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Physics Faculty Publications

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Articles 601 - 630 of 2178

Full-Text Articles in Physical Sciences and Mathematics

Networks Identify Productive Forum Discussions, Adrienne L. Traxler, A. Gavrin, Rebecca Lindell Sep 2018

Networks Identify Productive Forum Discussions, Adrienne L. Traxler, A. Gavrin, Rebecca Lindell

Physics Faculty Publications

Discussion forums provide a channel for students to engage with peers and course material outside of class, accessible even to commuter and nontraditional populations. Forums can build classroom community and aid learning, but students do not always take up these tools. We use network analysis to compare three semesters of forum logs from an introductory calculus-based physics course. The networks show dense structures of collaboration that differ significantly between semesters, even though aggregate participation statistics remain steady. After characterizing network structure for each semester, we correlate students’ centrality—a numeric measure of network position—with final course grade. Finally, we use a …

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Question 1: Plastic Straws; Question 2: Casino Sevens, Larry Weinstein Sep 2018

Question 1: Plastic Straws; Question 2: Casino Sevens, Larry Weinstein

Physics Faculty Publications

The article offers questions on 1) the impact that American plastic straws have on the environment, and 2) the probable longest streak of consecutive sevens in casino craps games in the entire history of Las Vegas, Nevada.

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Asymmetric Relativistic Fermi Gas Model For Quasielastic Lepton-Nucleus Scattering, M. B. Barbaro, A. De Pace, T. W. Donnelly, J. A. Caballero, G. D. Megias, J. W. Van Orden Sep 2018

Asymmetric Relativistic Fermi Gas Model For Quasielastic Lepton-Nucleus Scattering, M. B. Barbaro, A. De Pace, T. W. Donnelly, J. A. Caballero, G. D. Megias, J. W. Van Orden

Physics Faculty Publications

We develop an asymmetric relativistic Fermi gas model for the study of the electroweak nuclear response in the quasielastic region. The model takes into account the differences between neutron and proton densities in asymmetric (N> Z) nuclei, as well as differences in the neutron and proton separation energies. We present numerical results for both neutral and charged-current processes, focusing on nuclei of interest for ongoing and future neutrino oscillation experiments. We point out some important differences with respect to the commonly employed symmetric Fermi gas model.

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Photoproduction Of K+ K- Meson Pairs On The Proton, S. Lombardo, M. Battaglieri, A. Celentano, A. D'Angelo, R. De Vita, A. Filippi, D. I. Glazier, M. Khachatryan, A. Klein, Y. Prok, The Clas Collaboration Sep 2018

Photoproduction Of K+ K- Meson Pairs On The Proton, S. Lombardo, M. Battaglieri, A. Celentano, A. D'Angelo, R. De Vita, A. Filippi, D. I. Glazier, M. Khachatryan, A. Klein, Y. Prok, The Clas Collaboration

Physics Faculty Publications

The exclusive reaction γp → pK+K− was studied in the photon energy range 3.0–3.8 GeV and momentum transfer range 0.6 < −t< 1.3 GeV2. Data were collected with the CLAS detector at the Thomas Jefferson National Accelerator Facility. In this kinematic range the integrated luminosity was approximately 20 pb−1. The reaction was isolated by detecting the K+ and the proton in CLAS, and reconstructing the K− via the missing-mass technique. Moments of the dikaon decay angular distributions were extracted from the experimental data. Besides the dominant contribution of the ϕ meson in the P wave, …

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Catalysis Of Stark-Tuned Interactions Between Ultracold Rydberg Atoms, A. L. Win, W. D. Williams, T. J. Carroll, C. I. Sukenik Sep 2018

Catalysis Of Stark-Tuned Interactions Between Ultracold Rydberg Atoms, A. L. Win, W. D. Williams, T. J. Carroll, C. I. Sukenik

Physics Faculty Publications

We have experimentally investigated a catalysis effect in the resonant energy transfer between ultracold 85Rb Rydberg atoms. We studied the time dependence of the process, 34p + 34p → 34s + 35s, and observed an enhancement of 34s state population when 34d state atoms are added. We have also performed numerical model simulations, which are in qualitative agreement with experiment and indicate that the enhancement arises from a redistribution of p-state atoms due to the presence of the d-state atoms.

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Probing High-Momentum Protons And Neutrons In Neutron-Rich Nuclei, M. Duer, C. L. A. S. Collaboration, O. Hen, E. Piasetzky, H. Hakobyan, L. B. Weistein, M. Braverman, Gerard P. Gilfoyle, Et. Al. Aug 2018

Probing High-Momentum Protons And Neutrons In Neutron-Rich Nuclei, M. Duer, C. L. A. S. Collaboration, O. Hen, E. Piasetzky, H. Hakobyan, L. B. Weistein, M. Braverman, Gerard P. Gilfoyle, Et. Al.

Physics Faculty Publications

The atomic nucleus is one of the densest and most complex quantum-mechanical systems in nature. Nuclei account for nearly all the mass of the visible Universe. The properties of individual nucleons (protons and neutrons) in nuclei can be probed by scattering a high-energy particle from the nucleus and detecting this particle after it scatters, often also detecting an additional knocked-out proton. Analysis of electron- and proton-scattering experiments suggests that some nucleons in nuclei form close-proximity neutron–proton pairs with high nucleon momentum, greater than the nuclear Fermi momentum. However, how excess neutrons in neutron-rich nuclei form such close-proximity pairs remains unclear. …

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Dark Energy Survey Year 1 Results: Cosmological Constraints From Galaxy Clustering And Weak Lensing, T. M. C. Abbott, F. B. Abdalla, A. Alarcon, J. Aleksic, S. Allam, S. Allen, A. Amara, J. Annis, J. Asorey, S. Avila, D. Bacon, E. Balbinot, M. Banerji, N. Banik, Wayne Barkhouse Aug 2018

Dark Energy Survey Year 1 Results: Cosmological Constraints From Galaxy Clustering And Weak Lensing, T. M. C. Abbott, F. B. Abdalla, A. Alarcon, J. Aleksic, S. Allam, S. Allen, A. Amara, J. Annis, J. Asorey, S. Avila, D. Bacon, E. Balbinot, M. Banerji, N. Banik, Wayne Barkhouse

Physics Faculty Publications

We present cosmological results from a combined analysis of galaxy clustering and weak gravitational lensing, using 1321  deg2 of griz imaging data from the first year of the Dark Energy Survey (DES Y1). We combine three two-point functions: (i) the cosmic shear correlation function of 26 million source galaxies in four redshift bins, (ii) the galaxy angular autocorrelation function of 650,000 luminous red galaxies in five redshift bins, and (iii) the galaxy-shear cross-correlation of luminous red galaxy positions and source galaxy shears. To demonstrate the robustness of these results, we use independent pairs of galaxy shape, photometric-redshift estimation and validation, …

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Measurements Of The Gamma(Upsilon)P -> P ’Pi(+)Pi(- )Cross Section With The Clas Detector For 0.4 Gev2 < Q(2) < 1.0 Gev2 And 1.3 Gev < W < 1.825 Gev, G. Fedotov, Iu A. Skorodumina, V. D. Burkert, R. W. Gothe, K. Hicks, V. Mokeev, S. Adhikari, Gerard P. Gilfoyle, Et. Al. Aug 2018

Measurements Of The Gamma(Upsilon)P -> P ’Pi(+)Pi(- )Cross Section With The Clas Detector For 0.4 Gev2 < Q(2) < 1.0 Gev2 And 1.3 Gev < W < 1.825 Gev, G. Fedotov, Iu A. Skorodumina, V. D. Burkert, R. W. Gothe, K. Hicks, V. Mokeev, S. Adhikari, Gerard P. Gilfoyle, Et. Al.

Physics Faculty Publications

New results on the single-differential and fully integrated cross sections for the process γvp -> p'π+π- are presented. The experimental data were collected with the CLAS detector at Jefferson Laboratory. Measurements were carried out in the kinematic region of the reaction invariant mass W from 1.3 to 1.825 GeV and the photon virtuality Q2 from 0.4 to 1.0 GeV2. The cross sections were obtained in narrow Q2 bins (0.05 GeV2) with the smallest statistical uncertainties achieved in double-pion electroproduction experiments to date. The results were found to be in …

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Activity Pattern Of School/University Tenants And Their Family Members In Metro Manila – Philippines, Simonas Kecorius, Everlyn Gale Tamayo, Maria Cecilia Galvez, Leizel Madueño, Grace Betito, Mylene Gonzaga-Cayetano, Edgar Vallar, Alfred Wiedensohler Aug 2018

Activity Pattern Of School/University Tenants And Their Family Members In Metro Manila – Philippines, Simonas Kecorius, Everlyn Gale Tamayo, Maria Cecilia Galvez, Leizel Madueño, Grace Betito, Mylene Gonzaga-Cayetano, Edgar Vallar, Alfred Wiedensohler

Physics Faculty Publications

Existing studies that focus on personal exposure to or the deposition dose of particulate pollution in developing regions are limited. Hence, in this study, as a first step, we present results on how people spend their daily time in Metro Manila, Philippines. This information is critical to assessing personal exposure to and the deposition dose of particulate pollutants. We found that people spend less time at home on workdays than weekends (52% versus 70%), the fraction of time spent at work/school increases with age until retirement, adult males spend less time at home than females (18% versus 28%), and people …

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A New Research Approach For Observing And Characterizing Land-Atmosphere Feedback, Volker Wulfmeyer, David D. Turner, B. Baker, R. Banta, A. Behrendt, T. Bonin, W. A. Brewer, M. Buban, A. Choukulkar, R. Dumas, R. M. Hardesty, T. Heus, J. Ingwersen, D. Lange, T. R. Lee, S. Metzendorf, S. K. Muppa, T. Meyers, R. Newsom, M. Osman, S. Raasch, J. Santanello, C. Senff, F. Späth, T. Wagner, T. Weckwerth Aug 2018

A New Research Approach For Observing And Characterizing Land-Atmosphere Feedback, Volker Wulfmeyer, David D. Turner, B. Baker, R. Banta, A. Behrendt, T. Bonin, W. A. Brewer, M. Buban, A. Choukulkar, R. Dumas, R. M. Hardesty, T. Heus, J. Ingwersen, D. Lange, T. R. Lee, S. Metzendorf, S. K. Muppa, T. Meyers, R. Newsom, M. Osman, S. Raasch, J. Santanello, C. Senff, F. Späth, T. Wagner, T. Weckwerth

Physics Faculty Publications

No abstract provided.

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Measurements Of The Γv P → P'Π+Π− Cross Section With The Clas Detector For 0.4 Gev2 < Q2 < 1.0 Gev2 And 1.3 Gev < W < 1.825 Gev, G. V. Fedotov, Iu. A. Skorodumina, V. D. Burkert, R. W. Gothe, G. Charles, M. Khachatryan, A. Klein, Y. Prok, Z. W. Zhao, Clas Collaboration Aug 2018

Measurements Of The Γv P → P'Π+Π− Cross Section With The Clas Detector For 0.4 Gev2 < Q2 < 1.0 Gev2 And 1.3 Gev < W < 1.825 Gev, G. V. Fedotov, Iu. A. Skorodumina, V. D. Burkert, R. W. Gothe, G. Charles, M. Khachatryan, A. Klein, Y. Prok, Z. W. Zhao, Clas Collaboration

Physics Faculty Publications

New results on the single-differential and fully integrated cross sections for the process γvp → p'π+π− are presented. The experimental data were collected with the CLAS detector at Jefferson Laboratory. Measurements were carried out in the kinematic region of the reaction invariant mass W from 1.3 to 1.825 GeV and the photon virtuality Q2 from 0.4 to 1.0 GeV2. The cross sections were obtained in narrow Q2 bins (0.05 GeV2) with the smallest statistical uncertainties achieved in double-pion electroproduction experiments to date. The results were found to be in agreement with previously …

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Probing High-Momentum Protons And Neutrons In Neutron-Rich Nuclei, The Clas Collaboration, L. B. Weinstein, S. Bültmann, D. Bulumulla, G. Charles, G. Dodge, F. Hauenstein, C. E. Hyde, A. Klein, S. Nadeeshani, Y. Prok, Z. W. Zhao Aug 2018

Probing High-Momentum Protons And Neutrons In Neutron-Rich Nuclei, The Clas Collaboration, L. B. Weinstein, S. Bültmann, D. Bulumulla, G. Charles, G. Dodge, F. Hauenstein, C. E. Hyde, A. Klein, S. Nadeeshani, Y. Prok, Z. W. Zhao

Physics Faculty Publications

The atomic nucleus is one of the densest and most complex quantum-mechanical systems in nature. Nuclei account for nearly all the mass of the visible Universe. The properties of individual nucleons (protons and neutrons) in nuclei can be probed by scattering a high-energy particle from the nucleus and detecting this particle after it scatters, often also detecting an additional knocked-out proton. Analysis of electron- and proton-scattering experiments suggests that some nucleons in nuclei form close-proximity neutron–proton pairs with high nucleon momentum, greater than the nuclear Fermi momentum. However, how excess neutrons in neutron-rich nuclei form such close-proximity pairs remains unclear. …

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High-Brilliance, High-Flux Compact Inverse Compton Light Source, K. E. Deitrick, G. A. Krafft, B. Terzić, J. R. Delayen Aug 2018

High-Brilliance, High-Flux Compact Inverse Compton Light Source, K. E. Deitrick, G. A. Krafft, B. Terzić, J. R. Delayen

Physics Faculty Publications

The Old Dominion University Compact Light Source (ODU CLS) design concept is presented-a compact Inverse Compton Light Source (ICLS) with flux and brilliance orders of magnitude beyond conventional laboratory-scale sources and greater than other compact ICLS designs. This concept utilizes the physics of inverse Compton scattering of an extremely low emittance electron beam by a laser pulse of rms length of approximately two-thirds of a picosecond (2/3 ps). The accelerator is composed of a superconducting radio frequency (SRF) reentrant gun followed by four double-spoke SRF cavities. After the linac are three quadrupole magnets to focus the electron beam to the …

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First Measurement Of Ξ− Polarization In Photoproduction, J. Bono, L. Guo, K. P. Adhikari, M. J. Amaryan, G. Charles, G. Gavalian, M. Khachatryan, A. Klein, Y. Prok, J. Zhang, Z. W. Zhao Aug 2018

First Measurement Of Ξ− Polarization In Photoproduction, J. Bono, L. Guo, K. P. Adhikari, M. J. Amaryan, G. Charles, G. Gavalian, M. Khachatryan, A. Klein, Y. Prok, J. Zhang, Z. W. Zhao

Physics Faculty Publications

Despite decades of studies of the photoproduction of hyperons, both their production mechanisms and their spectra of excited states are still largely unknown. While the parity-violating weak decay of hyperons offers a means of measuring their polarization, which could help discern their production mechanisms and identify their excitation spectra, no such study has been possible for doubly strange baryons in photoproduction, due to low production cross sections. However, by making use of the reaction γ p → K+K+Ξ−, we have measured, for the first time, the induced polarization, P, and the transferred polarization from circularly polarized …

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Effect Of Self-Bias On Cylindrical Capacitive Discharge For Processing Of Inner Walls Of Tubular Structures-Case Of Srf Cavities, J. Upadhyay, J. Peshl, S. Popović, A.-M. Valente-Feliciano, L. Vušković Aug 2018

Effect Of Self-Bias On Cylindrical Capacitive Discharge For Processing Of Inner Walls Of Tubular Structures-Case Of Srf Cavities, J. Upadhyay, J. Peshl, S. Popović, A.-M. Valente-Feliciano, L. Vušković

Physics Faculty Publications

Cylindrical capacitive discharge is a convenient medium for generating reactive ions to process inner walls superconductive radio-frequency (SRF) cavities. These cavities, used in particle accelerators, presents a three-dimensional structure made of bulk Niobium, with axial cylindrical symmetry. Manufactured cavity walls are covered with Niobium oxides and scattered particulates, which must be removed for desired SRF performance. Cylindrical capacitive discharge in a mixture of Ar and Cl2 is a sole and natural non-wet acid choice to purify the inner surfaces of SRF cavities by reactive ion etching. Coaxial cylindrical discharge is generated between a powered inner electrode and the grounded …

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Compensation Of Non-Linear Bandwidth Broadening By Laser Chirping In Thomson Sources, C. Maroli, V. Petrillo, I. Drebot, L, Serafini, B. Terzić, G. A. Krafft Aug 2018

Compensation Of Non-Linear Bandwidth Broadening By Laser Chirping In Thomson Sources, C. Maroli, V. Petrillo, I. Drebot, L, Serafini, B. Terzić, G. A. Krafft

Physics Faculty Publications

A new laser chirping prescription is derived by means of the phase-stationary method for an inci- dent Gaussian laser pulse in conjunction with a Li enard-Wiechert calculation of the scattered radia- tion flux and spectral brilliance. This particularly efficient laser chirp has been obtained using the electric field of the laser and for electrons and radiation on axis. The frequency modulation is some- what reduced with respect to that proposed in the previous literature, allowing the application of this procedure to lasers with larger values of the parameter a0. Numerical calculations have been performed using mildly focused and …

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Exclusive Photoproduction Of Pi Degrees Up To Large Values Of Mandelstam Variables S, T, And U With Clas, M. C. Kunkel, M. J. Amaryan, I. I. Strakovsky, J. Ritman, G. R. Goldstein, K. P. Adhikari, S. Adhikari, Gerard P. Gilfoyle, Et. Al. Jul 2018

Exclusive Photoproduction Of Pi Degrees Up To Large Values Of Mandelstam Variables S, T, And U With Clas, M. C. Kunkel, M. J. Amaryan, I. I. Strakovsky, J. Ritman, G. R. Goldstein, K. P. Adhikari, S. Adhikari, Gerard P. Gilfoyle, Et. Al.

Physics Faculty Publications

Exclusive photoproduction cross sections have been measured for the process γp -> pπ0 [e+ e- (γ)] with the Dalitz decay final state using tagged photon energies in the range of Eγ = 1.275 – 5.425 GeV. The complete angular distribution of the final state π0, for the entire photon energy range up to large values of t and u, has been measured for the first time. The data obtained show that the cross section dσ / dt, at mid to large angles, decreases with energy as s-6.89 +/- 0.26 …

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Globular Cluster Population Of The Hst Frontier Fields Galaxy J07173724+3744224, Nathan L. Carlson, Madina R. Sultanova, Sandanuwan P. Kalawila Vithanage, Wayne A. Barkhouse, Gihan L. Ipita Kaduwa Gamage, Cody M. Rude, Omar López-Cruz Jul 2018

Globular Cluster Population Of The Hst Frontier Fields Galaxy J07173724+3744224, Nathan L. Carlson, Madina R. Sultanova, Sandanuwan P. Kalawila Vithanage, Wayne A. Barkhouse, Gihan L. Ipita Kaduwa Gamage, Cody M. Rude, Omar López-Cruz

Physics Faculty Publications

We present the first measurement of the globular cluster (GC) population surrounding the elliptical galaxy J07173724+3744224 (⁠z" role="presentation" style="box-sizing: border-box; margin: 0px; padding: 0px; border: 0px; font-variant: inherit; font-stretch: inherit; line-height: normal; font-family: inherit; vertical-align: baseline; display: inline; word-spacing: normal; overflow-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; position: relative;">zz = 0.1546). This galaxy is located in the foreground in the field-of-view of the Hubble Space Telescope (HST) Frontier Fields observations of galaxy cluster MACS J0717.5+3745 (⁠z" role="presentation" style="box-sizing: border-box; margin: 0px; padding: 0px; border: 0px; font-variant: inherit; font-stretch: …

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Semi-Inclusive Pi(0) Target And Beam-Target Asymmetries From 6 Gev Electron Scattering With Clas, S. Jawalkar, S. Koirala, H. Avakian, P. Bosted, K. A. Griffioen, C. Keith, S. E. Kuhn, Gerard P. Gilfoyle, Et. Al. Jul 2018

Semi-Inclusive Pi(0) Target And Beam-Target Asymmetries From 6 Gev Electron Scattering With Clas, S. Jawalkar, S. Koirala, H. Avakian, P. Bosted, K. A. Griffioen, C. Keith, S. E. Kuhn, Gerard P. Gilfoyle, Et. Al.

Physics Faculty Publications

We present precision measurements of the target and beam-target spin asymmetries from neutral pion electroproduction in deep-inelastic scattering (DIS) using the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. We scattered 6-GeV, longitudinally polarized electrons off longitudinally polarized protons in a cryogenic 14NH3 target, and extracted double and single target spin asymmetries for ep→e′ π0 X in multidimensional bins in four-momentum transfer (1.0 2 < 3.2 GeV2), Bjorken -x (0.12 < x < 0.48), hadron energy fraction (0.4 < z 0.7), tranverse pion meomentum (0 < PT < 1.0 GeV), and azimuthal angle ϕh between the lepton scattering and hadron production planes. We extracted asymmetries as a function of both x …

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Entropy Driven Phase Transition In Polymer Gels: Mean Field Theory, Miron Kaufman Jul 2018

Entropy Driven Phase Transition In Polymer Gels: Mean Field Theory, Miron Kaufman

Physics Faculty Publications

We present a mean field model of a gel consisting of P polymers, each of length L and Nz polyfunctional monomers. Each polyfunctional monomer forms z covalent bonds with the 2P bifunctional monomers at the ends of the linear polymers. We find that the entropy dependence on the number of polyfunctional monomers exhibits an abrupt change at Nz = 2P/z due to the saturation of possible crosslinks. This non-analytical dependence of entropy on the number of polyfunctionals generates a first-order phase transition between two gel phases: one poor and the other rich in poly-functional molecules.

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Mini‐Review: The Promise Of Piezoelectric Polymers, Timothy D. Usher, Kimberley R. Cousins, Renwu Zhang, Stephen Ducharme Jul 2018

Mini‐Review: The Promise Of Piezoelectric Polymers, Timothy D. Usher, Kimberley R. Cousins, Renwu Zhang, Stephen Ducharme

Physics Faculty Publications

Recent advances provide new opportunities in the field of polymer piezoelectric materials. Piezoelectric materials provide unique insights to the fundamental understanding of the solid state. In addition, piezoelectric materials have a wide range of applications, representing billions of dollars of commercial applications. However, inorganic piezoelectric materials have limitations that polymer ferroelectric materials can overcome, if certain challenges can be addressed. This mini-review is a practical summary of the current research and future directions in the investigation and application of piezoelectric materials with an emphasis on polymeric piezoelectric materials. We will assume that the reader is well versed in the subject …

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Item-Level Gender Fairness In The Force And Motion Conceptual Evaluation And The Conceptual Survey Of Electricity And Magnetism, Rachel Henderson, Paul Miller, John Stewart, Adrienne L. Traxler, Rebecca Lindell Jul 2018

Item-Level Gender Fairness In The Force And Motion Conceptual Evaluation And The Conceptual Survey Of Electricity And Magnetism, Rachel Henderson, Paul Miller, John Stewart, Adrienne L. Traxler, Rebecca Lindell

Physics Faculty Publications

Gender gaps on the most widely used conceptual inventories created by physics education researchers have been extensively studied. Most of the research exploring the consistent gender gaps has been performed at the student level using the total evaluation score; less research has been performed examining these assessments at the item level and this research has been predominately restricted to the Force Concept Inventory (FCI). Many studies have identified subsets of FCI items as unfair to either men or women. An item is fair if men and women of equal ability in conceptual physics score equally on the item. This study …

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Differential Cross Section For Γ D →Ωd Using Clas At Jefferson Lab, T. Chetry, K. Hicks, N. Compton, S. Adhikari, J. Ball, G. Charles, M. Khachatryan, Y. Prok, L. B. Weinstein, Z. W. Zhao Jul 2018

Differential Cross Section For Γ D →Ωd Using Clas At Jefferson Lab, T. Chetry, K. Hicks, N. Compton, S. Adhikari, J. Ball, G. Charles, M. Khachatryan, Y. Prok, L. B. Weinstein, Z. W. Zhao

Physics Faculty Publications

The cross section for coherent ω-meson photoproduction off the deuteron has been measured for the first time as a function of the momentum transfer t=(Pγ−Pω)2 and photon energy Eγ using the CLAS detector at the Thomas Jefferson National Accelerator Facility. The cross sections are measured in the energy range 1.4 γ<3.4 GeV. A model based on ω−N rescattering is consistent with the data at low and intermediate momentum transfer, |t|. For 2.8 γ<3.4 GeV, the total cross-section of ω−N scattering, based on fits within the framework of the Vector Meson Dominance model, is in the range of 30–40 mb.

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Finite-Volume Effects Due To Spatially Nonlocal Operators, Raúl A. Briceño, Juan V. Guerrero, Maxwell T. Hansen, Christopher J. Monahan Jul 2018

Finite-Volume Effects Due To Spatially Nonlocal Operators, Raúl A. Briceño, Juan V. Guerrero, Maxwell T. Hansen, Christopher J. Monahan

Physics Faculty Publications

Spatially nonlocal matrix elements are useful lattice-QCD observables in a variety of contexts, for example in determining hadron structure. To quote credible estimates of the systematic uncertainties in these calculations, one must understand, among other things, the size of the finite-volume effects when such matrix elements are extracted from numerical lattice calculations. In this work, we estimate finite- volume effects for matrix elements of nonlocal operators, composed of two currents displaced in a spatial direction by a distance ξ. We find that the finite-volume corrections depend on the details of the matrix element. If the external state is the lightest …

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One-Loop Evolution Of Parton Pseudo-Distribution Functions On The Lattice, Anatoly Radyushkin Jul 2018

One-Loop Evolution Of Parton Pseudo-Distribution Functions On The Lattice, Anatoly Radyushkin

Physics Faculty Publications

We incorporate recent calculations of one-loop corrections for the reduced Ioffe-time pseudo-distribution m(v, z(3)(2) thorn to extend the leading-logarithm analysis of lattice data obtained by Orginos et al. We observe that the one-loop corrections contain a large term reflecting the fact that effective distances involved in the most important diagrams are much smaller than the nominal distance z(3). The large correction in this case may be absorbed into the evolution term, and the perturbative expansion used for extraction of parton densities at the μ ≈ 2 GeV scale is under control. The extracted parton distribution is rather close to global …

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First Measurement Of The Ti(E, É) X Cross Section At Jefferson Lab, Jefferson Lab Hall A Collaboration, F. Hauenstein, C. Hyde Jul 2018

First Measurement Of The Ti(E, É) X Cross Section At Jefferson Lab, Jefferson Lab Hall A Collaboration, F. Hauenstein, C. Hyde

Physics Faculty Publications

To probeCPviolation in the leptonic sector usingGeVenergy neutrino beams in current and future experiments using argon detectors, precise models of the complex underlying neutrino and antineutrino interactions are needed. The E12-14-012 experiment at JeffersonLab HallAwas designed to perform a combined analysis of inclusive and exclusive electron scatterings on both argon (N = 22) and titanium (Z = 22) nuclei using GeV-energy electron beams. Themeasurement on titanium nucleus provides essential information to understand the neutrino scattering on argon, large contribution to which comes from scattering off neutrons. Here we report the first experimental study of electron-titanium scattering as double-differential cross section …

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Electron- And Positron-Impact Ionization Of Inert Gases, R. I. Campeanu, H. R. J. Walters, Colm T. Whelan Jun 2018

Electron- And Positron-Impact Ionization Of Inert Gases, R. I. Campeanu, H. R. J. Walters, Colm T. Whelan

Physics Faculty Publications

Triple-differential cross sections (TDCS) are presented for the electron and positron impact ionization of inert gas atoms in a range of geometries where a number of significant few body effects compete to define the shape of the TDCS. Using both positrons and electrons as projectiles has opened up the possibility of performing complementary studies which could effectively isolate competing interactions which cannot be separately detected in an experiment with a single projectile. A comparison is presented between theory and the recent experiments of [Gavin, deLucio, and DuBois, Phys. Rev. A95, 062703 (2017)] for e± and contrasted with the …

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Electrostatic Alignment Of Electrospun Peo Fibers By The Gap Method Increases Individual Fiber Modulus In Comparison To Non-Aligned Fibers Of Similar Diameter, Christopher Fryer, Meghan Scharnagl, Christine C. Helms Jun 2018

Electrostatic Alignment Of Electrospun Peo Fibers By The Gap Method Increases Individual Fiber Modulus In Comparison To Non-Aligned Fibers Of Similar Diameter, Christopher Fryer, Meghan Scharnagl, Christine C. Helms

Physics Faculty Publications

Studies on the alignment, physical and mechanical properties of individual electrospun fibers provide insight to their formation, production and optimization. Here we measure the alignment, diameter and modulus of individual fibers formed using the electrostatic gap method. We find electrostatic alignment produces fibers with a smaller diameter than their nonaligned counterparts have. Therefore, due to the dependence of fiber modulus on diameter aligned fibers have a higher modulus. Furthermore, we show that aligned and nonaligned fibers of the similar diameter have different moduli. Aligned fibers have a modulus 1.5 to 2 times larger than nonaligned fibers of the similar diameter.

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High Power Generation Of Thz From 1550-Nm Photoconductive Emitters, A. Mingardi, W. D. Zhang, E. R. Brown, A. D. Feldman, T. E. Harvey, And R.P. Mirin May 2018

High Power Generation Of Thz From 1550-Nm Photoconductive Emitters, A. Mingardi, W. D. Zhang, E. R. Brown, A. D. Feldman, T. E. Harvey, And R.P. Mirin

Physics Faculty Publications

Two photoconductive emitters - one with a self-complementary square spiral antenna, and the other with a resonant slot antenna - were fabricated on a GaAs epilayer embedded with ErAs quantum dots. Driven with 1550 nm mode-locked lasers, ~117 μW broadband THz power was generated from the device with the spiral antenna, and ~1.2 μW from the device with resonant slot antenna. The optical-to-THz conversion is through extrinsic photoconductivity.

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The Dark Energy Survey Image Processing Pipeline, E. Morganson, R. A. Gruendl, F. Menanteau, M. Carrasco Kind, Y.-C. Chen, G. Daues, A. Drlica-Wagner, D. N. Friedel, M. Gower, M. W. G. Johnson, M. D. Johnson, R. Kessler, F. Paz-Chinchón, D. Petravick, C. Pond, B. Yanny, S. Allam, R. Armstrong, Wayne A. Barkhouse, K. Bechtol, A. Benoit-Lévy, G. M. Bernstein, E. Bertin, E. Buckley-Geer, R. Covarrubias, S. Desai, H. T. Diehl, D. A. Goldstein, D. Gruen, T. S. Li, H. Lin, J. Marriner, J. J. Mohr, E. Neilsen, C.-C. Ngeow, K. Paech, E. S. Rykoff, M. Sako, I. Sevilla-Noarbe, E. Sheldon, F. Sobreira, D. L. Tucker, W. Wester May 2018

The Dark Energy Survey Image Processing Pipeline, E. Morganson, R. A. Gruendl, F. Menanteau, M. Carrasco Kind, Y.-C. Chen, G. Daues, A. Drlica-Wagner, D. N. Friedel, M. Gower, M. W. G. Johnson, M. D. Johnson, R. Kessler, F. Paz-Chinchón, D. Petravick, C. Pond, B. Yanny, S. Allam, R. Armstrong, Wayne A. Barkhouse, K. Bechtol, A. Benoit-Lévy, G. M. Bernstein, E. Bertin, E. Buckley-Geer, R. Covarrubias, S. Desai, H. T. Diehl, D. A. Goldstein, D. Gruen, T. S. Li, H. Lin, J. Marriner, J. J. Mohr, E. Neilsen, C.-C. Ngeow, K. Paech, E. S. Rykoff, M. Sako, I. Sevilla-Noarbe, E. Sheldon, F. Sobreira, D. L. Tucker, W. Wester

Physics Faculty Publications

The Dark Energy Survey (DES) is a five-year optical imaging campaign with the goal of understanding the origin of cosmic acceleration. DES performs a ~5000 deg2 survey of the southern sky in five optical bands (g, r, i, z, Y) to a depth of ~24th magnitude. Contemporaneously, DES performs a deep, time-domain survey in four optical bands (g, r, i, z) over ~27 deg2. DES exposures are processed nightly with an evolving data reduction pipeline and evaluated for image quality to determine if they need to be retaken. Difference imaging and transient source detection are also …

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