# Elementary Particles and Fields and String Theory Commons™

## All Articles in Elementary Particles and Fields and String Theory

944 full-text articles. Page 1 of 34.

2021 University of Mississippi

#### Curved Spacetime In The Causal Set Approach To Quantum Gravity, Ayush Dhital

##### Honors Theses

Causal Set theory is an approach to quantum gravity. In this approach, the spacetime continuum is assumed to be discrete rather than continuous. The discrete points in a causal set can be seen as a continuum spacetime if they can be embedded in a manifold such that the causal structure is preserved. In this regard, a manifold can be constructed by embedding a causal set preserving causal information between the neighboring points. In this thesis, some of the fundamental properties of causal sets are discussed and the curvature and dimension information of Minkowski, de Sitter, and Anti-de Sitter spaces is ...

Exploring Manifoldlike Causal Sets And Their Dimensions, 2021 University of Mississippi

#### Exploring Manifoldlike Causal Sets And Their Dimensions, Santosh Bhandari

##### Honors Theses

Causal Set Theory is an approach to quantum gravity that tries to replace the continuum spacetime structure of general relativity with the spacetime that has the property of discreteness and causality. From the standpoint of causal set theory, our spacetime is made up of discrete points that are causally related to one another. A causal set is said to be manifoldlike if it can be faithfully embedded in a Lorentzian manifold. In this thesis, some of the fundamental properties of causal sets are discussed. The first chapter is devoted to the historical background of quantum gravity with a discussion of ...

2021 University of Massachusetts Amherst

#### A Search For New Resonances Decaying Into A Weak Vector Boson And A Higgs Boson In Hadronic Final States With The Atlas Detector At The Large Hadron Collider, Zachary Alden Meadows

##### Doctoral Dissertations

A search for heavy resonances decaying to a $W$ or $Z$ boson and a Higgs boson in the final state is described. The search uses $139\ \mathrm{fb}^{-1}$ of proton-proton collision data at $\sqrt{s} = 13$ TeV collected by the ATLAS detector at the CERN Large Hadron Collider from 2015 to 2018. The results are presented in terms of constraints on a simplified model with a heavy vector triplet. Upper limits are set on the production cross-section times branching fraction for resonances decaying into a W/Z boson and a Higgs boson in the mass range between 1.2 ...

La Teoria Relativista De La Gravitacion De Einstein, 2021 Livre de Lyon

#### La Teoria Relativista De La Gravitacion De Einstein, Manuel Almeyda Arroyo

##### Science and Mathematical Science

No abstract provided.

Role Of Boundary Conditions In Quantum Computations Of Scattering Observables, 2021 Old Dominion University

#### Role Of Boundary Conditions In Quantum Computations Of Scattering Observables, Raúl A. Briceño, Juan V. Guerrero, Maxwell T. Hansen, Alexandru M. Sturzu

##### Physics Faculty Publications

Quantum computing may offer the opportunity to simulate strongly interacting field theories, such as quantum chromodynamics, with physical time evolution. This would give access to Minkowski-signature correlators, in contrast to the Euclidean calculations routinely performed at present. However, as with present-day calculations, quantum computation strategies still require the restriction to a finite system size, including a finite, usually periodic, spatial volume. In this work, we investigate the consequences of this in the extraction of hadronic and Compton-like scattering amplitudes. Using the framework presented in Briceno et al. [Phys. Rev. D 101, 014509 (2020)], we estimate the volume effects for various ...

Beam Spin Asymmetry In Semi-Inclusive Electroproduction Of Hadron Pairs, 2021 Old Dominion University

#### Beam Spin Asymmetry In Semi-Inclusive Electroproduction Of Hadron Pairs, M. J. Amaryan, M. Hattawy, S. E. Kuhn, Y. Prok, J. Zhang, Z. W. Zhao, Et Al., Clas Collaboration

##### Physics Faculty Publications

A first measurement of the longitudinal beam spin asymmetry ALU in the semi-inclusive electroproduction of pairs of charged pions is reported. ALU is a higher-twist observable and offers the cleanest access to the nucleon twist-3 parton distribution function e(x). Data have been collected in the Hall-B at Jefferson Lab by impinging a 5.498-GeV electron beam on a liquid-hydrogen target, and reconstructing the scattered electron and the pion pair with the CLAS detector. One-dimensional projections of the AsinLUϕR moments are extracted for the kinematic variables of interest in the valence quark region. The understanding ...

Energy-Dependent Π⁺Π⁺Π⁺ Scattering Amplitude From Qcd, 2021 Old Dominion University

#### Energy-Dependent Π⁺Π⁺Π⁺ Scattering Amplitude From Qcd, Maxwell T. Hansen, Raúl A. Briceño, Robert G. Edwards, Christopher E. Thomas, David J. Wilson

##### Physics Faculty Publications

Focusing on three-pion states with maximal isospin π⁺π⁺π⁺, we present the first nonperturbative determination of an energy-dependent three-hadron scattering amplitude from first-principles QCD. The calculation combines finite-volume three-hadron energies, extracted using numerical lattice QCD, with a relativistic finite-volume formalism, required to interpret the results. To fully implement the latter, we also solve integral equations that relate an intermediate three-body K matrix to the physical three-hadron scattering amplitude. The resulting amplitude shows rich analytic structure and a complicated dependence on the two-pion invariant masses, represented here via Dalitz-like plots of the scattering rate.

Neural-Network Analysis Of Parton Distribution Functions From Ioqffe-Time Pseudodistributions, 2021 Old Dominion University

#### Neural-Network Analysis Of Parton Distribution Functions From Ioqffe-Time Pseudodistributions, Luigi Del Debbio, Tommaso Giani, Joseph Karpie, Kostas Orginos, Anatoly Radyushkin, Savvas Zafeiropoulos

##### Physics Faculty Publications

We extract two nonsinglet nucleon Parton Distribution Functions from lattice QCD data for reduced Ioffe-time pseudodistributions. We perform such analysis within the NNPDF framework, considering data coming from different lattice ensembles and discussing in detail the treatment of the different source of systematics involved in the fit. We introduce a recipe for taking care of systematics and use it to perform our extraction of light-cone PDFs.

2020 Chitkara University School of Engineering and Technology, Chitkara University, Solan Himachal Pradesh, India

#### Published Research Documents In Nuclear And High Energy Physics From 1996-2019: A Bibliometric Analysis Of Leading Countries In Comparison With India, Ishwar Dutt Sharma Dr

##### Library Philosophy and Practice (e-journal)

A bibliometric analysis of scientific research production of the top five most productive countries in comparison with India in nuclear and high energy physics is presented during the period 1996-2019 using Scopus-linked SCImago electronic database. To validate the present study, some selected bibliometric indicators such as published documents, their citations and citations per document has been studied. In total, 769180 research documents were published worldwide in journal, conference proceedings and in book series. United States (16.47%), Germany(8.64%), Japan (6.65%), China (6.41%) and Russian Federation (5.89%) were the top most productive countries rankwise, whereas India ...

2020 University of Massachusetts Amherst

#### Searching For New Physics At Colliders And From Precision Measurements, Yong Du

##### Doctoral Dissertations

Beyond the great triumph of the Standard Model of particle physics, several fundamental questions remain unknown with the framework of the Standard Model. Among them are the non-zero neutrino masses, the dark matter and the baryon asymmetry of the Universe. Answers to these questions require new physics beyond the Standard Model and searching for the new physics beyond the SM has been a major task for modern particle physicists. The signal of this new physics can be searched through colliders, low- and high-energy precision measurements, as well as precision cosmological observation. Here I present my work in searching for the ...

Introduction To Classical Field Theory, 2020 Department of Physics, Utah State University

#### Introduction To Classical Field Theory, Charles G. Torre

##### All Complete Monographs

This is an introduction to classical field theory. Topics treated include: Klein-Gordon field, electromagnetic field, scalar electrodynamics, Dirac field, Yang-Mills field, gravitational field, Noether theorems relating symmetries and conservation laws, spontaneous symmetry breaking, Lagrangian and Hamiltonian formalisms.

Physics 516: Electromagnetic Phenomena (Spring 2020), 2020 University of Pennsylvania

#### Physics 516: Electromagnetic Phenomena (Spring 2020), Philip C. Nelson

##### Department of Physics Papers

These course notes are made publicly available in the hope that they will be useful. All reports of errata will be gratefully received. I will also be glad to hear from anyone who reads them, whether or not you find errors: pcn@upenn.edu.

2020 Old Dominion University

#### Measurement Of Pion-Pion Final State Interactions In Η → Π +Π −Γ With Clas At Jefferson Lab, Torri C. Jeske

##### Physics Theses & Dissertations

Decays of pseudoscalar mesons proceed from the chiral anomaly, which arises from spontaneous chiral symmetry breaking. In the limit of massless quarks (chiral limit), the η → π +π −γ the decay width is determined solely by the box anomaly term in the Wess Zumino Witten Lagrangian. Since the physical quarks are not massless, the decay region of the η meson is far from the chiral limit and thus proper inclusion of the momentum dependence is essential to reproduce the measured decay width. Several theoretical frameworks have been proposed to describe these interactions. We report a new measurement of the α ...

Deeply Virtual Compton Scattering At Hall A, Jefferson Lab, 2020 Old Dominion University

#### Deeply Virtual Compton Scattering At Hall A, Jefferson Lab, Mohamed Nuhman Hashir Rashad

##### Physics Theses & Dissertations

The Standard Model of particle physics defines quarks and leptons as the basic building blocks of all matter. The interaction between them are mediated by force carrying gauge bosons. Quantum ChromoDynamics (QCD), the theory that explains the strong interaction is still not complete enough to derive the physical observables of a Quark-Gluon system from the fundamental degrees of freedom of it’s constituents. Experimentally observable single particle densities provide important insights into our understanding of the quark-gluon system and hence help fill in the gaps of QCD. Generalized Parton Distributions (GPDs) provide simultaneous information of both spacial and longitudinal momentum ...

2020 University of New Mexico

#### From Wave Propagation To Spin Dynamics: Mathematical And Computational Aspects, Oleksii Beznosov

##### Mathematics & Statistics ETDs

In this work we concentrate on two separate topics which pose certain numerical challenges. The first topic is the spin dynamics of electrons in high-energy circular accelerators. We introduce a stochastic differential equation framework to study spin depolarization and spin equilibrium. This framework allows the mathematical study of known equations and new equations modelling the spin distribution of an electron bunch. A spin distribution is governed by a so-called Bloch equation, which is a linear Fokker-Planck type PDE, in general posed in six dimensions. We propose three approaches to approximate solutions, using analytical and modern numerical techniques. We also present ...

Precision Measurement Of The Beam-Normal Single-Spin Asymmetry In Forward-Angle Elastic Electron-Proton Scattering, 2020 William & Mary

#### Precision Measurement Of The Beam-Normal Single-Spin Asymmetry In Forward-Angle Elastic Electron-Proton Scattering, Qweak Collaboration, David Armstrong, Wouter Deconinck, K. Bartlett, J. C. Cornejo, R. D. Carlini, James F. Dowd, J. M. Finn, Valerie M. Gray, K. Grimm, J. R. Hoskins, J. P. Leckey, Jeong Han Lee, Joshua A. Magee, Victoria F. Owen

##### Arts & Sciences Articles

A beam-normal single-spin asymmetry generated in the scattering of transversely polarized electrons from unpolarized nucleons is an observable related to the imaginary part of the two-photon exchange process. We report a 2% precision measurement of the beam-normal single-spin asymmetry in elastic electron-proton scattering with a mean scattering angle of theta_lab = 7.9 degrees and a mean energy of 1.149 GeV. The asymmetry result is B_n = -5.194 +- 0.067 (stat) +- 0.082 (syst) ppm. This is the most precise measurement of this quantity available to date and therefore provides a stringent test of two-photon exchange models at far-forward scattering ...

2020 The Graduate Center, City University of New York

#### Particle Dynamics In Anti-De Sitter Space By Eih Method, Jiusi Lei

##### Dissertations, Theses, and Capstone Projects

Following the work of Einstein, Infeld and Hoffmann, we show that particle dynamics in Anti-de Sitter spacetime can be built up by regarding singularities in spacetime manifold as the source of particles.

Since gauge fields play a foundational role in the action, the singularities are chosen to be point-like instantons. Their winding number, defined by an integration on the spheres surrounding those singularities, will turn out to be related to their masses. And their action, derived from the Chern-Simons forms, will be a co-adjoint orbit action, with group element g ∈ SO(4, 2) describing the collective coordinates of the particle ...

2020 Old Dominion University

#### Simulation And Development Of The Radial Time Projection Chamber For The Bonus12 Experiment In Clas12, Nathan M. Dzbenski

##### Physics Theses & Dissertations

Knowledge of the structure of nucleons (i:e: protons and neutrons) is a central topic of interest to nuclear/particle physicists. Much more is known about the structure of the proton than the neutron due to the lack of high-density free neutron targets. The Barely Off-shell Nucleon Structure experiment (BONuS12) at Jefferson Lab (JLab) is a second generation experiment upgraded/optimized to advance our knowledge of the neutron's structure using the deep-inelastic scattering of electrons off deuterium. Typically, since deuterium is a nuclear target, corrections for off-shell and nuclear binding effects must be taken into account in order to ...

2020 The Graduate Center, City University of New York

#### Generalized Four-Dimensional Effective Hadronic Supersymmetry Based On Quantum Chromodynamics (Qcd), Enxi Yu

##### Dissertations, Theses, and Capstone Projects

New discovery in multiple laboratories around the globe has shown a supersymmetry between hadrons—baryons and mesons. In order to generalize the phenomenological hadronic supersymmetry, the spin-flavor SU(6) symmetry need an extension. This thesis present how we can extend SU(6) symmetry so that hadronic supersymmetry can be included. In the future, this extension can be also applied to pentaquark and tetraquark bags, for which there is an ongoing research in laboratories.

Small-X Qcd Calculations With A Biased Ensemble, 2020 The Graduate Center, City University of New York

#### Small-X Qcd Calculations With A Biased Ensemble, Gary Kapilevich

##### Dissertations, Theses, and Capstone Projects

In this dissertation, I will argue that we can study functional fluctuations in unintegrated gluon distributions, in the MV model as well as JIMWLK, using reweighting techniques, which will allow me to calculate QCD observables with "biased ensembles". This technique will enable me to study rare functional configurations of the gluon distributions, that might have been selected for in, for example, the centrality criteria used by the ATLAS and ALICE collaborations. After a review of these techniques, as well as a review of QCD physics at high energy in general, I will use biased ensembles to compute observables in two ...