Physics Commons^™

Beam-Based Target Alignment For Mu2e, Helenka Casler

Dissertations, Theses, and Capstone Projects

The Mu2e Experiment is a precision experiment at Fermi National Accelerator Laboratory, searching for charged lepton flavor violation (CLFV) in the conversion of a muon to an electron in the presence of an atomic nucleus. In order to achieve the expected single-event sensitivity of 3 × 10^-17 , Mu2e will require an intense muon beam, generated via pion decay. These pions are the product of a proton beam striking a radiatively-cooled tungsten target. In order to maximize pion production and prevent target failure, the beam will have to be aligned with the target center to within 0.5 mm. The …

One-Loop Corrections To Dihadron Production In Dis At Small X, Filip Bergabo

Dissertations, Theses, and Capstone Projects

We calculate the one-loop corrections to dihadron production in Deep Inelastic Scattering (DIS) at small x using the Color Glass Condensate formalism. We show that all UV and soft singularities cancel while the collinear divergences are absorbed into quark and anti quark-hadron fragmentation functions. Rapidity divergences lead to JIMWLK evolution of dipoles and quadrupoles describing multiple-scatterings of the quark anti-quark dipole on the target proton/nucleus. The resulting cross section is finite and can be used for phenomenological studies of dihadron angular correlations at small x in a future Electron-Ion Collider (EIC).

Astrophysics, Cosmology And Particle Phenomenology At The Energy Frontier, Jorge Fernandez Soriano

Dissertations, Theses, and Capstone Projects

This dissertation consists of two parts, treating significantly separated fields. Each part consists on several chapters, each treating a somewhat isolated topic from the rest. In each chapter, I present some of the work developed during my passage through the graduate program, which has mostly been published elsewhere.

Part I – Cosmic Rays and Particle Physics

• Chapter 1: In this chapter we present an introduction to the topic of cosmic ray physics, with an special focus on the so-called ultra high energy cosmic rays: their potential origins, effects during their propagation between their sources and Earth, the different techniques used …

Magnetic Field Effects On The Physics Of Neutron Stars, Aric A. Hackebill

Dissertations, Theses, and Capstone Projects

In the context of neutron stars (NS), dense-magnetized quark and hadron models have been well studied under the assumption that the system's pressures are isotropic. However, the pressures determined from semi-classical statistical averaging of the energy momentum tensor in the presence of a uniform background magnetic field are anisotropic with different pressures arising along and perpendicular to the magnetic field direction. Since large magnetic fields are expected to be present in the interior of NS, it is important to understand the roll the pressure anisotropy plays. While considering the pressure anisotropy, we revisit some important calculations in NS physics.

We …

The Separation Of Charm And Bottom Decays Measured In P+Au Collisions At 200 Gev, Zhiyan Wang

Dissertations, Theses, and Capstone Projects

It has long been observed experimentally, from previous heavy-flavor electron measurements, that heavy quarks are subject to substantial modifications of their momentum spectrum. Using the PHENIX detector at the Relativistic Heavy Ion Collider (RHIC), measurements of the production of open heavy flavor hadrons with charm and bottom quarks in p+Au collisions at 200 GeV are studied and presented in this thesis. Distance of closest approach analysis of electron tracks is used to study the semileptonic decay electrons from charm and bottom hadrons. The results include invariant yield and fraction of bottom electrons. In addition to the p+p and Au+Au collisions’ …

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. …

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, 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 …

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 …

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 …

Baryons And Interactions In Magnetic Fields, Amol Deshmukh

Dissertations, Theses, and Capstone Projects

The QCD external field problem allows one to probe the rich behavior of strongly interacting systems under external conditions, including the modification of hadron structure and interactions due to external electromagnetic fields. These dynamics, moreover, are likely relevant to describe the physics in the interiors of magnetars and in non-central heavy-ion collisions, for which large magnetic fields upwards of $10^{19}$ Gauss are conceivable. Additionally motivated by lattice QCD calculations in external fields, we study the behavior of single- and two-baryon (specifically, two-nucleon) systems in large magnetic fields. The dependence of single-baryon energies on magnetic fields is explored using chiral dynamics. …

Some 2-Categorical Aspects In Physics, Arthur Parzygnat

Dissertations, Theses, and Capstone Projects

2-categories provide a useful transition point between ordinary category theory and infinity-category theory where one can perform concrete computations for applications in physics and at the same time provide rigorous formalism for mathematical structures appearing in physics. We survey three such broad instances. First, we describe two-dimensional algebra as a means of constructing non-abelian parallel transport along surfaces which can be used to describe strings charged under non-abelian gauge groups in string theory. Second, we formalize the notion of convex and cone categories, provide a preliminary categorical definition of entropy, and exhibit several examples. Thirdly, we provide a universal description …

New Classical Solutions In Supergravity, Zhibai Zhang

Dissertations, Theses, and Capstone Projects

In this Ph.D. thesis we construct three classes of new solutions to supergravity theories in various dimensions and study their properties. The first class is reduction ansatz of 10D and 11D supergravity on Ricci-flat and noncompact manifolds. These reductions are from a scaling limit of the famous spherical reductions, and can be solely supported by warp factors. The second class contains a large number of String/M theory solutions that have Lifshitz or Schrodinger scaling symmetry, obtained from marginally deforming the geometry of internal dimensions of previous solutions. We propose that these new solutions are dual to marginal deformations of certain …

Yang-Mills Theories As Deformations Of Massive Integrable Models, Axel Cortes Cubero

Dissertations, Theses, and Capstone Projects

Yang Mills theory in 2+1 dimensions can be expressed as an array of coupled (1+1)-dimensional principal chiral sigma models. The SU(N) principal chiral sigma model in 1+1 dimensions is integrable, asymptotically free and has massive excitations. We calculate all the form factors and two- point correlation functions of the Noether current and energy-momentum tensor, in

't Hooft's large-N limit (some form factors can be found even at finite N). We use these new form factors to calculate physical quantities in (2+1)-dimensional Yang-Mills theory, generalizing previous SU(2) by P. Orland to SU(N). The anisotropic gauge theory is related to standard isotropic …

Initial Conditions In High-Energy Collisions, Elena Petreska

Dissertations, Theses, and Capstone Projects

This thesis is focused on the initial stages of high-energy collisions in the saturation regime. We start by extending the McLerran-Venugopalan distribution of color sources in the initial wave-function of nuclei in heavy-ion collisions. We derive a fourth-order operator in the action and discuss its relevance for the description of color charge distributions in protons in high-energy experiments. We calculate the dipole scattering amplitude in proton-proton collisions with the quartic action and find an agreement with experimental data. We also obtain a modification to the fluctuation parameter of the negative binomial distribution of particle multiplicities in proton-proton experiments. The result …

Gauge/ Gravity Correspondence, Bulk Locality And Quantum Black Holes, Debajyoti Sarkar

Dissertations, Theses, and Capstone Projects

The aim of this dissertation is threefold. We begin by the study of two parallel ideal cosmic strings in the presence of non-minimal scalar fields and spin- 1 gauge fields. We show that the contributions of the non-minimal term on the interaction energy between the strings are similar to that of the gauge field for a particular value of non-minimal coupling parameter. In this context we clarify some of the issues that arise when comparing the renormalization of black hole entropy and entanglement entropy using the replica trick.

In the second part of the dissertation we study the process of …