Bulletin of the American Physical Society
APS April Meeting 2021
Volume 66, Number 5
Saturday–Tuesday, April 17–20, 2021; Virtual; Time Zone: Central Daylight Time, USA
Session L12: Hadronic Physics IILive

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Sponsoring Units: DNP Chair: Ramona Vogt, LLNL/UC Davis 
Sunday, April 18, 2021 3:45PM  3:57PM Live 
L12.00001: The Dterm and Force Densities on the Light Front Adam Freese, Gerald Miller Spatial densities of local currents such as energy, momentum, pressure and shear forces are defined through matrix elements of local operators between physically realizable states. We show that one can relate spatial densities to Fourier transforms if light front coordinates are used, and that the spatial description is limited to the two spatial dimensions transverse to the light front. The relationships of the twodimensional mass density, pressure, and shear force densities to the gravitational form factors are given, and stability conditions for the Dterm are derived on the light front. [Preview Abstract] 
Sunday, April 18, 2021 3:57PM  4:09PM Live 
L12.00002: Interpolating 't Hooft Model between the Instant Form Dynamics and the LightFront Dynamics Bailing Ma, ChuengRyong Ji The $1+1$ dimensional QCD in the large $N_c$ limit, known as the 't Hooft model, exhibits confinement as well as mass gap phenomena. It was originally formulated in the Light Front Dynamics (LFD), and utilizing the simplifications of the LFD formulation, such as the boost invariance, 't Hooft was able to solve the model even analytically. Since then, it was formulated also in the Instant Form Dynamics (IFD) and later on solved numerically in the moving frames of the meson. In this work, we reformulate the 't Hooft model in the quantization form interpolating between the LFD and the IFD. Introducing an interpolation angle parameter, $\delta$, we connect the ordinary IFD formalism with the LFD where the vacuum structure is very distinguished. We present the single quark's mass gap equations, along with their solutions, before showing the quarkantiquark bound state equations. While the bound state equation depends on the dynamical forms, the mass spectra of the mesons solved from it turn out to be independent of the value of $\delta$ as expected. We present the solutions of the meson mass spectra, as well as their wavefunction solutions in different interpolating forms. [Preview Abstract] 
Sunday, April 18, 2021 4:09PM  4:21PM Live 
L12.00003: Valence Structure of Pion from Lattice QCD: Physical Mass, Chiral Quarks Xiang Gao We study pion valence structure from lattice QCD using three mixed action ensambles including a physical pion mass with fine lattice spacings of a $=$ 0.04, 0.06 and 0.076 fm. Our analysis use ratiobased schemes to renormalize the equaltime bilocal quarkbilinear matrix elements. We extract first few moments and reconstruct the xdependent PDF using NNLO leadingtwist perturbative matching formula, and investigate the mass dependence as well as approaching continuum limit. Two DomainWall ensambles are used to cross check our estimate. [Preview Abstract] 
Sunday, April 18, 2021 4:21PM  4:33PM Live 
L12.00004: Pion Structure from Lattice QCD Joseph Karpie, Kostas Orginos, Savvas Zafeiropoulos, Raza Sufian, Colin Egerer, David Richards, JianWei Qiu The partonic structure of the pion is of particular theoretical interest due to its role as the lightest bound state and a Nambu Goldstone boson. Few experimental results, compared to the nucleon, are available for determining the shape of the valence quark parton distribution and the shape of the large $x$ behavior differs between different analyses. New approaches in Lattice QCD provide additional data for determining the shape of the quark parton distribution. We will present recent calculations of two observables, the parton pseudodistribution function and the Lattice Cross Section, which factorize into the parton distribution function (PDF), just as experimental cross sections do. The resulting PDFs are both consistent with each other and with phenomenological analyses. A study of the systematic errors with in the calculation are presented. [Preview Abstract] 
Sunday, April 18, 2021 4:33PM  4:45PM Live 
L12.00005: Towards HighPrecision Parton Distributions From Lattice QCD via Distillation Colin Egerer, Christos Kallidonis, Konstantinos Orginos, Anatoly Radyushkin, David Richards, Savvas Zafeiropoulos The pseudodistribution formalism is one such lattice methodology capable of extracting lightcone distributions from matrix elements of suitably constructed Euclidean nonlocal operators of a spacelike extent. Leveraging the distillation spatial smearing program, we extract the unpolarized isovector valence quark PDF of the nucleon via a direct 1loop matching of the Ioffetime pseudodistribution and model PDFs. We benchmark the efficacy and systematics inherent to this choice by also extracting the PDF from the matched lightcone Ioffetime distribution. The tempering of excitedstates and improved spatial sampling afforded by distillation lead to higherquality Ioffetime distributions relative to the literature, and exhibit DGLAP evolution in the shortdistance regime. We explore the role of highertwist effects by extending the spacelike Wilson lines present in our calculation to regimes wherein polynomial$z^2$ corrections are expected to be large. Comparisons are made between PDFs extracted from our analysis and those from phenomenological determinations. [Preview Abstract] 
Sunday, April 18, 2021 4:45PM  4:57PM Live 
L12.00006: Systematic Extraction of Pion Parton Distributions Using Threshold Resummation Patrick Barry, ChuengRyong Ji, Nobuo Sato, Wally Melnitchouk Following our recent Monte Carlo determination of the pionâ€™s PDFs from DrellYan (DY) and leading neutron electroproduction data, we extend the analysis by including effects from threshold resummation. At higher orders in the strong coupling, $\alpha_s$, large logarithmic corrections due to soft gluon emissions become important in the $q\bar{q}$ channel of the DY partonic cross section near threshold, which can be summed over all orders of $\alpha_s$. However, different prescriptions exist for how the threshold resummation is implemented, for instance, using varying levels of approximation in the Minimal Prescription with cosine, expansion, and double Mellin methods. We report the Monte Carlo results of the first simultaneous fit to the valence, sea, and gluon distributions in the pion taking into account the ambiguities in the resummation calculations. We present the wide ranges of valence distributions at large $x$ and the effective behavior of the valence distribution as $x$ approaches $1$. [Preview Abstract] 
Sunday, April 18, 2021 4:57PM  5:09PM Live 
L12.00007: Array of Uncommon/Unusual Subatomic Particles Gh. Saleh, M. J. Faraji The smallest known primary building blocks of the physical universe and the interactions between them have been studied by Particle Physics. In studying of subatomic particles, the focus is on single particles or small groups of particles, not the billions of atoms or molecules which they made an entire universe. In Saleh Theory Photon is a particle with constant rest mass. It is the primary building blocks of electrons and protons and neutrons and therefore the physical universe. Photon is an object that is ejects from the stars at a very high speed and is scattered in the environment. Photons are usually separated from the stars lonely, but sometimes it would be separate in pairs, triples, multiples, and hundreds and thousands. Among a single photon, electron and large protons (thousands and millions of aggregated photons), there is a set of uncommon/unusual photons that do not have a specific shape or model, like interstellar objects between celestial objects, such as neutrinos, $\pi $ mesons, etc. They usually have dozens of names, properties and symbols. In this article we have presented our study about different type of theses particles and their properties. [Preview Abstract] 
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