Bulletin of the American Physical Society
2020 Fall Meeting of the APS Division of Nuclear Physics
Volume 65, Number 12
Thursday–Sunday, October 29–November 1 2020; Time Zone: Central Time, USA
Session GA: Conference Experience for Undergraduates Poster Session I (4:00pm - 4:35pm) |
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GA.00001: A Graphical User Interface-Based Framework for Ultracold Neutron Monte Carlo Simulations Mina Kemp The mean lifetime of a free neutron ($\tau_{n}$) is tied to several tests of the Standard Model, such as unitarity of the CKM matrix. In order to significantly probe topics such as this, a measurement of $\tau_{n}$ with a precision exceeding 0.1s is required. The goal of the UCN$\tau$ collaboration is to attain this measurement by means of a “bottle method” wherein ultracold neutrons (UCNs) are confined in a volume using strong magnetic field gradients. Assessing subtle systematic effects in experiments such as these depends in part on high-fidelity simulations. Standard neutron Monte Carlo codes, however, are not typically designed for simulating neutrons with energies as low as those of UCNs, which means that custom codes must be developed. This precludes the possibility of taking advantage of existing geometry or data visualization tools in a straightforward way, prompting the development of a new graphical user interface (GUI)-based framework for the UCN Monte Carlo code $\textit{UCNtransport}$. This framework allows for the construction/modification of geometries as well as the projection of simulation results onto these geometries. In this presentation, I will describe the creation process, physics-driven design decisions, and current capabilities of this new framework. [Preview Abstract] |
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GA.00002: TTU Ion Generator Development AUSTIN MARLER, Mustafa Rajabali A Cesium sputter ion source has been repurposed into a laser ablation ion source. Utilizing an existing sputter source we have modified its structure to include the properties of a laser ion source where the target is renewed by rotating the target while the laser's focus remains fixed. This source is simulated using an open source ion beam extraction simulation named IBSimu. Preliminary results for this ion beam will be presented in this work: DOE grant: DE-SC0016988 [Preview Abstract] |
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GA.00003: Measurement of $\pi^0$-hadron Azimuthal Correlations in $\sqrt{s_{_{NN}}}=200$ GeV $d$+Au Collisions with PHENIX Shuhang Li The Color Glass Condensate (CGC) explains both single particle and particle pair yield reductions at forward rapidity in $d$+Au collisions relative to $p$+$p$ collisions at the Relativistic Heavy Ion Collider (RHIC). The CGC also predicts the away-side width in two-particle azimuthal correlations will be broadened. In 2016, PHENIX collected $d$+Au data at $\sqrt{s_{_{NN}}}=200$ GeV. In this data, we can measure the $\pi^0$s in $|\eta|<0.35$ and $3<|\eta|<3.8$ and charge hadrons in $|\eta|<0.35$ and $1.4<|\eta|<2.2$. We measured $\pi^0$-hadron azimuthal correlations with different pair $\eta$ ranges. By varying the $p_T$ of the particles and the $\Delta\eta$ of the particle pairs, we can vary the $Q^2$ and $x$ of the target nucleus. The current status of the measurement will be shown. [Preview Abstract] |
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GA.00004: Pion and Kaon Distribution Amplitudes in the Continuum Limit Carson Honkala, Rui Zhang, Huey-Wen Lin, Jiunn-Wei Chen We present a lattice-QCD calculation of the pion, kaon and $\eta _{\mathrm{s}}$ distribution amplitudes using large-momentum effective theory (LaMET). Our calculation is carried out using three ensembles with 2$+$1$+$1 flavors of highly improved staggered quarks (HISQ), generated by MILC collaboration, at 310-MeV pion mass with 0.06, 0.09 and 0.12 fm lattice spacings. We use clover fermion action for the valence quarks and tune the quark mass to match the lightest light and strange masses in the sea. The resulting lattice matrix elements are nonperturbatively renormalized in regularization-independent momentum-subtraction (RI/MOM) scheme and extrapolated to the continuum. We use two approaches to extract the x-dependence of the meson distribution amplitudes: 1) we fit the renormalized matrix elements in coordinate space to an assumed distribution form through a one-loop matching kernel; 2) we use a machine-learning algorithm trained on pseudo lattice-QCD data to make predictions on the lattice data. We found the results are consistent between these methods with the latter method giving a less smooth shape. Both approaches suggest that as the quark mass increases, the distribution amplitude becomes narrower. Our pion distribution amplitude has broader distribution than predicted by light-front constituent-quark model, and the moments of our pion distributions agree with previous lattice-QCD results using the operator production expansion. [Preview Abstract] |
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GA.00005: Simulating the MARS Detector Response to a Cf-252 Source Duy Hoang, Rebecca Rapp, Diana Parno The COHERENT experiment is designed to measure neutrino scattering at tens of MeV on various nuclear targets. COHERENT is the first experiment that has successfully measured the coherent elastic neutrino-nucleus scattering interaction in multiple detectors using neutrinos produced by the Spallation Neutron Source at Oak Ridge National Laboratory. However, neutron signals are a background for the COHERENT detectors. To address this, there is a dedicated neutron monitoring system: the Multiplicity and Recoil Spectrometer (MARS). This work describes an effort to model the Cf-252 neutron source as a calibration source using a GEANT4 simulation. The simulation generates neutron and gamma energy deposit data for the MARS neutron-monitoring detector to compare to previously collected calibration data to model the MARS detector's response. [Preview Abstract] |
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GA.00006: Sorting neutron resonances by spin groups using a machine learning technique. Pedro Rodríguez Fernández, Sophia Hollick, David Brown, Gustavo Nobre The nuclear level density is a key input for modeling nuclear reactions. The most discriminative constraint on the level density is the level spacing at the neutron separation energy, D. Efforts such as the Reference Input Parameter Library (RIPL) and the Atlas of Neutron Resonances, have compiled the average level spacing of most known isotopes. Because of the challenge of classifying every neutron resonance in the correct spingroup, the values of the average spacings compiled in these two resources differ. This project focuses on the first steps of the development of a machine learning technique, to try and resolve this classification problem. Initial results using random matrix theory motivated fits to the Nearest Neighbor Spacing Distribution (NNSD) demonstrated that we can determine resonance spin group somewhat reliably. [Preview Abstract] |
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GA.00007: Computational Methods to Develop a Magneto-ionization Spacecraft Shield for Interplanetary Travel (the MISSFIT Collaboration) David Atri Schuller, Justin Brutger, Keegan Finger, Luke Hofmann, Trace Johnson, Julie LaFranzo, Lorien MacEnulty, Molly McCord, Gavin Menning, Ethan Morton, Noah Peterson, Athanasios Petridis, Ajal R.C., William Thomas, Daniel Viscarra This work aims to develop radiation-shielding solutions for manned interplanetary travel using a combination of magnetic fields, ionization chambers and passive absorbers by developing the computational methods required to properly simulate the propagation of high-energy particles through such systems. We develop a code to compute a magnetic field around the proposed spacecraft employing the matrix relaxation method. The resulting magnetic field is used to calculate the trajectory of charged particles through various gaseous and solid media with a particle propagation code. The program is fully relativistic and employs SRIM to calculate the energy loss of such particles as they travel through the passive absorption shield. The aim of this work is to produce highly accurate results illustrating the motion of charged particles through analysis of case studies with varying energies, incident angles, and magnetic field configurations. A deterministic code is used currently, but a Monte-Carlo method to compute statistics for particle motion is being developed. [Preview Abstract] |
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GA.00008: Gluon Generalized Parton Distributions and the Angular Momentum Sum Rule Emma Yeats, Simonetta Liuti, Brandon Kriesten, Philip Velie, Fernanda Yepez-Lopez Understanding how the proton spin is carried by its constituents, the quarks and gluons, represents one of the main challenges in particle physics. In particular, the generalized parton distributions, $H_{q,g},$, E_{q,g}$, which are found in the matrix elements for the deeply virtual Compton scattering process, allow us to measure the total angular momentum carried by the quarks and gluons, $J_q$ and $J_g$, respectively. The latter are obtained as the second moment of the generalized parton distributions in the $x$ variable. The nucleon helicity-flip distributions $E_q$ and $E_g$, are lesser known than their counterparts $H_q$ and $H_g$, because their forward limit values cannot be obtained from inclusive processes. Here we present a model calculation of $E_g$ in the reggeized diquark model, using recent lattice QCD calculations to take into account its normalization. Based on our model calculation, we study the impact of $E_g$ on the proton angular momentum sum rule. [Preview Abstract] |
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GA.00009: Operational and data analysis improvements for a quantum-enhanced search for dark matter axions Huaijin Wang HAYSTAC is the first axion dark matter haloscope to circumvent the quantum limit using vacuum squeezing technology. The experiment utilizes the resonant conversion of axions to microwave photons in a high Q cavity in the presence of a strong magnetic field, and implements a squeezed-state receiver system to enhance the search rate. The Phase 2 operation observes no signature of dark matter axions over the combined 16.96-17.12 and 17.14-17.28 $\mu eV/c^2$ mass range, and achieves $90\%$ exclusion for axion-photon couplings above $g_{\gamma}$ = 1.38 $ \times g_{\gamma}^{KSVZ}$. In this talk, I will describe upgrades made to operational procedures and data analysis programs for the Phase 2 experiment, including characterizations of microwave cavity response and squeezed state receiver circuit properties, as well as updates and run-time improvements to the data analysis program. [Preview Abstract] |
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GA.00010: Creation of Pseudo-data Synthetic Waveforms for the BL2 Experiment Scarlett Wilson, Lara Blokland, Di'Arra Mostella, Nadia Fomin, Geoffrey Greene The BL2 experiment at the NIST Center for Neutron Research aims to measure the neutron lifetime through the beam method by counting decay protons. Once neutrons decay, protons are trapped by the Pseudo-Penning Trap and a magnetic field. The signals in the detector can have multiple defects as protons arrive from the trap. Pseudo-data is produced to mimic these known defects which results in the creation of synthetic waveforms for various types of waveform analysis. Files with 100,000$+$ waveforms were produced with realistic event probabilities. In addition to files with pseudo-data containing realistic probabilities, data files were created for each type of defect exclusively to differentiate between waveform events (without realistic event probabilities) and to finetune waveform analysis for each event. I will present the results of creating pseudo-data synthetic waveforms that help improve the accuracy of the various waveform analysis techniques. [Preview Abstract] |
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GA.00011: Strangeness-Neutral Equation of State for QCD with a Critical Point Damien Price, Angel Nava, Claudia Ratti, Jamie Stafford, Debora Mcoczek, Jacquelyn Noronha-Hostler, Paolo Parotto We construct a family of equations of state for QCD in the temperature range 30$\le $ T$\le $800 MeV and in the chemical potential range 0$\le \mu _{\mathrm{B}}\le $450 MeV. These equations of state match available lattice QCD results up to O($\mu_{\mathrm{B}}$\textasciicircum 4)and in each of them we place a critical point in the 3D Ising model universality class. The position of this critical point can be chosen in the range of chemical potentials covered by the second Beam Energy Scan at RHIC. Our results for the pressure, entropy density, baryon density, energy density and speed of sound can be used as inputs in the hydrodynamical simulations of the fireball created in heavy ion collisions. We follow the approach presented in Ref. [1], but we extend it to a more realistic scenario for heavy-ion collisions, namely to a situation in which the strangeness and electric charge chemical potentials are non-zero, and they are functions of T and $\mu_{\mathrm{B\thinspace }}$chosen such that the total strangeness in the system is zero, and the total electric charge is a fraction of the total baryon number. These choices reflect the net-strangeness and net-electric charge content of the colliding nuclei in the collision. [Preview Abstract] |
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GA.00012: Quality control of sPHENIX EMCal blocks Mason Housenga The sPHENIX experiment at Brookhaven National Lab's (BNL's) Relativistic Heavy Ion Collider will study collisions of protons and nuclei. sPHENIX was designed to accurately explore properties of the Quark Gluon Plasma and to investigate effects in "cold" Quantum Chromo Dynamics with the first physics beams scheduled for 2023. Being the primary detector to identify and measure the energies of electrons and photons, the sPHENIX Electromagnetic Calorimeter (EMCal) is one of the key ingredients to enable this broad set of measurements. The EMCal consists of tungsten absorber blocks with embedded scintillating fibers. The Nuclear Physics Group of the University of Illinois at Urbana-Champaign is currently in the process of producing almost 4000 of these absorber blocks. Before a block is shipped to BNL, its quality with respect to dimensional accuracy, density, light transmission and scintillation properties is evaluated at UIUC. This poster will discuss these testing processes and the monitoring tools available to quickly access and evaluate each block's overall quality. [Preview Abstract] |
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GA.00013: The detectability of fast time oscillations in supernova neutrino flux and energy in DUNE (Deep Underground Neutrino Experiment) Aryil Bechtel, Kate Scholberg During a type II core collapse supernova, initial perturbations in infalling matter can lead to intense turbulence and sloshing of the shock front, a phenomenon dubbed ``Standing Accretion Shock Instability'' (SASI). SASI could play an important role in the reignition of the shock wave, a poorly understood process that leads to the expulsion of the star's outer shell. It has been shown that the sloshing motions of SASI would cause time-dependent oscillations in neutrino number flux and neutrino energy emitted from the supernova. These oscillations may be measurable by neutrino detectors on earth. Understanding our current prospects of measuring SASI can help us improve our detection abilities in anticipation of a type II event. In this study, we seek to examine what analysis techniques, detector parameters, and event conditions could increase the prospect of observing SASI with the upcoming DUNE 40 kiloton liquid argon detector. We used SNoWGLoBES software and a simulation of a 27 solar-mass progenitor to model what the detector will measure. A likelihood ratio in the frequency domain was used as a SASI detection indicator for neutrino fluxes at different distances. Using results across many shot-noised time series, we found that SASI activity can be identified in around 90 percent of the cases with about 10 percent false identification rate for supernovae within 4 kpc. We are currently researching ways to incorporate neutrino energy oscillations into a likelihood ratio test as well as comparing results to other simulated supernova models. [Preview Abstract] |
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GA.00014: Gettysburg College Proton Accelerator Ezequiel Linares The proton accelerator at Gettysburg College creates beams of protons with energies approximately 50-200 keV. The low-energy particles that are generated are applicable to the study of material surfaces such as in the proton damage of polydimethylsiloxane (PDMS), a coating on satellites that protects components from energetic particles. The stability of the proton beam’s energy and flux is crucial to get reliable data on how protons affect the surfaces. Recently an Arduino-based feedback system and monitor were developed to control the beam energy and stability. I am working on a replacement control system that uses the LabWindows-CVI software. This setup will allow for better control and monitoring of various aspects of the experiment in a versatile and flexible programing environment. In the poster, the creation of the feedback system in LabWindows-CVI will be discussed along with the PID algorithm that is used to stabilize the beam energy. [Preview Abstract] |
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GA.00015: Modern Deuteron Form Factor Parameterization. Asia Parker, Douglas Higinbotham, Fatiha Benmokhtar \textbf{Abstract:} \newline The determination of the deuteron form factors is essential for both the understanding of the simplest bound nuclear system and for the future EIC where elastic deuteron scattering one can determine the polarization of a stored deuteron beam. ~New deuteron elastic data from the Jefferson Lab LEDEX experiment, as well as previous results, will be used to perform new parameterization of the deuteron form factors. ~Our fit will ensure proper analytic properties so that it can be used beyond the range of the data without having singularities and nonphysical behavior that many previous parameterizations have. [Preview Abstract] |
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GA.00016: Energy Systematics of the Coulomb Effect in Au+Au Collisions at STAR Jinming Nian In Au+Au collisions at STAR, the colliding ions leave a positively charged interaction region, especially in the low energy collisions of the Beam Energy Scan II (BES-II) and Fixed-Target programs. Due to the Coulomb potential of this positive source, positively charged particles are pushed to higher momentum, while negatively charged particles are pulled to lower momentum. This is most evident in the charged pions since they are the lightest hadrons and are produced copiously. By fitting the final ratio of pions ($\pi^{+}/\pi^{-}$) as a function of $m_{T} - m_{0}$ with a physics motivated model, we can extract the Coulomb potential, $V_{C}$, and initial pion ratio, $R_{i}$. These allow us to study the volume of the fireball and the charge chemical potential, respectively. Results from multiple STAR Fixed-Target and BES-II energies will be presented along with comparisons to AGS, SIS, and SPS experiments. [Preview Abstract] |
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GA.00017: Extraction of the Boer-Mulders Function from Unpolarized SIDIS Data Benjamin Gordon, Andreas Metz, Daniel Pitonyak, Alexei Prokudin, Adam Rilatt One avenue to study the 3D momentum-space tomography of hadrons is through high-energy electron-nucleon semi-inclusive deep-inelastic scattering (SIDIS) collisions, which are sensitive to parton intrinsic transverse momentum \textit{kT}. One finds that even in unpolarized SIDIS collisions, angular modulations, such as cos(2phi), occur in the cross section. The cos(2phi) dependence comes from two sources: a correlation between parton transverse spin and \textit{kT}, encoded in the twist-2 Boer-Mulders transverse momentum dependent (TMD) function that couples to the Collins TMD function; and a higher-twist (twist-4) so-called Cahn effect involving unpolarized TMD functions. In this work we study SIDIS data from HERMES, COMPASS, and CLAS in order to extract the Boer-Mulders function, considering also the contribution from the Cahn effect. We include not only cos(2phi) asymmetry data, but also HERMES and COMPASS multiplicity data as well as electron-positron annihilation data from BELLE, BaBar, and BESIII simultaneously in our analysis. [Preview Abstract] |
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