Physical Sciences and Mathematics Commons^™

Asymptotic Behaviour Of Hyperbolic Partial Differential Equations, Shi-Zhuo Looi

Theses and Dissertations--Mathematics

We investigate the asymptotic behaviour of solutions to a range of linear and nonlinear hyperbolic equations on asymptotically flat spacetimes. We develop a comprehensive framework for the analysis of pointwise decay of linear and nonlinear wave equations on asymptotically flat manifolds of three space dimensions that are allowed to be time-varying or nonstationary, including quasilinear wave equations. The Minkowski space and time-varying perturbations thereof are included among these spacetimes. A result on scattering for a nonlinear wave equation with finite-energy solutions on nonstationary spacetimes is presented. This work was motivated in part by the investigation of more precise asymptotic behaviour …

A Scattering Result For The Fifth-Order Kp-Ii Equation, Camille Schuetz

Theses and Dissertations--Mathematics

We will prove scattering for the fifth-order Kadomtsev-Petviashvilli II (fifth-order KP-II) equation. The fifth-order KP-II equation is an example of a nonlinear dispersive equation which takes the form $u_t=Lu + NL(u)$ where $L$ is a linear differential operator and $NL$ is a nonlinear operator. One looks for solutions $u(t)$ in a space $C(\R,X)$ where $X$ is a Banach space. For a nonlinear dispersive differential equation, the associated linear problem is $v_t=Lv$. A solution $u(t)$ of the nonlinear equation is said to scatter if as $t \to \infty$, the solution $u(t)$ approaches a solution $v(t)$ to the linear problem in the …

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 …

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 …

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 …

Inelastic Neutron Scattering Studies Of 76Ge And 76Se: Relevance To Elevance To Neutrinoless Double-Β Decay, B. P. Crider, E. E. Peters, T. J. Ross, Marcus T. Mcellistrem, Francisco M. Prados-Estévez, J. M. Allmond, J. R. Vanhoy, Steven W. Yates

Chemistry Faculty Publications

Inelastic neutron scattering measurements were performed at the University of Kentucky Accelerator Laboratory on enriched ⁷⁶Ge and ⁷⁶Se scattering samples. From measurements at incident neutron energies from 2.0 to 4.0 MeV, many new levels were identified and characterized in each nucleus; level lifetimes, transition probabilities, multipole mixing ratios, and other properties were determined. In addition, γ-ray cross sections for the ⁷⁶Ge(n,n′γ) reaction were measured at neutron energies up to 5.0 MeV, with the goal of determining the cross sections of γ rays in 2040-keV region, which corresponds to the region of interest in the neutrinoless double β …

Inelastic Neutron Scattering Studies Of 132,134Xe: Elucidating Structure In A Transitional Region And Possible Interferences For 0vββ Searches, E. E. Peters, T. J. Ross, B. P. Crider, S. F. Ashley, Anagha Chakraborty, M. D. Hennek, Ajay Kumar, S. H. Liu, Marcus T. Mcellistrem, Francisco M. Prados-Estévez, J. S. Thrasher, Steven W. Yates

Chemistry Faculty Publications

Highly enriched (> 99.9%) ¹³²Xe and ¹³⁴Xe gases were converted to solid ¹³²XeF₂ and ¹³⁴XeF₂ and were used as scattering samples for inelastic neutron scattering measurements at the University of Kentucky Accelerator Laboratory (UKAL). Lifetimes of levels up to 3.5MeV in excitation energy in these xenon isotopes were measured using the Doppler-shift attenuation method, allowing the determination of reduced transition probabilities. Gamma rays corresponding to new transitions and levels have been observed. In particular, tentative new excited 0⁺ states and associated decays have been examined in an effort to elucidate the structure of …

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

Measurement Of “Pretzelosity” Asymmetry Of Charged Pion Production In Semi-Inclusive Deep Inelastic Scattering On A Polarized 3He Target, K. Allada, C. Dutta, A. Kolarkar, Wolfgang Korsch, Y. Zhang, X. Qian, J. Huang, J. Katich, Y. Wang, K. Aniol, J. R. M. Annand, T. Averett

Physics and Astronomy Faculty Publications

An experiment to measure single-spin asymmetries of semi-inclusive production of charged pions in deep-inelastic scattering on a transversely polarized ³He target was performed at Jefferson Laboratory in the kinematic region of 0.16<x<0.35 and 1.42<2.7 GeV² Pretzelosity asymmetries on ³He, which are expressed as the convolution of the h^⊥_1T transverse-momentum-dependent distribution functions and the Collins fragmentation functions in the leading order, were measured for the first time. Under the effective polarization approximation, we extracted the corresponding neutron asymmetries from the measured ³He asymmetries and cross-section ratios between the proton and ³He. Our results show that both …

Single Spin Asymmetries In Charged Kaon Production From Semi-Inclusive Deep Inelastic Scattering On A Transversely Polarized 3He Target, C. Dutta, A. Kolarkar, Wolfgang Korsch, Y. X. Zhao, Y. Wang, K. Allada, K. Aniol, J. R. M. Annand, T. Averett, F. Benmokhtar, W. Bertozzi, P. C. Bradshaw, P. Bosted

Physics and Astronomy Faculty Publications

We report the first measurement of target single spin asymmetries of charged kaons produced in semi-inclusive deep inelastic scattering of electrons off a transversely polarized ³He target. Both the Collins and Sivers moments, which are related to the nucleon transversity and Sivers distributions, respectively, are extracted over the kinematic range of 0.1<x_bj<0.4 for K⁺ and K⁻ production. While the Collins and Sivers moments for K⁺ are consistent with zero within the experimental uncertainties, both moments for K⁻ favor negative values. The Sivers moments are compared to the theoretical prediction from a phenomenological fit to the …

Measurement Of The Target-Normal Single-Spin Asymmetry In Deep-Inelastic Scattering From The Reaction 3He↑(E,E′)X, K. Allada, C. Dutta, A. Kolarkar, Wolfgang Korsch, J. Katich, X. Qian, Y. X. Zhao, K. Aniol, J. R. M. Annand, T. Averett, F. Benmokhtar, W. Bertozzi, P. C. Bradshaw, P. Bosted

Physics and Astronomy Faculty Publications

We report the first measurement of the target-normal single-spin asymmetry in deep-inelastic scattering from the inclusive reaction ³He^↑(e,e′)X on a polarized ³He gas target. Assuming time-reversal invariance, this asymmetry is strictly zero in the Born approximation but can be nonzero if two-photon-exchange contributions are included. The experiment, conducted at Jefferson Lab using a 5.89 GeV electron beam, covers a range of 1.7<W<2.9 GeV, 1.0<Q²<4.0 GeV² and 0.16<x<6.5. Neutron asymmetries were extracted using the effective nucleon polarization and measured proton-to-³He cross-section ratios. The measured neutron asymmetries are negative with an average value of (−1.09±0.38)×10⁻² for invariant mass W>2 …

The Ultraviolet-Optical Albedo Of Broad Emission Line Clouds, Kirk Korista, Gary J. Ferland

Physics and Astronomy Faculty Publications

We explore the effective UV-optical albedos of a variety of types of broad emission line clouds, as well as their possible effects on the observed spectra of active galactic nuclei (AGNs). An important albedo source in moderately ionized ionization-bounded clouds is that which is due to neutral hydrogen: Rayleigh scattering of continuum photons off the extreme damping wings of Lyα. The photons resulting from this scattering mechanism may contribute significantly to the Lyα emission line, especially in the very broad wings. In addition, line photons emitted near 1200 Å (e.g., N V λ1240) that stream toward the neutral portion of …