Physics Commons^™

Constraints On Parton Distribution Functions Imposed By Hadronic Experiments, Boting Wang

Physics Theses and Dissertations

The theoretical uncertainties of the Large Hadron Collider (LHC) observables are decreasing with the increasing statistics of the LHC experiments, and it is becoming more and more important to reduce the uncertainties in the knowledge of the nucleon structure. The latest LHC high-energy experiments, future experimental proposals, and computational tools are expected to enhance the knowledge of the nucleon structure. However, the global analysis that assesses their impact on Parton Distribution Functions (PDFs) knowledge is computationally expensive due to the corresponding large size of data. I developed a new approach that can make a quick preliminary evaluation to help the …

Dark Matter Production Beyond The Thermal Wimp Paradigm: An Exploration Of Early Matter Domination Scenarios, Jacek Ksawery Osinski

Physics & Astronomy ETDs

In the standard thermal history of the Universe, the energy density is dominated by radiation throughout the postinflationary era, until matter-radiation equality after big bang nucleosynthesis (BBN). However, we currently do not have any observational probes of the pre-BBN period, and radiation domination (RD) is therefore an assumption. Generic early Universe models predict the presence of additional components in the postinflationary Universe which can lead to periods of nonstandard evolution before the onset of BBN. A prominent example of such a period is a phase of early matter domination (EMD) in which the Universe undergoes matter-dominated expansion for a time, …

Consistency Checks For Two-Body Finite-Volume Matrix Elements: Conserved Currents And Bound States, Raúl A. Briceño, Maxwell T. Hansen, Andrew W. Jackura

Physics Faculty Publications

Recently, a framework has been developed to study form factors of two-hadron states probed by an external current. The method is based on relating finite-volume matrix elements, computed using numerical lattice QCD, to the corresponding infinite-volume observables. As the formalism is complicated, it is important to provide nontrivial checks on the final results and also to explore limiting cases in which more straightforward predictions may be extracted. In this work we provide examples on both fronts. First, we show that, in the case of a conserved vector current, the formalism ensures that the finite-volume matrix element of the conserved charge …

Pion Valence Structure From Ioffe-Time Parton Pseudodistribution Functions, Bálint Joó, Joseph Karpie, Kostas Orinos, Anatoly V. Radyushkin, David G. Richards, Raza Sabbir Sufian, Savvas Zafeiropoulos

Physics Faculty Publications

We present a calculation of the pion valence quark distribution extracted using the formalism of reduced Ioffe-time pseudodistributions or more commonly known as pseudo-PDFs. Our calculation is carried out on two different 2 + 1 flavor QCD ensembles using the isotropic-clover fermion action, with lattice dimensions 24³ × 64 and 32³ × 96 at the lattice spacing of a = 0.127 fm, and with the quark mass equivalent to a pion mass of m_π ≃ 415 MeV. We incorporate several combinations of smeared-point and smeared-smeared pion source-sink interpolation fields in obtaining the lattice QCD matrix elements using …

Relativistic Quantum Heat Engine From Uncertainty Relation Standpoint, Pritam Chattopadhyay, Goutam Paul

Journal Articles

Established heat engines in quantum regime can be modeled with various quantum systems as working substances. For example, in the non-relativistic case, we can model the heat engine using infinite potential well as a working substance to evaluate the efficiency and work done of the engine. Here, we propose quantum heat engine with a relativistic particle confined in the one-dimensional potential well as working substance. The cycle comprises of two isothermal processes and two potential well processes of equal width, which forms the quantum counterpart of the known isochoric process in classical nature. For a concrete interpretation about the relation …

Measurement Of The Production Cross Section Of Four Top Quarks In Proton-Proton Collisions At 13 Tev, Caleb Fangmeier

Department of Physics and Astronomy: Dissertations, Theses, and Student Research

The field of particle physics involves not only searches for new particles and measurements of their interactions, but also the design and construction of advanced particle detectors. This thesis presents the measurement of the production cross section of four top quarks in proton-proton collisions at a center-of-mass energy of 13 TeV using 137 fb$^{-1}$ of integrated luminosity recorded by the CMS experiment at the LHC. This analysis considers events in the final state of a same-sign pair of leptons, notable for being a final state with relatively few Standard Model background events. A boosted decision tree is utilized to discriminate …

Graded Quivers, Generalized Dimer Models And Toric Geometry, Sebastián Franco, Azeem Hasan

Publications and Research

The open string sector of the topological B-model on CY (m+2)-folds is described by m-graded quivers with superpotentials. This correspondence extends to general m the well known connection between CY (m+2)-folds and gauge theories on the world-volume of D(5-2m)-branes for m = 0, ..., 3. We introduce m-dimers, which fully encode the m-graded quivers and their superpotentials, in the case in which the CY (m+2)-folds are toric. Generalizing the well known m = 1,2 cases, m-dimers significantly simplify the connection between geometry and m-graded quivers. A key …

Longitudinal Bunch Profile Diagnostic For Magnetized Electron Beams, Mark Stefani, Fay Hannon

Electrical & Computer Engineering Faculty Publications

The study of magnetized electron beam has become a high priority for its use in ion beam cooling as part of electron ion colliders and the potential of easily forming flat beams with a large aspect ratio. In this paper, a new diagnostic is described with the purpose of studying longitudinal and transverse magnetized beam properties. The device is a modification to a typical pepper-pot. Specifically, this 1D pepper-pot was designed for use with a transverse deflecting cavity for longitudinal bunch profile measurements of magnetized beams.

Transverse Uncorrelated Emittance Diagnostic For Magnetized Electron Beams, Fay Hannon, Mark Stefani

Electrical & Computer Engineering Faculty Publications

The study of magnetized electron beam has become a high priority for its use in ion beam cooling as part of electron ion colliders and the potential of easily forming flat beams for various applications. In this paper, a purpose-specific diagnostic is described with the intention of studying transverse magnetized beam properties. The device is a modification to the classic pepper-pot, used in this context to measure the uncorrelated components of transverse emittance in addition to the typical effective emittance. The limitations of traditional methods are discussed, and simulated demonstrations of the new technique shown.

Complete Matching For Quasidistribution Functions In Large Momentum Effective Theory, Wei Wang, Jian-Hui Zhang, Shuai Zhao, Ruilin Zhu

Physics Faculty Publications

We complete the procedure of extracting parton distribution functions (PDFs) using large momentum effective theory at leading power accuracy in the hadron momentum. We derive a general factorization formula for the quasi-PDFs in the presence of mixing and give the corresponding hard matching kernel at O(α_s), both for the unpolarized and for the polarized quark and gluon quasi-PDFs. Our calculation is performed in a regularization-independent momentum subtraction scheme. The results allow us to match the nonperturbatively renormalized quasi-PDFs to normal PDFs in the presence of mixing and therefore can be used to extract flavor-singlet quark PDFs as well …

Numerical Exploration Of Three Relativistic Particles In A Finite Volume Including Two-Particle Resonances And Bound States, Fernando Romero-López, Stephen R. Sharpe, Tyler D. Blanton, Raúl A. Briceño, Maxwell T. Hansen

Physics Faculty Publications

In this work, we use an extension of the quantization condition, given in ref. [1], to numerically explore the finite-volume spectrum of three relativistic particles, in the case that two-particle subsets are either resonant or bound. The original form of the relativistic three-particle quantization condition was derived under a technical assumption on the two-particle K matrix that required the absence of two-particle bound states or narrow two-particle resonances. Here we describe how this restriction can be lifted in a simple way using the freedom in the definition of the K-matrix-like quantity that enters the quantization condition. With this in hand, …

Comparing Proton Momentum Distributions In A = 2 And 3 Nuclei Via 2H 3H And 3He (E,E′P) Measurements, R. Cruz-Torres, F. Hauenstein, A. Schmidt, D. Nguyen, D. Abrams, H. Albataineh, S. Alsalmi, D. Androic, K. Aniol, W. Armstrong, J. Arrington, H. Atac, D. Bulumulla, C. E. Hyde, V. Khachatryan, M. N.H. Rashad, L. B. Weinstein, Z. Y. Ye, J. Zhang, Jefferson Lab Hall A Tritium Collaboration

Physics Faculty Publications

We report the first measurement of the (e, e' p) reaction cross-section ratios for Helium-3 (³He), Tritium (³H), and Deuterium (d). The measurement covered a missing momentum range of 40 ≤ p_miss ≤ 550 MeV/c, at large momentum transfer ({Q²} ≈ 1.9 (GeV/c)²) and x_B > 1, which minimized contributions from non quasi-elastic (QE) reaction mechanisms. The data is compared with planewave impulse approximation (PWIA) calculations using realistic spectral functions and momentum distributions. The measured and PWIA-calculated cross-section ratios for ³He/d and ³H/d extend to just above the typical …

Obituary: Anthony Starace (1945-2019)

Anthony F. Starace Publications

Anthony Starace, George Holmes University Professor of physics, died Sept. 5 from complications related to pancreatitis. He was 74.

Starace was born July 24, 1945, in the Queens borough of New York City. He graduated from Stuyvesant High School and earned his bachelor’s degree from Columbia University in 1966 before moving west to the University of Chicago, where he earned his doctorate under adviser Ugo Fano in 1971. It was in Chicago that he met Katherine Fritz of Beatrice, Nebraska, his wife of 51 years.

Following a postdoctoral appointment at Imperial College London, Starace moved to Lincoln as an assistant …

Unitarity Of The Infinite-Volume Three-Particle Scattering Amplitude Arising From A Finite-Volume Formalism, Raúl A. Briceño, Maxwell T. Hansen, Stephen R. Sharpe, Adam P. Szczepaniak

Physics Faculty Publications

Hansen and Sharpe [Phys. Rev. D 92, 114509 (2015)] derived a relation between the scattering amplitude of three identical bosons,M₃, and a real function referred to as the divergence-free K matrix and denoted K_df;3. The result arose in the context of a relation between finite-volume energies and K_df;3, derived to all orders in the perturbative expansion of a generic low-energy effective field theory. In this work we set aside the role of the finite volume and focus on the infinite-volume relation between K_df;3 and M₃. We show that, for any …

Physics And Mathematics Of Graded Quivers, Azeem Hasan

Dissertations, Theses, and Capstone Projects

A graded quiver with superpotential is a quiver whose arrows are assigned degrees c ∈ {0, 1, · · · , m}, for some integer m ≥ 0, with relations generated by a superpotential of degree m − 1. For m = 0, 1, 2, 3 they often describe the open string sector of D-brane systems; in particular, they capture the physics of D(5 − 2m)-branes at local Calabi-Yau (CY) (m + 2)- fold singularities in type IIB string theory. We introduce m-dimers, which fully encode the m-graded quivers and their superpotentials, in the case in which the CY (m …

On Different Parametrizations Of Feynman Integrals, Ray Daniel Sameshima

Dissertations, Theses, and Capstone Projects

In this doctoral thesis, we discuss and apply advanced techniques for the calculations of scattering amplitudes which, on the one hand, allow us to compute cross sections and differential distributions at high precision and, on the other hand, give us deep mathematical insights on the mathematical structures of Feynman integrals.

We start by presenting phenomenological calculations relevant for the experimental analyses at the Large Hadron Collider. We use the resummation of soft gluon emission corrections to study the associated production of a top pair and a Z boson to next-to-next-to-leading logarithmic accuracy, and compute the total cross section and differential …

Yields Of Weakly Bound Light Nuclei As A Probe Of The Statistical Hadronization Model, Yiming Cai, Thomas D. Cohen, Boris A. Gelman, Yukari Yamauchi

Publications and Research

The statistical hadronization model successfully describes the yields of hadrons and light nuclei from central heavy-ion collisions over a wide range of energies. It is a simple and efficient phenomenological framework in which the relative yields for very high energy collisions are essentially determined by a single model parameter—the chemical freeze-out temperature. Recent measurements of yields of hadrons and light nuclei covering over nine orders of magnitudes from the ALICE collaboration at the Large Hadron Collider were described by the model with remarkable accuracy with a chemical freeze-out temperature of 156.5 ± 1.5 MeV. A key physical question is whether …

Probing Uncertainty Relations In Non-Commutative Space, Pritam Chattopadhyay, Ayan Mitra, Goutam Paul

Journal Articles

In this paper, we compute uncertainty relations for non-commutative space and obtain a better lower bound than the standard one obtained from Heisenberg’s uncertainty relation. We also derive the reverse uncertainty relation for product and sum of uncertainties of two incompatible variables for one linear and another non-linear model of the harmonic oscillator. The non-linear model in non-commutating space yields two different expressions for Schrödinger and Heisenberg uncertainty relation. This distinction does not arise in commutative space, and even in the linear model of non-commutative space.

Master Integrals For The Two-Loop, Non-Planar Qcd Corrections To Top-Quark Pair Production In The Quark-Annihilation Channel, Matteo Becchetti, Roberto Bonciani, Valerio Casconi, Andrea Ferroglia, Simone Lavacca, Andreas Von Manteuffel

Publications and Research

We present the analytic calculation of the Master Integrals for the two-loop, non-planar topologies that enter the calculation of the amplitude for top-quark pair hadroproduction in the quark-annihilation channel. Using the method of differential equations, we expand the integrals in powers of the dimensional regulator ε and determine the expansion coefficients in terms of generalized harmonic polylogarithms of two dimensionless variables through to weight four.

A Search For Boosted Low Mass Resonances Decaying To The Bb̅ Final State And Produced In Association With A Jet At √S = 13 Tev With The Atlas Detector, Matthew Feickert

Physics Theses and Dissertations

A search in the high momentum regime for new resonances, produced in association with a jet, decaying into a pair of bottom quarks is presented using an integrated luminosity of 80.5 fb^-1 of proton-proton collisions at center-of-mass energy √s = 13 TeV recorded by the ATLAS detector at the Large Hadron Collider. The search was performed for low mass resonances, including the Standard Model Higgs boson and leptophobic Z' dark matter mediators, in the mass range of 100 GeV to 200 GeV. For the Standard Model Higgs boson, the observed signal strength is μH = 5.8 ± 3.1 (stat.) …

Massive Elementary Particles In The Standard Model And Its Supersymmetric Triplet Higgs Extension, Keping Xie

Physics Theses and Dissertations

In this dissertation, we focus on massive elementary particles in the Standard Model and its supersymmetric triplet Higgs extension.

In the first part, we start with a review of electroweak (EW) sector in the Standard Model. Motivated by nonzero neutrino masses, we consider triplet scalars in addition to the Standard Model. The vacuum expectation values of scalar triplets are strongly constrained by the $\rho$ parameter, extracted from electroweak precision measurements. Therefore, we introduce a custodial symmetry to weaken this constraint and obtain the well-known Georgi-Machacek (GM) Model. The GM model still requires fine-tuning to satisfy the $\rho$ parameter constraint. It …

Pnnl Dark Matter Bubble Chamber Simulation, Carl M. Krutz

STAR Program Research Presentations

Based on observations of interactions between objects on a cosmic scale, scientists have determined that a large percentage (85%) of the universe’s mass is not visible. Weakly Interacting Massive Particles (WIMPs) are one of the primary candidates for this dark matter. Many current projects seek to find WIMPs through various search methods. The PICO dark matter experiment involves observing an underground chamber at SNOLAB for bubbles created when energy in the form of radiation is deposited in a superheated liquid. The group at Pacific Northwest National Lab (PNNL) working on the PICO project seeks to develop improvements to the project’s …

Search For Resonant Double Higgs Production With Bbzz Decays In The Bbℓℓνν Final State In Pp Collisions At √S = 13 Tev, Rami Kamalieddin

Department of Physics and Astronomy: Dissertations, Theses, and Student Research

Since the discovery of the Higgs boson in 2012 by the ATLAS and CMS experiments, most of the quantum mechanical properties that describe the long-awaited Higgs boson have been measured. Due to the outstanding work of the LHC, over a hundred of fb⁻¹ of proton collisions data have been delivered to both experiments. Finally, it became sensible for analyses teams to start working with a very low cross section processes involving the Higgs boson, e.g., a recent success in observing ttH and VHbb processes. One of the main remaining untouched topics is a double Higgs boson production. However, an …

Dual Superconformal Symmetry Of N = 2 Chern-Simons Theory With Fundamental Matter At Large N, Karthik Inbasekar, Sachin Jain, Sucheta Majumdar, Pranjal Nayak, Turmoli Neogi, Ritam Sinha, Tarun Sharma, V. Umesh

Physics and Astronomy Faculty Publications

Dual conformal symmetry and Yangian symmetry are symmetries of amplitudes that have aided the study of scattering amplitudes in highly supersymmetric theories like N = 4 SYM and ABJM. However, in general such symmetries are absent from the theories with lesser or no supersymmetry. In this paper, we show that the tree level 2 → 2 scattering amplitude in the 3d N = 2 Chern-Simons theory coupled to a fundamental chiral multiplet is dual superconformal invariant. In the ’t Hooft large N limit, the 2 → 2 scattering amplitude in this theory has been shown to be tree-level exact in …

Factorization Of Jet Cross Sections In Heavy-Ion Collisions, Jian-Wei Qiu, Felix Ringer, Nobuo Sato, Pia Zurita

Physics Faculty Publications

We propose a new phenomenological approach to establish QCD factorization of jet cross sections in the heavy-ion environment. Starting from a factorization formalism in proton-proton collisions, we introduce medium modified jet functions to capture the leading interaction of jets with the hot and dense QCD medium. A global analysis using a Monte Carlo sampling approach is performed in order to reliably determine the new jet functions from the nuclear modification factor of inclusive jets at the LHC. We find that gluon jets are significantly more suppressed due to the presence of the medium than quark jets. In addition, we observe …

Slow Light With Interleaved P-N Junction To Enhance Performance Of Integrated Mach-Zehnder Silicon Modulators, Marco Passoni, Dario Gerace, Liam O'Faolain, Lucio Claudio Andreani

Cappa Publications

Slow light is a very important concept in nanophotonics, especially in the context of photonic crystals. In this work, we apply our previous design of band-edge slow light in silicon waveguide gratings [M. Passoni et al, Opt. Express 26, 8470 (2018)] to Mach-Zehnder modulators based on the plasma dispersion effect. The key idea is to employ an interleaved p-n junction with the same periodicity as the grating, in order to achieve optimal matching between the electromagnetic field profile and the depletion regions of the p-n junction. The resulting modulation efficiency is strongly improved as compared to common modulators based on …

Performance Of Plastic Electron Optics Components Fabricated Using A 3d Printer, Phillip Wiebe, Peter Beierle, Hua-Chieh Shao, Bret Gergely, Anthony F. Starace, Herman Batelaan

Anthony F. Starace Publications

We show images produced by an electron beam deflector, a quadrupole lens and a einzel lens fabricated from conducting and non-conducting plastic using a 3D printer. Despite the difficulties associated with the use of plastics in vacuum, such as outgassing, poor conductivity, and print defects, the devices were used successfully in vacuum to steer, stretch and focus electron beams to millimeter diameters. Simulations indicate that much smaller focus spot sizes might be possible for such 3D-printed plastic electron lenses taking into account some possible surface defects. This work was motivated by our need to place electron optical components in difficult-to-access …

Analytic Generalized Description Of A Perturbative Nonparaxial Elegant Laguerre-Gaussian Phasor For Ultrashort Pulses In The Time Domain, Andrew Vikartofsky, Ethan C. Jahns, Anthony F. Starace

Anthony F. Starace Publications

An analytic expression for a polychromatic phasor representing an arbitrarily short elegant Laguerre-Gauss (eLG) laser pulse of any spot size and LG mode is presented in the time domain as a nonrecursive, closed-form perturbative expansion valid to any order of perturbative correction. This phasor enables the calculation of the complex electromagnetic fields for such beams without requiring the evaluation of any Fourier integrals. It is thus straightforward to implement in analytical or numerical applications involving eLG pulses.

Charting The Space Of 3d Cfts With A Continuous Global Symmetry, Anatoly Dymarsky, Joao Penedones, Emilio Trevisani, Alessandro Vichi

Physics and Astronomy Faculty Publications

We study correlation functions of a conserved spin-1 current J_μ in three dimensional Conformal Field Theories (CFTs). We investigate the constraints imposed by permutation symmetry and current conservation on the form of three point functions ⟨J_μJ_νO_Δ,ℓ⟩ and the four point function ⟨J_μJ_νJ_ρJ_σ⟩ and identify the minimal set of independent crossing symmetry conditions. We obtain a recurrence relation for conformal blocks for generic spin-1 operators in three dimensions. In the process, we improve several technical points, facilitating the use of recurrence relations. By applying …

Exact Generalized Partition Function Of 2d Cfts At Large Central Charge, Anatoly Dymarsky, Kirill Pavlenko

Physics and Astronomy Faculty Publications

We discuss generalized partition function of 2d CFTs on thermal cylinder decorated by higher qKdV charges. We propose that in the large central charge limit qKdV charges factorize such that generalized partition function can be rewritten in terms of auxiliary non-interacting bosons. The explicit expression for the generalized free energy is readily available in terms of the boson spectrum, which can be deduced from the conventional thermal expectation values of qKdV charges. In other words, the picture of the auxiliary non-interacting bosons allows extending thermal one-point functions to the full non-perturbative generalized partition function. We verify this conjecture for the …