Bulletin of the American Physical Society
2015 Annual Spring Meeting of the APS Ohio-Region Section
Volume 60, Number 3
Friday–Saturday, March 27–28, 2015; Kent, Ohio
Session B3: Particle/Nuclear Physics |
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Chair: Peter Tandy, Kent State University Room: KSU Student Center 315 |
Friday, March 27, 2015 3:00PM - 3:15PM |
B3.00001: Towards finding the single-particle content of two-dimensional adjoint QCD Uwe Trittmann The single-particle content of two-dimensional adjoint QCD remains elusive due to the inability to distinguish single- from multi-particle states. To find a criterion we compare several approximations to the theory. Starting from the asymptotic theory (no pair production, only singular operators), we construct sets of eigenfunctions in the lowest parton sectors of the theory. A perturbative treatment of the omitted operators is performed. We find that multi-particle states are absent if pair-production is disallowed. Evidence for a double Regge trajectory of single-particle states is presented. [Preview Abstract] |
Friday, March 27, 2015 3:15PM - 3:30PM |
B3.00002: The effect of deformation on nuclear level density Gabriela Popa, Frazier Baker A study of the systematic behavior of nuclear level density for 20 \textless A \textless 70 has been performed. A code was developed to download the data from the nuclear data base and extract the energy levels together with their spin and parity assignments. The numbers of states per energy level were calculated under both assumptions of spherical and deformed nuclei. The density of states is calculated and plotted for comparison under both scenarios. [Preview Abstract] |
Friday, March 27, 2015 3:30PM - 3:45PM |
B3.00003: Studies of Space Charge Effects in Liquid Argon Time Projection Chambers Micah Groh Space charge accumulation due to ionization of argon atoms by cosmic rays incident on liquid argon time projection chambers (LArTPCs) can distort the electric field inside the TPC, affecting the resolution of positional measurements. This effect is particularly relevant for LArTPC detectors located near or on the surface, such as MicroBooNE and the future detectors of Fermilab's short-baseline neutrino program.The purpose of these studies is to explore the effects of space charge in liquid argon time projection chambers, with particular focus on the 35 ton experimental LArTPC prototype for the ELBNF project at Fermilab. A simplified model for the charge density and electric field within the chamber are used to determine the effects of space charge on the electric field, electron drift velocity, and particle paths in the TPC.I will present results demonstrating that electric fields with a lower magnitude have a noticeably stronger effect from space charge. Ongoing studies will include the effects of the liquid argon flow inside the TPC. These studies will be valuable to interpret data from the ELBNF 35 ton detector, to be collected in Spring 2015. [Preview Abstract] |
Friday, March 27, 2015 3:45PM - 4:00PM |
B3.00004: Partial-wave analysis of $\gamma p \to \eta p$ and $\gamma p \to K^+ \Lambda$ Brian Hunt, D.M. Manley The goal of our research is to improve our knowledge of the properties of nucleon resonances using techniques of a multichannel partial-wave (PW) analysis. Currently many predicted resonances have yet to be found, while the properties of several known resonances are relatively uncertain. To resolve these issues, one must analyze photoproduction reactions, which help us to determine properties of resonances that decouple from the $\pi N$ channel. The present work focuses on adding into a multichannel fit two such photoproduction reactions: $\gamma p \to \eta p$ and $\gamma p \to K^+ \Lambda$. During this talk, preliminary results will be discussed that focus on the dominant PW contributions of each reaction, and how adding the photoproduction reactions has altered, and possibly improved, the multichannel hadronic fits. [Preview Abstract] |
Friday, March 27, 2015 4:00PM - 4:15PM |
B3.00005: Measurement of $K^0$ photoproduction on liquid deuterium ChandraSekhar Akondi, D.M. Manley Measurements of $K^0$ photoproduction on a liquid deuterium target were performed using the Crystal Ball and TAPS detectors at the Glasgow tagged photon facility of the Mainz Microtron, MAMI-C. Events for $\gamma n \to K^0 \Lambda$, $\gamma n \to K^0 \Sigma^0$, and $\gamma p \to K^0 \Sigma^+$ are identified by selecting events with six to eight clusters, which correspond to final-state photons or nucleons. We will compare results of Monte Carlo simulations using GEANT-4 with preliminary results for the measured data. [Preview Abstract] |
Friday, March 27, 2015 4:15PM - 4:30PM |
B3.00006: Discharge Voltage Utilization in Electric Propulsion Devices Jerry Ross In the field of space propulsion the world is divided into two camps: Chemical and Electric. Electric propulsion (EP) devices, such as the Hall thruster, are gaining use for space travel against their chemically propelled counterparts because of the propellant mass savings that EP can offer. This reduction in propellant mass allows for a lighter spacecraft and/or a more massive payload. Many missions, however, are time sensitive and electric propulsion devices are not capable of producing the levels of thrust necessary to meet the trip-time demands. In these missions, chemical thrusters must be used as the primary propulsion device at the expense of a increased onboard propellent mass. The result is that many of today's spacecraft have both a primary propulsion device, such as a chemical rocket, as well as an auxiliary device for stationkeeping tasks, often an electric propulsion rocket. Dual systems require dual propellant tanks, power supplies, mass flow controllers, etc. Therefore, there is a desire in the electric propulsion community to create an EP device that can function both as a primary and auxiliary device for a spacecraft. Research has shown unmodified Hall thrusters exhibit poor thrust efficiency as primary devices. This presentation details the inner workings of a [Preview Abstract] |
Friday, March 27, 2015 4:30PM - 4:45PM |
B3.00007: Departures from Standard Equipartition for Anharmonically Coupled Masses with a Quartic Term Christopher Watenpool, Donald Priour Using Monte Carlo simulations, we examine 1D chains of masses where a harmonic coupling is augmented by a quartic perturbation for which the strength may be weak, moderate, or strong. For the case of a single particle in a mixed harmonic/quartic well, thermodynamic observables may be calculated exactly with the thermally averaged potential energy ranging from $\frac{1}{2} k_{\mathrm{B}} T$ for the pristine harmonic well (i.e. consistent with standard equipartition) to $\frac{1}{4} k_{\mathrm{B}} T$ in the case of a dominant quartic term. We calculate and exhibit mean energies and RMS displacements for a variety of temperatures and perturbation strengths, and we extrapolate to the thermodynamic limit by considering large chains of masses. We comment on how the system auto-correlation time is impacted by the quartic perturbation. [Preview Abstract] |
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