# Bulletin of the American Physical Society

# 87th annual meeting of the Southeastern Section of the APS

## Volume 65, Number 19

## Thursday–Friday, November 5–6, 2020; Virtual

## Session B03: Medium Energy Nuclear Physics 1 |
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Chair: Lamiaa El-Fassi, Mississippi State University |

Thursday, November 5, 2020 11:00AM - 11:12AM |
B03.00001: Resonant Hadronic Form Factors Keegan Sherman, Raul Briceno, Andrew Jackura, Felipe Ortega-Gama One of the primary goals of modern day hadronic physics is to understand how quarks and gluons align themselves to form the states of quantum chromodynamics (QCD). However, due to confinement, quarks and gluons cannot be observed directly. Thus, we are forced to study the structure of the states they form, hadrons. The simplest structural information we can obtain are form factors, for example elastic electromagnetic form factors which give us access to information about the shape of these states, like the radius. For stable hadrons, like the proton, measuring form factors is a well understood process. However, most hadrons are unstable states called resonances which decay on the order of $10^{-23}$ seconds. Therefore, if we wish to measure form factors of these states, we must also consider their short lifetime. Here we introduce a new amplitude from which it would be possible to extract resonant hadronic form factors. [Preview Abstract] |

Thursday, November 5, 2020 11:12AM - 11:24AM |
B03.00002: Transitions of Two-body States in a Box. Felipe Ortega-Gama, Raul Briceno, Andrew Jackura, Keegan Sherman The proton and neutron, along with their excitations, are some of the earliest known bound states of quarks that are described by the theory of quantum chromo-dynamics (QCD). Although their properties cannot be calculated using perturbative analytical tools, the determination of non-perturbative dynamics can be carried out with Lattice QCD (LQCD), a numeric implementation of QCD. LQCD relies on a discretization of a finite volume (FV) spacetime to regularize and calculate observables. Even when most of the uncertainties are systematically improvable, there are certain quantities that suffer from unavoidable substantial FV effects. In this talk I describe the development of a formalism that corrects the FV effects of transitions that involve states of two hadrons. After that, I will comment on the need to constrain the analytical form of the infinite volume amplitude which describes these two-hadron interactions to be able to correctly determine the response of the resonant excitations. These efforts seek to produce a quantitative description of the resonant nuclear spectrum, make definite statements about their structural origin, and resolve puzzles that obscure our current understanding of QCD. [Preview Abstract] |

Thursday, November 5, 2020 11:24AM - 11:36AM |
B03.00003: Loop Corrections to Baryon Properties in Relativistic Chiral SU(3) Effective Theory Marston Copeland, Chueng-Ryong Ji, Wally Melnitchouk We calculate the pseudoscalar meson loop contributions to the properties of flavor SU(3) octet and decuplet baryons using a relativistic chiral effective theory framework consistent with Lorentz and gauge invariance. A finite range regularization prescription is applied and compared with dimensional regularization to show better convergence at higher meson masses. Renormalization prescriptions are discussed and renormalized expressions are fit to lattice QCD data. Results showing loop contributions to baryon masses, sigma terms, and flavor symmetries in parton distributions are presented. Results are also compared with previous heavy baryon (nonrelativistic) calculations in the literature. [Preview Abstract] |

Thursday, November 5, 2020 11:36AM - 11:48AM |
B03.00004: Imaging the Nucleon Glue and Sea Philip Velie, Simonetta Liuti, Brandon Kriesten, Emma Yeats, Fernanda Yepez-Lopez 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] |

Thursday, November 5, 2020 11:48AM - 12:00PM |
B03.00005: Modeling the DVCS Cross Section with Deep Learning Brandon Kriesten, Jake Grigsby, Joshua Hoskins, Simonetta Liuti, Peter Alonzi Imaging the 3D partonic structure of the nucleon is a fundamental goal of every major nuclear experimental program, such as the electron ion collider (EIC). Ji first proposed deeply virtual Compton scattering (DVCS) as a probe for imaging the spatial distribution of the partons by fourier transform of the exchanged momentum transfer between the initial and final proton. The extraction of observables from deeply virtual exclusive reactions in a clear and concise formalism was a necessity. We recently presented a completely covariant description of the DVCS process. In our helicity formalism, we extract the Compton form factors H and E separately using a generalization of the Rosenbluth method such that the dependence on Q2 is clear. In addition, using state of the art neural network techniques, we perform an analysis of the DVCS cross section and show initial steps toward a global neural network extraction of Compton form factors. [Preview Abstract] |

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