Bulletin of the American Physical Society
APS April Meeting 2020
Volume 65, Number 2
Saturday–Tuesday, April 18–21, 2020; Washington D.C.
Session T20: Neutrinos VII ā Precision MeasurementsFocus Live
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Sponsoring Units: DNP Chair: Kyle Leach, Colorado School of Mines Room: Washington 5 |
Monday, April 20, 2020 3:30PM - 3:42PM Live |
T20.00001: Simulations of Cosmogenically Induced Neutrons for LEGEND-1000 Clay Barton The LEGEND (Large Enriched Germanium Experiment for Neutrinoless Double-beta decay) Collaboration aims to develop a phased, $^{76}$Ge-based double-beta decay experimental program with discovery potential at a half-life beyond 10$^{28}$ years, using existing resources as appropriate to expedite physics results. The host site for the second phase, LEGEND-1000, has yet to be selected. One factor impacting site selection is the background generated by cosmogenics (muons). The most important component of this background is the muon-induced neutrons, because these neutrons can create radioactive isotopes which decay long after the muon veto window. Using a GEANT4-based module, the cosmogenic background is currently being studied. This module allows for the testing of possible shielding configurations and materials. By using parametrized formulas for the properties of the incident muons, potential host sites can also be modeled. This work seeks to inform the design of LEGEND-1000 using simulation results, as well as to assist in the site selection for this next phase. [Preview Abstract] |
Monday, April 20, 2020 3:42PM - 3:54PM Live |
T20.00002: Neutron Background from (alpha,n) Reactions for LEGEND Tupendra Oli Neutrinoless double beta $(0 \nu \beta \beta)$ decay is a hypothesized nuclear process which, if observed, would unambiguously demonstrate the violation of lepton number conservation, an observed symmetry of Standard Model of particle physics, and establish the Majorana nature of neutrinos. Majorana fermions are particles that are their own antiparticles. Taking advantage of different approaches made by current generation 76Ge experiments, GERDA and Majorana Demonstrator, to achieve ultra-low background and the best energy resolution, LEGEND (Large Enriched Germanium Experiment for Neutrinoless Double beta decay) aims to develop a phased neutrinoless double beta decay experimental program using 200 kg active mass in the initial phase and 1000 kg active mass in the ultimate phase. In order to achieve further background reduction, a comprehensive understanding of all sources of background is very crucial and neutron-induced background is one of them. Neutrons can be produced either by natural radioactivity via $(\alpha,n)$ reactions and spontaneous fissions from detector components, or by cosmic ray muons. This talk will discuss possible background contributions from the neutrons produced from the natural radioactivity within detector components. [Preview Abstract] |
Monday, April 20, 2020 3:54PM - 4:06PM Live |
T20.00003: High-performance Generic Neutrino Detection in MicroBooNE Xiangpan Ji MicroBooNE is a Liquid Argon Time Projection Chamber (LArTPC) operating near the surface. The main physics goals of this experiment include studying the nature of the low-energy excess events observed in MiniBooNE and measuring the neutrino-Argon interaction cross section. With a large drift time, the cosmic rays are a major background to the neutrino interaction events. In this talk, I will describe a series of novel event reconstruction techniques that are used to reject cosmic muon backgrounds. With these tools, high-performance neutrino detection is achieved with a signal-to-background ratio above four while maintaining detection efficiency above 80\% for charge-current $\nu_\mu$ interaction events. [Preview Abstract] |
Monday, April 20, 2020 4:06PM - 4:18PM Live |
T20.00004: Project 8: Measuring the Neutrino Mass using Cyclotron Radiation Emission Spectroscopy Luiz de Viveiros Project 8 is an experiment that seeks to determine the mass of the electron neutrino via the precise measurement of the electron energy in beta decays, with a goal sensitivity of $40\,\mathrm{meV/c}^2$. We have developed a novel technique called Cyclotron Radiation Emission Spectroscopy (CRES), which allows single electron detection and characterization through the measurement of cyclotron radiation emitted by magnetically-trapped electrons produced by a gaseous radioactive source. The technique has been successfully demonstrated on a small scale in waveguides to detect radiation from single electrons, and to measure the continuous spectrum from tritium. The next phase of the experiment will move to larger volumes to increase sensitivity, requiring implementation of CRES in a free-space radiation environment instrumented with a phased antenna array. We present a brief overview of the Project 8 experimental program, highlighting the preliminary measurement of the tritium beta spectrum using CRES in a small scale prototype, and the development of the techniques needed to deploy CRES at large scales. [Preview Abstract] |
Monday, April 20, 2020 4:18PM - 4:30PM Live |
T20.00005: Simulation and design progress toward the Project 8 Phase III Free Space CRES Demonstrator Penny Slocum The Project 8 collaboration is developing a novel approach toward a direct neutrino mass measurement using Cyclotron Radiation Emission Spectroscopy (CRES). Beta decay electrons from a gaseous tritium source are trapped in a 1 T magnetic field where they emit 1 fW of cyclotron radiation for approximately 1 ms. The resulting electron energy spectrum is examined near its 18.6 keV endpoint for distortion due to the effective mass of the electron neutrino. Phases I and II of Project 8 have demonstrated this new spectroscopic technique successfully in waveguides. The next advancement of the experiment will be implemented in free space with radiation to be detected using a phased array of antennas. We examine design constraints deriving from systematic effects in the free space experiment, using the Locust simulation software. We discuss the results of the simulation effort and its implications for design work. [Preview Abstract] |
Monday, April 20, 2020 4:30PM - 4:42PM Live |
T20.00006: Track and event reconstruction for Project 8. Yu-Hao Sun Project 8 is an experiment planning to measure the neutrino mass by the tritium endpoint approach. Near the endpoint of the beta spectrum of tritium, the spectrum is distorted by the neutrino mass. Project 8 is developing the CRES (Cyclotron Radiation Emission Spectroscopy) technique for determining the electron energy spectrum by measuring the frequencies of cyclotron radiation from single electrons in a magnetic trap. The signals of electrons show up as tracks on frequency-time spectrograms. Electrons may scatter from a molecule, lose energy, and start a new track. Head to tail grouping of electron tracks constructs events. Initial energies of electrons are calculated from start frequencies of events. In this talk, track and event reconstruction, especially in phase II of project 8, will be described. In this phase, the first measurement of a continuous electron energy spectrum from tritium beta decay will be made using the CRES technique. The track and event reconstruction has been implemented to ensure zero background false event in 100 days of data taking with 90{\%} confidence, while maintaining precision and efficiency. [Preview Abstract] |
Monday, April 20, 2020 4:42PM - 4:54PM Live |
T20.00007: Tritium Beta Decay is Analyzed to Explain the Prediction of a 3.66 keV Antineutrino. The Velocities and Angles of Decay Products Are Given. Edward Mackouse The Trump T Boson rest mass is the sum of the electron antineutrino and electron rest masses =.51466 MeV. The Kinetic Energy (KE) of the T Boson is given as 18.57 keV and is the sum of the antineutrino and electron KE. For the mean KE for electrons of 5.7 keV, the electron would have a radial velocity of 0.148c which would also be the radial component of velocity for the antineutrino and for the T Boson Forces such as QV cross B separate the electron from the antineutrino and the T Boson. The following chart shows Electron kinetic energies, antineutrino angles, and T (combined) angles. Electron keV 1 6 12 16 18 18.57 T- angles 76 55 36 21 09 0 Antineutrino angles 87 81 77 72 - - At the minimum electron KE, the angles approach 90 degrees. The antineutrino at 81 degrees travels 6.6 times as far as a 5.7 keV electron and can produce up to 12.5 eV of KE in a collision with a secondary electron. The 12.5 eV KE verifies an antineutrino rest mass of 3.66 keV in Tritium beta decay. Other beta decays can produce secondary electrons with more than 12.5 eV of KE. [Preview Abstract] |
Monday, April 20, 2020 4:54PM - 5:06PM Not Participating |
T20.00008: Investigation of neutron-induced backgrounds in isotopes of molybdenum for 0$\nu\beta\beta$ decay searches Mary Kidd, Werner Tornow, Sean Finch Double-beta decay searches with bolometric crystals are extremely promising due to their excellent energy resolution, detection efficiency, and pulse-shape discrimination. Additionally, they can be constructed from a variety of materials, including many enriched double-beta decay candidates such as $^{100}$Mo. With a Q-value of 3034.40 $\pm$ 0.17 keV, and a natural abundance of 9.82\%, $^{100}$Mo is an excellent candidate for the study 0$\nu\beta\beta$ decay. One potential background for observing this transition is neutron inelastic scattering on isotopes of molybdenum. In $^{100}$Mo, a nuclear level with energy 3039.4 $\pm$ 1.0 keV cascades to the ground state. Though none of the individual gamma rays emitted in this de-excitation lie in the region of interest, if they all interact within a single bolometric crystal, they will sum to a value within the ROI. Even with an enriched $^{100}$Mo sample, other isotopes of molybdenum will be present. The isotopes $^{95}$Mo and $^{97}$Mo also have energy levels that lie within the ROI: 3037 keV and 3035 keV respectively. The decay schemes of these levels are unknown, so we can only search for decays to the ground state. We report our initial results in the investigation of $^{nat}$Mo(n,nā$\gamma$) with 4.5 MeV neutrons. [Preview Abstract] |
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