Physics Commons^™

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 “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 …

Effects Of Ether Vs. Ester Linkage On Lipid Bilayer Structure And Water Permeability., S. Deren Guler, D. Dipon Ghosh, Jianjun Pan, John Mathai, Mark Zeidel, John Nagle, Stephanie Tristram-Nagle

Prof. Stephanie Tristram-Nagle Ph.D.

The structure and water permeability of bilayers composed of the ether-linked lipid, dihexadecylphosphatidylcholine (DHPC), were studied and compared with the ester-linked lipid, dipalmitoylphosphaditdylcholine (DPPC). Wide angle X-ray scattering on oriented bilayers in the fluid phase indicate that the area per lipid A is slightly larger for DHPC than for DPPC. Low angle X-ray scattering yields A=65.1A(2) for DHPC at 48 degrees C. LAXS data provide the bending modulus, K(C)=4.2x10(-13)erg, and the Hamaker parameter H=7.2x10(-14)erg for the van der Waals attractive interaction between neighboring bilayers. For the low temperature phases with ordered hydrocarbon chains, we confirm the transition from a tilted …

Molecular Structures Of Fluid Phase Phosphatidylglycerol Bilayers As Determined By Small Angle Neutron And X-Ray Scattering., Jianjun Pan, Frederick Heberle, Stephanie Tristram-Nagle, Michelle Szymanski, Mary Koepfinger, John Katsaras, Norbert Kucerka

Prof. Stephanie Tristram-Nagle Ph.D.

We have determined the molecular structures of commonly used phosphatidylglycerols (PGs) in the commonly accepted biologically relevant fluid phase. This was done by simultaneously analyzing small angle neutron and X-ray scattering data, with the constraint of measured lipid volumes. We report the temperature dependence of bilayer parameters obtained using the one-dimensional scattering density profile model - which was derived from molecular dynamics simulations - including the area per lipid, the overall bilayer thickness, as well as other intrabilayer parameters (e.g., hydrocarbon thickness). Lipid areas are found to be larger than their phosphatidylcholine (PC) counterparts, a result likely due to repulsive …

Alamethicin Aggregation In Lipid Membranes., Jianjun Pan, Stephanie Tristram-Nagle, John Nagle

Prof. Stephanie Tristram-Nagle Ph.D.

X-ray scattering features induced by aggregates of alamethicin (Alm) were obtained in oriented stacks of model membranes of DOPC(diC18:1PC) and diC22:1PC. The first feature obtained near full hydration was Bragg rod in-plane scattering near 0.11 A(-1) in DOPC and near 0.08 A(-1) in diC22:1PC at a 1:10 Alm:lipid ratio. This feature is interpreted as bundles consisting of n Alm monomers in a barrel-stave configuration surrounding a water pore. Fitting the scattering data to previously published molecular dynamics simulations indicates that the number of peptides per bundle is n = 6 in DOPC and n >or= 9 in diC22:1PC. The larger …

Crac Motif Peptide Of The Hiv-1 Gp41 Protein Thins Sopc Membranes And Interacts With Cholesterol., Alexander Greenwood, Jianjun Pan, Thalia Mills, John Nagle, Richard Epand, Stephanie Tristram-Nagle

Prof. Stephanie Tristram-Nagle Ph.D.

This study uses low-angle (LAXS) and wide-angle (WAXS) X-ray synchrotron scattering, volume measurements and thin layer chromatography to determine the structure and interactions of SOPC, SOPC/cholesterol mixtures, SOPC/peptide and SOPC/cholesterol/peptide mixtures. N-acetyl-LWYIK-amide (LWYIK) represents the naturally-occurring CRAC motif segment in the pretransmembrane region of the gp41 protein of HIV-1, and N-acetyl-IWYIK-amide (IWYIK), an unnatural isomer, is used as a control. Both peptides thin the SOPC bilayer by approximately 3 A, and cause the area/unit cell (peptide+SOPC) to increase by approximately 9 A2 from the area/lipid of SOPC at 30 degrees C (67.0+/-0.9 A2). Model fitting suggests that LWYIK's average position …

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 …

Fully Differential Cross Sections For Electron-Impact Excitation-Ionization Of Aligned D₂, Esam Ali, A. L. Harris, J. Lower, E. Weigold, Chuang-Gang Ning, Don H. Madison

Physics Faculty Research & Creative Works

We examine fully differential cross sections for 176 eV electron-impact dissociative excitation-ionization of orientated D2 for transitions to final ion states 2sσ_g, 2pσ_u, and 2pπ_u. In previous work [Phys. Rev. A 88, 062705 (2013)PLRAAN1050-294710.1103/PhysRevA.88.062705], we calculated these cross sections using the molecular four-body distorted wave (M4DW) method with the ground-state D2 wave function being approximated by a product of two Dyson 1s-type orbitals. The theoretical results were compared with experimental measurements for five different orientations of the target molecule (four in the scattering plane and one perpendicular to the scattering plane). For the unresolved …

Monte Carlo Simulations Of Atmospheric Loss By Stellar Winds From Exoplanets, Daniel P. Violette

University Scholar Projects

Hot Jupiters are a class of extra-solar planets. Massive gas giants on the same size scale as Jupiter, they orbit their host stars closely. This proximity results in large stellar winds capable of stripping away a planet’s atmosphere. Developing a more complete understanding of atmospheric mass loss and evolution in planetary bodies is critical, and Hot Jupiter systems are accessible analogues.

This project will seek to create a computational model capable of estimating mass loss rates due to stellar winds. A Monte Carlo method is utilized to take an ensemble of single, high-energy energetic neutral particles, produced by kilo-electronvolt stellar …

Monte Carlo Simulations Of Atmospheric Loss By Stellar Winds From Exoplanets, Daniel Violette

Honors Scholar Theses

Hot Jupiters are a class of extra-solar planets. Massive gas giants on the same size scale as Jupiter, they orbit their host stars closely. This proximity results in large stellar winds capable of stripping away a planet’s atmosphere. Developing a more complete understanding of atmospheric mass loss and evolution in planetary bodies is critical, and Hot Jupiter systems are accessible analogues.

This project will seek to create a computational model capable of estimating mass loss rates due to stellar winds. A Monte Carlo method is utilized to take an ensemble of single, high-energy energetic neutral particles, produced by kilo-electronvolt stellar …

Born-Oppenheimer Study Of Two-Component Few-Particle Systems Under One-Dimensional Confinement, Nirav P. Mehta

Physics and Astronomy Faculty Research

The energy spectrum, atom-dimer scattering length, and atom-trimer scattering length for systems of three and four ultracold atoms with δ-function interactions in one dimension are presented as a function of the relative mass ratio of the interacting atoms. The Born-Oppenheimer approach is used to treat three-body (“HHL”) systems of one light and two heavy atoms, as well as four-body (“HHHL”) systems of one light and three heavy atoms. Zero-range interactions of arbitrary strength are assumed between different atoms, but the heavy atoms are assumed to be noninteracting among themselves. Fermionic and bosonic heavy atoms with both positive and negative parity …

Spin And Orbital Moments And Magnetic Order In Fe3o4 Nanoparticle Assemblies, Yanping Cai

Theses and Dissertations

Fe3O4 magnetic nanoparticles of 5 to 11 nm in size were prepared by organic methods. Particle size was analyzed by both X-ray Diffraction (XRD) and Transmission Electron Microscopy (TEM) techniques. Zero Field Cooling (ZFC) / Field Cooling (FC) and magnetization loop measurements were recorded by VSM, and they confirmed superparamagnetic behavior in the sample. The blocking temperature is found to be in the range of 30 K ~ 170 K. It has a dependence on the particle size. ZFC / FC curves also indicate the presence of magnetic coupling between particles. X-ray Magnetic Circular Dichroism (XMCD) measurements of these nanoparticles …

The Investigation Of The Molecular Mechanism Of Rhodopsin Activation By Small Angle Neutron Scattering And Small Angle X-Ray Scattering Techniques, Kurt William Van Delinder

Wayne State University Theses

Rhodopsin is a visual pigment found within the rod photoreceptor cells of the retina. It is a visual protein found within human beings and commonly shared amongst other vertebrate species. The major pigment protein is responsible for converting photons into chemical signals, which stimulates biological processes in the nervous system, and this allows the ability to then sense light [4]. The process of how rhodopsin is activated is believed to be understood with the introduction of a time ordered sequence of intermediate states. However, there are still major gaps and inconsistencies regarding the large-scale conformational changes that follow photoactivation. The …

Time-Reversal Symmetric Resolution Of Unity Without Background Integrals In Open Quantum Systems, Naomichi Hatano, Gonzalo Ordonez

Scholarship and Professional Work - LAS

We present a new complete set of states for a class of open quantum systems, to be used in expansion of the Green’s function and the time-evolution operator. A remarkable feature of the complete set is that it observes time-reversal symmetry in the sense that it contains decaying states (resonant states) and growing states (anti-resonant states) parallelly. We can thereby pinpoint the occurrence of the breaking of time-reversal symmetry at the choice of whether we solve Schrödinger equation as an initial-condition problem or a terminal-condition problem. Another feature of the complete set is that in the subspace of the central …

Scattering Of A Point-Like Anapole, Kyle Whitcomb

Summer Research

Majorana fermions, being elementary particles with half-integer spin which are their own antiparticle, are a hypothetical class of particle that are not currently in the Standard Model of particle physics. This research investigates the properties of Majorana fermions by calculating the scattering angle due to electromagnetic interactions between Majorana fermions and electrons. Since Majorana fermions interact solely via an electromagnetic term called the anapole moment, which is relatively weak compared to other terms, this problem was solved in the framework of quantum electrodynamics modeling the Majorana fermion as a point-like anapole. Additionally, since there is no restriction on the mass …

Data Analysis Techniques, Differential Cross Sections, And Spin Density Matrix Elements For The Reaction ᵞp → Φp, K.P. Adhikari, D. Adikaram, M.J. Amaryan, A. Klein, S. Koirala, Clas Collaboration

Physics Faculty Publications

High-statistics measurements of differential cross sections and spin density matrix elements for the reaction ᵞp → ϕp have been made using the CLAS detector at Jefferson Lab. We cover center-of-mass energies (√s) from 1.97 to 2.84 GeV, with an extensive coverage in the ϕ production angle. The high statistics of the data sample made it necessary to carefully account for the interplay between the ϕ natural lineshape and effects of the detector resolution, that are found to be comparable in magnitude. We study both the charged-(ϕ → K⁺ K^-) and neutral( ϕ → (K^O_SK …

Measurement Of Double-Polarization Asymmetries In The Quasielastic ³→He (→E, E' D) Process, M. Mihovilovic, G. Jin, M. Canan, S. Golge, R. Schiavilla, Jefferson Lab Hall A. Collaboration

Physics Faculty Publications

We present a precise measurement of double-polarization asymmetries in the ³→He (→e, e' d) reaction. This particular process is a uniquely sensitive probe of hadron dynamics in ³He and the structure of the underlying electromagnetic currents. The measurements have been performed in and around quasielastic kinematics at Q² = 0.25(GeV/c)² for missing momenta up to 270 MeV/c. The asymmetries are in fair agreement with the state-of-the-art calculations in terms of their functional dependencies on p_m and ω, but are systematically offset. Beyond the region of the quasielastic peak, the discrepancies become even more pronounced. Thus, our …

Beam-Spin Asymmetries From Semi-Inclusive Pion Electroproduction, K. P. Adhikari, M. J. Amaryan, C. Hyde, S. Koirala, S. E. Kuhn, L. B. Weinstein, Et Al., The Clas Collaboration

Physics Faculty Publications

We have measured the moment A^{sin ɸ}_LU corresponding to the polarized electron beam-spin asymmetry in semi-inclusive deep inelastic scattering. A^{sin ɸ}_LU is a twist-3 quantity providing information about quark-gluon correlations. Data were taken with the CLAS Spectrometer at Jefferson Lab using a 5.498 GeV longitudinally polarized electron beam and an unpolarized liquid hydrogen target. All three pion channels (π⁺,π⁰ and π^-) were measured simultaneously over a large range of kinematics within the virtuality range Q² ≈ 1.0- 4.5 GeV². The observable was measured with better than 1% statistical …

Data Analysis Techniques, Differential Cross Sections, And Spin Density Matrix Elements For The Reaction 𝛾p → Φp, K. P. Adhikari, D. Adikaram, M. J. Amaryan, C. E. Hyde, S. Koirala, S. E. Kuhn, M. Mayer, I. Niculescu, Et Al., The Clas Collaboration

Physics Faculty Publications

High-statistics measurements of differential cross sections and spin density matrix elements for the reaction γp→ϕp have been made using the CLAS detector at Jefferson Lab. We cover center-of-mass energies (√s) from 1.97 to 2.84 GeV, with an extensive coverage in the ϕ production angle. The high statistics of the data sample made it necessary to carefully account for the interplay between the ϕ natural lineshape and effects of the detector resolution, that are found to be comparable in magnitude. We study both the charged- (ϕ→K⁺K⁻) and neutral- (ϕ→K⁰_SK⁰_L) K^{→ …}