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A search is underway to find baryon resonances that have been predicted, but yet remain unobserved. Nucleon resonances, due to their broad energy widths, overlap and must be disentangled in order to be identified. Meson photoproduction observables related to the orientation of the spin of the incoming photon and the spin of the target proton are useful tools to deconvolve the nucleon resonance spectrum. These observables are particularly sensitive to interference between phases of the complex amplitudes. A set of these observables has been measured using the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab with linearly-polarized photons having energies from 725 to 1575 MeV with polar angle values of cos(theta) between -0.8 and 0.9 and transversely-polarized protons in the Jefferson Lab FRozen Spin Target (FROST). By fitting neutron yields from gamma p -> pi^+ n over azimuthal scattering angle, the observables \H and P have been extracted. These observables manifest as azimuthal modulations in the yields for the double-polarization experiment. Preliminary results for these observables will be presented and compared with predictions provided by the SAID Partial-Wave Analysis Facility.
ContributorsLee, Robert John (Author) / Dugger, Michael (Thesis director) / Ritchie, Barry (Committee member) / Department of Physics (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
In nuclear physics, there is a discrepancy between theory and experiment concerning the number of existing nucleon resonances. Current models predict far more states than have been observed. In particular, few searches have found excited nucleon resonances with energies above 2.2 GeV in the K Lambda channel. To investigate high-mass nucleon resonances, efficiency-corrected yields of the reaction ep --> e K+ Lambda(1520) --> e K+ K- p in the center-of-mass energy range 2.1-4.5 GeV are constructed utilizing Jefferson Lab's CLAS12 detector. This paper presents the results of an analysis searching for high-mass nucleon resonances in the K Lambda channel between 2.1-4.5 GeV.
ContributorsOsar, Rebecca (Author) / Dugger, Michael (Thesis director) / Ritchie, Barry (Committee member) / Barrett, The Honors College (Contributor) / Department of Physics (Contributor) / School of International Letters and Cultures (Contributor)
Created2023-05
Description
A cloud chamber allows the naked eye to observe the beta- particle track produced from certain radioactive isotopes. These cloud chambers can be used during radiation education, as they allow beta emitting isotopes to be seen. Within the apparatus, the white track that forms as a result of alcohol condensation, codenstates on the ions. These ions are left by electrons released from a radioactive isotope. In this experiment, a cloud chamber apparatus was placed under the conditions of a magnetic field. When a beta isotope is inserted into the chamber, the magnetic field should bend the beta-particle track. By measuring the radius of curvature of the electron tracks, the velocity is then observed. This velocity of the beta particle can then be used to calculate the kinetic energy, and ultimately can be utilized to identify the isotope.
The understanding of the methodology for identifying isotopes, nuclear waste cleanup can be effectively handled. In cases of environmental radioactivity, Geiger counters can only identify regions that are contaminated, as well as the number of radioactive particles per second within the region. Unfortunately they fail to determine the energy of each isotope. The identification of radioisotopes aid in the handling of cleanup and safety precautions.
This thesis focuses on the hardware and construction of the apparatus used, diving into electronics and particle physics. The software as well as future data collection and analysis will be conducted by Natjalia Bogdanovic, for defense in Spring 2020.
The understanding of the methodology for identifying isotopes, nuclear waste cleanup can be effectively handled. In cases of environmental radioactivity, Geiger counters can only identify regions that are contaminated, as well as the number of radioactive particles per second within the region. Unfortunately they fail to determine the energy of each isotope. The identification of radioisotopes aid in the handling of cleanup and safety precautions.
This thesis focuses on the hardware and construction of the apparatus used, diving into electronics and particle physics. The software as well as future data collection and analysis will be conducted by Natjalia Bogdanovic, for defense in Spring 2020.
ContributorsZand, Nicole Hanna (Author) / Tucker, Ross (Thesis director) / Lee, Robert (Committee member) / School of Mathematical and Natural Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
Description
The current observable universe is made of matter due to baryon/antibaryon asymmetry. The Deep Underground Neutrino Experiment is an international experiment through the Fermi National Accelerator Laboratory that will study neutrinos. In this study, the detection efficiency for low energy supernova neutrinos was examined in order to improve energy reconstruction for neutrino energies less than 40 MeV. To do this, supernova neutrino events were simulated using the LarSoft simulation package with and without background. The ratios between the true data and reconstructed data were compared to identify the deficiencies of the detector, which were found to be low energies and high drift times. The ratio between the true and reconstructed data was improved by applying the physical limits of the detector. The efficiency of the improved ratio of the clean data was found to be 93.2% and the efficiency of the improved ratio with the data with background was 82.6%. The study suggests that a second photon detector at the far wall of the detector would help improve the resolutions at high drift times and low neutrino energies.
ContributorsProcter-Murphy, Rachel Grace (Co-author) / Procter-Murphy, Rachel (Co-author) / Ritchie, Barry (Thesis director) / LoSecco, John (Committee member) / School of Earth and Space Exploration (Contributor) / Department of Physics (Contributor) / School of Mathematical and Statistical Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
Description
Different tools have been developed by physicists to detect particle interactions, including one tool called a cloud chamber. A cloud chamber is a device that uses a supersaturated alcohol vapor to outline the paths of subatomic particles. It requires an adequate source of radiation, either background radiation or a radioactive element, that is placed inside the chamber and allowed to decay. The particles emitted from the decaying element form tracks, as a result of the condensation of the supersaturated alcohol. This condensation ionizes the particles as they are being emitted, which creates the visible track. In order to produce curved tracks, which are necessary for data analysis, a suitable magnetic field must also be applied to the moving particles. As these particles come into contact with the magnetic field, their tracks curve, allowing for measurements of the radius of curvature for each track to be deduced. The radius of curvature can then be used to determine the identity of the atomic nucleus that the emitted particle came from. Computer programming can be applied to this process to make it faster and more efficient. This thesis project involved the composition of a software that could control a cloud chamber apparatus set up to view the beta decay of Pb-210 and analyze the tracks produced by emitted electrons to determine their radius of curvature. By the completion of this project, a software was developed that could accurately detect tracks from test images and control several parts of a cloud chamber.
ContributorsBogdanovic, Natalija (Author) / Tucker, Ross (Thesis director) / Solis, Francisco (Committee member) / School of Social and Behavioral Sciences (Contributor) / School of Mathematical and Natural Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
Description
In this project, we created a code that was able to simulate the dynamics of a three site Hubbard model ring connected to an infinite dissipative bath and driven by an electric field. We utilized the master equation approach, which will one day be able to be implemented efficiently on a quantum computer. For now we used classical computing to model one of the simplest nontrivial driven dissipative systems. This will serve as a verification of the master equation method and a baseline to test against when we are able to implement it on a quantum computer. For this report, we will mainly focus on classifying the DC component of the current around our ring. We notice several expected characteristics of this DC current including an inverse square tail at large values of the electric field and a linear response region at small values of the electric field.
ContributorsJohnson, Michael (Author) / Chamberlin, Ralph (Thesis director) / Ritchie, Barry (Committee member) / School of Mathematical and Statistical Sciences (Contributor) / Department of Physics (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05