Bulletin of the American Physical Society
APS April Meeting 2018
Volume 63, Number 4
Saturday–Tuesday, April 14–17, 2018; Columbus, Ohio
Session D09: Beyond Standard Model Physics II |
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Sponsoring Units: DPF Chair: Antonio Boveia, Ohio State University Room: A111 |
Saturday, April 14, 2018 3:30PM - 3:42PM |
D09.00001: Gravitational Self-interactions of a highly degenerate quantum scalar field Yaqi Han, Sankha Chakrabarty, Seishi Enomoto, Pierre Sikivie, Elisa Todarello We give a description of the quantum evolution of a homogeneous self-gravitating condensate in critical expansion and show how it differs from its classical counterpart. We show that in quantum description, parametric resonance would cause the quanta to jump in pairs into an increasing amount of low-wavevector modes over time. While the condensate persists forever in the classical picture, it would be depleted rapidly in the quantum picture. We estimate the time scale for the condensate to get completely depleted. [Preview Abstract] |
Saturday, April 14, 2018 3:42PM - 3:54PM |
D09.00002: Maximal duration of classicality in highly degenerate interacting Bosonic systems Elisa Todarello, Sankha Chakrabarty, Seishi Enomoto, Yaqi Han, Pierre Sikivie We study sets of oscillators that interact by exchanging quanta. We identify initial states for which the system obeys classical field equations as long as possible. The simulations are paralleled to an analytical treatment of homogeneous condensates with attractive contact interactions and of homogeneous self-gravitating condensates in critical expansion. We argue that inhomogeneous condensates obey classical field equations for shorter times than homogeneous ones. [Preview Abstract] |
Saturday, April 14, 2018 3:54PM - 4:06PM |
D09.00003: Non-dependence of the decay rates of $^{123}$I and $^{99m}$Tc on Earth-Sun distance Joseph Borrello, Alan Wuosmaa, Mark Watts In 2009, Jenkins {\it et. al}. reported a cyclic variation with a period of one year in the decay rates of $^{32}$Si (T$_{1/2}$= 153 y) and $^{226}$Ra (T$_{1/2}$=1600 y), based on reviews of previously published decay data for those nuclei. It was suggested that this variation was related to the annual variation of the solar-neutrino flux due to varying Earth-Sun distance, implying surprising new physics. This result was subsequently examined by other researchers, and has been the subject of over thirty papers published since that time. We have searched for such a variation in the decay rates of two shorter-lived radionuclides which have not previously been studied for annual variation: $^{123}$I (T$_{1/2}$=13.2235 h) and $^{99m}$Tc (T$_{1/2}$=6.0067 h). Half-lives of these radionuclides were measured repeatedly over a period of 2 years. Spectral analysis of the accumulated half-life data using the Lomb-Scargle method demonstrated no periodic dependence of either half-life, and in particular no evidence for a variation with a period of 1 year. [Preview Abstract] |
Saturday, April 14, 2018 4:06PM - 4:18PM |
D09.00004: Subluminal Magnetic Monopole Search with NOvA Martin Frank The existence of the magnetic monopole has eluded physicists for centuries. The NOvA far detector (FD), used for neutrino oscillation searches, has the additional capability to search for magnetic monopoles at subluminal velocities. With a surface area of over 4,000 m\textsuperscript{2} and a location near the earth's surface, the 14 kT FD provides us with the unique opportunity to be sensitive to potential low-mass monopoles that lack the penetrating power to reach underground experiments. We have designed a novel data-driven triggering scheme that continuously searches the FD's live data for monopole-like structures. At the offline level, the largest challenge in reconstructing monopoles is to reduce the 148,000 Hz speed-of-light cosmic ray background. In this talk, I will present the trigger algorithm that we employ and the offline reconstruction algorithm that will be used for the first NOvA monopole search. [Preview Abstract] |
Saturday, April 14, 2018 4:18PM - 4:30PM |
D09.00005: Search for fractional charged particles with the \sc {Majorana Demonstrator} Ralph Massarczyk Neutrinoless double-beta decay searches play a major role in determining neutrino properties. Located at the Sanford Underground Research Facility in Lead, South Dakota, the {\sc Majorana} collaboration is operating an ultra-low background detector array to search for this decay in $^\mathrm{76}$Ge. A mile underground, heavily shielded, and with its low energy thresholds and excellent energy resolution, the array of germanium detectors also allows searches of new physics beyond the standard model. Here, we present one such search for free particles with electrical charges less than the elementary charge, which are predicted by some extensions of the standard model. Such particles have not been observed and direct searches can restrict model parameter space. Using the results from our first year of physics data with the {\sc Demonstrator}, new direct-detection limits on the flux of lightly ionizing particles with charges as low as $e/1000$ can be set. The talk will give an overview on the experimental analysis and discuss the results. This material is based upon work supported by the U.S. DoE, Office of Science, Office of Nuclear Physics, the Particle Astrophysics and Nuclear Physics Programs of the National Science Foundation, and Sanford Underground Research Facility. [Preview Abstract] |
Saturday, April 14, 2018 4:30PM - 4:42PM |
D09.00006: Abstract Withdrawn
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Saturday, April 14, 2018 4:42PM - 4:54PM |
D09.00007: Sub-GeV and other rare event searches with the LUX detector Lucie Tvrznikova The Large Underground Xenon (LUX) experiment was a two-phase liquid/gas xenon time projection chamber designed for the direct detection of potential dark matter candidate particles. LUX contained 250 kg of active liquid xenon and was installed 1.5 km underground from 2012 to 2016 at the Sanford Underground Research Facility in Lead, South Dakota (USA). LUX results include constraints on WIMP-nucleon spin dependent and independent couplings spanning a wide range of WIMP masses above a few GeV, as well as limits on Axions and Axion-Like Particles (ALPs). Direct detection of dark matter candidates with masses below the GeV scale is not possible for pure nuclear recoil signals due to the low signal yield of the nuclear recoil events. However, by considering the inelastic channel of photon emission from bremsstrahlung during the nuclear recoil, this limitation can be overcome. An overview of these various searches performed by the LUX detector will be presented. [Preview Abstract] |
Saturday, April 14, 2018 4:54PM - 5:06PM |
D09.00008: Searching for neutron-antineutron oscillation in the Deep Underground Neutrino Experiment Yuyang Zhou, Georgia Karagiorgi, Jeremy Hewes The imbalance of matter and antimatter in the universe remains one of the most perplexing unsolved problems in physics. In order to explain this phenomenon, grand unified theories (GUT) have proposed the existence of baryon number violating processes. One such process is neutron-antineutron oscillation. The future Deep Underground Neutrino Experiment (DUNE) can search for argon-bound neutron-antineutron oscillation. The signature of this process in the DUNE Far Detector is special in that its final states form a unique, star-shaped event topology. This striking topology and the DUNE detector readout operating principle (that of a liquid argon time projection chamber (LArTPC)) allows the implementation of deep learning image classification techniques to search for these interactions. The detection of this process would not only revolutionize our understanding of the origin of matter in the universe, but also serve as the foundation for new, GUT-scale physics to be discovered. In this presentation, we explore the feasibility of applying this methodology in DUNE and report on the current status of a sensitivity evaluation. [Preview Abstract] |
Saturday, April 14, 2018 5:06PM - 5:18PM |
D09.00009: Steps Toward Proper Neutron-Antineutron and Atmospheric Neutrino Simulation in DUNE. Joshua Barrow, Yuri Kamyshkov Babu et al. have recently proposed a model of post-sphaleron baryogenesis following the electroweak phase transition. Their theory naturally gives rise to a plausible baryon abundance, and a $\Delta $B$=$2 six-quark operator which allows for the transformation of a neutron (n) into an antineutron (nbar). Using n bound in Ar, DUNE currently plans to include n-nbar oscillation events in their nucleon decay searches. Using refined physics inputs in GENIE and group-developed generators (and others), modeling is underway on intranuclear interactions mimicking n-nbar annihilation and atmospheric $\nu $ in Ar nuclei. Eliminating $\nu $ background is challenging for liquid Ar TPCs at DUNE, so analysis of multiple generators becomes important to asses MC uncertainties, hopefully improving statistics and oscillation time limits. Assessing such uncertainties is a work in progress. [Preview Abstract] |
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