Bulletin of the American Physical Society
Joint Spring 2016 Meeting of the Texas Sections of APS, AAPT, and Zone 13 of the SPS
Volume 61, Number 3
Thursday–Saturday, March 31–April 2 2016; Beaumont, Texas
Session F2: APS Session - Nuclear Physics & High Energy Physics |
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Chair: James Drachenberg, Lamar University Room: 210 |
Saturday, April 2, 2016 10:30AM - 10:54AM |
F2.00001: Recent Developments in Transverse Spin Physics at RHIC Invited Speaker: James Drachenberg For decades, an enduring conundrum has been the origin of large azimuthal asymmetries in the production of hadrons from interactions involving a single beam of transversely spin-polarized protons. While the origins remain a mystery, theoretical and experimental engagement of this challenge has unlocked tantalizing opportunities for new insight into nucleon structure and more expansive formulations of pQCD, e.g.~including transverse-momentum dependent parton densities (TMDs). The RHIC experiments continue this exploration through measurements of observables sensitive to the transversity, Sivers, and Collins functions in high-energy polarized-proton collisions. Recent breakthroughs may illuminate further longstanding questions: Do hadronic interactions paint the same picture as those seen in semi-inclusive deep-inelastic scattering? How do TMDs evolve with changing kinematics? Beyond existing probes, future measurements will enable even wider frontiers in understanding pQCD and nucleon structure. [Preview Abstract] |
Saturday, April 2, 2016 10:54AM - 11:06AM |
F2.00002: Parton distribution functions probed in ultraperipheral collisions at the CERN Large Hadron Collider James Thomas, C.A. Bertulani, N. Brady, D. B. Clark, E. Godat, A. Kusina, F. Olness Vector meson production in ultra-peripheral pA and AA collisions at the CERN Large Hadron Collider (LHC) are very sensitive to Parton Distribution Functions (PDF) as well as to their leading-order, next-to-leading-order, and medium corrections. This process is a complimentary tool to explore the effects of different PDFs in particle production in proton-nucleus and nucleus-nucleus central collisions. Existing and forthcoming data available, e.g., from ALICE and CMS, may be used in conjunction with our theoretical predictions to constrain the PDFs which best match their event rates. We make predictions for rapidity distributions and for cross sections of J/Psi, psi(2S), and Upsilon production at $\sqrt{s_{NN}}=2.76$ TeV and $\sqrt{s_{NN}}=5.02$ TeV. [Preview Abstract] |
Saturday, April 2, 2016 11:06AM - 11:18AM |
F2.00003: A generalization of the Golden Rule of a resonant state Rafael de la Madrid We present a generalization of Fermi's Golden Rule that yields the decay rate of a resonance. From this decay rate, we extract an energy distribution of decay events of a resonance that, contrary to Fermi's Golden Rule, involves the Breit-Wigner distribution. [Preview Abstract] |
Saturday, April 2, 2016 11:18AM - 11:30AM |
F2.00004: Dynamical Coupling of Pygmy and Giant Resonances in Relativistic Coulomb Excitation Nathan Brady, Thomas Aumann, Carlos Bertulani, James Thomas We study the Coulomb excitation of pygmy dipole resonances (PDR) in heavy ion reactions at $100$ MeV/nucleon and above. The reactions $^{68}$Ni + $^{197}$Au and $^{68}$Ni + $^{208}$Pb are taken as practical examples. Our goal is to address the question of the influence of giant resonances on the PDR as the dynamics of the collision evolve. We show that the coupling to the giant resonances affects considerably the excitation probabilities of the PDR, a result that indicates the need of an improved theoretical treatment of the reaction dynamics at these bombarding energies. [Preview Abstract] |
Saturday, April 2, 2016 11:30AM - 11:42AM |
F2.00005: The decay scheme development of the decay chain $^{\mathrm{74}}$Cu$\to ^{\mathrm{74}}$Zn$\to^{\mathrm{74}}$Ga$\to^{\mathrm{74}}$Ge using statistically significant $\gamma \gamma $ coincidences method. Durga Siwakoti, Umesh Silwal, James L Tracy, Jr., Dr. Jeff Allen Winger Previous studies of the decay scheme development of the $\beta $-decay chain $^{\mathrm{74}}$Cu$\to^{\mathrm{74}}$Zn$\to^{\mathrm{74}}$Ga$\to ^{\mathrm{74}}$Ge was limited due to low production rates for the parent nuclei and low detection efficiencies. In this current HRIBF experiment, nearly pure beam of $^{\mathrm{74}}$Cu was used to study the decay chain using LeRIBSS setup where even low intensity $\gamma $-ray could be detected. The decay schemes were developed from the $\gamma \gamma $ and $\beta \gamma $ Coincidence data obtained from the experiment taken in the energy range 20-5200 keV and compared to existing data at the National Nuclear Database Center (NNDC). For energy gated $\gamma \gamma $ spectra, possible peaks were fitted to a standard Gaussian function to determine the relevant peak area on both peak gate and an adjacent background gate to enable us to identify the statistically significant peaks. By this careful analysis, we have established new transition lines and energy levels for all three daughter nuclei and also readjusted some previously placed transitions due to better understanding of the $\gamma \gamma $ relationships. [Preview Abstract] |
Saturday, April 2, 2016 11:42AM - 11:54AM |
F2.00006: Wire bond protection of periodic Lorentz forces and humidity induced corrosion through thin polyurethane coatings Matthew Kurth, Joseph M. Izen, Rusty Boyd Aluminum wedge wire bonds are common in pixel and strip detectors for particle detectors. Unlike commercial applications, bulk encapsulation of wire bonds has not been used in the high radiation, extended temperature range environment of solid-state tracking detectors. Bare aluminum wire bonds are vulnerable to condensation-induced corrosion and oscillations from periodic Lorentz forces. Polyurethane-coated wire bonds are being investigated for use with the ATLAS ITk upgrade. Systematic radiation exposures with Sandia National Laboratory's Co 60 gamma source replicates the anticipated lifetime dose at several ITk locations. The damping of mechanical oscillations, corrosion resistance, and the effects of thermal cycling and irradiation of polyurethane-coated wire bonds is reported. [Preview Abstract] |
Saturday, April 2, 2016 11:54AM - 12:06PM |
F2.00007: New Noise Subtraction Methods in Lattice QCD Suman Baral, Walter Wilcox Lattice QCD calculations of quark loop operators are extremely time-consuming to evaluate.~To calculate these diagrams we use stochastic noise methods, which employ a randomly generated set of noise vectors to project out physical signals. This is done with linear equation solvers like GMRES-DR (Generalized Minimum RESidual algorithm-Deflated and Restarted) for the first noise, and GMRES-Proj (similar algorithm projected over eigenvectors) for remaining noises. In this context, we are attempting to employ matrix deflation algorithms to reduce statistical uncertainty in these time-consuming lattice calculations. In addition, we are developing noise suppression algorithms using polynomial subtraction techniques, as well as combining deflation and polynomial methods in an original way. [Preview Abstract] |
Saturday, April 2, 2016 12:06PM - 12:30PM |
F2.00008: New superconducting magnet technology can make OpenMRI screening for breast cancer affordable and save women’s lives Invited Speaker: Peter McIntyre |
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