Physics Commons^™

Measurement Of The Target-Normal Single-Spin Asymmetry In Quasielastic Scattering From The Reaction 3He↑(E,E′ ), Chiranjib Dutta, Wolfgang Korsch, Y.-W. Zhang, E. Long, M. Mihovilovič, G. Jin, K. Allada, B. Anderson, J. R. M. Annand, T. Averett, C. Ayerbe-Gayoso, W. Boeglin

Physics and Astronomy Faculty Publications

We report the first measurement of the target single-spin asymmetry, A_y, in quasielastic scattering from the inclusive reaction ³He^↑(e,e′ ) on a ³He gas target polarized normal to the lepton scattering plane. Assuming time-reversal invariance, this asymmetry is strictly zero for one-photon exchange. A nonzero A_y can arise from the interference between the one- and two-photon exchange processes which is sensitive to the details of the substructure of the nucleon. An experiment recently completed at Jefferson Lab yielded asymmetries with high statistical precision at Q²=0.13, 0.46, and …

Experimental And Theoretical Basis For A Closed-Form Spectral Brdf Model, Samuel D. Butler

Theses and Dissertations

The microfacet class of BRDF models is frequently used to calculate optical scatter from realistic surfaces using geometric optics, but has the disadvantage of not being able to consider wavelength dependence. This dissertation works toward development of a closed-form approximation to the BRDF that is suitable for hyperspectral remote sensing by presenting measured BRDF data of 12 different materials at four different incident angles and up to seven different wavelengths between 3.39 and 10.6 micrometer. The data was intended to be fit to various microfacet BRDF models to determine an appropriate form of the wavelength scaling. However, when fitting the …

Eletron-Helium Laser-Assisted Free-Free Scattering For Incident Energies From 30 - 200 Ev: Effects Of Polarization Direction, B. A. Deharak, Benjamin Nosarzewski, Mahsa Siavashpouri, Nicholas L. S. Martin

Physics and Astronomy Faculty Publications

We report on experiments that examine electron-helium scattering in the presence of an Nd:YAG laser field of 1.17 eV photons. At each incidentelectron energy (30, 60, and 200 eV), the laser polarization direction is varied within a plane perpendicular to the Watson approximation calculations.

Inelastic Neutron Scattering Cross Sections For 76Ge Relevant To Background In Neutrinoless Double-Β Decay Experiments, Benjamin P. Crider, Erin Elizabeth Peters, J. M. Allmond, Marcus T. Mcellistrem, Francisco M. Prados-Estévez, T. J. Ross, J. R. Vanhoy, Steven W. Yates

Physics and Astronomy Faculty Publications

The experimental signature in searches for the neutrinoless double-β decay of ⁷⁶Ge is a peak near 2039 keV in the spectrum. Given the low probability of the process, it is important that the background in this region be well understood. Inelastic scattering reactions with neutrons from muon-induced interactions and (α,n) reactions in the surrounding materials or in the detector can provide contributions to the background. We have measured the production cross sections for γ rays from the ⁷⁶Ge(n,n'γ ) reaction in the 2039-keV region at incident neutron energies up to …

Quantum Mechanics With A Quartic Dispersion Law, Joanna Ruhl

Graduate Masters Theses

Creation of three-dimensional matter waves, the three-dimensional analog of one-dimensional solitons, has been a goal of experimental physics for some time. A recent proposal has suggested that changing the dispersion law from quadratic to quartic for ultra cold atoms in a shaken lattice should allow for the creation of these objects. In this thesis, we develop the theoretical basis for quantum mechanics with a quartic dispersion law. The probability current functional is constructed from the corresponding time-dependent Schrödinger equation, and used to derive the junction conditions that connect the derivatives of the wavefunction on one side of a potential discontinuity …

Compton Scattering From The Deuteron Below Pion-Production Threshold, L. S. Myers, J. R. M. Annand, J. Brudvik, G. Feldman, K. G. Fissum, H. W. Grießhammer, K. Hansen, S. S. Henshaw, L. Isaksson, R. Jebali, Michael A. Kovash, M. Lundin, D. G. Middleton, A. M. Nathan, B. Schröder, S. C. Stave

Physics and Astronomy Faculty Publications

Differential cross sections for elastic scattering of photons from the deuteron have recently been measured at the Tagged-Photon Facility at theMAX IV Laboratory in Lund, Sweden. These first new measurements in more than a decade further constrain the isoscalar electromagnetic polarizabilities of the nucleon and provide the first-ever results above 100 MeV, where the sensitivity to the polarizabilities is increased. We add 23 points between 70 and 112 MeV, at angles 60^◦, 120^◦, and 150^◦. Analysis of these data using a chiral effective field theory indicates that the cross sections are both self-consistent and …

Paraxial Full-Field Cloaking, Joseph S. Choi, John C. Howell

Mathematics, Physics, and Computer Science Faculty Articles and Research

We complete the ‘paraxial’ (small-angle) ray optics cloaking formalism presented previously [Opt. Express 22, 29465 (2014)], by extending it to the full-field of light. Omnidirectionality is then the only relaxed parameter of what may be considered an ideal, broadband, field cloak. We show that an isotropic plate of uniform thickness, with appropriately designed refractive index and dispersion, can match the phase over the whole visible spectrum. Our results support the fundamental limits on cloaking for broadband vs. omnidirectionality, and provide insights into when anisotropy may be required.

Measurement Of The Scattering Cross Section Of Slow Neutrons On Liquid Parahydrogen From Neutron Transmission, K. B. Grammer, R. Alarcon, L. Barrón-Palos, D. Blyth, J. D. Bowman, J. Calarco, Christopher Crawford, K. Craycroft, D. Evans, N. Fomin, J. Fry, M. Gericke, R. C. Gillis, G. L. Greene, J. Hamblen, C. Hayes, S. Kucuker, R. Mahurin, M. Maldonado-Velázquez, E. Martin, M. Mccrea, P. E. Mueller, M. Musgrave, H. Nann, S. I. Penttilä, W. M. Snow, Z. Tang, W. S. Wilburn

Physics and Astronomy Faculty Publications

Liquid hydrogen is a dense Bose fluid whose equilibrium properties are both calculable from first principles using various theoretical approaches and of interest for the understanding of a wide range of questions in many-body physics. . . .

The remainder of this abstract can be read at:

http://dx.doi.org/10.1103/PhysRevB.91.180301

Rapidity Evolution Of Gluon Tmd From Low To Moderate X, I. Balitsky, A. Tarasov

Physics Faculty Publications

We study how the rapidity evolution of gluon transverse momentum dependent distribution changes from nonlinear evolution at small x << 1 to linear evolution at moderate x ∼ 1.

Separated Response Functions In Exclusive, Forward Π± Electroproduction On Deuterium, G. M. Huber, H. P. Blok, A. Klein, L. M. Qin, K. Vansyoc, Jefferson Lab, Fπ Collaboration

Physics Faculty Publications

Background: Measurements of forward exclusive meson production at different squared four-momenta of the exchanged virtual photon, Q², and at different four-momentum transfer, t, can be used to probe QCD's transition from meson-nucleon degrees of freedom at long distances to quark-gluon degrees of freedom at short scales. Ratios of separated response functions in π^- and π⁺ electroproduction are particularly informative. The ratio for transverse photons may allow this transition to be more easily observed, while the ratio for longitudinal photons provides a crucial verification of the assumed pole dominance, needed for reliable extraction of the pion form …

Direct Observation Of Quark-Hadron Duality In The Free Neutron F2 Structure Function, I. Niculescu, G. Niculescu, W. Melnitchouk, J. Arrington, M. E. Christy, S. Kuhn

Physics Faculty Publications

Using the recently published data from the BONuS(Barely Off-shell Nucleon Structure) experiment at Jefferson Lab, which utilized a spectator tagging technique to extract the inclusive electron-free neutron scattering cross section, we obtain the first direct observation of quark-hadron duality in the neutron F₂ structure function. The data are used to reconstruct the lowest few (N = 2, 4, and 6) moments of F₂ in the three prominent nucleon resonance regions, as well as the moments integrated over the entire resonance region. Comparison with moments computed from global parametrizations of parton distribution functions suggest that quark-hadron duality holds locally …

Accuracy Of Theory For Calculating Electron Impact Ionization Of Molecules, Hari Chaluvadi

Doctoral Dissertations

The study of electron impact single ionization of atoms and molecules has provided valuable information about fundamental collisions. The most detailed information is obtained from triple differential cross sections (TDCS) in which the energy and momentum of all three final state particles are determined. These cross sections are much more difficult for theory since the detailed kinematics of the experiment become important. There are many theoretical approximations for ionization of molecules. One of the successful methods is the molecular 3-body distorted wave (M3DW) approximation. One of the strengths of the DW approximation is that it can be applied for any …

Transverse Momentum Dependent (Tmd) Parton Distribution Functions: Status And Prospects, R. Angeles-Martinez, A. Bacchetta, I. I. Balitsky, D. Boer, M. Boglione, R. Boussarie, F. A. Ceccopieri, I. O. Cherednikov, P. Connor, M. G. Echevarria, G. Ferrera, J. Grados Luyando, F. Hautmann, H. Jung, T. Kasemets, K. Kutak, J. P. Lansberg, A. Lelek, G. Lykasov, J. D. Madrigal Martinez, P. J. Mulders, E. R. Nocera, E. Petreska, C. Pisano, R. Plaċakyte, V. Radescu, M. Radici, G. Schnell, I. Scimemi, A. Signori, L. Szymanowski, S. Taheri Monfared, F.F. Van Der Veken, H. J. Van Haevermaet, P. Van Mechelen, A. A. Vladimirov, S. Wallon

Physics Faculty Publications

We review transverse momentum dependent (TMD) parton distribution functions, their application to topical issues in high-energy physics phenomenology, and their theoretical connections with QCD resummation, evolution and factorization theorems. We illustrate the use of TMDs via examples of multi-scale problems in hadronic collisions. These include transverse momentum q_T spectra of Higgs and vector bosons for low q_T, and azimuthal correlations in the production of multiple jets associated with heavy bosons at large jet masses. We discuss computational tools for TMDs, and present the application of a new tool, TMD_LIB, to parton density fits and parameterizations.