# Elementary Particles and Fields and String Theory Commons™

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

1,026 full-text articles. Page 1 of 36.

2021 University of Massachusetts Amherst

#### A Search For Exotic Higgs Decays Or: How I Learned To Stop Worrying And Love Long-Lived Particles, Jackson Burzynski

##### Doctoral Dissertations

A novel search for exotic decays of the Higgs boson to pairs of long-lived neutral particles, each decaying to a bottom quark pair, is performed using 139 fb-1 of sqrt{s} = 13 TeV proton-proton collision data collected with the ATLAS detector at the LHC. Events consistent with the production of a Higgs boson in association with a leptonically-decaying Z boson are analyzed. Long-lived particle (LLP) decays are reconstructed from inner detector tracks as displaced vertices with high mass and track multiplicity relative to Standard Model processes. The analysis selection requires the presence of at least two displaced vertices, effectively ...

2021 University of Massachusetts Amherst

#### Search For Resonant Pair Production Of Higgs Bosons In The Four B-Quark Final State With The Atlas Detector, Dale Abbott

##### Doctoral Dissertations

A search for heavy resonances decaying to Higgs boson pairs in the $b\overline{b}b\overline{b}$ final state with 139 $fb^{-1}$ of LHC proton-proton (pp) collision data collected at $\sqrt{s} = 13$ TeV obtained by the ATLAS detector during the 2015-2018 time period. Two benchmark signals are studied, both of which decay into a Higgs boson pair: a spin-2 Kaluza-Klein Graviton and a scalar resonance. This thesis studies high transverse momentum (boosted) resonances, which range from 900-5000 GeV. No statistically significant excesses are observed and the results are found to be compatible with the Standard Model. Upper ...

2021 University of Tennessee, Knoxville

#### A Study Of Systematic Uncertainties For A Photon-Like Low Energy Excess Search At Microboone, Gray Yarbrough

##### Doctoral Dissertations

The premise of this dissertation is the study of and reduction of systematic uncertainties in the MicroBooNE experiment at the Fermi National Accelerator Laboratory. MicroBooNE is a short-baseline oscillation experiment using the innovative liquid argon time projection chamber technology to study, with unprecedented detail, neutrino interactions. The primary goal of MicroBooNE is the investigation of the MiniBooNE low energy excess (LEE) of electron neutrino events, a result which raised fundamental questions on the existence of sterile neutrinos with broad implications to the field of particle physics. The principal study of this dissertation is a study of systematics as part of ...

2021 Northeastern Illinois University

#### Acoustic Parameters As Discriminators Of Wall Events In Pico Dark Matter Search Data, Lucia Volkova

##### University Honors Program Senior Projects

Bubble chambers are one of several detector types that particle physicists use to search for the as-yet-undetected dark matter. The PICO collaboration – formed from the merger of the similar PICASSO and COUPP experiments – runs such a bubble detector using superheated fluorocarbons (with and without iodine). Bubbles that form along chamber walls exhibit different behavior than those which nucleate in the bulk of the target liquid due to shape distortions from the wall boundary; in previous analyses when searching for dark matter, these wall events have been cut from the data to control for the differing behavior using information available from ...

Calculation And Modeling Of The Neutron’S Magnetic Moment, 2021 University of Tennessee, Knoxville

#### Calculation And Modeling Of The Neutron’S Magnetic Moment, Abhyuday Sharda

##### Masters Theses

This thesis presents the current state of neutron magnetic moment calcu- lations. It details the development of calculations through history. It also delves into an experiment measuring the neutron magnetic moment. It ex- plores other methods by which calculations can be improved to get a better/ more accurate number. The conclusion is that there are still a lot of areas unexplored in context of the calculation of neutron magnetic moment and areas relevant to be worked upon are detailed.

Analysis Of Possible Hybrid Meson Decay, 2021 Union College - Schenectady, NY

#### Analysis Of Possible Hybrid Meson Decay, Jasper Bergh

##### Honors Theses

This research looked at data from the GlueX experiment at the Thomas Jefferson National Accelerator Facility to search for evidence of the π1(1600) particle, an exotic hybrid meson, decaying to an eta' and π0. We specifically looked into decays of the eta' to an eta, π+, and π-, with the eta decaying to 3 πo's. We successfully reconstructed an eta from the 3 πo's, and an eta' from the eta, π+, and π-. However, we did not observe the π1(1600), but, a 6:1 ratio of signal to background in the eta' mass. With more statistics ...

2021 Syracuse University

#### Beyond The Standard Models Of Particle Physics And Cosmology, Gabriele Rigo

##### Dissertations - ALL

Despite their numerous successes both from the theoretical and experimental point of view, conceptual and observational evidence suggests the Standard Models of Particle Physics and Cosmology should be considered incomplete theories, reliable only within their well-defined regime of validity. This dissertation covers various possible extensions of those models from the theoretical, phenomenological and model-building perspective. The topics analyzed range from extra-dimensional approaches to the hierarchy problem, to the AdS/CFT description of perturbative anomaly inflow, and new probes of vacuum energy in neutron stars and gravitational waves.

2021 The University of Western Ontario

#### Field Theories From Physical Requirements: Noether's First Theorem, Energy-Momentum Tensors And The Question Of Uniqueness, Mark Robert Baker

##### Electronic Thesis and Dissertation Repository

An axiomatic approach to physics is proposed for obtaining classical gauge theories from a common set of physical requirements based on standard features of special relativistic field theories such as gauge invariance, conformal invariance and being in four dimensions. This approach involves the use of Noether's first theorem to directly obtain a unique, complete set of equations from the symmetries of the action. However, implementation of this procedure is obstructed by issues of ambiguity and non-uniqueness associated with the conserved tensors in the majority of special relativistic field theories. In the introductory chapter, we outline the three major problems ...

2021 Macalester College

#### Model Of Electromagnetic Waves In An Axion-Induced Parity Symmetry Violation, Sarah Lipstone

##### Macalester Journal of Physics and Astronomy

Axion particles have been postulated to resolve the strong CP problem in Quantum chromodynamics. The axion field may double as the inflaton field that produces cosmic inflation. In this project, we use a combination of analytical and numerical analysis to study how axion-induced parity symmetry violation affects the dynamics of electromagnetic waves.

Towards Neutron Transformation Searches, 2021 The Univeristy of Tennessee

#### Towards Neutron Transformation Searches, Joshua L. Barrow

##### Doctoral Dissertations

To probe the origins of the baryon asymmetry, baryon number violation, the last unconfirmed Sakharov condition, must be definitively observed experimentally. Similarly, the nature of dark matter is currently unknown, and calls out for new candidates to be investigated. Each of these issues can be considered through the study of neutron transformations.

Some rare baryon number violating processes, such as neutron-antineutron transformations, are expected to probe baryogenesis. Here, I show progress on this discovery target through construction of more accurate Monte Carlo models, the design of future detectors, creation of more complete atmospheric neutrino background simulations, and use of automated ...

2021 University of Tennessee, Knoxville

#### Measuring Electron Diffusion And Constraining The Neutral Current Π0 Background For Single-Photon Events In Microboone, Andrew Mogan

##### Doctoral Dissertations

Liquid Argon Time Projection Chambers (LArTPCs) are a rising technology in the field of experimental neutrino physics. LArTPCs use ionization electrons and scintillation light to reconstruct neutrino interactions with exceptional calorimetric and position resolution capabilities. Here, I present two analyses conducted in the MicroBooNE LArTPC at Fermilab: a measurement of the longitudinal electron diffusion coefficient, DL, in the MicroBooNE detector and a constraint of the systematic uncertainty on MicroBooNE's single-photon analysis due to the dominant neutral current (NC) π0 background. Longitudinal electron diffusion modifies the spatial and timing resolution of the detector, and measuring it will help correct for ...

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 ...

Composite Gravity In Curved Spacetime, 2021 William & Mary

#### Composite Gravity In Curved Spacetime, Austin Batz

This work presents the development of a quantum theory of gravity motivated by diffeomorphism-invariance and background-independence. A composite graviton state that satisfies the linearized Einstein’s field equations has been identified via perturbative expansion about a curved vacuum spacetime. The emergence of this gravitational interaction is discussed, as well as cancellation of tadpoles and treatment of ultraviolet divergences via dimensional regularization. In other words, the formalism of quantum field theory is used to identify a gravitational interaction as an emergent phenomenon rather than as a fundamental aspect of nature. The lattice is proposed as a candidate for a physical regulator ...

2021 University of Louisville

#### Software Validation And Data Quality Monitoring Of The Klm Detector At Belle Ii., Dustyn Hofer

##### College of Arts & Sciences Senior Honors Theses

The Belle II Experiment at the SuperKEKB collider in Tsukuba, Japan is the latest of a new generation of B-factory experiments, designed to produce B meson particles in abundance. The aim of the Belle II experiment is to "discover new physics in the decay of the bottom quark (b), charm quark (c) and tau lepton (τ) and explore the dark sector." The SuperKEKB collider aims to produce instantaneous luminosities of upwards of 8 × 1035 cm−2 s−1, nearly an order of magnitude higher than previous B- factory experiments Belle and BABAR. Software packages, such as physics modules for the ...

Physics 516: Electromagnetic Phenomena (Spring 2020), 2021 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.

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 ...

Exploring Qcd Factorization At Moderate Energy Scales, 2021 Old Dominion University

#### Exploring Qcd Factorization At Moderate Energy Scales, Eric Alan Moffat

##### Physics Theses & Dissertations

Asymptotic freedom in QCD facilitates the use of partonic degrees of freedom over short distances, but physical processes are sensitive to a wide range of scales. Thus, it is necessary in QCD calculations to utilize a factorization scheme to separate a process into perturbative and non-perturbative factors. This separation relies on an assumption that one energy scale is infinitely larger than the other scales involved in the process. However, much experimental research in areas such as nucleon structure and quark-hadron duality occur at more moderate energy scales where that basic assumption may not be true but perturbative calculations should still ...

Copper Clusters: Study Of Geometric Structure Using Computer Simulation, 2021 Ferghana Polytechnic Institute

#### Copper Clusters: Study Of Geometric Structure Using Computer Simulation, Nodirbek Ikromjonovich Ibrokhimov

##### Karakalpak Scientific Journal

In this work, we investigated the geometric structure of small neutral copper clusters with low energy using the MD (Molecular Dynamics) method. When calculating the processes of interatomic interaction, we used a potential EAM (Embedded-atom method). A computer model of Cun (n = 2-13) clusters has been created. The geometric shapes of the Cu2, Cu3, Cu4, Cu5, Cu6, Cu7, Cu8, Cu9, Cu10, Cu11, Cu12, and Cu13 clusters have been studied and the structural parameters (Cu-Cu bond distance) have been calculated. The results obtained in the computer model were ...

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.