Astrophysics and Astronomy Commons^™

Centrality Dependence Of Low-Momentum Direct-Photon Production In Au+Au Collisions At √Snn =200 Gev, Andrew Marshall Adare, Gyöngyi Baksay, László A. Baksay, Marcus Hohlmann, Phenix Collaboration

Aerospace, Physics, and Space Science Faculty Publications

The PHENIX experiment at RHIC has measured the centrality dependence of the direct photon yield from Au+Au collisions at √sNN=200 GeV down to pT=0.4 GeV/c. Photons are detected via photon conversions to e+e- pairs and an improved technique is applied that minimizes the systematic uncertainties that usually limit direct photon measurements, in particular at low pT. We find an excess of direct photons above the Ncoll-scaled yield measured in p+p collisions. This excess yield is well described by an exponential distribution with an inverse slope of about 240MeV/c in the pT range 0.6-2.0 GeV/c. While the shape of the pT …

The Effect Of Direct Electron-Positron Pair Production On Relativistic Feedback Rates, Igor B. Vodopiyanov, Joseph R. Dwyer, Eric S. Cramer, R. J. Lucia, Hamid K. Rassoul

Aerospace, Physics, and Space Science Faculty Publications

Runaway electron avalanches developing in thunderclouds in high electric field become self-sustaining due to relativistic feedback via the production of backward propagating positrons and backscattered X-rays. To date, only positrons created from pair production by gamma rays interacting with the air have been considered. In contrast, direct electron-positron pair production, also known as "trident process," occurs from the interaction of energetic runaway electrons with atomic nuclei, and so it does not require the generation of a gamma ray mediator. The positrons produced in this process contribute to relativistic feedback and become especially important when the feedback factor value approaches unity. …

Taurus, Luis M. Torres Cantu

Natural Sciences Student Research Presentations

The purpose of this project was to gather information about the stars and objects in the constellation Taurus. This is a project for the Natural Sciences Poster Session at Parkland College.

Cygnus The Swan, Emily J. Oldham

Natural Sciences Student Research Presentations

The purpose of this project was to gather information about the stars and objects in the constellation Cygnus. This is a project for the Natural Sciences Poster Session at Parkland College.

Evidence Of Attenuation Of Vhe Blazar Spectra By Extragalactic Background Light, Cameron Allen

Physics

The spectrum of two blazar objects, 1ES 1959+650 and 1ES 2344+514, are analyzed for evidence of interactions with the Extragalactic Background Light (EBL), using combined data from the Very Energetic Radiation Imaging Telescope Array System and the Fermi Gamma-ray Space Telescope, By analyzing the distinct curvature across the combined spectrum, we infer that the very-high energy (VHE) gamma-rays must be attenuated by interactions with the EBL. We also find that the measured 1ES 1959+650 spectrum is sensitive to the intrinsic blazar model, with a preference for a power-law with an exponential cutoff (EPWL). The measured curvature is a combination of …

Lattice Study Of Quark And Glue Momenta And Angular Momenta In The Nucleon, M. Deka, T. Doi, Y. B. Yang, B. Chakraborty, S. J. Dong, Terrence Draper, M. Glatzmaier, M. Gong, H. W. Lin, Keh-Fei Liu, D. Mankame, N. Mathur, T. Streuer

Physics and Astronomy Faculty Publications

We report a complete calculation of the quark and glue momenta and angular momenta in the proton. These include the quark contributions from both the connected and disconnected insertions. The quark disconnected insertion loops are computed with Z₄ noise, and the signal-to-noise ratio is improved with unbiased subtractions. The glue operator is comprised of gauge-field tensors constructed from the overlap operator. The calculation is carried out on a 16³×24 quenched lattice at β=6.0 for Wilson fermions with κ=0.154, 0.155, and 0.1555, which correspond to pion masses at 650, 538, and 478 MeV, respectively. The chirally …

Kibble-Zurek Scaling In Holographic Quantum Quench: Backreaction, Sumit R. Das, Takeshi Morita

Physics and Astronomy Faculty Publications

We study gauge and gravity backreaction in a holographic model of quantum quench across a superfluid critical transition. The model involves a complex scalar field coupled to a gauge and gravity field in the bulk. In earlier work (arXiv:1211.7076) the scalar field had a strong self-coupling, in which case the backreaction on both the metric and the gauge field can be ignored. In this approximation, it was shown that when a time dependent source for the order parameter drives the system across the critical point at a rate slow compared to the initial gap, the dynamics in the critical region …

Astronomy 102 Stars, Galaxies, The Universe Fall 2015, Erik Johnson

Astronomy Courses

No abstract provided.

Astronomy 102 Stars, Galaxies, The Universe Spring 2015, Erik Johnson

Astronomy Courses

No abstract provided.

Astronomy 101 Online The Solar System Summer 2015, Pam Friese, Katrina Wefel

Astronomy Courses

No abstract provided.

Identification Of Magnetite In Lunar Regolith Breccia 60016: Evidence For Oxidized Conditions At The Lunar Surface, Katherine H. Joy, Channon Visscher, Michael E. Zolensky, Takashi Mikouchi, Kenji Hagiya, Kazumasa Ohsumi, David A. Kring

Faculty Work Comprehensive List

Lunar regolith breccias are temporal archives of magmatic and impact bombardment processes on the Moon. Apollo 16 sample 60016 is an ‘ancient’ feldspathic regolith breccia that was converted from a soil to a rock at ~3.8 Ga. The breccia contains a small (70 × 50 μm) rock fragment composed dominantly of an Fe-oxide phase with disseminated domains of troilite. Fragments of plagioclase (An95-97), pyroxene (En74-75, Fs21-22,Wo3-4) and olivine (Fo66-67) are distributed in and adjacent to the Fe-oxide. The silicate minerals have lunar compositions that are similar to anorthosites. Mineral chemistry, synchrotron X-ray Absorption Near Edge Spectroscopy (XANES) and X-ray Diffraction …

Note: Improved Line Strengths Of Rovibrational And Rotational Transitions Within The X3Σ⁻ Ground State Of Nh, James S.A. Brooke, Peter F. Bernath, Colin M. Western

Chemistry & Biochemistry Faculty Publications

Recently, a line list including positions and transition strengths was published for the NH X³Σ⁻ rovibrational and rotational transitions. The calculation of the transition strengths requires a conversion of transition matrix elements from Hund’s case (b) to (a). The method of this conversion has recently been improved during other work on the OH X²Π rovibrational transitions, by removing an approximation that was present previously. The adjusted method has been applied to the NH line list, resulting in more accurate transition strengths. An updated line list is presented that contains all possible transitions with v′ and …

Unmatter Plasma, Relativistic Oblique-Length Contraction Factor, Neutrosophic Diagram And Neutrosophic Degree Of Paradoxicity: Articles And Notes, Florentin Smarandache

Branch Mathematics and Statistics Faculty and Staff Publications

This book has four parts. In the first part, we collected five recent papers, published before in Progress in Physics, but reviewed. In the first paper, we approach a novel form of plasma, Unmatter Plasma. The electron-positron beam plasma was generated in the laboratory in the beginning of 2015. This experimental fact shows that unmatter, a new form of matter that is formed by matter and antimatter bind together (mathematically predicted a decade ago) really exists. That is the electron-positron plasma experiment of 2015 is the experimentum crucis verifying the mathematically predicted unmatter. In the second paper, we generalize the …

An Economic Analysis Of Mars Exploration And Colonization, Clayton Knappenberger 15

Honor Scholar Theses

No abstract provided.

On X-Ray Pulsations In Beta Cephei-Type Variables, L. Oskinova, H. Todt, D. Huenemoerder, S. Hubrig, Richard Ignace, W.-R. Hamann, L. Balona

ETSU Faculty Works

Beta Cephei-type variables are early B-type stars that are characterized by oscillations observable in their optical light curves. At least one Beta Cep-variable also shows periodic variability in X-rays. Here we study the X-ray light curves in a sample of beta Cep-variables to investigate how common X-ray pulsations are for this type of stars. We searched the Chandra and XMM-Newton X-ray archives and selected stars that were observed by these telescopes for at least three optical pulsational periods. We retrieved and analyzed the X-ray data for kappa Sco, beta Cru, and alpha Vir. The X-ray light curves of these objects …

First Measurement Of The Polarization Observable E In The P→ (Ɣ→, Π+) In Reaction Up To 2.25 Gev, S. Strauch, W. J. Briscoe, M. Döring, E. Klempt, V. A. Nikonov, E. Pasyuk, D. Rönchen, A.V. Sarantsev, I. Strakovsky, R. Workman, K. P. Adhikari, D. Adikaram, L. El Fassi

Physics Faculty Publications

First results from the longitudinally polarized frozen-spin target (FROST) program are reported. The double-polarization observable E, for the reaction ɣ^→p^→→π+n, has been measured using a circularly polarized tagged-photon beam, with energies from 0.35 to 2.37 GeV. The final-state pions were detected with the CEBAF Large Acceptance Spectrometer in Hall B at the Thomas Jefferson National Accelerator Facility. These polarization data agree fairly well with previous partial-wave analyses at low photon energies. Over much of the covered energy range, however, significant deviations are observed, particularly in the high-energy region where high-L multipoles contribute. The data have been …

Precision Measurements Of Aⁿ1 In The Deep Inelastic Regime, D. S. Parno, D. Flay, M. Posik, M. Canan, C. Hyde, The Jefferson Lab Hall A Collaboration

Physics Faculty Publications

We have performed precision measurements of the double-spin virtual-photon asymmetry A₁ on the neutron in the deep inelastic scattering regime, using an open-geometry, large-acceptance spectrometer and a longitudinally and transversely polarized ³He target. Our data cover a wide kinematic range 0.277 <= x <= 0.548 at an average Q² value of 3.078(GeV/c)², doubling the available high-precision neutron data in this xrange. We have combined our results with world data on proton targets to make a leading-order extraction of the ratio of polarized-to-unpolarized parton distribution functions for up quarks and for down quarks in the same kinematic range. Our data are consistent with …

Question 1: Star Speeds; Question 2: Slurping Gasoline, Larry Weinstein

Physics Faculty Publications

One piece of evidence that the center of our galaxy contains a super-massive black hole came from measuring the speed of a star orbiting that black hole. What is the maximum speed of that star?

If instead of carrying their gas in fuel tanks, cars “slurped up” a stream of gas as they drove, how thick a stream of gas would each car need?

Human Behavior During Spaceflight - Evidence From An Analog Environment, Kenny M. Arnaldi, Guy Smith, Jennifer E. Thropp

Journal of Aviation/Aerospace Education & Research

Spaceflight offers a multitude of stressors to humans living and working in space, originating from the external space environment and the life-support system. Future space participants may be ordinary people with different medical and psychosocial backgrounds who may not receive the intense spaceflight preparation of astronauts. Consequently, during a mission, a space participant’s mood and behavior could differ from a trained astronaut. This study was an exploratory research project that used an artificial habitat to replicate an orbital environment and the activities performed by humans in space. The study evaluated whether the type of environment affects mood and temperament. Two …

Interdisciplinary Connections Between Science & Theatre, Jessica N. Dotson

Theses and Dissertations

Abstract

INTERDISCIPLINARY CONNECTIONS BETWEEN SCIENCE & THEATRE

Jessica Nicole Dotson

A thesis submitted in partial fulfillment of the requirements for the degree of Master of Fine Arts at Virginia Commonwealth University.

Virginia Commonwealth University, 2015.

Major Director: Dr. Noreen C. Barnes, Director of Graduate Studies, Associate Professor of Theatre

In the 1990s, astronomer Peter Usher was searching for new ways to teach his introductory astronomy class at Pennsylvania State University. He began to engage his students by searching for astronomical connections from other disciplines. His focus was turned to the arts, especially the works of William Shakespeare. Usher found, while …