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 HA: Conference Experience for Undergraduates Poster Session II (4:40pm - 5:15pm) |
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HA.00001: ABSTRACT WITHDRAWN |
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HA.00002: Pythia Study of Rapidity-Separated Two-Particle Correlations in $\sqrt{s}$=200 GeV $p$+$p$ collisions. Yifan Yuan, Nathan Grau The PHENIX detector at the Relativistic Heavy Ion Collider collected data from $\sqrt{s_{_{NN}}}$ = 200 GeV $d$+Au collisions in 2016. This data set includes the MPC-EX which enhances $\pi^{0}$ identification at forward rapidity sensitive to low-$x$ partons in the Au nucleus. We are measuring $\pi^{0}$-hadron two particle azimuthal correlations in this data set for pairs separated in rapidity. We used PYTHIA to gain an intuition on how the away-side width is dependent on parton kinematics. In this poster, we will show the results of two-particle correlations in PYTHIA8. We find that the away-side width broadens with the rapidity gap. For triggers in the forward rapidity, the away-side width increases with $x$ of the target. [Preview Abstract] |
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HA.00003: Investigation of a GEM based neutron detector for the MoNA Collaboration Maya Watts, Alder Fulton, Thomas Baumann, Thomas Redpath, Paul Gueye The technological advances of gas detector technologies, especially in the areas of micromegas and gas electron multipliers (GEMs), has enabled sub-mm position accuracy and pico-second timing resolution that have impacted greatly the fields of low and high energy nuclear physics research. The MoNA Collaboration is investigating the development of a Gas Photo-Multiplier (GPM) that will be coupled to plastic scintillators for a next generation neutron detector to complement the existing MoNA-LISA neutron array. Preliminary work includes measurement of the light attenuation in a 1 cm x 10 cm x 110 cm BC408 scintillator using an alpha source, comparison of the data with a Geant4 simulation and the construction and testing of a standard GEM detector. We will provide an update on the progress of this work. [Preview Abstract] |
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HA.00004: Abstract Withdrawn
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HA.00005: Using machine learning techniques to interface between experimental cross sections and QCD theory parameters Eleni Tsitinidi, Rida Shahid, Yasir Alanazi, Manal Almaeen, Michelle Kuchera, Yaohang Li, Wally Melnitchouk, Raghu Ramanujan, Nobuo Sato We map experimental high-energy scattering data to quantum probability distributions that characterize nucleon structure and the emergence of hadrons in terms of the quark and gluon degrees of freedom of QCD. We train three network architectures, a mixture density network (MDN) an autoencoder (AE) and a combination of the two (AEMDN) to address the inverse problem of transforming observable space into theoretical parameter space. Gradually increasing the dimensionality of the parameter space and hyperbox size of possible cross sections, we test the limits of this approach. The mixture density component provides the possibility of multiple-parameter solutions being produced along with their probabilities. This approach has been used to accurately predict collinear parton distribution functions to within one standard deviation and with a chi^2 ~ 1, comparable to the current fitting methods. This tool constitutes a new generation of QCD analysis and will be instrumental for the design and analysis of high-energy experiments. [Preview Abstract] |
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HA.00006: Angular distributions of dark scattered neutrons in plastic scintillators Andrea Robinson, Caroline Capuano, Anthony Kuchera, Paul Gueye Experimental studies of nuclei near the neutron drip line often rely on simulation to interpret the results. The accuracy of simulating neutron scattering in plastic scintillators is imperative, and a previous experiment conducted by the MoNA Collaboration at the Los Alamos Neutron Science Center (LANSCE) highlighted the need to improve these simulations, particularly by increasing knowledge of dark scattered neutrons. The latter occur when neutrons leave insufficient light to be detected, making it difficult to accurately reconstruct their trajectories. One of the goals of this experiment was to measure the angular distribution of dark scattered neutrons using a plastic scintillator array optimized to study dark scattering. 2D (limited to the center of each detector) and 3D (across the entire detector) angular distributions were determined for incoming neutrons with energies of 50-400 MeV. Additionally, preliminary scattering probabilities were calculated. These results provide necessary information needed to more accurately model neutron scattering in plastic scintillators. [Preview Abstract] |
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HA.00007: Abstract Withdrawn
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HA.00008: Unfolding Techniques for Pion-in-Jet Multiplicity Measurements at STAR Elizabeth Jennings The process by which scattered quarks and gluons ``fragment'', or convert into hadrons, remains one of the more mysterious phenomena in modern physics. In particular, the gluon fragmentation function is not well constrained. Measurements of hadrons in jets are a promising tool to shed new light on this phenomenon. The STAR experiment at Brookhaven National Laboratory has measured spin asymmetries of pions in jets to investigate the Collins effect. The spin-averaged multiplicities of pions in jets contribute to the denominator of the Collins asymmetry. Consequently, spin-averaged pion-in-jet multiplicities measured at STAR can provide new information on gluon fragmentation functions and also information useful to global analyses of the Collins effect. Measuring these multiplicities accurately requires a multi-dimensional unfolding, e.g.~to correct for bin migration due to detector efficiency and smearing of jet and pion momentum from finite detector resolution. New data analysis tools such as machine learning and neural networks may provide opportunities to improve these unfolding corrections and reduce systematic uncertainties associated with these analyses. This poster presents the status of comparing several ways to perform these unfolding corrections. [Preview Abstract] |
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HA.00009: Imaging the Nucleon Glue and Sea~ Philip Velie, Brandon Kriesten, Emma Yeats, Fernanda Yepez-Lopez, Simonetta Liuti Imaging the 3D structure of the nucleon is a fundamental goal of every major nuclear physics program. With the rapid development of deeply virtual Compton scattering experiments spanning unprecedented kinematic regimes, there is a need for flexible models of generalized parton distribution functions (GPDs) to place constraints on experimental observables. The proposed low-x electron-ion collider (EIC) kinematic settings are dominated by gluon dynamics; therefore, modelling sea quark and gluon GPDs is crucial. We are developing flexible GPD models of the nucleon glue and sea using a spectator diquark model where we fit the momentum transfer dependence to lattice QCD calculations of the gravitational form factors. Through Fourier transform of the momentum transfer variable t, we can develop femtographic images of the transverse spatial dependence of the glue and sea in the nucleon as it would appear at an EIC. [Preview Abstract] |
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HA.00010: Implementing an equation of state with baryon number, strangeness, and electric charge in relativistic hydrodynamics Lydia Spychalla, Jacquelyn Noronha-Hostler, Travis Dore, Matt Sievert, Debora Mroczek The search for the critical point of the quark gluon plasma (QGP) is limited by our theoretical models at large baryon densities. Relativistic viscous hydrodynamical models have been very successful at describing experimental data at zero baryon density. This project seeks to incorporate the effects of three conserved charges of quantum chromodynamics (baryon number B, strangeness S, and electric charge Q) into the equation of state used in relativistic hydrodynamic simulations in order to study the QGP at large baryon densities. We develop a code with a multidimensional interpolation function and rootfinder, which is done over a 4-dimensional grid and provides a mapping between temperature and chemical potentials, into entropy and the densities of conserved quantities. We couple this code to ICCING, which is a new code that initializes conserved charges from gluon-splitting-generated sea quarks at the LHC, and find that even at these energies the QGP explores a wide range in chemical potentials in the quantum chromodynamics phase diagram. [Preview Abstract] |
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HA.00011: Comparing pion production data to Geant4 simulation Aria Salyapongse, Rebecca Rapp, Diana Parno The COHERENT collaboration uses the Spallation Neutron Source at the Oak Ridge National Laboratory in Tennessee as a source of free neutrinos. These neutrinos are produced when the 1 GeV pulsed proton beam impinges on a liquid mercury target, producing pions, which eventually lead to substantial neutrino production. In the investigation into coherent elastic neutrino-nucleus scattering the collaboration has previously used a 10% error on the calculations, which comes from comparing an older model implementation to world neutrino flux data. In this work an effort has been made to better quantify how well some reference Geant4 physics lists describe the neutrino production process. Here we present the comparisons of the four models of pion production simulation to old and recent pion-production data on different targets to assess the agreement between models and data. [Preview Abstract] |
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HA.00012: Comparison of Kaon distributions in data and MC for CLAS12 Michael Veltre, Harut Avakian, Fatiha Benmokhtar \textbf{Abstract:} \newline It is well known that protons and neutrons are made from constituents called quarks and gluons, which give substructure to these particles. The goal of this project is to make measurements of the transverse momentum distributions of the quarks that provide a three-dimensional map of quarks in the nuclear medium. This knowledge provides the basis of our understanding of protons and neutrons in terms of the dynamics of their internal constituents. This abstract focuses on the study of strange meson production providing access to strange quark distributions and hadronization. This is feasible with semi-inclusive deep inelastic scattering of electrons off proton and deuteron targets in Hall B at Jefferson Lab.~I will be presenting my analysis of Kaons resulting from these SIDIS data and~~compare the results to a full Monte-Carlo simulation. I will be mainly focusing on Kaon's momentum and angular distributions.~~~~ [Preview Abstract] |
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HA.00013: $\backslash $pardApplication of Clustering ML Algorithms on Neutron Lifetime Data$\backslash $pard Eli Carter h $-abstract-$\backslash $pardThe BL2 experiment is an absolute counting experiment that hopes to experimentally find the neutron lifetime using the beam method. In BL2, different classes of events are recorded by the system. These can include multiple protons being trapped at once, neutrons decaying outside the trapping area, and cosmic rays interfering. Previously, mathematical transformations and filters were used to separate out the true and multiple hits from noise. These methods can still leave ambiguity between different types of events and require a user to determine which filter to apply. This paper will explore the application of clustering algorithms to the data, using it to group the different types of events. The KMEANS, DBSCAN, and HDBSCAN algorithms will be applied to the data, analyzed, and the best will be tested on generated pseudo data to find its accuracy.$\backslash $pard-/abstract-$\backslash $\tex [Preview Abstract] |
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HA.00014: Determining the feasibility of using jets with large resolution parameters to analyze heavy ion collisions with sPHENIX Christopher Aviles Bramer The study of jets produced in heavy ion collisions can provide insight into the properties of the medium of deconfined quarks and gluons created by the very same collisions. Jets are streams of elementary particles sometimes produced by the collisions of high energy partons that then fragment and hadronize. These jets (which can be described by pQCD assuming a high enough momentum) strongly interact with the quark-gluon plasma (QGP) formed during heavy ion collisions, thus providing information about the properties of QGP. Thus, it is important to know if analyzing collisions using jets with reclustered large resolution parameters would be beneficial to understanding QGP. Using sPHENIX simulation data with 200GeV as the center of mass energy could provide information about the viability of different sizes of jet resolution parameters as used to analyze the results of heavy ion collisions. This would be accomplished by clustering jets with smaller resolution parameters (R $=$ 0.2 or smaller) together to create a clustered jet with a much larger parameter (R $=$ 0.6 or larger), and then reporting on the jet energy scale and jet resolution that results from such measurements. [Preview Abstract] |
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HA.00015: Block construction and testing for the sPHENIX electromagnetic calorimeter Mina Mazeikis The sPHENIX detector is the successor to the Pioneering High Energy Nuclear Interacting Experiment (PHENIX) detector at Brookhaven National Laboratory’s Relativistic Heavy Ion Collider (RHIC). The sPHENIX detector will measure quark-gluon plasma properties and is composed of layers of sub detectors, one of which is the electromagnetic calorimeter, or the EMCal. The EMCal measures the position and energy of photons, electrons, and positrons, and is constructed of absorber blocks that contain scintillating fibers embedded in a mixture of tungsten powder and epoxy. Variations in block shape allow for an arrangement that gives the EMCal full azimuthal coverage. The EMCal will consist of 6144 EMCal blocks with a total of 24576 readout channels providing the required resolution. The Nuclear Physics Lab at UIUC constructs the EMCal blocks and performs quality control testing before shipping them to BNL. Beginning with raw materials, the block construction process is complex and continuously evolving to overcome complications that arise when manufacturing this state-of-the-art calorimeter. This poster will discuss the individual steps of EMCal block construction and the testing process. [Preview Abstract] |
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HA.00016: Study of the Chiral Magnetic Effect with Pair Invariant Mass Using Anomalous-Viscous Fluid Dynamics Leon Tong High-energy heavy-ion collisions aim to create a deconfined quark gluon plasma (QGP). The QGP may acquire a chirality imbalance through vacuum transition, and manifest a charge separation along the magnetic field generated by spectator protons, known as the chiral magnetic effect (CME) [1]. The CME-induced charge separation has been extensively searched for using azimuthal correlations between two charged hadrons ($\Delta \gamma )$. In particular, the invariant mass of the hadron pair has been explored to relate the observed $\Delta \gamma $ to non-CME mechanisms, such as resonance decays [2]. We shall apply the same analysis to heavy-ion events simulated by the anomalous-viscous fluid dynamics (AVFD) model, which can be implemented with and without the CME signal. By comparing the two cases, we want to determine the roles of the CME signal and the resonance decays in the landscape of the pair invariant mass, and help interpret the experimental data. [1] D. Kharzeev, Progress in Particle and Nuclear Physics 75 (2014) 133. [2] J. Adam [STAR Collaboration], arXiv:2006.05035. [Preview Abstract] |
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HA.00017: \textsc{THE ORIGIN OF HADRON PRODUCTION IN DEEP INELASTIC SCATTERING} Scott Dolan, Alexei Prokudin, Leonard Gamberg We discuss the impact of data selection on the determination of non-perturbative transverse momentum dependence in semi-inclusive deep-inelastic scattering. In particular, we implement the recently introduced criteria that allow selection of data predominantly in the current fragmentation region, and apply this framework to pion and kaon multiplicity data from HERMES and COMPASS experiments. We compare the resulting unpolarized transverse momentum dependent distributions with previous extractions, and discuss the potential impact of the data selection criteria on future experiments at Jefferson Lab 12 and the Electron-Ion Collider. [Preview Abstract] |
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