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Full-Text Articles in Physical Sciences and Mathematics
Precision Determination Of The Neutral Weak Form Factor Of ^48ca, D. Adhikari, (...), David S. Armstrong, Et Al.
Precision Determination Of The Neutral Weak Form Factor Of ^48ca, D. Adhikari, (...), David S. Armstrong, Et Al.
Arts & Sciences Articles
We report a precise measurement of the parity-violating (PV) asymmetry APV in the elastic scattering of longitudinally polarized electrons from 48Ca. We measure APV=2668±106(stat)±40(syst) parts per billion, leading to an extraction of the neutral weak form factor FW(q=0.8733 fm−1)=0.1304±0.0052(stat)±0.0020(syst) and the charge minus the weak form factor Fch−FW=0.0277±0.0055. The resulting neutron skin thickness Rn−Rp=0.121±0.026(exp)±0.024(model) fm is relatively thin yet consistent with many model calculations. The combined CREX and PREX results will have implications for future energy density functional calculations and on the density dependence of the symmetry energy of nuclear matter.
Beyond The Petermann Limit: Prospect Of Increasing Sensor Precision Near Exceptional Points, David D. Smith, Hongrok Chang, Eugeniy E. Mikhailov, Selim M. Shahriar
Beyond The Petermann Limit: Prospect Of Increasing Sensor Precision Near Exceptional Points, David D. Smith, Hongrok Chang, Eugeniy E. Mikhailov, Selim M. Shahriar
Arts & Sciences Articles
Experiments near the lock-in region in maximally dissipative non-Hermitian systems, e.g., conventional laser gyroscopes near the deadband, have run up against the Petermann limit, where excess noise exactly cancels any scale-factor enhancement resulting in no overall enhancement in precision. As a result, one might be tempted to conclude that exceptional points (EPs) generally cannot be used to increase the precision of laser sensors. Indeed, using a linear eigenmode analysis we show that the Petermann limit applies not just to maximally dissipative systems, but for any type of EP, owing to the fact that EPs are rotationally invariant. It turns out, …
Orbital-Selective Metallicity In The Valence-Bond Liquid Phase Of Li2 Ruo3, Patrick Mcardle, Fei-Ting Huang, Junjie Yang, (...), M. M. Qazilbash
Orbital-Selective Metallicity In The Valence-Bond Liquid Phase Of Li2 Ruo3, Patrick Mcardle, Fei-Ting Huang, Junjie Yang, (...), M. M. Qazilbash
Arts & Sciences Articles
Li2RuO3 (LRO) forms a valence bond crystal at room temperature. It undergoes a high temperature phase transition that involves structural, magnetic, and electronic changes leading to an exotic valence bond liquid state. The orbital degrees of freedom are thought to be fundamental to the evolution of LRO properties across the phase transition. We report temperature dependent broadband (100–26000cm–1) reflectance measurements on single crystals of LRO to elucidate structural and transport properties. Specifically, the phonon and electronic properties of LRO were investigated through the phase transition. We report that above the transition temperature (Tc≈500K), the optical band gap closes for electrons …
New Measurements Of The Beam-Normal Single Spin Asymmetry In Elastic Electron Scattering Over A Range Of Spin-0 Nuclei, D. Adhikari, (...), David S. Armstrong, Et Al.
New Measurements Of The Beam-Normal Single Spin Asymmetry In Elastic Electron Scattering Over A Range Of Spin-0 Nuclei, D. Adhikari, (...), David S. Armstrong, Et Al.
Arts & Sciences Articles
We report precision determinations of the beam-normal single spin asymmetries (An) in the elastic scattering of 0.95 and 2.18 GeV electrons off 12C, 40Ca, 48Ca, and 208Pb at very forward angles where the most detailed theoretical calculations have been performed. The first measurements of An for 40Ca and 48Ca are found to be similar to that of 12C, consistent with expectations and thus demonstrating the validity of theoretical calculations for nuclei with Z≤20. We also report An for 208Pb at two new momentum transfers (Q2) extending the previous measurement. Our new data confirm the surprising result previously reported, with all …
Determination Of The ^27al Neutron Distribution Radius From A Parity-Violating Electron Scattering Measurement, D. Androic, David S. Armstrong, Et Al.
Determination Of The ^27al Neutron Distribution Radius From A Parity-Violating Electron Scattering Measurement, D. Androic, David S. Armstrong, Et Al.
Arts & Sciences Articles
We report the first measurement of the parity-violating elastic electron scattering asymmetry on 27Al. The 27Al elastic asymmetry is APV=2.16±0.11(stat)±0.16(syst) ppm, and was measured at ⟨Q2⟩=0.02357±0.00010 GeV2, ⟨θlab⟩=7.61°±0.02°, and ⟨Elab⟩=1.157 GeV with the Qweak apparatus at Jefferson Lab. Predictions using a simple Born approximation as well as more sophisticated distorted-wave calculations are in good agreement with this result. From this asymmetry the 27Al neutron radius Rn=2.89±0.12 fm was determined using a many-models correlation technique. The corresponding neutron skin thickness Rn−Rp=−0.04±0.12 fm is small, as expected for a light nucleus with a neutron excess of only 1. This result thus serves …
Hyperspectral Infrared Imaging Of Surface Phonon-Polaritons In Srtio3, D. J. Lahneman, M. M. Qazilbash
Hyperspectral Infrared Imaging Of Surface Phonon-Polaritons In Srtio3, D. J. Lahneman, M. M. Qazilbash
Arts & Sciences Articles
Polaritons have a demonstrated impact on nanophotonic applications in the midinfrared through visible spectral range. Surface phonon-polaritons (SPhPs) offer a way to bring the potential of polaritons to the longer infrared wavelengths. Strontium titanate (STO) is a perovskite polar dielectric with diverse technologically advantageous properties and it can support SPhPs in a uniquely broad spectral range of the far infrared. Despite these advantages, STO has mostly been overlooked as a nanophotonic material. In this work we investigate SPhP propagation in STO in the far-infrared through midinfrared spectral range using broadband, near-field nanospectroscopy. We developed a tabletop, laser sustained plasma light …
Measurement Of The Beam-Normal Single-Spin Asymmetry For Elastic Electron Scattering From ^12c And ^27al, D. Androic, David S. Armstrong, Et Al.
Measurement Of The Beam-Normal Single-Spin Asymmetry For Elastic Electron Scattering From ^12c And ^27al, D. Androic, David S. Armstrong, Et Al.
Arts & Sciences Articles
We report measurements of the parity-conserving beam-normal single-spin elastic scattering asymmetries Bn on 12C and 27Al, obtained with an electron beam polarized transverse to its momentum direction. These measurements add an additional kinematic point to a series of previous measurements of Bn on 12C and provide a first measurement on 27Al. The experiment utilized the Qweak apparatus at Jefferson Lab with a beam energy of 1.158 GeV. The average laboratory scattering angle for both targets was 7.7∘, and the average Q2 for both targets was 0.024 37 GeV2 (Q=0.1561 GeV). The asymmetries are Bn=−10.68±0.90(stat)±0.57(syst) ppm for 12C and Bn=−12.16±0.58(stat)±0.62(syst) ppm …
Accurate Determination Of The Neutron Skin Thickness Of ^208pb Through Parity-Violation In Electron Scattering, D. Adhikari, (...), David S. Armstrong, Et Al.
Accurate Determination Of The Neutron Skin Thickness Of ^208pb Through Parity-Violation In Electron Scattering, D. Adhikari, (...), David S. Armstrong, Et Al.
Arts & Sciences Articles
We report a precision measurement of the parity-violating asymmetry APV in the elastic scattering of longitudinally polarized electrons from 208Pb. We measure APV=550±16(stat)±8(syst) parts per billion, leading to an extraction of the neutral weak form factor FW(Q2=0.00616 GeV2)=0.368±0.013. Combined with our previous measurement, the extracted neutron skin thickness is Rn−Rp=0.283±0.071 fm. The result also yields the first significant direct measurement of the interior weak density of 208Pb: ρ0W=−0.0796±0.0036(exp)±0.0013(theo) fm−3 leading to the interior baryon density ρ0b=0.1480±0.0036(exp)±0.0013(theo) fm−3. The measurement accurately constrains the density dependence of the symmetry energy of nuclear matter near saturation density, with implications for the size and …
Partially Metal-Coated Tips For Near-Field Nanospectroscopy, Yujia Zhang, Xinzhong Chen, (...), M. M. Qazilbash, Et Al.
Partially Metal-Coated Tips For Near-Field Nanospectroscopy, Yujia Zhang, Xinzhong Chen, (...), M. M. Qazilbash, Et Al.
Arts & Sciences Articles
Scanning probes with functional optical responses are key components of scanning near-field optical microscopes. For nanospectroscopy performed at IR and terahertz (THz) frequencies, one major challenge is that the commonly used metal-coated silicon tips yield nonadjustable coupling efficiency across the spectrum, which greatly limits the signal-to-noise ratio. Here, we test the possibility of a generic design scheme for wavelength-selective tip enhancement via finite-element numerical modeling. We employ a Si-based tip with various gold-coating lengths on the top, yielding a customizable near-field field strength at the tip apex. Calculations show a wavelength-dependent enhancement factor of the metal-coated tip due to the …
Precision Measurement Of The Beam-Normal Single-Spin Asymmetry In Forward-Angle Elastic Electron-Proton Scattering, D. Androic, David S. Armstrong, Et Al.
Precision Measurement Of The Beam-Normal Single-Spin Asymmetry In Forward-Angle Elastic Electron-Proton Scattering, D. Androic, David S. Armstrong, Et Al.
Arts & Sciences Articles
A beam-normal single-spin asymmetry generated in the scattering of transversely polarized electrons from unpolarized nucleons is an observable related to the imaginary part of the two-photon exchange process. We report a 2% precision measurement of the beam-normal single-spin asymmetry in elastic electron-proton scattering with a mean scattering angle of theta_lab = 7.9 degrees and a mean energy of 1.149 GeV. The asymmetry result is B_n = -5.194 +- 0.067 (stat) +- 0.082 (syst) ppm. This is the most precise measurement of this quantity available to date and therefore provides a stringent test of two-photon exchange models at far-forward scattering angles …
Demonstration Of The Lateral Ac Skin Effect Using A Pickup Coil, Anne E. Blackwell, Andrew P. Rotunno, Seth Aubin
Demonstration Of The Lateral Ac Skin Effect Using A Pickup Coil, Anne E. Blackwell, Andrew P. Rotunno, Seth Aubin
Arts & Sciences Articles
We present a simple demonstration of the skin effect by observing the current distribution in a wide rectangular strip conductor driven at frequencies in the 0.25–5 kHz range. We measure the amplitude and phase of the current distribution as a function of the transverse position and find that they agree well with numerical simulations: The current hugs the edges of the strip conductor with a significant variation in phase across the width. The experimental setup is simple, uses standard undergraduate physics instructional laboratory equipment, and is easy to implement as a short in-class demonstration. Our study is motivated by modeling …
Measurement Of The 3he Spin-Structure Functions And Of Neutron (3he) Spin-Dependent Sum Rules At 0.035 ≤ Q2 ≤ 0.24 Gev2, Jefferson Lab E97-110 Collaboration, David S. Armstrong
Measurement Of The 3he Spin-Structure Functions And Of Neutron (3he) Spin-Dependent Sum Rules At 0.035 ≤ Q2 ≤ 0.24 Gev2, Jefferson Lab E97-110 Collaboration, David S. Armstrong
Arts & Sciences Articles
The spin-structure functions g1 and g2, and the spin-dependent partial cross-section σTT have been extracted from the polarized cross-sections differences, σ| ν, Q 2 and σ⊥ ν, Q 2 measured for the 3 > He(e>, e' )X reaction, in the E97-110 experiment at Jefferson Lab. Polarized electrons with energies from 1.147 to 4.404 GeV were scattered at angles of 6◦ and 9◦ from a longitudinally or transversely polarized 3He target. The data cover the kinematic regions of the quasi-elastic, resonance production and beyond. From the extracted spin-structure functions, the first moments 1 (Q2) , 2 (Q2) and ITT Q 2 …
Parity-Violating Inelastic Electron-Proton Scattering At Low Q^2 Above The Resonance Region, D. Androic, David S. Armstrong, Qweak Collaboration
Parity-Violating Inelastic Electron-Proton Scattering At Low Q^2 Above The Resonance Region, D. Androic, David S. Armstrong, Qweak Collaboration
Arts & Sciences Articles
We report the measurement of the parity-violating asymmetry for the inelastic scattering of electrons from the proton, at Q2=0.082GeV2 and W=2.23 GeV, above the resonance region. The result AInel=−13.5±2.0(stat)±3.9(syst) ppm agrees with theoretical calculations, and helps to validate the modeling of the γZ interference structure functions FγZ1 and FγZ2 used in those calculations, which are also used for determination of the two-boson exchange γ−Z box diagram (□γZ) contribution to parity-violating elastic scattering measurements. A positive parity-violating asymmetry for inclusive π− production was observed, as well as positive beam-normal single-spin asymmetry for scattered electrons and a negative beam-normal single-spin asymmetry for …
Spatial Multiplexing Of Squeezed Light By Coherence Diffusion, Jian Sun, (...), Eugeniy E. Mikhailov, Irina Novikova, Et Al.
Spatial Multiplexing Of Squeezed Light By Coherence Diffusion, Jian Sun, (...), Eugeniy E. Mikhailov, Irina Novikova, Et Al.
Arts & Sciences Articles
Spatially splitting nonclassical light beams is in principle prohibited due to noise contamination during beam splitting. We propose a platform based on thermal motion of atoms to realize spatial multiplexing of squeezed light. Light channels of separate spatial modes in an antirelaxation coated vapor cell share the same long-lived atomic coherence jointly created by all channels through the coherent diffusion of atoms, which in turn enhances the individual channel’s nonlinear process responsible for light squeezing. Consequently, it behaves as squeezed light in one optical channel transferring to other distant channels even with laser powers below the threshold for squeezed light …
Second-Order Dirac Superconductors And Magnetic Field Induced Majorana Hinge Modes, Sayed Ali Akbar Ghorashi, Xiang Hu, Taylor L. Hughes, Enrico Rossi
Second-Order Dirac Superconductors And Magnetic Field Induced Majorana Hinge Modes, Sayed Ali Akbar Ghorashi, Xiang Hu, Taylor L. Hughes, Enrico Rossi
Arts & Sciences Articles
We identify three-dimensional higher-order superconductors characterized by the coexistence of one-dimensional Majorana hinge states and gapless surface states. We show how such superconductors can be obtained starting from the model of a spinful quadrupolar semimetal with two orbitals and adding an s-wave superconducting pairing term. By considering all the possible s-wave pairings satisfying Fermi-Dirac statistics we obtain six different superconducting models. We find that for two of these models a flat band of hinge Majorana states coexist with surface states, and that these models have a nonvanishing quadrupolelike topological invariant. Two of the other models, in the presence of a …
Strong Electron-Boson Coupling In The Iron-Based Superconductor Bafe1.9pt0.1as2 Revealed By Infrared Spectroscopy, Zhen Xing, Shanta Saha, J. Paglione, M. M. Qazilbash
Strong Electron-Boson Coupling In The Iron-Based Superconductor Bafe1.9pt0.1as2 Revealed By Infrared Spectroscopy, Zhen Xing, Shanta Saha, J. Paglione, M. M. Qazilbash
Arts & Sciences Articles
Understanding the formation of Cooper pairs in iron-based superconductors is one of the most important topics in condensed matter physics. In conventional superconductors, the electron-phonon interaction leads to the formation of Cooper pairs. In conventional strong-coupling superconductors like lead (Pb), the features due to electron-phonon interaction are evident in the infrared absorption spectra. Here we investigate the infrared absorption spectra of the iron arsenide superconductor BaFe1.9Pt0.1As2. We find that this superconductor has fully gapped (nodeless) Fermi surfaces, and we observe the strong-coupling electron-boson interaction features in the infrared absorption spectra. Through modeling with the Eliashberg function based on Eliashberg theory, …
Topological Changes Of Wave Functions Associated With Hamiltonian Monodromy, C. Chen, John B. Delos
Topological Changes Of Wave Functions Associated With Hamiltonian Monodromy, C. Chen, John B. Delos
Arts & Sciences Articles
Almost everything that happens in classical mechanics also shows up in quantum mechanics when we know where to look for it. A phenomenon in classical mechanics involves topological changes in action-angle loops as a result of passage around a “monodromy circuit.” This phenomenon is known by the short name “Hamiltonian monodromy” (or, more ponderously, “nontrivial monodromy of action and angle variables in integrable Hamiltonian systems”). In this paper, we show a corresponding change in quantum wave functions: These wave functions change their topological structure in the same way that the corresponding classical action-angle loops change.
Microwave Ac Zeeman Force For Ultracold Atoms, C. T. Fancher, A. J. Pyle, A. P. Rotunno, Seth Aubin
Microwave Ac Zeeman Force For Ultracold Atoms, C. T. Fancher, A. J. Pyle, A. P. Rotunno, Seth Aubin
Arts & Sciences Articles
We measure the ac Zeeman force on an ultracold gas of 87Rb due to a microwave magnetic field targeted to the 6.8 GHz hyperfine splitting of these atoms. An atom chip produces a microwave near field with a strong amplitude gradient, and we observe a force over three times the strength of gravity. Our measurements are consistent with a simple two-level theory for the ac Zeeman effect and demonstrate its resonant, bipolar, and spin-dependent nature. We observe that the dressed-atom eigenstates gradually mix over time and have mapped out this behavior as a function of magnetic field and detuning. We …
Isotope Shifts In The 7 S → 8 S Transition Of Francium: Measurements And Comparison To Ab Initio Theory, M. R. Kalita, J. A. Behr, (...), Seth Aubin, Et Al.
Isotope Shifts In The 7 S → 8 S Transition Of Francium: Measurements And Comparison To Ab Initio Theory, M. R. Kalita, J. A. Behr, (...), Seth Aubin, Et Al.
Arts & Sciences Articles
We observe the electric-dipole forbidden 7s→8s transition in the francium isotopes 208−211Fr and 213Fr using a two-photon excitation scheme. We collect the atoms online from an accelerator and confine them in a magneto-optical trap for the measurements. In combination with previous measurements of the 7s→7p1/2 transition we perform a King plot analysis. We compare the thus-determined ratio of the field shift constants (1.228 ± 0.019) to results obtained from new ab initio calculations (1.234 ± 0.010).
Cosmogenic Neutron Production At Daya Bay, Daya Bay Collaboration, (…), R. D. Mckeown, W. Wang, Et Al.
Cosmogenic Neutron Production At Daya Bay, Daya Bay Collaboration, (…), R. D. Mckeown, W. Wang, Et Al.
Arts & Sciences Articles
Neutrons produced by cosmic ray muons are an important background for underground experiments studying neutrino oscillations, neutrinoless double beta decay, dark matter, and other rare-event signals. A measurement of the neutron yield in the three different experimental halls of the Daya Bay Reactor Neutrino Experiment at varying depth is reported. The neutron yield in Daya Bay's liquid scintillator is measured to be Y-n = (10.26 +/- 0.86) x 10(-5), (10.22 +/- 0.87) x 10(-5), and (17.03 +/- 1.22) x 10(-5) mu(-1)g(-1)cm(2) at depths of 250, 265, and 860 meters-water-equivalent. These results are compared to other measurements and the simulated neutron …
Experimental Observation Of Classical Dynamical Monodromy, M. P. Nerem, D. Salmon, S. Aubin, John B. Delos
Experimental Observation Of Classical Dynamical Monodromy, M. P. Nerem, D. Salmon, S. Aubin, John B. Delos
Arts & Sciences Articles
A Hamiltonian system is said to have nontrivial monodromy if its fundamental action-angle loops do not return to their initial topological state at the end of a closed circuit in angular momentum-energy space. This process has been predicted to have consequences which can be seen in dynamical systems, called dynamical monodromy. Using an apparatus consisting of a spherical pendulum subject to magnetic potentials and torques, we observe nontrivial monodromy by the associated topological change in the evolution of a loop of trajectories.
Isoscalar Pi Pi, K(K)Over-Bar, Eta Eta Scattering And The Sigma, F(0),F(2) Mesons From Qcd, Raul A. Briceno, Jozef J. Dudek, Robert G. Edwards, David J. Wilson
Isoscalar Pi Pi, K(K)Over-Bar, Eta Eta Scattering And The Sigma, F(0),F(2) Mesons From Qcd, Raul A. Briceno, Jozef J. Dudek, Robert G. Edwards, David J. Wilson
Arts & Sciences Articles
We present the first lattice QCD study of coupled isoscalar pi pi, K (K) over bar, eta eta S- and D-wave scattering extracted from discrete finite-volume spectra computed on lattices which have a value of the light quark mass corresponding to m(pi) similar to 391 MeV. In the J(P) = 0(+) sector we find analogues of the experimental sigma and f(0)(980) states, where the sigma appears as a stable bound-state below pi pi threshold, and, similar to what is seen in experiment, the f(0)(980) manifests itself as a dip in the pi pi cross section in the vicinity of the …
Experimental Observation Of Classical Dynamical Monodromy, M. P. Nerem, D. Salmon, Seth Aubin, John B. Delos
Experimental Observation Of Classical Dynamical Monodromy, M. P. Nerem, D. Salmon, Seth Aubin, John B. Delos
Arts & Sciences Articles
A Hamiltonian system is said to have nontrivial monodromy if its fundamental action-angle loops do not return to their initial topological state at the end of a closed circuit in angular momentum-energy space. This process has been predicted to have consequences which can be seen in dynamical systems, called dynamical monodromy. Using an apparatus consisting of a spherical pendulum subject to magnetic potentials and torques, we observe nontrivial monodromy by the associated topological change in the evolution of a loop of trajectories.
Detecting A Heavy Neutrino Electric Dipole Moment At The Lhc, Marc Sher, Justin R. Stevens
Detecting A Heavy Neutrino Electric Dipole Moment At The Lhc, Marc Sher, Justin R. Stevens
Arts & Sciences Articles
The milliQan Collaboration has proposed to search for millicharged particles by looking for very weakly ionizing tracks in a detector installed in a cavern near the CMS experiment at the LHC. We note that another form of exotica can also yield weakly ionizing tracks. If a heavy neutrino has an electric dipole moment (EDM), then the milliQan experiment may be sensitive to it as well. In particular, writing the general dimension-5 operator for an EDM with a scale of a TeV and a one-loop factor, one finds a potential EDM as high as a few times 10(-17) e-cm, and models …
Highly Repeatable Nanoscale Phase Coexistence In Vanadium Dioxide Films, T. J. Huffman, D. J. Lahneman, (...), M. M. Qazilbash
Highly Repeatable Nanoscale Phase Coexistence In Vanadium Dioxide Films, T. J. Huffman, D. J. Lahneman, (...), M. M. Qazilbash
Arts & Sciences Articles
It is generally believed that in first-order phase transitions in materials with imperfections, the formation of phase domains must be affected to some extent by stochastic (probabilistic) processes. The stochasticity would lead to unreliable performance in nanoscale devices that have the potential to exploit the transformation of physical properties in a phase transition. Here we show that stochasticity at nanometer length scales is completely suppressed in the thermally driven metal-insulator transition (MIT) in sputtered vanadium dioxide (VO2) films. The nucleation and growth of domain patterns of metallic and insulating phases occur in a strikingly reproducible way. The completely deterministic nature …
Tetraquark Operators In Lattice Qcd And Exotic Flavour States In The Charm Sector, Gavin K. C. Cheung, Christopher E. Thomas, Jozef J. Dudek, Robert G. Edwards
Tetraquark Operators In Lattice Qcd And Exotic Flavour States In The Charm Sector, Gavin K. C. Cheung, Christopher E. Thomas, Jozef J. Dudek, Robert G. Edwards
Arts & Sciences Articles
We present a general class of operators resembling compact tetraquarks which have a range of colour-flavour-spin structures, transform irreducibly under the symmetries of the lattice and respect other relevant symmetries. These constructions are demonstrated in lattice QCD calculations with light quarks corresponding to m(pi) = 391 MeV. Using the distillation framework, correlation functions involving large bases of meson-meson and tetraquark operators are computed in the isospin-1 hidden-charm and doubly-charmed sectors, and finite-volume spectra are extracted with the variational method. We find the spectra are insensitive to the addition of tetraquark operators to the bases of meson-meson operators. For the first …
First Measurement Of Proton's Charge Form Factor At Very Low Q(2) With Initial State Radiation, M. Mihovilovic, K. Griffioen, Et Al.
First Measurement Of Proton's Charge Form Factor At Very Low Q(2) With Initial State Radiation, M. Mihovilovic, K. Griffioen, Et Al.
Arts & Sciences Articles
We report on a new experimental method based on initial-state radiation (ISR) in e-p scattering, which exploits the radiative tail of the elastic peak to study the properties of electromagnetic processes and to extract the proton charge form factor (G(E)(P)) at extremely small Q(2). The ISR technique was implemented in an experiment at the three-spectrometer facility of the Mainz Microtron (MAMI). This led to a precise validation of radiative corrections far away from elastic line and provided first measurements of G(E)(P) for 0.001 <= Q(2) <= 0.004 (GeV/c)(2). (C) 2017 The Authors. Published by Elsevier B.V.
Drifts, Currents, And Power Scrape-Off Width In Solps-Iter Modeling Of Diii-D, E. T. Meier, R. J. Goldston, E. G. Kaveeva, M. A. Makowski, S. Mordijck
Drifts, Currents, And Power Scrape-Off Width In Solps-Iter Modeling Of Diii-D, E. T. Meier, R. J. Goldston, E. G. Kaveeva, M. A. Makowski, S. Mordijck
Arts & Sciences Articles
The effects of drifts and associated flows and currents on the width of the parallel heat flux channel (lambda(q)) in the tokamak scrape-offlayer (SOL) are analyzed using the SOLPS-ITER 2D fluid transport code. Motivation is supplied by Goldston's heuristic drift (HD) model for lambda(q), which yields the same approximately inverse poloidal magnetic field dependence seen in multi-machine regression. The analysis, focusing on a DIII-D H-mode discharge, reveals HD-like features, including comparable density and temperature fall-off lengths in the SOL, and up-down ion pressure asymmetry that allows net cross-separatrix ion magnetic drift flux to exceed net anomalous ion flux. In experimentally …
Broadband Near-Field Infrared Spectroscopy With A High Temperature Plasma Light Source, D. J. Lahneman, T. J. Huffman, Peng Xu, M. M. Qazilbash
Broadband Near-Field Infrared Spectroscopy With A High Temperature Plasma Light Source, D. J. Lahneman, T. J. Huffman, Peng Xu, M. M. Qazilbash
Arts & Sciences Articles
Scattering-type scanning near-field optical microscopy (S-SNOM) has enormous potential as a spectroscopy tool in the infrared spectral range where it can probe phonon resonances and carrier dynamics at the nanometer lengths scales. However, its applicability is limited by the lack of practical and affordable table-top light sources emitting intense broadband infrared radiation in the 100 cm(-1) to 2,500 cm(-1) spectral range. This paper introduces a high temperature plasma light source that is both ultra-broadband and has much more radiant power in the infrared spectral range than conventional, table-top thermal light sources such as the globar. We implement this plasma lamp …
Measurement Of The Beam Asymmetry Sigma For Pi(0) And Eta Photoproduction On The Proton At E-Gamma=9 Gev, H. Al Ghoul, (...), Justin R. Stevens, Et Al.
Measurement Of The Beam Asymmetry Sigma For Pi(0) And Eta Photoproduction On The Proton At E-Gamma=9 Gev, H. Al Ghoul, (...), Justin R. Stevens, Et Al.
Arts & Sciences Articles
We report measurements of the photon beam asymmetry Sigma for the reactions (gamma) over right arrowp -> p pi(0) and gamma p -> p eta from the GLUEX experiment using a 9 GeV linearly polarized, tagged photon beam incident on a liquid hydrogen target in Jefferson Lab's Hall D. The asymmetries, measured as a function of the proton momentum transfer, possess greater precision than previous pi(0) measurements and are the first. measurements in this energy regime. The results are compared with theoretical predictions based on t-channel, quasiparticle exchange and constrain the axial-vector component of the neutral meson production mechanism in …