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2017

Physics Faculty Publications

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Full-Text Articles in Physics

Erosion In Extruder Flows: Analytical And Numerical Study, Miron Kaufman, Petru S. Fodor Dec 2017

Erosion In Extruder Flows: Analytical And Numerical Study, Miron Kaufman, Petru S. Fodor

Physics Faculty Publications

© 2017 Author(s). We consider the erosion of particles (e.g. carbonblack agglomerates) advected by the polymeric flow in a single screw extruder. We assume a particle to be made of primary fragments bound together. In the erosion process a primary fragment breaks out of a given particle. Particles disperse because of the shear stresses imparted by the fluid. The time evolution of the numbers of particles of different sizes is described by the Bateman coupled differential equations developed a century ago to model radioactivity. Using the particle size distribution we compute an entropic fragmentation index which varies from 0 for …

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Measuring Polarized Emission In Clusters In The Cmb S4 Era, Louis Thibaut, Emory F. Bunn, Benjamin Wandelt, Joseph Silk Dec 2017

Measuring Polarized Emission In Clusters In The Cmb S4 Era, Louis Thibaut, Emory F. Bunn, Benjamin Wandelt, Joseph Silk

Physics Faculty Publications

The next generation of CMB experiments (CMB Stage-4) will produce a Sunyaev-Zel’dovich (SZ) cluster catalog containing ∼105 objects, two orders of magnitudes more than currently available. In this paper, we discuss the detectability of the polarized signal generated by scattering of the CMB quadrupole on the cluster electron gas using this catalog. We discuss the possibility of using this signal to measure the relationship between cluster optical depth and mass. We find that the area of observation of S4 maximizes the signal-to-noise (S/N) on the polarized signal but that this S/N is extremely small for an individual cluster, of order …

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Endothelial Nitric Oxide Synthase Oxygenase On Lipid Nanodiscs: A Nano-Assembly Reflecting Native-Like Function Of Enos, Ghaith Altawallbeh, Mohammad M. Haque, Kiril A. Streletzky, Dennis J. Stuehr, Mekki Bayachou Dec 2017

Endothelial Nitric Oxide Synthase Oxygenase On Lipid Nanodiscs: A Nano-Assembly Reflecting Native-Like Function Of Enos, Ghaith Altawallbeh, Mohammad M. Haque, Kiril A. Streletzky, Dennis J. Stuehr, Mekki Bayachou

Physics Faculty Publications

© 2017 Elsevier Inc. Endothelial nitric oxide synthase (eNOS) is a membrane-anchored enzyme. To highlight the potential role and effect of membrane phospholipids on the structure and activity of eNOS, we have incorporated the recombinant oxygenase subunit of eNOS into lipid nanodiscs. Two different size distribution modes were detected by multi-angle dynamic light scattering both for empty nanodiscs, and nanodiscs-bound eNOSoxy. The calculated hydrodynamic diameter for mode 1 species was 9.0 nm for empty nanodiscs and 9.8 nm for nanodisc bound eNOSoxy. Spectroscopic Griess assay was used to measure the enzymatic activity. Remarkably, the specific activity of nanodisc-bound eNOSoxy is …

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Stabilization Of Hypoxia Inducible Factor By Cobalt Chloride Can Alter Renal Epithelial Transport, Subhra Nag, Andrew Resnick Dec 2017

Stabilization Of Hypoxia Inducible Factor By Cobalt Chloride Can Alter Renal Epithelial Transport, Subhra Nag, Andrew Resnick

Physics Faculty Publications

© 2017 The Authors. Given the importance of the transcriptional regulator hypoxia-inducible factor-1 (HIF-1) for adaptive hypoxia responses, we examined the effect of stabilized HIF-1α on renal epithelial permeability and directed sodium transport. This study was motivated by histological analysis of cystic kidneys showing increased expression levels of HIF-1α and HIF-2α. We hypothesize that compression induced localized ischemia-hypoxia of normal epithelia near a cyst leads to local stabilization of HIF-1α, leading to altered transepithelial transport that encourages cyst expansion. We found that stabilized HIF-1α alters both transcellular and paracellular transport through renal epithelial monolayers in a manner consistent with secretory …

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A Glimpse Of Gluons Through Deeply Virtual Compton Scattering On The Proton, M. Defurne, A. Marti Jimenez-Arguello, Z. Ahmed, H. Albataineh, K. Allada, K. A. Aniol, V. Bellini, M. Benali, W. Boeglin, P. Bertin, M. Canan, C. E. Hyde, M. N. H. Rashad Nov 2017

A Glimpse Of Gluons Through Deeply Virtual Compton Scattering On The Proton, M. Defurne, A. Marti Jimenez-Arguello, Z. Ahmed, H. Albataineh, K. Allada, K. A. Aniol, V. Bellini, M. Benali, W. Boeglin, P. Bertin, M. Canan, C. E. Hyde, M. N. H. Rashad

Physics Faculty Publications

The internal structure of nucleons (protons and neutrons) remains one of the greatest outstanding problems in modern nuclear physics. By scattering high-energy electrons off a proton we are able to resolve its fundamental constituents and probe their momenta and positions. Here we investigate the dynamics of quarks and gluons inside nucleons using deeply virtual Compton scattering (DVCS)-a highly virtual photon scatters off the proton, which subsequently radiates a photon. DVCS interferes with the Bethe-Heitler (BH) process, where the photon is emitted by the electron rather than the proton. We report herein the full determination of the BH-DVCS interference by exploiting …

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Lattice Qcd Exploration Of Parton Pseudo-Distribution Functions, Kostas Orginos, Anatoly Radyushkin, Joseph Karpie, Savvas Zafeiropoulos Nov 2017

Lattice Qcd Exploration Of Parton Pseudo-Distribution Functions, Kostas Orginos, Anatoly Radyushkin, Joseph Karpie, Savvas Zafeiropoulos

Physics Faculty Publications

We demonstrate a new method of extracting parton distributions from lattice calculations. The starting idea is to treat the generic equal-time matrix element M(Pz(3), z(3)(2)) as a function of the Ioffe time nu = Pz(3) and the distance z(3). The next step is to divide M(Pz(3), z(3)(2)) by the rest-frame density M(0, z(3)(2)). Our lattice calculation shows a linear exponential z(3)-dependence in the rest-frame function, expected from the Z(z(3)(2)) factor generated by the gauge link. Still, we observe that the ratio M (Pz(3), z(3)(2))/M(Pz(3), z(3)(2)) has a Gaussian-type behavior with respect to z(3) for 6 values of P used in …

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Evaluation Of Wrf Scm Simulations Of Stratocumulus-Topped Marine And Coastal Boundary Layers And Improvements To Turbulence And Entrainment Parameterizations, Mohamed S. Ghonima, Handa Yang, Chang Ki Kim, Thijs Heus, Jan Kleissl Nov 2017

Evaluation Of Wrf Scm Simulations Of Stratocumulus-Topped Marine And Coastal Boundary Layers And Improvements To Turbulence And Entrainment Parameterizations, Mohamed S. Ghonima, Handa Yang, Chang Ki Kim, Thijs Heus, Jan Kleissl

Physics Faculty Publications

© 2017. The Authors. Stratocumulus-topped boundary layers (STBLs) are notoriously difficult to parameterize in single-column models due to the strong inversion layer across which entrainment mixing plays an important role in modulating the boundary layer mass, energy, and moisture balances. We compare three different WRF planetary boundary layer (PBL) schemes (Yonsei University, YSU; Asymmetric Convective Model version 2, ACM2; Mellor-Yamada-Nakanishi-Niino, MYNN) against large eddy simulations (LES) to find out that they underestimate entrainment flux in stratocumulus over both ocean and coastal land. Hence, the PBL schemes produce a cooler, moister STBL with higher liquid water content. In order to improve …

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Surface Impedance And Optimum Surface Resistance Of A Superconductor With An Imperfect Surface, Alex Gurevich, Takayuki Kubo Nov 2017

Surface Impedance And Optimum Surface Resistance Of A Superconductor With An Imperfect Surface, Alex Gurevich, Takayuki Kubo

Physics Faculty Publications

We calculate a low-frequency surface impedance of a dirty, s-wave superconductor with an imperfect surface incorporating either a thin layer with a reduced pairing constant or a thin, proximity-coupled normal layer. Such structures model realistic surfaces of superconducting materials which can contain oxide layers, absorbed impurities, or nonstoichiometric composition. We solved the Usadel equations self-consistently and obtained spatial distributions of the order parameter and the quasiparticle density of states which then were used to calculate a low-frequency surface resistance Rs (T) and the magnetic penetration depth λ(T) as functions of temperature in the limit of local London electrodynamics. It …

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First Exclusive Measurement Of Deeply Virtual Compton Scattering Off 4He: Toward The 3d Tomography Of Nuclei, M. Hattawy, N. A. Baltzell, R. Dupré, K. Hafidi, S. Stepanyan, S. Bültmann, R. De Vita, A. El Alaoui, L. El Fassi, H. Egiyan, B. Torayev, D. Adikaram, M. J. Amaryan, G. Charles, M. Khachatryan, A. Klein, S. E. Kuhn, M. Mayer, Y. Prok, L. B. Weinstein, Z. W. Zhao Nov 2017

First Exclusive Measurement Of Deeply Virtual Compton Scattering Off 4He: Toward The 3d Tomography Of Nuclei, M. Hattawy, N. A. Baltzell, R. Dupré, K. Hafidi, S. Stepanyan, S. Bültmann, R. De Vita, A. El Alaoui, L. El Fassi, H. Egiyan, B. Torayev, D. Adikaram, M. J. Amaryan, G. Charles, M. Khachatryan, A. Klein, S. E. Kuhn, M. Mayer, Y. Prok, L. B. Weinstein, Z. W. Zhao

Physics Faculty Publications

We report on the first measurement of the beam-spin asymmetry in the exclusive process of coherent deeply virtual Compton scattering off a nucleus. The experiment uses the 6 GeV electron beam from the Continuous Electron Beam Accelerator Facility (CEBAF) accelerator at Jefferson Lab incident on a pressurized 4He gaseous target placed in front of the CEBAF Large Acceptance Spectrometer (CLAS). The scattered electron is detected by CLAS and the photon by a dedicated electromagnetic calorimeter at forward angles. To ensure the exclusivity of the process, a specially designed radial time projection chamber is used to detect the recoiling 4 …

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Fermi Questions, Question 1: Trumpet Spit; Question 2: Tall Buildings, Larry Weinstein Oct 2017

Fermi Questions, Question 1: Trumpet Spit; Question 2: Tall Buildings, Larry Weinstein

Physics Faculty Publications

A quiz concerning physics is presented on topics such as the amount of saliva consumed by trumpeter Louis Armstrong during his career and the effect of buildings in the rotational inertia of the planet Earth.

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Intercalation Of Si Between Mos2 Layers, Rik Van Bremen, Qirong Yao, Soumya Banerjee, Deniz Cakir, Nuri Oncel, Harold J.W. Zandvliet Sep 2017

Intercalation Of Si Between Mos2 Layers, Rik Van Bremen, Qirong Yao, Soumya Banerjee, Deniz Cakir, Nuri Oncel, Harold J.W. Zandvliet

Physics Faculty Publications

We report a combined experimental and theoretical study of the growth of sub-monolayer amounts of silicon (Si) on molybdenum disulfide (MoS2). At room temperature and low deposition rates we have found compelling evidence that the deposited Si atoms intercalate between the MoS2 layers. Our evidence relies on several experimental observations: (1) Upon the deposition of Si on pristine MoS2 the morphology of the surface transforms from a smooth surface to a hill-and-valley surface. The lattice constant of the hill-and-valley structure amounts to 3.16 Å, which is exactly the lattice constant of pristine MoS2. (2) The transitions from hills to valleys …

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Pure E And B Polarization Maps Via Wiener Filtering, Emory F. Bunn, Benjamin Wandelt Aug 2017

Pure E And B Polarization Maps Via Wiener Filtering, Emory F. Bunn, Benjamin Wandelt

Physics Faculty Publications

In order to draw scientific conclusions from observations of cosmic microwave background (CMB) polarization,it is necessary to separate the contributions of the E and B components of the data. For data with incomplete sky coverage, there are ambiguous modes, which can be sourced by either E or B signals. Techniques exist for producing “pure” E and B maps, which are guaranteed to be free of cross-contamination, although the standard method, which involves constructing an eigenbasis, has a high computational cost. We show that such pure maps can be thought of as resulting from the application of a Wiener filter to …

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Microhh 1.0: A Computational Fluid Dynamics Code For Direct Numerical Simulation And Large-Eddy Simulation Of Atmospheric Boundary Layer Flows, Chiel C. Van Heerwaarden, Bart J.H. Van Stratum, Thijs Heus, Jeremy A. Gibbs, Evgeni Fedorovich, Juan Pedro Mellado Aug 2017

Microhh 1.0: A Computational Fluid Dynamics Code For Direct Numerical Simulation And Large-Eddy Simulation Of Atmospheric Boundary Layer Flows, Chiel C. Van Heerwaarden, Bart J.H. Van Stratum, Thijs Heus, Jeremy A. Gibbs, Evgeni Fedorovich, Juan Pedro Mellado

Physics Faculty Publications

© 2017 Author(s). This paper describes MicroHH 1.0, a new and open-source (www.microhh.org) computational fluid dynamics code for the simulation of turbulent flows in the atmosphere. It is primarily made for direct numerical simulation but also supports large-eddy simulation (LES). The paper covers the description of the governing equations, their numerical implementation, and the parameterizations included in the code. Furthermore, the paper presents the validation of the dynamical core in the form of convergence and conservation tests, and comparison of simulations of channel flows and slope flows against well-established test cases. The full numerical model, including the associated parameterizations for …

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Angular Distribution Of Single-Photon Superradiance In A Dilute And Cold Atomic Ensemble, A. S. Kuraptsev, I. M. Sokolov, M. D. Havey Aug 2017

Angular Distribution Of Single-Photon Superradiance In A Dilute And Cold Atomic Ensemble, A. S. Kuraptsev, I. M. Sokolov, M. D. Havey

Physics Faculty Publications

On the basis of a quantum microscopic approach we study the dynamics of the afterglow of a dilute Gaussian atomic ensemble excited by pulsed radiation. Taking into account the vector nature of the electromagnetic field we analyze in detail the angular and polarization distribution of single-photon superradiance of such an ensemble. The dependence of the angular distribution of superradiance on the length of the pulse and its carrier frequency as well as on the size and the shape of the atomic clouds is studied. We show that there is substantial dependence of the superradiant emission on the polarization and the …

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Exploring The Gender Gap In The Conceptual Survey Of Electricity And Magnetism, Rachel Henderson, Gay Stewart, John Stewart, Lynnette Michaluk, Adrienne L. Traxler Jul 2017

Exploring The Gender Gap In The Conceptual Survey Of Electricity And Magnetism, Rachel Henderson, Gay Stewart, John Stewart, Lynnette Michaluk, Adrienne L. Traxler

Physics Faculty Publications

The “gender gap” on various physics conceptual evaluations has been extensively studied. Men’s average pretest scores on the Force Concept Inventory and Force and Motion Conceptual Evaluation are 13% higher than women’s, and post-test scores are on average 12% higher than women’s. This study analyzed the gender differences within the Conceptual Survey of Electricity and Magnetism (CSEM) in which the gender gap has been less well studied and is less consistent. In the current study, data collected from 1407 students (77% men, 23% women) in a calculus-based physics course over ten semesters showed that male students outperformed female students on …

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Higher-Twist Corrections To Gluon Tmd Factorization, I. Balitsky, A. Tarasov Jul 2017

Higher-Twist Corrections To Gluon Tmd Factorization, I. Balitsky, A. Tarasov

Physics Faculty Publications

We calculate power corrections to TMD factorization for particle production by gluon-gluon fusion in hadron-hadron collisions.

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Review Of Optical Detection Of Single Molecules Beyond The Diffraction And Diffusion Limit Using Plasmonic Nanostructures, Farzia Karim, Todd B. Smith, Chenglong Zhao Jun 2017

Review Of Optical Detection Of Single Molecules Beyond The Diffraction And Diffusion Limit Using Plasmonic Nanostructures, Farzia Karim, Todd B. Smith, Chenglong Zhao

Physics Faculty Publications

Single-molecule detection has become a unique and indispensable tool for the study of molecular motions and interactions at the single-molecule level. Unlike ensemble measurement where the information is averaged, single-molecule analysis yields invaluable information on both the individual molecular properties and their microenvironment. Among the various technologies for the detection of single molecules, the detection with optical methods has many advantages in terms of its high sensitivity, electrical passiveness, and robustness. The recent advances in the engineering of either the excitation light or the solution of the molecules have paved the way for enhanced single-molecule detection. We present recent developments …

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Rosenbluth Separation Of The Π0 Electroproduction Cross Section Off The Neutron, M. Mazouz, Z. Ahmed, H. Albataineh, K. Allada, K. A. Aniol, V. Bellini, M. Benali, W. Boeglin, P. Bertin, M. Canan, C. E. Hyde, S. Koirala, M. N. H. Rashad Jun 2017

Rosenbluth Separation Of The Π0 Electroproduction Cross Section Off The Neutron, M. Mazouz, Z. Ahmed, H. Albataineh, K. Allada, K. A. Aniol, V. Bellini, M. Benali, W. Boeglin, P. Bertin, M. Canan, C. E. Hyde, S. Koirala, M. N. H. Rashad

Physics Faculty Publications

We report the first longitudinal-transverse separation of the deeply virtual exclusive π0 electroproduction cross section off the neutron and coherent deuteron. The corresponding four structure functions dσL/dt, dσT/dt, dσLT/dt, and dσTT/dt are extracted as a function of the momentum transfer to the recoil system at Q2 = 1.75 GeV2 and xB = 0.36. The ed -> edπ0 cross sections are found compatible with the small values expected from theoretical models. The en -> enπ0 cross sections show a dominance from the response to transversely polarized …

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Electromagnetic Design Of A Superconducting Twin Axis Cavity, S. U. De Silva, H. Park, J. R. Delayen, F. Marhauser, A. Hutton May 2017

Electromagnetic Design Of A Superconducting Twin Axis Cavity, S. U. De Silva, H. Park, J. R. Delayen, F. Marhauser, A. Hutton

Physics Faculty Publications

The twin-axis cavity is a new kind of rf superconducting cavity that consists of two parallel beam pipes, which can accelerate or decelerate two spatially separated beams in the same cavity. This configuration is particularly effective for high-current beams with low-energy electrons that will be used for bunched beam cooling of high-energy protons or ions. The new cavity geometry was designed to create a uniform accelerating or decelerating fields for both beams by utilizing a TM110 dipole mode. This paper presents the design rf optimization of a 1497 MHz twin-axis single-cell cavity, which is currently under fabrication.

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Fermi Questions, Question 1: Too Many Mosquitoes; Question 2: Tug Of War, Larry Weinstein May 2017

Fermi Questions, Question 1: Too Many Mosquitoes; Question 2: Tug Of War, Larry Weinstein

Physics Faculty Publications

A quiz concerning the number of mosquitoes required to drain a human of blood and the amount of rope-tension in a tug of war contest.

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Development Of A Superconducting Twin Axis Cavity, H. Park, F. Marhauser, A. Hutton, S. U. De Silva, J. R. Delayen May 2017

Development Of A Superconducting Twin Axis Cavity, H. Park, F. Marhauser, A. Hutton, S. U. De Silva, J. R. Delayen

Physics Faculty Publications

Superconducting cavities with two separate accelerating axes have been proposed in the past for energy recovery linac applications. While the study showed the advantages of such cavity, the designs present serious fabrication challenges. Hence the proposed cavities have never been built. The new design, elliptical twin cavity, proposed by Jefferson Lab and optimized by Center for Accelerator Science at Old Dominion University, allows similar level of engineering and fabrication techniques of a typical elliptical cavity. This paper describes preliminary LOM and HOM spectrum, engineering and fabrication processes of the twin axis cavity.

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Modeling Local Crabbing Dynamics In The Jleic Ion Collider Ring, Salvador Sosa Guitron, Vasiliy Morozov, Jean Delayen May 2017

Modeling Local Crabbing Dynamics In The Jleic Ion Collider Ring, Salvador Sosa Guitron, Vasiliy Morozov, Jean Delayen

Physics Faculty Publications

The Jefferson Lab Electron-Ion Collider (JLEIC) design considers a 50 mrad crossing angle at the Interaction Point. Without appropriate compensation, this could geometrically reduce the luminosity by an order of magnitude. A local crabbing scheme is implemented to avoid the luminosity loss: crab cavities are placed at both sides of the interaction region to restore a head-on collision scenario. In this contribution, we report on the implementation of a local crabbing scheme in the JLEIC ion ring. The effects of this correction scheme on the stability of proton bunches are analyzed using the particle tracking software elegant.

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Trim Tuning Of Sps-Series Dqw Crab Cavity Prototypes, S. Verdú-Andrés, J. Skaritka, Q. Wu, A. Ratti, S. Baurac, C. H. Boulware, T. Grimm, J. Yancey, W. Clemens, E. A. Mcewen, H. Park May 2017

Trim Tuning Of Sps-Series Dqw Crab Cavity Prototypes, S. Verdú-Andrés, J. Skaritka, Q. Wu, A. Ratti, S. Baurac, C. H. Boulware, T. Grimm, J. Yancey, W. Clemens, E. A. Mcewen, H. Park

Physics Faculty Publications

The final steps in the manufacturing of a superconducting RF cavity involve careful tuning before the final welds to match the target frequency as fabrication tolerances may introduce some frequency deviations. The target frequency is chosen based on analysis of the shifts induced by remaining processing steps including acid etching and cool down. The baseline fabrication of a DQW crab cavity for the High Luminosity LHC (HL-LHC) envisages a first tuning before the cavity subassemblies are welded together. To produce a very accurate final result, subassemblies are trimmed to frequency in the last machining steps, using a clamped cavity assembly …

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Wakefield Analysis Of Superconducting Rf-Dipole Cavities, Subashini De Silva, Jean Delayen May 2017

Wakefield Analysis Of Superconducting Rf-Dipole Cavities, Subashini De Silva, Jean Delayen

Physics Faculty Publications

RF-dipole crabbing cavities are being considered for a variety of crabbing applications. Some of the applications are the crabbing cavity systems for LHC High Luminosity Upgrade and the proposed Electron-Ion Collider for Jefferson Lab. The design requirements in the current applications require the cavities to incorporate complex damping schemes to suppress the higher order modes that may be excited by the high intensity proton or electron beams traversing through the cavities. The number of cavities required to achieve the desired high transverse voltage, and the complexity in the cavity geometries also contributes to the wakefields generated by beams. This paper …

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What Are The Low-Q And Large-X Boundaries Of Collinear Qcd Factorization Theorems?, E. Moffat, W. Melnitchouk, T. C. Rogers, N. Sato May 2017

What Are The Low-Q And Large-X Boundaries Of Collinear Qcd Factorization Theorems?, E. Moffat, W. Melnitchouk, T. C. Rogers, N. Sato

Physics Faculty Publications

Familiar factorized descriptions of classic QCD processes such as deeply inelastic scattering (DIS) apply in the limit of very large hard scales, much larger than nonperturbative mass scales and other nonperturbative physical properties like intrinsic transverse momentum. Since many interesting DIS studies occur at kinematic regions where the hard scale, Q ∼ 1-2 GeV, is not very much greater than the hadron masses involved, and the Bjorken scaling variable xbj is large, xbj ≳ 0.5, it is important to examine the boundaries of the most basic factorization assumptions and assess whether improved starting points are needed. Using an …

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Target And Double Spin Asymmetries Of Deeply Virtual Π0 Production With A Longitudinally Polarized Proton Target And Clas, A. Kim, H. Avakian, V. Burkert, K. Joo, W. Kim, K. P. Adhikari, Z. Akbar, S. Anefalos Pereira, R. A. Badui, M. Battaglieri, S. Bültmann, A. Klein, S E. Kuhn, Y. Prok, B. Torayev, L. B. Weinstein, J. Zhang May 2017

Target And Double Spin Asymmetries Of Deeply Virtual Π0 Production With A Longitudinally Polarized Proton Target And Clas, A. Kim, H. Avakian, V. Burkert, K. Joo, W. Kim, K. P. Adhikari, Z. Akbar, S. Anefalos Pereira, R. A. Badui, M. Battaglieri, S. Bültmann, A. Klein, S E. Kuhn, Y. Prok, B. Torayev, L. B. Weinstein, J. Zhang

Physics Faculty Publications

The target and double spin asymmetries of the exclusive pseudoscalar channel e→p→→epπ0 were measured for the first time in the deep-inelastic regime using a longitudinally polarized 5.9 GeV electron beam and a longitudinally polarized proton target at Jefferson Lab with the CEBAF Large Acceptance Spectrometer (CLAS). The data were collected over a large kinematic phase space and divided into 110 four-dimensional bins of Q2, xB, −t and ϕ. Large values of asymmetry moments clearly indicate a substantial contribution to the polarized structure functions from transverse virtual photon amplitudes. The interpretation of experimental data in terms of …

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Kinematics Of Subluminous O And B Stars By Surface Helium Abundance, P. Martin, C. S. Jeffery, Naslim N., V. M. Woolf May 2017

Kinematics Of Subluminous O And B Stars By Surface Helium Abundance, P. Martin, C. S. Jeffery, Naslim N., V. M. Woolf

Physics Faculty Publications

The majority of hot subdwarf stars are low-mass core-helium-burning stars. Their atmospheres are generally helium deficient; however, a minority have extremely helium-rich surfaces. An additional fraction have an intermediate surface-helium abundance, occasionally accompanied by peculiar abundances of other elements. We have identified a sample of 88 hot subdwarfs including 38 helium-deficient, 27 intermediate-helium and 23 extreme-helium stars for which radial-velocity and proper-motion measurements, together with distances, allow a calculation of galactic space velocities. We have investigated the kinematics of these three groups to determine whether they belong to similar or different Galactic populations. The majority of helium-deficient subdwarfs in our …

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Fermi Questions, Question 1: Penny Floors; Question 2: Secondhand Smoke, Larry Weinstein Apr 2017

Fermi Questions, Question 1: Penny Floors; Question 2: Secondhand Smoke, Larry Weinstein

Physics Faculty Publications

A quiz concerning the cost to tile the floor of a room and negative effect of secondhand smoke is presented.

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Factorization Breaking Of Adt For Polarized Deuteron Targets In A Relativistic Framework, Sabine Jeschonnek, J. W. Van Orden Apr 2017

Factorization Breaking Of Adt For Polarized Deuteron Targets In A Relativistic Framework, Sabine Jeschonnek, J. W. Van Orden

Physics Faculty Publications

We discuss the possible factorization of the tensor asymmetry AdT measured for polarized deuteron targets within a relativistic framework. We define a reduced asymmetry and find that factorization holds only in plane wave impulse approximation and if p waves are neglected. Our numerical results show a strong factorization breaking once final state interactions are included. We also compare the d-wave content of the wave functions with the size of the factored, reduced asymmetry and find that there is no systematic relationship of this quantity to the d-wave probability of the various wave functions.

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Exclusive Η Electroproduction At W > 2 Gev With Clas And Transversity Generalized Parton Distributions, I. Bedlinskiy, V. Kubarovsky, P. Stoler, K. P. Adhikari, Z. Akbar, S. Anefalos Pereira, H. Avakian, J. Ball, N. A. Baltzell, M. Battaglieri, C. E. Hyde, M. Khachatryan, S E. Kuhn, Y. Prok, B. Torayev, L. B. Weinstein Mar 2017

Exclusive Η Electroproduction At W > 2 Gev With Clas And Transversity Generalized Parton Distributions, I. Bedlinskiy, V. Kubarovsky, P. Stoler, K. P. Adhikari, Z. Akbar, S. Anefalos Pereira, H. Avakian, J. Ball, N. A. Baltzell, M. Battaglieri, C. E. Hyde, M. Khachatryan, S E. Kuhn, Y. Prok, B. Torayev, L. B. Weinstein

Physics Faculty Publications

The cross section of the exclusive η electroproduction reaction ep -> e'p' η was measured at Jefferson Laboratory with a 5.75 GeV electron beam and the CLAS detector. Differential cross sections d4σ /dtdQ2 dxBd φη and structure functions σU=σT + εσL, σTT, and σLT, as functions of t, were obtained over a wide range of Q2 and xB. The η structure functions are compared with those previously measured for π0 at the same kinematics. At low t, both π …

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