Elementary Particles and Fields and String Theory Commons^™

Machine Learning In Fundamental Physics: From Early Universe Signatures To Qcd Evolution, Brandon Stevenson

Physics Theses and Dissertations

In both cosmology and small-x quantum chromodynamics, the relevant theoretical predictions are well-defined but expensive to evaluate repeatedly over broad parameter spaces or large ensembles of simulated data. The central question of this thesis is when machine learning can accelerate those calculations without weakening the reliability of the final physics conclusions. The thesis develops and tests this idea in three settings. First, it studies the Derivative Approximation for Likelihoods (DALI) as a means of diagnosing when Fisher-matrix forecasts cease to be trustworthy in cosmological parameter inference. Second, it investigates graph-based spherical neural networks for estimating primordial non-Gaussianity directly from simulated …

Utilizing Computer Modeling To Optimize Electric Fields Within Xenon Time Projection Chambers, Miles Meloni

Honors Theses

XENONnT is a physics experiment designed with the goal of detecting dark matter particles. The detector is a time projection chamber; a series of charged electrodes creates an electric field, surrounding a central body filled with liquid and gaseous xenon. Photomultiplier tubes (PMTs), positioned on either end of the chamber, serve to detect light signals. We seek to minimize the root mean square of the electric field norms experienced by the PMTs. This quantity corresponds to the variance in the electric field observed by the PMTs. Establishing a consistent electric field is important to maintaining these sensitive components. The electric …

Search For Higgs Boson Pair Production In The Two Light Leptons And One Tau Final State Using Proton-Proton Collision Data With $\Sqrt{S} = 13$ Tev At The Lhc From The Atlas Detector, Susan Bataju

Physics Theses and Dissertations

In this thesis, a search is presented for the pair production of Higgs bosons in a final state containing two same-charge light leptons (e/$\mu$) and one opposite-charge hadronically decaying tau lepton ($\tau_{h}$). The search is based on a data sample of proton-proton (pp) collisions at a center-of-mass energy $\sqrt{s}$ = 13 TeV, collected by the ATLAS detector during Run 2 (2015-2018) of the Large Hadron Collider (LHC), corresponding to an integrated luminosity of 140 fb$^{-1}$. The Standard Model predicts that the Higgs potential has a non-zero expectation value leading to the spontaneous breaking of electroweak symmetry and when some fundamental …

A Novel Approach To Model The Pion Structure Using Advanced Polynomial Functions, Lucas Kotz

Physics Theses and Dissertations

In the coming years, new experiments at the Electron-Ion Collider (EIC) and the Large Hadron Collider (LHC) will provide unprecedented insight into the building blocks of matter. To make the most of these opportunities, scientists must reduce uncertainties in the theoretical models that connect what we observe in experiments to what is happening inside particles like protons and pions. A critical part of these models involves describing how a particles momentum is shared among its internal components – quarks and gluons.

This work focuses on improving how we model the internal structure of the pion. We propose a new approach …

Measuring Cosmic Rays With Muon Detectors (Quarknet), Aiden Burton, Jack W. Maseberg

SACAD: Scholarly Activities

We report measurement of atmospheric muon particles originating from cosmic rays. Using four QuarkNet project scintillators in an unstacked geometry, we are counting muons in coincidence with each other. We are currently refurbishing a second detector apparatus and will soon be capable of measuring coincidence events for larger shower surface areas using a total of eight scintillators.

Questioning Reality: The Progressive Development Of Modern Physics, Joshua Lancman

STEM Month

Humanity has a tendency to divide time. The past is distinct from the present which is entirely separate from the future. In supposedly 20-20 vision history is neatly divided into different sections, distinct eras with sharp lines between them. What is present and in the future is always modern. What is past is something else with another name.

Yet time is not divided so neatly. We know this living through it: years and decades blend into one another in a non-uniform progression. To divide human history into separate eras is a necessary simplification, as it helps to ascribe order onto …

Global Fits In The Supersymmetric Georgi-Machacek Model, Yingnan Xu

Physics Theses and Dissertations

In this dissertation, we study a supersymmetric extension of the Standard Model with Higgs triplets in the scalar sector. We begin with a review of the Standard Model (SM), particularly the electroweak sector and the Higgs mechanism. In the SM, the Higgs mechanism requires the presence of a complex Higgs doublet to break the electroweak symmetry and endow particles with a mass; this process is called Spontaneous Symmetry Breaking (SSB). Although this is the simplest possibility, higher scalar representations may also contribute to the electroweak breaking process (EWSB). The extent to which these higher representations contribute to EWSB is constrained …

The Search For Photonuclear Interactions Of Muons Utilizing Test Beam Data At The Large Hadron Collider, Miranda M. Williams

2024 Spring Honors Capstone Projects - Archive

The ATLAS Detector is one of four different types of detectors within the Large Hadron Collider and is used to study the fundamental theories of the universe. Within the ATLAS experiment, beams of known composition and energies – otherwise known as “test beams” – are one of the many methods used to study specific physical phenomena. In this study, a test beam of muons with an energy of 160 GeV was analyzed to search for evidence of photonuclear interactions. This necessitated analyzing and filtering over 50,000 total events using specific parameters that would indicate such an event had occurred. To …

Questioning Reality: The Progressive Development Of Modern Physics, Joshua Lancman

STEM for Success Showcase

Humanity has a tendency to divide time. The past is distinct from the present which is entirely separate from the future. In supposedly 20-20 vision history is neatly divided into different sections, distinct eras with sharp lines between them. What is present and in the future is always modern. What is past is something else with another name.

Yet time is not divided so neatly. We know this living through it: years and decades blend into one another in a non-uniform progression. To divide human history into separate eras is a necessary simplification, as it helps to ascribe order onto …

Progress In Physics: Twentieth Year Of Publication, Florentin Smarandache, Andreas Ries, Pierre Millette, Ebenezer Chifu

Branch Mathematics and Statistics Faculty and Staff Publications

The journal Progress in Physics was created in January 2005 on behalf of many influential scientists with whom we were in correspondence. The main reason was that publications in other journals were allowed only if the submitter was affiliated with a scientific institution or research organization. Given this situation, many working scientists finding themselves partially employed or unemployed, such as in between research grants, find themselves unable to publish their research results. Even e-print archives such as Cornell’s arXiv required scientific affiliation and still follow this policy.

Analytic Solutions Of The Dglap Evolution And Theoretical Uncertainties, A. Simonelli

Physics Faculty Publications

The energy dependence for the singlet sector of Parton Distributions Functions (PDFs) is described by an entangled pair of ordinary linear differential equations. Although there are no exact analytic solutions, it is possible to provide approximated results depending on the assumptions and the methodology adopted. These results differ in their sub-leading, neglected terms and ultimately they are associated with different treatments of the theoretical uncertainties. In this work, a novel analytic approach in Mellin space is presented and a new methodology for obtaining closed and exponentiated analytic solutions is devised. Different results for the DGLAP evolution at Next-Leading-Order are compared, …

Event Generators For High-Energy Physics Experiments, J. M. Campbell, M. Diefenthaler, T. J. Hobbs, S. Höche, J. Isaacson, F. Kling, S. Mrenna, J. Reuter, S. Alioli, J. R. Andersen, C. Andreaopoulos, A. M. Ankowski, E.C. Aschenauer, A. Ashkenazi, M. D. Baker, J. L. Barrow, M. Van Beekveld, G. Beswick, S. Bhattacharya, K. Zapp, Et Al.

Physics Faculty Publications

We provide an overview of the status of Monte-Carlo event generators for high-energy particle physics. Guided by the experimental needs and requirements, we highlight areas of active development, and opportunities for future improvements. Particular emphasis is given to physics models and algorithms that are employed across a variety of experiments. These common themes in event generator development lead to a more comprehensive understanding of physics at the highest energies and intensities, and allow models to be tested against a wealth of data that have been accumulated over the past decades. A cohesive approach to event generator development will allow these …

Towards Unpolarized Gpds From Pseudo-Distributions, Hervé Dutrieux, Robert G. Edwards, Colin Egerer, Joseph Karpie, Christopher Monahan, Kostas Orginos, Anatoly Radyushkin, David Richards, Eloy Romero, Savvas Zafeiropoulos

Physics Faculty Publications

We present an exploration of the unpolarized isovector proton generalized parton distributions (GPDs) H^u−d(x, ξ, t) and E^u−d(x, ξ, t) in the pseudo-distribution formalism using distillation. Taking advantage of the large kinematic coverage made possible by this approach, we present results on the moments of GPDs up to the order x³ — including their skewness dependence — at a pion mass m_π = 358 MeV and a lattice spacing a = 0.094 fm.

Conformal Bk Equation At Qcd Wilson-Fisher Point, I. Balitsky, G. A. Chirilli

Physics Faculty Publications

High-energy scattering in pQCD in the Regge limit is described by the evolution of Wilson lines governed by the BK equation [1, 2]. In the leading order, the BK equation is conformally invariant and the eigenfunctions of the linearized BFKL equation are powers. It is a common belief that at d ≠ 4 the BFKL equation is useless since unlike d = 4 case it cannot be solved by usual methods. However, we demonstrate that at critical Wilson-Fisher point of QCD the relevant part of NLO BK restores the conformal invariance so the solutions are again powers. As a check …

Search For Higgs Boson Pair Production In The Multiple Lepton Final State Using Proton-Proton Collision Data At √S =13 Tev From The Atlas Detector, Santosh Parajuli

Physics Theses and Dissertations

In this thesis, a search is presented for the production of Higgs boson pairs in final states containing three light leptons (e/mu). The analysis utilizes data collected by the ATLAS detector at the Large Hadron Collider from proton-proton (pp) collisions at a center-of-mass energy of √s=13 TeV, corresponding to an integrated luminosity of 140 fb-1. The investigation aims to identify any significant deviations from the expected background levels defined by the Standard Model. The Higgs boson, as the cornerstone of the electroweak symmetry breaking mechanism, plays a crucial role in our understanding of particle physics. Studying the production of Higgs …

A Study Of Data/Monte Carlo Agreement In Charmed Baryon Decays At Belle Ii, Kaitlyn Thurmond

Honors Theses

The Belle II experiment at the SuperKEKB electron-positron accelerator facility in Tsukuba, Japan has a primary goal of searching for new physics beyond the Standard Model of particle physics. Extremely precise measurements of particle decays will be compared with Standard Model predictions in order to expose the presence of new particles and interactions. These measurements are prepared using simulated samples to avoid potential biases when studying the data. The Belle II collaboration produces two types of simulated samples for this purpose. One is produced with consistent calibration payloads and another with payloads calibrated as a function of data taking. This …

An Analysis Of Detection Asymmetry Using Baryon Decays In Belle Ii, Matthew Mestayer

Honors Theses

The purpose of this study was to determine the detection asymmetry of the Belle II detector using decays of two common baryons, Λ⁰ → ��π^- and Σ⁺ → ��π⁰. A Monte Carlo simulation of both decays was used to determine the validity of signal isolation criteria. These criteria were then applied to the Belle II data, allowing for a comparison of the detection asymmetry in the data relative to the simulation. The results show a moderate detection asymmetry when using the Λ⁰ → ��π^- decay, particularly for forward-going baryons. For the Σ^{+ …}

Study Of Missing Mass Background In The Clas12 Detector, Jessie Hess, Gerard P. Gilfoyle, Lamya Baashen

Honors Theses

At Jefferson Lab we use the CLAS12 detector to measure the neutron magnetic form factor. An accurate measurement of the CLAS12 neutron detection efficiency (NDE) is required. We use the nuclear reaction ���� → ��′��+�� as a source of tagged neutrons and obtain the NDE from the ratio of expected neutrons to detected ones. We assume the final state consists of ��′��+�� only, use the ��′��+ information to predict the neutron's position(expected) and then search for that neutron(detected). We select neutrons with the missing mass (MM) technique. We use simulation to validate our methods. We simulated events with the Monte-Carlo …

New Physics In The Age Of Precision Cosmology, Vivian I. Sabla

Dartmouth College Ph.D Dissertations

The Lambda-cold dark matter (LCDM) model has become the standard model of cosmology because of its ability to reproduce a vast array of cosmological observations, from the earliest moments of our Universe, to the current period of accelerated expansion, which it does with great accuracy. However, the success of this model only distracts from its inherent flaws and ambiguities. LCDM is purely phenomenological, providing no physical explanation for the nature of dark matter, responsible for the formation and evolution of large-scale structure, and giving an inconclusive explanation for dark energy, which drives the current period of accelerated expansion.

Furthermore, cracks …

Gluon Transverse-Momentum-Dependent Distributions From Large-Momentum Effective Theory, Ruilin Zhu, Yao Ji, Jian-Hui Zhang, Shuai Zhao

Physics Faculty Publications

We demonstrate that gluon transverse-momentum-dependent parton distribution functions (TMDPDFs) can be extracted from lattice calculations of appropriate Euclidean correlations in large-momentum effective theory (LaMET). Based on perturbative calculations of gluon unpolarized and helicity TMDPDFs, we present a matching formula connecting them and their LaMET counterparts, where the latter are renormalized in a scheme facilitating lattice calculations and converted to the MS ¯ scheme. The hard matching kernel is given up to one-loop level. We also show that the perturbative result is independent of the prescription used for the pinch-pole singularity in the relevant correlations. Our results offer a guidance for …

Rapidity-Only Tmd Factorization At One Loop, Ian Balitsky

Physics Faculty Publications

Typically, a production of a particle with a small transverse momentum in hadron-hadron collisions is described by CSS-based TMD factorization at moderate Bjorken x_B ~ 1 and by k_T-factorization at small x_B. A uniform description valid for all x_B is provided by rapidity-only TMD factorization developed in a series of recent papers at the tree level. In this paper the rapidity-only TMD factorization for particle production by gluon fusion is extended to the one-loop level.

First Measurement Of Hard Exclusive 𝛑⁻Δ⁺⁺ Electroproduction Beam-Spin Asymmetries Off The Proton, S. Diehl, N. Trotta, K. Joo, P. Achenbach, Z. Akbar, W. R. Armstrong, H. Atac, H. Avakian, L. Baashen, N. A. Baltzell, L. Barion, M. Bashkanov, M. Battaglieri, I. Bedlinskiy, F. Benmokhtar, A. Bianconi, A. S. Biselli, F. Bossù, K.-T. Brinkman, M. Zurek, Et Al., Clas Collaboration

Physics Faculty Publications

The polarized cross-section ratio σLT′/σ₀ from hard exclusive π⁻Δ⁺⁺ electroproduction off an unpolarized hydrogen target has been extracted based on beam-spin asymmetry measurements using a 10.2  GeV/10.6  GeV incident electron beam and the CLAS12 spectrometer at Jefferson Lab. The study, which provides the first observation of this channel in the deep-inelastic regime, focuses on very forward-pion kinematics in the valence regime, and photon virtualities ranging from 1.5  GeV² up to 7  GeV². The reaction provides a novel access to the d-quark content of the nucleon and to p→Δ⁺⁺ transition generalized parton …

Full Treatment Of The Thrust Distribution In Single Inclusive E⁺E⁻ → H X Processes, M. Boglione, Andrea Simonelli

Physics Faculty Publications

Extending the transverse momentum dependent factorization to thrust dependent observables entails a series of difficulties, ultimately associated to the behavior of soft radiation. As a consequence, the definition of the transverse momentum dependent functions has to be revised, while preserving (and possibly extending) their universality properties. Moreover, the regularization of the rapidity divergences generates non trivial correlations between rapidity and thrust. In this paper, we show how to deal with these correlations in a consistent treatment of the thrust dependence of e⁺e⁻ → h X cross section, where the hadron transverse momentum is measured with respect to …

Symbolic Computation Of Squared Amplitudes In High Energy Physics With Machine Learning, Abdulhakim Alnuqaydan

Theses and Dissertations--Physics and Astronomy

The calculation of particle interaction squared amplitudes is a key step in the calculation of cross sections in high-energy physics. These complex calculations are currently performed using domain-specific symbolic algebra tools, where the computational time escalates rapidly with an increase in the number of loops and final state particles. This dissertation introduces an innovative approach: employing a transformer-based sequence-to-sequence model capable of accurately predicting squared amplitudes of Standard Model processes up to one-loop order when trained on symbolic sequence pairs. The primary objective of this work is to significantly reduce the computational time and, more importantly, develop a model that …

Classification Of Pixel Tracks To Improve Track Reconstruction From Proton-Proton Collisions, Kebur Fantahun, Jobin Joseph, Halle Purdom, Nibhrat Lohia

SMU Data Science Review

In this paper, machine learning techniques are used to reconstruct particle collision pathways. CERN (Conseil européen pour la recherche nucléaire) uses a massive underground particle collider, called the Large Hadron Collider or LHC, to produce particle collisions at extremely high speeds. There are several layers of detectors in the collider that track the pathways of particles as they collide. The data produced from collisions contains an extraneous amount of background noise, i.e., decays from known particle collisions produce fake signal. Particularly, in the first layer of the detector, the pixel tracker, there is an overwhelming amount of background noise that …

Improved Constraints On The Standard Model Higgs Self-Interaction Using A Search For Hh → 4b Via The Vector-Boson Fusion Production Mode At √S = 13 Tev In 126 Fb^-1 Of Data Collected By The Atlas Experiment, Christopher Milke

Physics Theses and Dissertations

A search for di-Higgs production via the Vector Boson Fusion mechanism decaying to 4 bottom quarks is performed using 126 fb−1 of data from Run 2 of ATLAS at √s = 13 TeV. The search was performed in the non-resonant regime, finding an upper bound on the production cross-section for the Standard Model VBF→HH→4b of about 200 times the Standard Model. Constraints are placed on both the HHVV coupling (which determines the W/Z-higgs four-point interaction strength) and HHH Higgs self-coupling scale factors at 95% confidence. The HHVV coupling scaling factor (κ2V ) is constrained to an observed interval between 0.09 …

A Performance Analysis Of The Belle Ii Detector, John Stacy

Honors Theses

The Belle II experiment has recently (2018) started data taking at the SuperKEKB electron-positron collider in Tsukuba, Japan. Detector performance studies are necessary to understand early data and prepare for more complex analyses. This study of the proton detection efficiency of the Belle II detector compares real and simulated data to find discrepancies with the intention to provide useful information for detector and calibration experts to better gauge detector performance. It also attempts to improve the characterization of proton identification efficiency at low momenta, which performs poorly under the current fitting model. This helps analysts exploring final states that include …

Monte Carlo Study Of Lepton Flavor Universality Violation In B Decays With Belle Ii Simulation, Sakul Mahat

Honors Theses

Belle II, the first super B-Factory experiment, is designed to make precise measurements of weak interaction parameters and search for New Physics beyond the Standard Model of particle physics. The Standard Model of particle physics is a theory that classifies all known elementary particles and describes three of the four known fundamental forces in the universe. Physics beyond the Standard Model that addresses the theoretical developments needed to explain the deficiencies in the Standard Model is often referred to as New Physics. One of the assumptions of the Standard Model is that the couplings of particles that mediate the weak …

Deeply Learning Deep Inelastic Scattering Kinematics, Markus Diefenthaler, Abdullah Farhat, Andrii Verbytskyi, Yuesheng Xu

Mathematics & Statistics Faculty Publications

We study the use of deep learning techniques to reconstruct the kinematics of the neutral current deep inelastic scattering (DIS) process in electron–proton collisions. In particular, we use simulated data from the ZEUS experiment at the HERA accelerator facility, and train deep neural networks to reconstruct the kinematic variables Q² and x. Our approach is based on the information used in the classical construction methods, the measurements of the scattered lepton, and the hadronic final state in the detector, but is enhanced through correlations and patterns revealed with the simulated data sets. We show that, with the appropriate selection …

Perturbative Unitarity And Nec Violation In Genesis Cosmology, Yong Cai, Ji Xu, Shuai Zhao, Siyi Zhou

Physics Faculty Publications

Explorations of the violation of null energy condition (NEC) in cosmology could enrich our understanding of the very early universe and the related gravity theories. Although a fully stable NEC violation can be realized in the “beyond Horndeski” theory, it remains an open question whether a violation of the NEC is allowed by some fundamental properties of UV-complete theories or the consistency requirements of effective field theory (EFT). We investigate the tree-level perturbative unitarity for stable NEC violations in the contexts of both Galileon and “beyond Horndeski” genesis cosmology, in which the universe is asymptotically Minkowskian in the past. We …