis:8211", "collection": "thesis", "collection_id": "8211", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:05022014-140735377", "primary_object_url": { "basename": "JArnold_THESIS.pdf", "content": "final", "filesize": 3419938, "license": "other", "mime_type": "application/pdf", "url": "/8211/1/JArnold_THESIS.pdf", "version": "v3.0.0" }, "type": "thesis", "title": "Baryon and Lepton Numbers in Particle Physics beyond the Standard Model", "author": [ { "family_name": "Arnold", "given_name": "Jonathan Mark", "clpid": "Arnold-Jonathan-Mark" } ], "thesis_advisor": [ { "family_name": "Wise", "given_name": "Mark B.", "orcid": "0000-0002-9125-801X", "clpid": "Wise-M-B" } ], "thesis_committee": [ { "family_name": "Wise", "given_name": "Mark B.", "orcid": "0000-0002-9125-801X", "clpid": "Wise-M-B" }, { "family_name": "Patterson", "given_name": "Ryan B.", "orcid": "0000-0002-5787-9517", "clpid": "Patterson-R-B" }, { "family_name": "Carroll", "given_name": "Sean M.", "orcid": "0000-0002-4226-5758", "clpid": "Carroll-S-M" }, { "family_name": "Cheung", "given_name": "Clifford W.", "orcid": "0000-0002-9983-9425", "clpid": "Cheung-Clifford" } ], "local_group": [ { "literal": "Caltech Theory" }, { "literal": "div_pma" } ], "abstract": "The works presented in this thesis explore a variety of extensions of the standard model of particle physics which are motivated by baryon number (B) and lepton number (L), or some combination thereof. In the standard model, both baryon number and lepton number are accidental global symmetries violated only by non-perturbative weak effects, though the combination B-L is exactly conserved. Although there is currently no evidence for considering these symmetries as fundamental, there are strong phenomenological bounds restricting the existence of new physics violating B or L. In particular, there are strict limits on the lifetime of the proton whose decay would violate baryon number by one unit and lepton number by an odd number of units.
\r\n\r\nThe first paper included in this thesis explores some of the simplest possible extensions of the standard model in which baryon number is violated, but the proton does not decay as a result. The second paper extends this analysis to explore models in which baryon number is conserved, but lepton flavor violation is present. Special attention is given to the processes of \u03bc to e conversion and \u03bc \u2192 e\u03b3 which are bound by existing experimental limits and relevant to future experiments.
\r\n\r\nThe final two papers explore extensions of the minimal supersymmetric standard model (MSSM) in which both baryon number and lepton number, or the combination B-L, are elevated to the status of being spontaneously broken local symmetries. These models have a rich phenomenology including new collider signatures, stable dark matter candidates, and alternatives to the discrete R-parity symmetry usually built into the MSSM in order to protect against baryon and lepton number violating processes.
", "doi": "10.7907/74JV-BN09", "publication_date": "2014", "thesis_type": "phd", "thesis_year": "2014" }, { "id": "thesis:8605", "collection": "thesis", "collection_id": "8605", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:07252014-082021105", "primary_object_url": { "basename": "BenClark_Thesis.pdf", "content": "final", "filesize": 460859, "license": "other", "mime_type": "application/pdf", "url": "/8605/1/BenClark_Thesis.pdf", "version": "v2.0.0" }, "type": "thesis", "title": "Magnetic Trapping of Atomic Tritium for Neutrino Mass Measurement", "author": [ { "family_name": "Clark", "given_name": "Benjamin Mathias", "clpid": "Clark-Benjamin-Mathias" } ], "thesis_advisor": [ { "family_name": "Patterson", "given_name": "Ryan B.", "clpid": "Patterson-R-B" } ], "thesis_committee": [ { "family_name": "Stone", "given_name": "Edward C.", "clpid": "Stone-E-C" }, { "family_name": "Libbrecht", "given_name": "Kenneth George", "clpid": "Libbrecht-K-G" }, { "family_name": "Filippone", "given_name": "Bradley W.", "clpid": "Filippone-B-W" }, { "family_name": "Frautschi", "given_name": "Steven C.", "clpid": "Frautschi-S-C" }, { "family_name": "Tombrello", "given_name": "Thomas A.", "clpid": "Tombrello-T-A" }, { "family_name": "Politzer", "given_name": "Hugh David", "clpid": "Politzer-H-D" }, { "family_name": "Adhikari", "given_name": "Rana", "clpid": "Adhikari-R" }, { "family_name": "Patterson", "given_name": "Ryan B.", "clpid": "Patterson-R-B" } ], "local_group": [ { "literal": "div_pma" } ], "abstract": "Improved measurement of the neutrino mass via β decay spectroscopy requires the development of new energy measurement techniques and a new β decay source. A promising proposal is to measure the β energy by the frequency of the cyclotron radiation emitted in a magnetic field and to use a high purity atomic tritium source. This thesis examines the feasibility of using a magnetic trap to create and maintain such a source. We demonstrate that the loss rate due to β decay heating is not a limiting factor for the design. We also calculate the loss rate due to evaporative cooling and propose that the tritium can be cooled sufficiently during trap loading as to render this negligible. We further demonstrate a design for the magnetic field which produces a highly uniform field over a large fraction of the trap volume as needed for cyclotron frequency spectroscopy while still providing effective trapping.", "doi": "10.7907/N1FG-5H27", "publication_date": "2014", "thesis_type": "senior_major", "thesis_year": "2014" }, { "id": "thesis:7770", "collection": "thesis", "collection_id": "7770", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:05302013-043445308", "type": "thesis", "title": "Studies of Z\u03b3 Production and Constraints on Anomalous Triple Gauge Couplings in pp Collisions at \u221as = 7 TeV", "author": [ { "family_name": "Veverka", "given_name": "Jan", "clpid": "Veverka-Jan" } ], "thesis_advisor": [ { "family_name": "Newman", "given_name": "Harvey B.", "orcid": "0000-0003-0964-1480", "clpid": "Newman-H-B" } ], "thesis_committee": [ { "family_name": "Newman", "given_name": "Harvey B.", "orcid": "0000-0003-0964-1480", "clpid": "Newman-H-B" }, { "family_name": "Wise", "given_name": "Mark B.", "orcid": "0000-0002-9125-801X", "clpid": "Wise-M-B" }, { "family_name": "Weinstein", "given_name": "Alan Jay", "orcid": "0000-0002-0928-6784", "clpid": "Weinstein-Alan-J-Physics" }, { "family_name": "Spiropulu", "given_name": "Maria", "orcid": "0000-0001-8172-7081", "clpid": "Spiropulu-M" }, { "family_name": "Patterson", "given_name": "Ryan B.", "orcid": "0000-0002-5787-9517", "clpid": "Patterson-R-B" } ], "local_group": [ { "literal": "div_pma" } ], "abstract": "In this thesis, we test the electroweak sector of the Standard Model of particle physics through the measurements of the cross section of the simultaneous production of the neutral weak boson Z and photon γ, and the limits on the anomalous Zγγ and ZZγ triple gauge couplings h3 and h4 with the Z decaying to leptons (electrons and muons). We analyze events collected in proton-proton collisions at center of mass energy of sqrt(s) = 7 TeV corresponding to an integrated luminosity of 5.0 inverse femtobarn. The analyzed events were recorded by the Compact Muon Solenoid detector at the Large Hadron Collider in 2011.
\r\n\r\nThe production cross section has been measured for hard photons with transverse momentum greater than 15 GeV that are separated from the the final state leptons in the eta-phi plane by Delta R greater than 0.7, whose sum of the transverse energy of hadrons over the transverse energy of the photon in a cone around the photon with Delta R less than 0.3 is less than 0.5, and with the invariant mass of the dilepton system greater than 50 GeV. The measured cross section value is 5.33 +/- 0.08 (stat.) +/- 0.25 (syst.) +/- 0.12 (lumi.) picobarn. This is compatible with the Standard Model prediction that includes next-to-leading-order QCD contributions: 5.45 +/- 0.27 picobarn.
\r\n\r\nThe measured 95 % confidence-level upper limits on the absolute values of the anomalous couplings h3 and h4 are 0.01 and 8.8E-5 for the Zγγ interactions, and, 8.6E-3 and 8.0E-5 for the ZZγ interactions. These values are also compatible with the Standard Model where they vanish in the tree-level approximation. They extend the sensitivity of the 2012 results from the ATLAS collaboration based on 1.02 inverse femtobarn of data by a factor of 2.4 to 3.1.
\r\n", "doi": "10.7907/QTWD-J259", "publication_date": "2013", "thesis_type": "phd", "thesis_year": "2013" }, { "id": "thesis:7655", "collection": "thesis", "collection_id": "7655", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:05022013-152247133", "type": "thesis", "title": "Measurement of the Direct CP Asymmetry in b\u2192s\u03b3 via Sum of Exclusive B Meson Decays Using the BABAR Detector", "author": [ { "family_name": "Ongmongkolkul", "given_name": "Piti", "clpid": "Ongmongkolkul-Piti" } ], "thesis_advisor": [ { "family_name": "Hitlin", "given_name": "David G.", "clpid": "Hitlin-D-G" } ], "thesis_committee": [ { "family_name": "Hitlin", "given_name": "David G.", "clpid": "Hitlin-D-G" }, { "family_name": "Patterson", "given_name": "Ryan B.", "clpid": "Patterson-R-B" }, { "family_name": "Wise", "given_name": "Mark B.", "clpid": "Wise-M-B" }, { "family_name": "Porter", "given_name": "Frank C.", "clpid": "Porter-F-C" } ], "local_group": [ { "literal": "div_pma" } ], "abstract": "We perform a measurement of direct CP violation in b to s\u03b3 ACP, and the measurement of a difference between Acp for neutral B and charged B mesons, Delta A_{X_s\\gamma}, using 429 inverse femtobarn of data recorded at the Upsilon(4S) resonance with the BABAR detector. B mesons are reconstructed from 16 exclusive final states. Particle identification is done using an algorithm based on Error Correcting Output Code with an exhaustive matrix. Background rejection and best candidate selection are done using two decision tree-based classifiers. We found $\\acp = 1.73%+-1.93%+-1.02% and Delta A_X_s\u03b3 = 4.97%+-3.90%+-1.45% where the uncertainties are statistical and systematic respectively. Based on the measured value of Delta A_X_sgamma, we determine a 90% confidence interval for Im C_8g/C_7gamma, where C_7gamma and C_8g are Wilson coefficients for New Physics amplitudes, at -1.64 < Im C_8g/C_7gamma < 6.52.", "doi": "10.7907/ZNVN-R508", "publication_date": "2013", "thesis_type": "phd", "thesis_year": "2013" }, { "id": "thesis:7043", "collection": "thesis", "collection_id": "7043", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:05172012-142723949", "primary_object_url": { "basename": "Moore_2012_thesis.pdf", "content": "final", "filesize": 35726359, "license": "other", "mime_type": "application/pdf", "url": "/7043/1/Moore_2012_thesis.pdf", "version": "v6.0.0" }, "type": "thesis", "title": "A Search for Low-Mass Dark Matter with the Cryogenic Dark Matter Search and the Development of Highly Multiplexed Phonon-Mediated Particle Detectors", "author": [ { "family_name": "Moore", "given_name": "David Craig", "clpid": "Moore-David-Craig" } ], "thesis_advisor": [ { "family_name": "Golwala", "given_name": "Sunil", "clpid": "Golwala-S-R" } ], "thesis_committee": [ { "family_name": "Golwala", "given_name": "Sunil", "clpid": "Golwala-S-R" }, { "family_name": "Hitlin", "given_name": "David G.", "clpid": "Hitlin-D-G" }, { "family_name": "Patterson", "given_name": "Ryan B.", "clpid": "Patterson-R-B" }, { "family_name": "Schwab", "given_name": "Keith C.", "clpid": "Schwab-K-C" } ], "local_group": [ { "literal": "Astronomy Department" }, { "literal": "div_pma" } ], "abstract": "A wide variety of astrophysical observations indicate that approximately 85% of the matter in the universe is nonbaryonic and nonluminous. Understanding the nature of this \"dark matter\" is one of the most important outstanding questions in cosmology. Weakly Interacting Massive Particles (WIMPs) are a leading candidate for dark matter since they would be thermally produced in the early universe in the correct abundance to account for the observed relic density of dark matter. If WIMPs account for the dark matter, then rare interactions from relic WIMPs should be observable in terrestrial detectors. Recently, unexplained excess events in the DAMA/LIBRA, CoGeNT, and CRESST-II experiments have been interpreted as evidence of scattering from WIMPs with masses ~10 GeV and spin-independent scattering cross sections of 10-41-10-40 cm2.
\r\n\r\nThe Cryogenic Dark Matter Search (CDMS II) attempts to identify WIMP interactions using an array of cryogenic germanium and silicon particle detectors located at the Soudan Underground Laboratory in northern Minnesota. In this dissertation, data taken by CDMS II are reanalyzed using a 2 keV recoil energy threshold to increase the sensitivity to WIMPs with masses ~10 GeV. These data disfavor an explanation for the DAMA/LIBRA, CoGeNT, and CRESST-II results in terms of spin-independent elastic scattering of WIMPs with masses \u227212 GeV, under standard assumptions. At the time of publication, they provided the strongest constraints on spin-independent elastic scattering from 5-9 GeV, ruling out previously unexplored parameter space.
\r\n\r\nTo detect WIMPs or exclude the remaining parameter space favored by the most popular models will ultimately require detectors with target masses \u22731 ton, requiring an increase in mass by more than two orders of magnitude over CDMS II. For cryogenic detectors such as CDMS, scaling to such large target masses will require individual detector elements to be fabricated more quickly and cheaply, while maintaining the nearly background-free operation of the existing experiment. We describe the development of athermal phonon mediated particle detectors using Microwave Kinetic Inductance Detectors (MKIDs), which could provide a simpler path to extending the CDMS detector technology to the ton scale. Results from prototype devices have demonstrated energy resolutions as good as \u03c3 = 0.55 keV at 30 keV, comparable to existing CDMS II detectors. Such designs can be scaled to kg-scale detector elements, while reducing the complexity of the detector fabrication and cryogenic readout electronics relative to existing designs. Since MKIDs are naturally multiplexed in the frequency domain, MKID-based designs also allow much finer pixelization of the phonon sensor, which is expected to enhance background rejection for large detectors while simultaneously reducing the number of wires needed to read out the detectors.
", "doi": "10.7907/X8JD-4R90", "publication_date": "2012-06-15", "thesis_type": "phd", "thesis_year": "2012" }, { "id": "thesis:7046", "collection": "thesis", "collection_id": "7046", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:05182012-101542629", "primary_object_url": { "basename": "thesis_Yousi_Ma_2012.pdf", "content": "final", "filesize": 12707137, "license": "other", "mime_type": "application/pdf", "url": "/7046/1/thesis_Yousi_Ma_2012.pdf", "version": "v7.0.0" }, "type": "thesis", "title": "Search for Signatures of Extra Dimensions in the Diphoton Mass Spectrum with the CMS Detector", "author": [ { "family_name": "Ma", "given_name": "Yousi", "clpid": "Ma-Yousi" } ], "thesis_advisor": [ { "family_name": "Newman", "given_name": "Harvey B.", "clpid": "Newman-H-B" } ], "thesis_committee": [ { "family_name": "Newman", "given_name": "Harvey B.", "clpid": "Newman-H-B" }, { "family_name": "Patterson", "given_name": "Ryan B.", "clpid": "Patterson-R-B" }, { "family_name": "Porter", "given_name": "Frank C.", "clpid": "Porter-F-C" }, { "family_name": "Frautschi", "given_name": "Steven C.", "clpid": "Frautschi-S-C" } ], "local_group": [ { "literal": "div_pma" } ], "abstract": "A search for signatures of extra dimensions in the diphoton invariant-mass spectrum has been performed with the Compact Muon Solenoid detector at the Large Hadron Collider. No excess of events above the standard model expectation is observed using a data sample collected in proton-proton collisions at \u221as = 7 TeV corresponding to an intergrated luminosity of 2.2 fb\u22121. In the context of the Randall\u2013Sundrum model, lower limits are set on the mass of the first graviton excitation in the range of 0.86\u20131.84 TeV, for values of the associated coupling parameter k \u0303between 0.01 and 0.10. Additionally, in the context of the large-extra-dimensions model, lower limits are set on the effective Planck scale in the range of 2.3\u20133.8 TeV at the 95% confidence level. These are the most restrictive bounds to date.", "doi": "10.7907/X33W-ZX56", "publication_date": "2012", "thesis_type": "phd", "thesis_year": "2012" }, { "id": "thesis:6399", "collection": "thesis", "collection_id": "6399", "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:05162011-162816431", "primary_object_url": { "basename": "thesis.pdf", "content": "final", "filesize": 17047380, "license": "other", "mime_type": "application/pdf", "url": "/6399/1/thesis.pdf", "version": "v4.0.0" }, "type": "thesis", "title": "Antineutrino Oscillations in the Atmospheric Sector", "author": [ { "family_name": "Himmel", "given_name": "Alexander I.", "clpid": "Himmel-Alexander-I" } ], "thesis_advisor": [ { "family_name": "Newman", "given_name": "Harvey B.", "orcid": "0000-0003-0964-1480", "clpid": "Newman-H-B" } ], "thesis_committee": [ { "family_name": "Newman", "given_name": "Harvey B.", "orcid": "0000-0003-0964-1480", "clpid": "Newman-H-B" }, { "family_name": "Patterson", "given_name": "Ryan B.", "orcid": "0000-0002-5787-9517", "clpid": "Patterson-R-B" }, { "family_name": "Wise", "given_name": "Mark B.", "orcid": "0000-0002-9125-801X", "clpid": "Wise-M-B" }, { "family_name": "Weinstein", "given_name": "Alan Jay", "orcid": "0000-0002-0928-6784", "clpid": "Weinstein-Alan-J-Physics" } ], "local_group": [ { "literal": "div_pma" } ], "abstract": "This thesis presents measurements of the oscillations of muon antineutrinos in the atmospheric sector, where world knowledge of antineutrino oscillations lags well behind the knowledge of neutrinos, as well as a search for \u03bd\u03bc \\to \u03bd\u0305 \u03bc transitions. Differences between neutrino and antineutrino oscillations could be a sign of physics beyond the Standard Model, including non-standard matter interactions or the violation of CPT symmetry. These measurements leverage the sign-selecting capabilities of the magnetized steel-scintillator MINOS detectors to analyze antineutrinos from the NuMI beam, both when it is in FHC and when it is in RHC. Antineutrino oscillations are observed at |\u0394m\u03052atm| = (3.36+0.46-0.40(stat)\u00b10.06(syst)) x 10- eV2 and sin2(2\u03b8\u030523 = 0.860+0.11-0.12(stat)\u00b1 0.01(syst). The oscillation parameters measured for antineutrinos and those measured by MINOS for neutrinos differ by a large enough margin that the chance of obtaining two values as discrepant as those observed is only 2%, assuming the two measurements arise from the same underlying mechanism, with the same parameter values. No evidence is seen for neutrino-to-antineutrino transitions.", "doi": "10.7907/7E4S-QQ82", "publication_date": "2011", "thesis_type": "phd", "thesis_year": "2011" } ]