Count rates and structure factors in anomalous soft x-ray scattering from cuprate superconductors
Abbamonte, P; Rusydi, A; Logvenov, G; Bozovic, [No Value; Sawatzky, GA; Venema, L.C.; Bozovic,; Pavuna, D
2002-01-01
It has recently been shown that x-ray diffraction from the doped holes in cuprates can be enhanced by 3-4 orders of magnitude by exploiting resonance effects in the oxygen K shell. This new type of anomalous scattering is direct way of probing ground state inhomogeneity in the mobile carrier liquid
Indian Academy of Sciences (India)
S B Appaji Gowda; M L Mallikarjuna; R Gowda; T K Umesh
2003-09-01
The real and imaginary parts, '() and ''() of the dispersion corrections to the forward Rayleigh scattering amplitude (also called anomalous scattering factors) for the elements La, Ce, Pr, Nd, Sm, Gd, Dy, Ho and Er, have been determined by a numerical evaluation of the dispersion integral that relates them through the optical theorem to the photoeffect cross-sections. The photoeffect cross-sections are derived from the total attenuation cross-section data set experimentally determined using high resolution high purity germanium detector in a narrow beam good geometry set-up for these elements in the photon energy range 5 to 1332 keV and reported earlier by the authors. Below 5 keV, Scoﬁeld’s photoeffect cross-sections compiled in XCOM program have been interpolated and used. Simple formulae for '' in terms of atomic number and energy have also been obtained. The data cover the energy region from 6 to 85 keV and atomic number from 57–68. The results obtained are found to agree fairly well with the other available data.
Anomalous decay and scattering processes of the eta meson
Kubis, Bastian
2015-01-01
We amend a recent dispersive analysis of the anomalous $\\eta$ decay process $\\eta\\to\\pi^+\\pi^-\\gamma$ by the effects of the $a_2$ tensor meson, the lowest-lying resonance that can contribute in the $\\pi\\eta$ system. While the net effects on the measured decay spectrum are small, they may be more pronounced for the analogous $\\eta'$ decay. There are nonnegligible consequences for the $\\eta$ transition form factor, which is an important quantity for the hadronic light-by-light scattering contribution to the muon's anomalous magnetic moment. We predict total and differential cross sections, as well as a marked forward-backward asymmetry, for the crossed process $\\gamma\\pi^-\\to\\pi^-\\eta$ that could be measured in Primakoff reactions in the future.
Anomalous Light Scattering by Topological PT-symmetric Particle Arrays
Ling, C. W.; Choi, Ka Hei; Mok, T. C.; Zhang, Zhao-Qing; Fung, Kin Hung
2016-12-01
Robust topological edge modes may evolve into complex-frequency modes when a physical system becomes non-Hermitian. We show that, while having negligible forward optical extinction cross section, a conjugate pair of such complex topological edge modes in a non-Hermitian -symmetric system can give rise to an anomalous sideway scattering when they are simultaneously excited by a plane wave. We propose a realization of such scattering state in a linear array of subwavelength resonators coated with gain media. The prediction is based on an analytical two-band model and verified by rigorous numerical simulation using multiple-multipole scattering theory. The result suggests an extreme situation where leakage of classical information is unnoticeable to the transmitter and the receiver when such a -symmetric unit is inserted into the communication channel.
Study of supported platinum catalysts by anomalous scattering
Energy Technology Data Exchange (ETDEWEB)
Georgopoulos, P.; Cohen, J.B.
1985-01-01
Platinum metal catalysts supported on silica gel and alumina were examined by wide-angle anomalous x-ray scattering at the Cornell High Energy Synchrotron Source. Complete removal of the support background features is achieved by this method, eliminating errors due to inaccurate background estimation. Platinum diffraction patterns from very-high-percentage metal-exposed catalysts were obtained for the first time, as well as from platinum supported on alumina. This technique is suitable for examining catalysts under working conditions and is superior to EXAFS for determinations of particle morphology and size distribution. 10 references, 8 figures.
Theory of Anomalous X-Ray Scattering in Orbital-Ordered Manganites
Ishihara, Sumio; Maekawa, Sadamichi
1998-04-01
We study the theory of the anomalous x-ray scattering in relation to its role as a detector of the orbital orderings and excitations in perovskite manganites. The scattering matrix is given by virtual electron excitations in Mn from the 1s level to the unoccupied 4p level. We find that the orbital dependence of the Coulomb interaction between 3d and 4p electrons is essential to the anisotropy of the scattering factor near the K edge. The calculated results in MnO6 clusters explain the forbidden reflections observed in La0.5Sr1.5MnO4 and LaMnO3. The possibility of observing orbital waves with x-ray scattering is discussed as well.
Effects of surface and interface scattering on anomalous Hall effect in Co/Pd multilayers
Guo, Z. B.
2012-09-27
In this paper, we report the results of surface and interface scattering on anomalous Hall effect in Co/Pd multilayers with perpendicular magnetic anisotropy. The surface scattering effect has been extracted from the total anomalous Hall effect. By scaling surface scattering contribution with ρAHs∼ργss, the exponent γ has been found to decrease with the increase of surface scattering resistivity, which could account for the thickness-dependent anomalous Hall effect. Interface diffusion induced by rapid thermal annealing modifies not only the magnetization and longitudinal resistivity but also the anomalous Hall effect; a large exponent γ ∼ 5.7 has been attributed to interface scattering-dominated anomalous Hall effect.
Borissov, A.; Kontar, E. P.; Threlfall, J.; Neukirch, T.
2017-09-01
The conversion of magnetic energy into other forms (such as plasma heating, bulk plasma flows, and non-thermal particles) during solar flares is one of the outstanding open problems in solar physics. It is generally accepted that magnetic reconnection plays a crucial role in these conversion processes. In order to achieve the rapid energy release required in solar flares, an anomalous resistivity, which is orders of magnitude higher than the Spitzer resistivity, is often used in magnetohydrodynamic (MHD) simulations of reconnection in the corona. The origin of Spitzer resistivity is based on Coulomb scattering, which becomes negligible at the high energies achieved by accelerated particles. As a result, simulations of particle acceleration in reconnection events are often performed in the absence of any interaction between accelerated particles and any background plasma. This need not be the case for scattering associated with anomalous resistivity caused by turbulence within solar flares, as the higher resistivity implies an elevated scattering rate. We present results of test particle calculations, with and without pitch angle scattering, subject to fields derived from MHD simulations of two-dimensional (2D) X-point reconnection. Scattering rates proportional to the ratio of the anomalous resistivity to the local Spitzer resistivity, as well as at fixed values, are considered. Pitch angle scattering, which is independent of the anomalous resistivity, causes higher maximum energies in comparison to those obtained without scattering. Scattering rates which are dependent on the local anomalous resistivity tend to produce fewer highly energised particles due to weaker scattering in the separatrices, even though scattering in the current sheet may be stronger when compared to resistivity-independent scattering. Strong scattering also causes an increase in the number of particles exiting the computational box in the reconnection outflow region, as opposed to along the
Acoustic metasurfaces for scattering-free anomalous reflection and refraction
Díaz-Rubio, A.; Tretyakov, S. A.
2017-09-01
Manipulation of acoustic wave fronts by thin and planar devices, known as metasurfaces, has been extensively studied, in view of many important applications. Reflective and refractive metasurfaces are designed using the generalized reflection and Snell's laws, which tell that local phase shifts at the metasurface supply extra momentum to the wave, presumably allowing arbitrary control of reflected or transmitted waves. However, as has been recently shown for the electromagnetic counterpart, conventional metasurfaces based on the generalized laws of reflection and refraction have important drawbacks in terms of power efficiency. This work presents a new synthesis method of acoustic metasurfaces for anomalous reflection and transmission that overcomes the fundamental limitations of conventional designs, allowing full control of acoustic energy flow. The results show that different mechanisms are necessary in the reflection and transmission scenarios for ensuring perfect performance. Metasurfaces for anomalous reflection require nonlocal response, which allows energy channeling along the metasurface. On the other hand, for perfect manipulation of anomalously transmitted waves, local and nonsymmetric response is required. These conclusions are interpreted through appropriate surface impedance models which are used to find possible physical implementations of perfect metasurfaces in each scenario. We hope that this advance in the design of acoustic metasurfaces opens new avenues not only for perfect anomalous reflection and transmission but also for realizing more complex functionalities, such as focusing, self-bending, or vortex generation.
Three-loop corrections to the soft anomalous dimension in multileg scattering
Almelid, Øyvind; Gardi, Einan
2016-01-01
We present the three-loop result for the soft anomalous dimension governing long-distance singularities of multi-leg gauge-theory scattering amplitudes of massless partons. We compute all contributing webs involving semi-infinite Wilson lines at three loops and obtain the complete three-loop correction to the dipole formula. We find that non-dipole corrections appear already for three coloured partons, where the correction is a constant without kinematic dependence. Kinematic dependence appears only through conformally-invariant cross ratios for four coloured partons or more, and the result can be expressed in terms of single-valued harmonic polylogarithms of weight five. While the non-dipole three-loop term does not vanish in two-particle collinear limits, its contribution to the splitting amplitude anomalous dimension reduces to a constant, and it only depends on the colour charges of the collinear pair, thereby preserving strict collinear factorization properties. Finally we verify that our result is consi...
Shen, Fei; An, Ning; Tao, Yifei; Zhou, Hongping; Jiang, Zhaoneng; Guo, Zhongyi
2017-08-01
We have investigated the scattering properties of an individual core-shell nanoparticle using the Mie theory, which can be tuned to support both electric and magnetic modes simultaneously. In general, the suppression of forward scattering can be realized by the second Kerker condition. Here, a novel mechanism has to be adopted to explain zero-forward scattering, which originates from the complex interactions between dipolar and quadrupolar modes. However, for lossy and lossless core-shell spherical nanoparticles, zero-forward scattering can never be achieved because the real parts of Mie expansion coefficients are always positive. By adding proper gain in dielectric shell, zero-forward scattering can be found at certain incident wavelengths, which means that all electric and magnetic responses in Mie scattering can be counteracted totally in the forward direction. In addition, if the absolute values of dipolar and quadrupolar terms are in the same order of magnitude, the local scattering minimum and maximum can be produced away from the forward and backward directions due to the interacting effect between the dipolar and quadrupolar terms. Furthermore, by adding suitable gain in shell, super-forward scattering can also be realized at certain incident wavelengths. We also demonstrated that anomalously weak scattering or superscattering could be obtained for the core-shell nanoparticles with suitable gain in shell. In particular, for such a choice of suitable gain in shell, we can obtain zero-forward scattering and anomalously weak scattering at the same wavelength as well as super-forward scattering at another wavelength. These features may provide new opportunities for cloaking, plasmonic lasers, optical antennas, and so on.
Anomalous couplings, resonances and unitarity in vector boson scattering
Energy Technology Data Exchange (ETDEWEB)
Sekulla, Marco
2015-12-04
The Standard Model of particle physics has proved itself as a reliable theory to describe interactions of elementary particles. However, many questions concerning the Higgs sector and the associated electroweak symmetry breaking are still open, even after (or because) a light Higgs boson has been discovered. The 2→2 scattering amplitude of weak vector bosons is suppressed in the Standard Model due to the Higgs boson exchange. Therefore, weak vector boson scattering processes are very sensitive to additional contributions beyond the Standard Model. Possible new physics deviations can be studied model-independently by higher dimensional operators within the effective field theory framework. In this thesis, a complete set of dimension six and eight operators are discussed for vector boson scattering processes. Assuming a scenario where new physics in the Higgs/Goldstone boson decouples from the fermion-sector and the gauge-sector in the high energy limit, the impact of the dimension six operator L{sub HD} and dimension eight operators L{sub S,0} and L{sub S,1} to vector boson scattering processes can be studied separately for complete processes at particle colliders. However, a conventional effective field theory analysis will violate the S-matrix unitarity above a certain energy limit. The direct T-matrix scheme is developed to allow a study of effective field theory operators consistent with basic quantum-mechanical principles in the complete energy reach of current and future colliders. Additionally, this scheme can be used preventively for any model, because it leaves theoretical predictions invariant, which already satisfies unitarity. The effective field theory approach is further extended by allowing additional generic resonances coupling to the Higgs/Goldstone boson sector, namely the isoscalar-scalar, isoscalar-tensor, isotensor-scalar and isotensor-tensor. In particular, the Stueckelberg formalism is used to investigate the impact of the tensor degree of
Muon's anomalous magnetic moment effects on laser assisted Coulomb scattering process
Taj, S; Idrissi, M El; Attaourti, Y; Oufni, L
2012-01-01
Laser assisted Coulomb scattering by relativistic electron and heavy electron (muon) is studied by using Salamin waves (Salamin 1993) in the Weak Field Approximation (WFA). Both electron and muon are described by the Dirac equation, with the anomalous magnetic moment effects fully included. The generalization of this paper to heavy electron (muon) gives interesting insights as to how the mass affects the magnitude of the differential cross sections. No significant difference in the muon's DCS with and without AMM effects was detected.
An extended anomalous fine structure of X-ray quasi-Bragg diffuse scattering from multilayers
Chernov, V A; Mytnichenko, S V
2001-01-01
An X-ray quasi-Bragg diffuse scattering anomalous fine structure technique was probed near the absorption Ni K-edge to study the interfacial structure of the Ni/C multilayer deposited by the laser ablation. Like other combinations of the EXAFS and diffraction techniques, this method has a spatial selectivity and was shown qualitatively to provide atomic structural information from the mixed interfacial layers. The possibilities and advantages of this technique are discussed.
Anomalous lattice vibrations of monolayer MoS 2 probed by ultraviolet Raman scattering
Liu, Hsiang Lin
2015-01-01
We present a comprehensive Raman scattering study of monolayer MoS
Andreazza, P.; Khelfane, H.; Lyon, O.; Andreazza-Vignolle, C.; Ramos, A. Y.; Samah, M.
2012-06-01
As atomic structure and morphology of particles are directly correlated to their functional properties, experimental methods probing local and average features of particles at the nanoscale elicit a growing interest. Anomalous small-angle X-ray scattering (ASAXS) is a very attractive technique to investigate the size, shape and spatial distribution of nanoobjects embedded in a homogeneous matrix or in porous media. The anomalous variation of the scattering factor close to an absorption edge enables element specific investigations. In the case of supported nano-objects, the use of grazing incidence is necessary to limit the probed depth. The combination of grazing incidence with the anomalous technique provides a powerful new method, anomalous grazing incidence small-angle X-ray scattering (AGISAXS), to disentangle complex chemical patterns in supported multi-component nano-structures. Nevertheless, a proper data analysis requires accurate quantitative measurements associated to an adapted theoretical framework. This paper presents anomalous methods applied to nanoalloys phase separation in the 1-10 nm size range, and focuses on the application of AGISAXS in bimetallic systems: nanocomposite films and core-shell supported nanoparticles.
Anomalous Light Scattering by Topological ${\\mathcal{PT}}$-symmetric Particle Arrays
Ling, C W; Mok, T C; Zhang, Z Q; Fung, Kin Hung
2016-01-01
Robust topological edge modes may evolve into complex-frequency modes when a physical system becomes non-Hermitian. We show that, while having negligible forward optical extinction cross section, a conjugate pair of such complex topological edge modes in a non-Hermitian $\\mathcal{PT}$-symmetric system can give rise to an anomalous sideway scattering when they are simultaneously excited by a plane wave. We propose a realization of such scattering state in a linear array of subwavelength resonators coated with gain media. The prediction is based on an analytical two-band model and verified by rigorous numerical simulation using multiple-multipole scattering theory. The result suggests an extreme situation where leakage of classical information is unnoticeable to the transmitter and the receiver when such a $\\mathcal{PT}$-symmetric unit is inserted into the communication channel.
Soft factors for double parton scattering at NNLO
Vladimirov, Alexey
2016-01-01
We show at NNLO that the soft factors for double parton scattering (DPS) for both integrated and unintegrated kinematics, can be presented entirely in the terms of the soft factor for single Drell-Yan process, i.e. the transverse momentum dependent (TMD) soft factor. Using the linearity of logarithm of TMD soft factor in rapidity divergences, we decompose the DPS soft factor matrices into a product of matrices with rapidity divergences in given sectors, and thus, define individual double parton distributions at NNLO. The rapidity anomalous dimension matrices for double parton distributions are presented in terms of TMD rapidity anomalous dimension. The analysis is done using the generating function approach to web diagrams. Significant part of the result is obtained from the symmetry properties of web diagrams without referring to explicit expressions or a particular rapidity regularization scheme. Additionally we present NNLO expression for the web diagram generating function for Wilson lines with two light-...
Soft factors for double parton scattering at NNLO
Energy Technology Data Exchange (ETDEWEB)
Vladimirov, Alexey [Institut für Theoretische Physik, Universität Regensburg,D-93040 Regensburg (Germany)
2016-12-13
We show at NNLO that the soft factors for double parton scattering (DPS) for both integrated and unintegrated kinematics, can be presented entirely in the terms of the soft factor for single Drell-Yan process, i.e. the transverse momentum dependent (TMD) soft factor. Using the linearity of the logarithm of TMD soft factor in rapidity divergences, we decompose the DPS soft factor matrices into a product of matrices with rapidity divergences in given sectors, and thus, define individual double parton distributions at NNLO. The rapidity anomalous dimension matrices for double parton distributions are presented in the terms of TMD rapidity anomalous dimension. The analysis is done using the generating function approach to web diagrams. Significant part of the result is obtained from the symmetry properties of web diagrams without referring to explicit expressions or a particular rapidity regularization scheme. Additionally, we present NNLO expression for the web diagram generating function for Wilson lines with two light-like directions.
Anomalously Hot Electrons due to Rescatter of Stimulated Raman Scattering in the Kinetic Regime
Winjum, B J; Tsung, F S; Mori, W B
2012-01-01
Using particle-in-cell simulations, we examine hot electron generation from electron plasma waves excited by stimulated Raman scattering and rescattering in the kinetic regime where the wavenumber times the Debye length (k\\lambda_D) is greater than 0.3 for backscatter. We find that for laser and plasma conditions of possible relevance to experiments at the National Ignition Facility (NIF), anomalously energetic electrons can be produced through the interaction of a discrete spectrum of plasma waves generated from SRS (back and forward scatter), rescatter, and the Langmuir decay of the rescatter-generated plasma waves. Electrons are bootstrapped in energy as they propagate into plasma waves with progressively higher phase velocities.
Interfacial scattering effect on anomalous Hall effect in Ni/Au multilayers
Zhang, Qiang
2017-04-21
The effect of interfacial scattering on anomalous Hall effect (AHE) was studied in the ${{\\\\left(\\\\text{N}{{\\\\text{i}}_{\\\\frac{36}{n}~\\\\text{nm}}}/\\\\text{A}{{\\\\text{u}}_{\\\\frac{12}{n}~\\\\text{nm}}}\\ ight)}_{n}}$ multilayers. Field-dependent Hall resistivity was measured in the temperature range of 5–300 K with the magnetic field up to 50 kOe. The anomalous Hall resistivity (${{\\ ho}_{\\\\text{AHE}}}$ ) was enhanced by more than six times at 5 K from n = 1 to n = 12 due to the increased interfacial scattering, whereas the longitudinal resistivity (${{\\ ho}_{xx}}$ ) was increased nearly three times. A scaling relation ${{\\ ho}_{\\\\text{AHE}}}\\\\sim \\ ho _{xx}^{\\\\gamma}$ with $\\\\gamma =1.85$ was obtained for ${{\\ ho}_{\\\\text{AHE}}}$ and ${{\\ ho}_{xx}}$ measured at 5 K, indicating that the dominant mechanism(s) of the AHE in these multilayers should be side-jump or/and intrinsic in nature. The new scaling relation ${{\\ ho}_{\\\\text{AHE}}}=\\\\alpha {{\\ ho}_{xx0}}+\\\\beta \\ ho _{xx0}^{2}+b\\ ho _{xx}^{2}$ (Tian et al 2009 Phys. Rev. Lett. 103 087206) has been applied to our data to identify the origin of the AHE in this type of multilayer.
Skew scattering dominated anomalous Hall effect in Cox(MgO)100-x granular thin films
Zhang, Qiang
2017-07-31
We investigated the mechanism(s) of the anomalous Hall effect (AHE) in magnetic granular materials by fabricating 100-nm-thick thin films of Co_{x}(MgO)_{100-x} with a Co volume fraction of 34≤x≤100 using co-sputtering at room temperature. We measured the temperature dependence of longitudinal resistivity (ρ_{xx}) and anomalous Hall resistivity (ρ_{AHE}) from 5 K to 300 K in all samples. We found that when x decreases from 100 to 34, the values of ρ_{xx} and ρ_{AHE} respectively increased by about four and three orders in magnitude. By linearly fitting the data, obtained at 5 K, of anomalous Hall coefficient (R_{s}) and of ρ_{xx} to log(R_{s})~γlog(ρ_{xx}), we found that our results perfectly fell on a straight line with a slope of γ= 0.97±0.02. This fitting value of γ in R_{s}∝ρ_{xx}^{γ} clearly suggests that skew scattering dominated the AHE in this granular system. To explore the effect of the scattering on the AHE, we performed the same measurements on annealed samples. We found that although both ρ_{xx} and ρ_{AHE} significantly reduced after annealing, the correlation between them was almost the same, which was confirmed by the fitted value, γ=0.99±0.03. These data strongly suggest that the AHE originates from the skew scattering in Co-MgO granular thin films no matter how strong the scatterings of electrons by the interfaces and defects is. This observation may be of importance to the development of spintronic devices based on MgO.
Fu, Han; Reich, K. V.; Shklovskii, B. I.
2016-07-01
We study the low temperature conductivity of the electron accumulation layer induced by the very strong electric field at the surface of an SrTiO3 sample. Due to the strongly nonlinear lattice dielectric response, the three-dimensional density of electrons n (x ) in such a layer decays with the distance from the surface x very slowly as n (x ) ∝1 /x12 /7 . We show that when the mobility is limited by the surface scattering the contribution of such a tail to the conductivity diverges at large x because of growing time electrons need to reach the surface. We explore truncation of this divergence by the finite sample width, by the bulk scattering rate, by the back gate voltage, or by the crossover to the bulk linear dielectric response with the dielectric constant κ . As a result we arrive at the anomalously large mobility, which depends not only on the rate of the surface scattering, but also on the physics of truncation. Similar anomalous behavior is found for the Hall factor, the magnetoresistance, and the thermopower.
Korda, V. Yu.; Molev, A. S.; Klepikov, V. F.; Korda, L. P.
2015-02-01
Using the evolutionary model-independent S -matrix approach, we show that a simultaneous correct description of the pictures of nuclear rainbow, prerainbow, and anomalous large-angle scattering (ALAS) in the 4He-40Ca elastic scattering can be achieved with help of the S -matrix moduli and the real nuclear phases exhibiting smooth monotonic dependencies on angular momentum, while the quantum deflection functions have a form characteristic of the nuclear rainbow case. The special role of the surface partial waves in the formation of ALAS is revealed.
Lin, D H
2003-01-01
Partial wave theory of a three dmensional scattering problem for an arbitray short range potential and a nonlocal Aharonov-Bohm magnetic flux is established. The scattering process of a ``hard shere'' like potential and the magnetic flux is examined. An anomalous total cross section is revealed at the specific quantized magnetic flux at low energy which helps explain the composite fermion and boson model in the fractional quantum Hall effect. Since the nonlocal quantum interference of magnetic flux on the charged particles is universal, the nonlocal effect is expected to appear in quite general potential system and will be useful in understanding some other phenomena in mesoscopic phyiscs.
Robustness of the fractal regime for the multiple-scattering structure factor
Katyal, Nisha; Botet, Robert; Puri, Sanjay
2016-08-01
In the single-scattering theory of electromagnetic radiation, the fractal regime is a definite range in the photon momentum-transfer q, which is characterized by the scaling-law behavior of the structure factor: S(q) ∝ 1 /q df. This allows a straightforward estimation of the fractal dimension df of aggregates in Small-Angle X-ray Scattering (SAXS) experiments. However, this behavior is not commonly studied in optical scattering experiments because of the lack of information on its domain of validity. In the present work, we propose a definition of the multiple-scattering structure factor, which naturally generalizes the single-scattering function S(q). We show that the mean-field theory of electromagnetic scattering provides an explicit condition to interpret the significance of multiple scattering. In this paper, we investigate and discuss electromagnetic scattering by three classes of fractal aggregates. The results obtained from the TMatrix method show that the fractal scaling range is divided into two domains: (1) a genuine fractal regime, which is robust; (2) a possible anomalous scaling regime, S(q) ∝ 1 /qδ, with exponent δ independent of df, and related to the way the scattering mechanism uses the local morphology of the scatterer. The recognition, and an analysis, of the latter domain is of importance because it may result in significant reduction of the fractal regime, and brings into question the proper mechanism in the build-up of multiple-scattering.
Directory of Open Access Journals (Sweden)
Guenter Goerigk
2016-03-01
Full Text Available Anomalous small angle scattering measurements have been applied to diluted solutions of anionic polyacrylates decorated by specifically-interacting Pb2+ cations, revealing partial collapse of the polyacrylate into pearl-like subdomains with a size on the order of a few nanometers. From the pure-resonant scattering contribution of the Pb2+ cations, and from subsequent analysis of the resonant-invariant, the amount of Pb2+ cations condensed onto the polyanions with respect to the total amount of Pb2+ cations in the solvent was estimated. In order to scrutinize systematic limitations in the determination of the chemical concentrations of resonant scattering counterions in the collapsed phase, Monte Carlo simulations have been performed. The simulations are based on structural confinements at variable size in the range of few nanometers, which represent the collapsed subdomains in the polyanions. These confinements were gradually filled to a high degree of the volume fraction with resonant scattering counterions giving access to a resonant-invariant at a variable degree of filling. The simulations revealed in the limit of small structures a significant underestimation of the true degree of filling of the collapsed subdomains when determining chemical concentrations of Pb2+ cations from the resonant invariant.
Scatter factors assessment in microbeam radiation therapy
Energy Technology Data Exchange (ETDEWEB)
Prezado, Y.; Martinez-Rovira, I.; Sanchez, M. [Laboratoire Imagerie et Modelisation en Neurobiologie et Cancerologie IMNC-UMR 8165, Centre National de la Recherche Scientifique (CNRS), Campus Universitaire, Bat. 440, 15 rue Georges Clemenceau, 91406 Orsay Cedex (France); Institut de Tecniques Energetiques, Universitat Politecnica de Catalunya, Diagonal 647, E-08028 Barcelona (Spain) and ID17 Biomedical Beamline, European Synchrotron Radiation Facility (ESRF), 6 Rue Jules Horowitz, B.P. 220, 38043 Grenoble Cedex (France); Servicio de Radiofisica, Complejo Hospitalario de Santiago de Compostela, Rua Choupana S/N, 15706 Santiago de Compostela (Spain)
2012-03-15
Purpose: The success of the preclinical studies in Microbeam Radiation Therapy (MRT) paved the way to the clinical trials under preparation at the Biomedical Beamline of the European Synchrotron Radiation Facility. Within this framework, an accurate determination of the deposited dose is crucial. With that aim, the scatter factors, which translate the absolute dose measured in reference conditions (2 x 2 cm{sup 2} field size at 2 cm-depth in water) to peak doses, were assessed. Methods: Monte Carlo (MC) simulations were performed with two different widely used codes, PENELOPE and GEANT4, for the sake of safety. The scatter factors were obtained as the ratio of the doses that are deposited by a microbeam and by a field of reference size, at the reference depth. The calculated values were compared with the experimental data obtained by radiochromic (ISP HD-810) films and a PTW 34070 large area chamber. Results: The scatter factors for different microbeam field sizes assessed by the two MC codes were in agreement and reproduced the experimental data within uncertainty bars. Those correction factors were shown to be non-negligible for the future MRT clinical settings: an average 30% lower dose was deposited by a 50 {mu}m microbeam with respect to the reference conditions. Conclusions: For the first time, the scatter factors in MRT were systematically studied. They constitute an essential key to deposit accurate doses in the forthcoming clinical trials in MRT. The good agreement between the different calculations and the experimental data confirms the reliability of this challenging micrometric dose estimation.
Soft-/rapidity- anomalous dimensions correspondence
Vladimirov, Alexey A
2016-01-01
We establish a correspondence between ultraviolet singularities of soft factors for multi-particle production and rapidity singularities of soft factors for multi-parton scattering. This correspondence is a consequence of a conformal mapping between scattering geometries. The correspondence is valid to all orders of perturbation theory and in this way provides a proof of rapidity renormalization procedure for multi-parton scattering soft factors (including the transverse momentum dependent (TMD) soft factor as a special case). As a by-product we obtain an exact relation between the rapidity anomalous dimension and the well-known soft anomalous dimension. The three-loop rapidity anomalous dimensions for TMD and a general multi-parton scattering are derived.
Plaut, Jeffrey J.; Saunders, R. Stephen; Stofan, E. R.; Kirk, R. L.; Schaber, G. G.; Soderblom, L. A.; Ford, P. G.; Pettengill, G. H.; Campbell, D. B.; Stacy, N. J. S.
1992-01-01
Magellan observations indicate that many venusian impact craters have associated surfaces, typically lower in backscatter and emissivity than the surroundings, that extend up to hundreds of kilometers to the west of craters, in parabolic planforms. During Magellan's second mapping cycle, a number of these parabolic features were imaged for a second time, under a different viewing geometry. In some cases, the SAR backscatter appearance of portions of the parabolic features was quite different in the two datasets. We present a description and preliminary interpretations of the anomalous appearance of these features as observed during Magellan's first and second mapping cycles.
Comparing the anomalous phonons in Fe(Te,Se) and (Fe,Ni)(Te,Se) via neutron scattering
Schneeloch, John; Xu, Zhijun; Gu, Genda; Zaliznyak, Igor; Winn, Barry; Rodriguez-Rivera, Jose; Birgeneau, Robert; Xu, Guangyong; Tranquada, John
We studied the anomalous acoustic-type phonons in the Fe(Te,Se) iron-based superconductor family that arise from the (100) Bragg peak, which is forbidden according to the reported crystal structure for these materials. Inelastic neutron scattering was performed on superconducting and non-superconducting crystals of various compositions. The (100) phonons were much weaker in a non-superconducting nickel-doped crystal than in a superconducting crystal with similar selenium fraction, but comparison with another non-superconducting crystal suggests the difference is not simply related to superconductivity. This composition dependence was observed for both transverse and longitudinal phonons. The temperature dependences of the (100) phonons resembled those of conventional phonons. We will discuss these results and possible explanations for the relation between composition and lattice dynamics in this system.
Johnson, Christian; The ATLAS collaboration
2017-01-01
Measurements of the cross sections of the production of three electroweak gauge bosons and of vector-boson scattering processes at the LHC constitute stringent tests of the electroweak sector of the Standard Model and provide a model-independent means to search for new physics at the TeV scale. The ATLAS collaboration searched for the production of three W bosons or of a W boson and a photon together with a Z or W boson at a center of mass energy of 8 TeV. ATLAS has also searched for the electroweak production of a heavy boson and a photon together with two jets. Evidence has been found for the exclusive production of W boson pairs. All results have been used to constrain anomalous quartic gauge couplings and have been compared to the latest theory predictions.
Li, Bing; The ATLAS collaboration
2017-01-01
Measurements of the cross sections of the production of three electroweak gauge bosons and of vector-boson scattering processes at the LHC constitute stringent tests of the electroweak sector of the Standard Model and provide a model-independent means to search for new physics at the TeV scale. The ATLAS collaboration has recently searched for the production of three W bosons or of a W boson and a photon together with a Z or W boson at a center of mass energy of 8 TeV. We also present searches for the electroweak production of a Z boson and a photon together with two jets. The results are compared to state-of-the art theory predictions and have been used to constrain anomalous quartic gauge couplings.
Li, Bing; The ATLAS collaboration
2017-01-01
Measurements of the cross sections of the production of three electroweak gauge bosons and of vector-boson scattering processes at the LHC constitute stringent tests of the electroweak sector of the Standard Model and provide a model-independent means to search for new physics at the TeV scale. The ATLAS collaboration has recently searched for the production of three $W$ bosons or of a $W$ boson and a photon together with a $Z$ or $W$ boson at a center of mass energy of 8 TeV. We also present searches for the electroweak production of a $Z$ boson and a photon together with two jets. The results are compared to state-of-the art theory predictions and have been used to constrain anomalous quartic gauge couplings.
Energy Technology Data Exchange (ETDEWEB)
Lima, J.C. de, E-mail: fsc1jcd@fisica.ufsc.br [Departamento de Física, Universidade Federal de Santa Catarina, Campus Universitário Trindade, S/N, C.P. 476, 88040-900 Florianópolis, Santa Catarina (Brazil); Poffo, C.M. [Departamento de Engenharia Mecânica, Universidade Federal de Santa Catarina, Campus Universitário Trindade, S/N, C.P. 476, 88040-900 Florianópolis, Santa Catarina (Brazil); Departamento de Física, Universidade Federal do Amazonas, 3000 Japiim, 69077-000 Manaus, Amazonas (Brazil); Souza, S.M. [Departamento de Física, Universidade Federal do Amazonas, 3000 Japiim, 69077-000 Manaus, Amazonas (Brazil); Machado, K.D. [Departamento de Física, Centro Politécnico, Universidade Federal do Paraná, 81531-990 Curitiba, Paraná (Brazil); Trichês, D.M. [Departamento de Física, Universidade Federal do Amazonas, 3000 Japiim, 69077-000 Manaus, Amazonas (Brazil); Grandi, T.A. [Departamento de Física, Universidade Federal de Santa Catarina, Campus Universitário Trindade, S/N, C.P. 476, 88040-900 Florianópolis, Santa Catarina (Brazil); Biasi, R.S. de [Seção de Engenharia Mecânica e de Materiais, Instituto Militar de Engenharia, 22290-270 Rio de Janeiro, RJ (Brazil)
2013-09-01
An amorphous Ti{sub 50}Ni{sub 25}Cu{sub 25} alloy was produced by 19 h of mechanical alloying. Anomalous wide angle x-ray scattering data were collected at six energies and six total scattering factors were obtained. By considering the data collected at two energies close to the Ni and Cu K edges, two differential anomalous scattering factors about the Ni and Cu atoms were obtained, showing that the chemical environments around these atoms are different. Eight factors were used as input data to the reverse Monte Carlo method used to compute the partial structure factors S{sub Ti3Ti}(K), S{sub Ti–Cu}(K), S{sub Ti–Ni}(K), S{sub Cu3Cu}(K), S{sub Cu–Ni}(K) and S{sub Ni–Ni}(K) and the partial pair distribution functions G{sub Ti3Ti}(r), G{sub Ti–Cu}(r), G{sub Ti–Ni}(r), G{sub Cu3Cu}(r), G{sub Cu–Ni}(r) and G{sub Ni–Ni}(r). From the RMC final atomic configuration and G{sub ij}(r) functions, the coordination numbers and interatomic atomic distances for the first neighbors were determined.
Energy Technology Data Exchange (ETDEWEB)
Ishii, H. A.
2002-06-11
Since its inception in the late 1970s, anomalous x-ray scattering (AXS) has been employed for chemically-specific structure determination in a wide variety of noncrystalline materials. These studies have successfully produced differential distribution functions (DDFs) which provide information about the compositionally-averaged environment of a specific atomic species in the sample. Despite the wide success in obtaining DDFs, there are very few examples of successful extraction of the fully-chemically-specific partial pair distribution functions (PPDFs), the most detailed description of an amorphous sample possible by x-ray scattering. Extracting the PPDFs is notoriously difficult since the matrix equation involved is ill-conditioned and thus extremely sensitive to errors present in the experimental quantities that enter the equation. Instead of addressing this sensitivity by modifying the data through mathematical methods, sources of error have been removed experimentally: A focusing analyzer crystal was combined with a position-sensitive linear detector to experimentally eliminate unwanted inelastic scattering intensity over most of the reciprocal space range probed. This instrumentation has been used in data collection for the extraction of PPDFs from amorphous (a)-MoGe{sub 3}. This composition arises as a phase separation endpoint in the Ge-rich region of the vapor-deposited Mo-Ge amorphous alloy system but is not present at equilibrium. Since the first Ge-rich compound in the Mo-Ge equilibrium system is MoGe{sub 2}, previous workers have speculated that perhaps a unique MoGe{sub 3} compound exists in the amorphous system. Rather than indicating a distinct MoGe{sub 3} compound with definitive local structure, however, the coordination results are more consistent with a densely-packed alloy having a wide range of solid solubility. Significant improvement in the quality and reliability of experimental PPDFs from a-MoGe{sub 3} by AXS has been achieved solely
Anomalous Behavior of High Quality Factor Planar Superconducting Resonators
Megrant, Anthony; Chen, Zijun; Chiaro, Ben; Dunsworth, Andrew; Quintana, Chris; Campbell, Brooks; Kelly, Julian; Barends, Rami; Chen, Yu; Jeffrey, Evan; Mutus, Josh; Neill, Charles; O'Malley, Peter; Sank, Daniel; Vainsencher, Amit; Wenner, Jim; White, Ted; Bochmann, Jorg; Hoi, Iochun; Palmstrom, Christopher; Martinis, John; Cleland, Andrew
2014-03-01
Superconducting coplanar waveguide resonators have proven to be invaluable tools in studying some of the decoherence mechanisms found in superconducting qubits. Surface two-level states tend to dominate decoherence at temperatures below Tc/10 and at very low microwave powers, assuming loss through other channels (e.g. quasiparticles, vortices, and radiation loss) has been mitigated through proper shielding and design. I will present recent measurements of resonators whose behavior diverges significantly from the standard two-level state model at low temperatures and low excitation energies, resulting in startling behavior of the internal quality factor. This research was funded by the Office of the Director of National Intelligence (ODNI), Intelligence Advanced Research Projects Activity (IARPA), through the Army Research Office grant W911NF-09-1-0375.
Energy Technology Data Exchange (ETDEWEB)
Carrado, K.A.; Thiyagarajan, P.; Winans, R.E.; Song, Kang [Argonne National Lab., IL (United States)
1997-09-01
The authors have exploited anomalous small angle x-ray scattering (ASAXS) to monitor the solvation behavior of Cu(II), Er(III) and Yb(III) ions within the interlayers of the natural aluminosilicate clay mineral montmorillonite. The ASAXS technique can reveal the distribution of specific metallic species within a heterogeneous and disordered matrix. The variations of signal intensity as a function of absorption energy were monitored for all of the metal-clays as a function of hydration. Two different hydration levels were probed: as prepared at ambient conditions, or so-called {open_quotes}dry{close_quotes} powders, and {open_quotes}wet{close_quotes} pastes. ASAXS intensities should increase with absorption energy if the metal ion is associated with the interlayer solvent (water in this case), and decrease if the metal ion is associated with the solid matrix. The results show that: (1) Cu(II) is solvated within the interlayers of the wet sample, as expected, and (2) Er(III) and Yb(III) decrease in ASAXS intensity with increased hydration. This latter result was not expected and there is speculation that these ions have associated as hydrolyzed products with the clay surface. The basic principles underlying SAXS and ASAXS will also be presented in this paper.
An anomalous small-angle X-ray scattering study on phase decomposition in a model superalloy NiCrAl
Energy Technology Data Exchange (ETDEWEB)
Bley, F.; Livet, F.; Simon, J.P. [Ecole Nationale Superieure d`Electrochimie et d`Electrometallurgie, 38 - Grenoble (France). Lab. de Thermodynamique et Physico-Chimie Metallurgiques; Lyon, O.; Okuda, H.
1998-12-01
The precipitation structure in a model nickel-based superalloy was examined by using anomalous X-ray small-angle scattering. Preliminary results are presented on the temporal power law of the precipitation growth and the partitioning of the solute atoms between the precipitates and the matrix. In the present experiment, the concentration of nickel was the same in the matrix and the precipitates, giving no contrast change near the nickel K edge. (orig.). 7 refs.
Institute of Scientific and Technical Information of China (English)
江凡; 古元新; 郑朝德; 范海福
2003-01-01
A new method of combining one-wavelength anomalous scattering (OAS) phasing and density modification has been described, in which the improved phases from density modification are re-introduced into OAS phasing. In this way, the phases could be improved iteratively until convergence. The OAS phasing method is based on the previously established sign-probability formula, which breaks the phase ambiguity in the OAS phasing. The implementation of this method has been awilable in CCP4 as OASIS. This method, although based on direct-methods, could also incorporate known phases and figures of merit into its sign-probability formula. In the implementation of OASIS, the known phases are from the positions of the anomalous scatters. In the current method, the known phases are from the density modification. The current method was tested on phasing a lysozyme crystal using anomalous scattering of sulphur atoms with diffraction data collected on an in-house x-ray source. The resulting map was well connected for the backbone atoms and clearly traceable, with an average map correlation coefficient of 0.6622 for the backbone atoms.
Universality of soft and collinear factors in hard scattering factorization
Collins, J C; Collins, John C.; Metz, Andreas
2004-01-01
Universality in QCD factorization of parton densities, fragmentation functions, and soft factors is endangered by the process dependence of the directions of Wilson lines in their definitions. We find a choice of directions that is consistent with factorization and that gives universality between e^+e^- annihilation, semi-inclusive deep-inelastic scattering, and Drell-Yan. Universality is only modified by a time-reversal transformation of the soft function and parton densities between Drell-Yan and the other processes, whose only effect is the known reversal of sign for T-odd parton densities like the Sivers function. The modifications of the definitions needed to remove rapidity divergences with light-like Wilson lines do not affect the results.
Energy Technology Data Exchange (ETDEWEB)
Sanishvili, R.; Besnard, C.; Camus, F.; Fleurant, M.; Pattison, P.; Bricogne, G.; Schiltz, M.; Biosciences Division; Ecole Polytechnique Federale de Lausanne; ESRF; Global Phasing Ltd.
2007-01-01
In this paper the anisotropy of anomalous scattering at the Br K-absorption edge in brominated nucleotides is investigated, and it is shown that this effect can give rise to a marked directional dependence of the anomalous signal strength in X-ray diffraction data. This implies that choosing the correct orientation for crystals of such molecules can be a crucial determinant of success or failure when using single- and multiple-wavelength anomalous diffraction (SAD or MAD) methods to solve their structure. In particular, polarized absorption spectra on an oriented crystal of a brominated DNA molecule were measured, and were used to determine the orientation that yields a maximum anomalous signal in the diffraction data. Out of several SAD data sets, only those collected at or near that optimal orientation allowed interpretable electron density maps to be obtained. The findings of this study have implications for instrumental choices in experimental stations at synchrotron beamlines, as well as for the development of data collection strategy programs.
Harvey, I; Hao, Q; Duke, E M; Ingledew, W J; Hasnain, S S
1998-07-01
The structure of rusticyanin, an acid-stable copper protein, has been determined at 2.1 A resolution by direct methods combined with the single-wavelength anomalous scattering (SAS) of copper (f" = 3.9 e-) and then conventionally refined (Rcryst = 18.7%, Rfree = 21.9%). This is the largest unknown protein structure (Mr approximately /= 16.8 kDa) to be determined using the SAS and direct-methods approach and demonstrates that by exploiting the anomalous signal at a single wavelength, direct methods can be used to determine phases at typical (approximately 2 A) macromolecular crystallographic resolutions. Extrapolating from the size of the anomalous signal for copper (f" approximately 4 e-), this result suggests that the approach could be used for proteins with molecular weights of up to 33 kDa per Se (f"max++ = 8 e- at the 'white line') and 80 kDa for a Pt derivative (f"max = 19 e- at the 'white line', L3 edge). The method provides a powerful alternative in solving a de novo protein structure without either preparing multiple crystals (i.e. isomorphous heavy-atom derivative plus native crystals) or collecting multi-wavelength anomalous diffraction (MAD) data.
Activated human neutrophils release hepatocyte growth factor/scatter factor.
LENUS (Irish Health Repository)
McCourt, M
2012-02-03
BACKGROUND: Hepatocyte growth factor or scatter factor (HGF\\/SF) is a pleiotropic cytokine that has potent angiogenic properties. We have previously demonstrated that neutrophils (PMN) are directly angiogenic by releasing vascular endothelial growth factor (VEGF). We hypothesized that the acute inflammatory response can stimulate PMN to release HGF. AIMS: To examine the effects of inflammatory mediators on PMN HGF release and the effect of recombinant human HGF (rhHGF) on PMN adhesion receptor expression and PMN VEGF release. METHODS: In the first experiment, PMN were isolated from healthy volunteers and stimulated with tumour necrosis factor-alpha (TNF-alpha), lipopolysaccharide (LPS), interleukin-8 (IL-8), and formyl methionyl-leucyl-phenylalanine (fMLP). Culture supernatants were assayed for HGF using ELISA. In the second experiment, PMN were lysed to measure total HGF release and HGF expression in the PMN was detected by Western immunoblotting. Finally, PMN were stimulated with rhHGF. PMN CD 11a, CD 11b, and CD 18 receptor expression and VEGF release was measured using flow cytometry and ELISA respectively. RESULTS: TNF-alpha, LPS and fMLP stimulation resulted in significantly increased release of PMN HGF (755+\\/-216, 484+\\/-221 and 565+\\/-278 pg\\/ml, respectively) compared to controls (118+\\/-42 pg\\/ml). IL-8 had no effect. Total HGF release following cell lysis and Western blot suggests that HGF is released from intracellular stores. Recombinant human HGF did not alter PMN adhesion receptor expression and had no effect on PMN VEGF release. CONCLUSIONS: This study demonstrates that pro-inflammatory mediators can stimulate HGF release from a PMN intracellular store and that activated PMN in addition to secreting VEGF have further angiogenic potential by releasing HGF.
Scattering form factors for self-assembled network junctions
Foster, T.; Safran, S. A.; Sottmann, T.; Strey, R.
2007-11-01
The equilibrium microstructures in microemulsions and other self-assembled systems show complex, connected shapes such as symmetric bicontinuous spongelike structures and asymmetric bicontinuous networks formed by cylinders interconnected at junctions. In microemulsions, these cylinder network microstructures may mediate the structural transition from a spherical or globular phase to the bicontinuous microstructure. To understand the structural and statistical properties of such cylinder network microstructures as measured by scattering experiments, models are needed to extract the real-space structure from the scattering data. In this paper, we calculate the scattering functions appropriate for cylinder network microstructures. We focus on such networks that contain a high density of network junctions that connect the cylindrical elements. In this limit, the network microstructure can be regarded as an assembly of randomly oriented, closed packed network junctions (i.e., the cylinder scattering contributions are neglected). Accordingly, the scattering spectrum of the network microstructure can be calculated as the product of the junction number density, the junction form factor, which describes the scattering from the surface of a single junction, and a structure factor, which describes the local correlations of different junctions due to junction interactions (including their excluded volume). This approach is applied to analyze the scattering data from a bicontinuous microemulsion with equal volumes of water and oil. In a second approach, we included the cylinder scattering contribution in the junction form factor by calculating the scattering intensity of Y junctions to which three rods with spherical cross section are attached. The respective theoretical predictions are compared with results of neutron scattering measurements on a water-in-oil microemulsion with a connected microstructure.
QCD factorization for forward hadron scattering at high energies
Ermolaev, B I; Troyan, S I
2011-01-01
We consider the QCD factorization of DIS structure functions at small x and amplitudes of 2->2 -hadronic forward scattering at high energy. We show that both collinear and k_T-factorization for these processes can be obtained approximately as reductions of a more general (totally unintegrated) form of the factorization. The requirement of ultraviolet and infrared stability of the factorization convolutions allows us to obtain restrictions on the fits for the parton distributions in k_T- and collinear factorization.
Wang, Hulin; The ATLAS collaboration
2016-01-01
Vector-boson scattering processes provide a unique way to probe the mechanism of electroweak symmetry breaking. Similar physics can be probed by studying the production of three gauge bosons. The results can also be used for a model-independent search for new physics at the TeV scale via anomalous quartic gauge couplings. The ATLAS collaboration has studied vector boson scattering in final states with two gauge bosons and two forward jets in 20.3 /fb of 8TeV proton-proton collision data, in particular two same-sign W bosons, a WZ boson pair, and a W or Z boson in association with an isolated photon. The studies are complemented by a search for anomalous vector boson production of WW+WZ pairs in their semileptonic decays to lnujj in association with two forward jets. The collaboration has used this data set as well to study the production of three gauge bosons. A search was carried out for the production of three W bosons. The cross sections for the production of a W or Z boson in association with two isolated...
Anomalously high thermoelectric power factor in epitaxial ScN thin films
DEFF Research Database (Denmark)
Kerdsongpanya, Sit; Van Nong, Ngo; Pryds, Nini;
2011-01-01
Thermoelectric properties of ScN thin films grown by reactive magnetron sputtering on Al2O3(0001) wafers are reported. X-ray diffraction and elastic recoil detection analyses show that the composition of the films is close to stoichiometry with trace amounts (∼1 at. % in total) of C, O, and F. We...... found that the ScN thin-film exhibits a rather low electrical resistivity of ∼2.94 μΩm, while its Seebeck coefficient is approximately ∼−86 μV/K at 800 K, yielding a power factor of ∼2.5 × 10−3 W/mK2. This value is anomalously high for common transition-metal nitrides. © 2011 American Institute...
Anomalously high thermoelectric power factor in epitaxial ScN thin films
Energy Technology Data Exchange (ETDEWEB)
Kerdsongpanya, Sit; Zukauskaite, Agne; Jensen, Jens; Birch, Jens; Lu Jun; Hultman, Lars; Wingqvist, Gunilla; Eklund, Per [Thin Film Physics Division, Department of Physics, Chemistry, and Biology (IFM), Linkoeping University, SE-581 83 Linkoeping (Sweden); Van Nong, Ngo; Pryds, Nini [Fuel Cells and Solid State Chemistry Division, Risoe National Laboratory for Sustainable Energy, Technical University of Denmark, DK-4000 Roskilde (Denmark)
2011-12-05
Thermoelectric properties of ScN thin films grown by reactive magnetron sputtering on Al{sub 2}O{sub 3}(0001) wafers are reported. X-ray diffraction and elastic recoil detection analyses show that the composition of the films is close to stoichiometry with trace amounts ({approx}1 at. % in total) of C, O, and F. We found that the ScN thin-film exhibits a rather low electrical resistivity of {approx}2.94 {mu}{Omega}m, while its Seebeck coefficient is approximately {approx}-86 {mu}V/K at 800 K, yielding a power factor of {approx}2.5 x 10{sup -3} W/mK{sup 2}. This value is anomalously high for common transition-metal nitrides.
Large Petermann factor in chaotic cavities with many scattering channels
Frahm, K M; Patra, M; Beenakker, C W J
1999-01-01
The quantum-limited linewidth of a laser cavity is enhanced above the Schawlow-Townes value by the Petermann factor K, due to the non-orthogonality of the cavity modes. The average Petermann factor $$ in an ensemble of cavities with chaotic scattering and broken time-reversal symmetry is calculated non-perturbatively using random-matrix theory and the supersymmetry technique, as a function of the decay rate $\\Gamma$ of the lasing mode and the number of scattering channels N. We find for $N\\gg 1$ that for typical values of $\\Gamma$ the average Petermann factor $\\propto \\sqrt{N}\\gg 1$ is parametrically larger than unity.
Sakai, Osamu; Suzuki, Taku T.
2017-06-01
The scattering of the electron-spin-polarized 4He+ beam on paramagnetic materials has an anomalously large asymmetric scattering component (ASC) around 5%, which is 104 of that expected from the spin-orbit coupling (SOC) for the potential of the target nucleus. In addition, the ASC of some materials (for example, Au and Pt) changes sign near the scattering angle (θ) of 90° unlike the result predicted by using the potential scattering theory. When the 4He+ approaches the target, virtual electron-transfer (ET) excitations between them occur. The effects of the SOC of electrons (SOEs) on the target atom in the ET intermediate state are studied within the frame of the lowest-order perturbation theory about the ET process. The ASC is caused through the combination of the quantum development of electron orbital states under the SOEs and the He nucleus motion in the intermediate state because the preferred orbital states for the ET depend on the position of the He nucleus. It is shown by a numerical calculation that the present process has the possibility of producing the ASC with a magnitude of around 0.1. In the present process, the ASC shows a θ dependence of cos θ sin θ, which changes sign at θ = 90° when the excited orbital in the ET state has the d-character like the Au and Pt cases.
Goerigk, G; Huber, K; Schweins, R
2007-10-21
The shrinking process of anionic sodium polyacrylate (NaPA) chains in aqueous solution induced by Sr2+ counterions was analyzed by anomalous small-angle x-ray scattering. Scattering experiments were performed close to the precipitation threshold of strontium polyacrylate. The pure-resonant scattering contribution, which is related to the structural distribution of the Sr2+ counterions, was used to analyze the extent of Sr2+ condensation onto the polyacrylate coils. A series of four samples with different ratios [Sr2+][NaPA] (between 0.451 and 0.464) has been investigated. From the quantitative analysis of the resonant invariant, the amount of Sr cations localized in the collapsed phase was calculated with concentrations v between 0.94x10(17) and 2.01x10(17) cm(-3) corresponding to an amount of Sr cations in the collapsed phase between 9% and 23% of the total Sr2+ cations in solution. If compared to the concentration of polyacrylate expressed in moles of monomers [NaPA], a degree of site binding of r=[Sr2+][NaPA] between 0.05 and 0.11 was estimated. These values clearly differ from r=0.25, which was established from former light scattering experiments, indicating that the counterion condensation starts before the phase border is reached and increases rather sharply at the border.
Vector and Axial Form Factors Applied to Neutrino Quasielastic Scattering
Budd, H; Arrington, J
2005-01-01
We calculate the quasielastic cross sections for neutrino scattering on nucleons using up to date fits to the nucleon elastic electromagnetic form factors GEp, GEn, GMp, GMn, and weak form factors. We show the extraction of Fa for neutrino experiments. We show how well \\minerva, a new approved experiment at FNAL, can measure Fa. We show the that Fa has a different contribution to the anti-neutrino cross section, and how the anti-neutrino data can be used to check Fa extracted from neutrino scattering.
An Effective Field Theory for Forward Scattering and Factorization Violation
Rothstein, Ira Z
2016-01-01
Starting with QCD, we derive an effective field theory description for forward scattering and factorization violation as part of the soft-collinear effective field theory (SCET) for high energy scattering. These phenomena are mediated by long distance Glauber gluon exchanges, which are static in time, localized in the longitudinal distance, where $|t| \\ll s$. In hard scattering, Glauber gluons can induce corrections which invalidate factorization. With SCET, Glauber exchange graphs can be calculated explicitly, and are distinct from graphs with soft, collinear, or ultrasoft gluons. We derive a complete basis of operators which describe the leading power effects of Glauber exchange. Key ingredients include regulating light-cone rapidity singularities and subtractions which prevent double counting. Our results include a novel all orders gauge invariant pure glue soft operator which appears between two collinear rapidity sectors. The 1-gluon Feynman rule for the soft operator coincides with the Lipatov vertex, b...
In-situ study of precipitates in Al-Zn-Mg-Cu alloys using anomalous small-angle x-ray scattering
Chun-Ming, Yang; Feng-Gang, Bian; Bai-Qing, Xiong; Dong-Mei, Liu; Yi-Wen, Li; Wen-Qiang, Hua; Jie, Wang
2016-06-01
In the present work, the precipitate compositions and precipitate amounts of these elements (including the size distribution, volume fraction, and inter-precipitate distance) on the Cu-containing 7000 series aluminum alloys (7150 and 7085 Al alloys), are investigated by anomalous small-angle x-ray scattering (ASAXS) at various energies. The scattering intensity of 7150 alloy with T6 aging treatment decreases as the incident x-ray energy approaches the Zn absorption edge from the lower energy side, while scattering intensity does not show a noticeable energy dependence near the Cu absorption edge. Similar results are observed in the 7085 alloy in an aging process (120 °C) by employing in-situ ASAXS measurements, indicating that the precipitate compositions should include Zn element and should not be strongly related to Cu element at the early stage after 10 min. In the aging process, the precipitate particles with an initial average size of ˜ 8 Å increase with aging time at an energy of 9.60 keV, while the increase with a slower rate is observed at an energy of 9.65 keV as near the Zn absorption edge. Project supported by the National Natural Science Foundation of China (Grant Nos. 11005143, 11405259, and 51274046) and the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry of China (Grant No. [2014]1685).
QCD factorization for forward hadron scattering at high energies
Energy Technology Data Exchange (ETDEWEB)
Ermolaev, B.I. [Ioffe Physico-Technical Institute, St. Petersburg (Russian Federation); Greco, M. [University Roma Tre, Department of Physics, Rome (Italy); INFN, Rome (Italy); Troyan, S.I. [St. Petersburg Institute of Nuclear Physics, Gatchina (Russian Federation)
2012-03-15
We consider the QCD factorization of DIS structure functions at small x and amplitudes of 2{yields}2 hadronic forward scattering at high energy. We show that both collinear and k{sub T} -factorization for these processes can be obtained approximately as reductions of a more general (totally unintegrated) form of the factorization. The requirement of ultraviolet and infrared stability of the factorization convolutions allows us to obtain restrictions on the fits for the parton distributions in k{sub T} - and collinear factorization. (orig.)
On Factorization of Coupled Channel Scattering S Matrices
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
We investigate the problem on how to factorize a coupled channel scattering S matrix into a product of simple S matrices. Simple S matrix solutions are found, respecting unitarity, analyticity and being real analytic. The phase shift and its physical meaning produced by these simple S matrices are discussed.
An effective field theory for forward scattering and factorization violation
Rothstein, Ira Z.; Stewart, Iain W.
2016-08-01
Starting with QCD, we derive an effective field theory description for forward scattering and factorization violation as part of the soft-collinear effective field theory (SCET) for high energy scattering. These phenomena are mediated by long distance Glauber gluon exchanges, which are static in time, localized in the longitudinal distance, and act as a kernel for forward scattering where | t| ≪ s. In hard scattering, Glauber gluons can induce corrections which invalidate factorization. With SCET, Glauber exchange graphs can be calculated explicitly, and are distinct from graphs involving soft, collinear, or ultrasoft gluons. We derive a complete basis of operators which describe the leading power effects of Glauber exchange. Key ingredients include regulating light-cone rapidity singularities and subtractions which prevent double counting. Our results include a novel all orders gauge invariant pure glue soft operator which appears between two collinear rapidity sectors. The 1-gluon Feynman rule for the soft operator coincides with the Lipatov vertex, but it also contributes to emissions with ≥ 2 soft gluons. Our Glauber operator basis is derived using tree level and one-loop matching calculations from full QCD to both SCETII and SCETI. The one-loop amplitude's rapidity renormalization involves mixing of color octet operators and yields gluon Reggeization at the amplitude level. The rapidity renormalization group equation for the leading soft and collinear functions in the forward scattering cross section are each given by the BFKL equation. Various properties of Glauber gluon exchange in the context of both forward scattering and hard scattering factorization are described. For example, we derive an explicit rule for when eikonalization is valid, and provide a direct connection to the picture of multiple Wilson lines crossing a shockwave. In hard scattering operators Glauber subtractions for soft and collinear loop diagrams ensure that we are not sensitive to
Analytical evaluation of atomic form factors: application to Rayleigh scattering
Safari, L; Amaro, P; Jänkälä, K; Fratini, F
2014-01-01
Atomic form factors are widely used for the characterization of targets and specimens, from crystallography to biology. By using recent mathematical results, here we derive an analytical expression for the atomic form factor within the independent particle model constructed from nonrelativistic screened hydrogenic wavefunctions. The range of validity of this analytical expression is checked by comparing the analytically obtained form factors with the ones obtained within the Hartee-Fock method. As an example, we apply our analytical expression for the atomic form factor to evaluate the differential cross section for Rayleigh scattering off neutral atoms.
Form factor ratio from unpolarized elastic electron-proton scattering
Pacetti, Simone; Tomasi-Gustafsson, Egle
2016-11-01
A reanalysis of unpolarized electron-proton elastic scattering data is done in terms of the electric to magnetic form factor squared ratio. This observable is in principle more robust against experimental correlations and global normalizations. The present analysis shows indeed that it is a useful quantity that contains reliable and coherent information. The comparison with the ratio extracted from the measurement of the longitudinal to transverse polarization of the recoil proton in polarized electron-proton scattering shows that the results are compatible within the experimental errors. Limits are set on the kinematics where the physical information on the form factors can be safely extracted. The results presented in this work bring a decisive piece of information to the controversy on the deviation of the proton form factors from the dipole dependence.
Duda, G; Kemper, A; Duda, Gintaras; Gondolo, Paolo; Kemper, Ann
2006-01-01
Theoretical calculations of neutralino cross sections with various nuclei are of great interest to direct dark matter searches such as CDMS, EDELWEISS, ZEPLIN, and other experiments. These cross sections and direct detection rates are generally computed with standard, one or two parameter model-dependent nuclear form factors, which may not exactly mirror the actual form factor for the particular nucleus in question. As is well known, elastic electron scattering can allow for very precise determinations of nuclear form factors and hence nuclear charge densities for spherical or near-spherical nuclei. We use charge densities derived from elastic electron scattering data to calculate model independent form factors for various target nuclei important in dark matter searches, such as Si, Ge, S, Ca and others. We have found that for nuclear recoils in the range of 1-100 keV significant differences in cross sections and rates exist when the model independent form factors are used. DarkSUSY, a publicly-available adva...
Factorization in semi-inclusive polarized deep inelastic scattering
Energy Technology Data Exchange (ETDEWEB)
Florian, D. de [Universidad Nacional de La Plata (Argentina). Lab. de Fisica Teorica; Garcia Canal, C.A. [Universidad Nacional de La Plata (Argentina). Lab. de Fisica Teorica; Sassot, R. [Buenos Aires Univ. Nacional (Argentina). Dept. de Fisica
1996-06-24
We calculate and analyze the O ({alpha}{sub s}) one-particle inclusive cross section in polarized deep inelastic lepton-hadron scattering, using dimensional regularization and the HVBM prescription for {gamma}{sub 5}. We discuss the factorization of all the collinear singularities related to the process, particularly those that are absorbed in the redefinition of the spin-dependent analogue of the recently introduced fracture functions. This is done in the usual MS scheme and in another one, called MS{sub p}, which factorizes soft contributions and guarantees the axial current (non-)conservation properties. (orig.).
The dust-scattering X-ray rings of the anomalous X-ray pulsar 1E 1547.0-5408
Tiengo, A; Esposito, P; Mereghetti, S; Giuliani, A; Costantini, E; Israel, G L; Stella, L; Turolla, R; Zane, S; Rea, N; Götz, D; Bernardini, F; Moretti, A; Romano, P; Ehle, M; Gehrels, N
2009-01-01
On 2009 January 22 numerous strong bursts were detected from the anomalous X-ray pulsar 1E 1547.0-5408. Swift/XRT and XMM-Newton/EPIC observations carried out in the following two weeks led to the discovery of three X-ray rings centered on this source. The ring radii increased with time following the expansion law expected for a short impulse of X-rays scattered by three dust clouds. Assuming different models for the dust composition and grain size distribution, we fit the intensity decay of each ring as a function of time at different energies, obtaining tight constrains on the distance of the X-ray source. Although the distance strongly depends on the adopted dust model, we find that some models are incompatible with our X-ray data, restricting to 4-8 kpc the range of possible distances for 1E 1547.0-5408. The best-fitting dust model provides a source distance of 3.91 +/- 0.07 kpc, which is compatible with the proposed association with the supernova remnant G 327.24-0.13, and implies distances of 2.2 kpc, 2...
Swenson, Jan; Elamin, Khalid; Chen, Guo; Lohstroh, Wiebke; Sakai, Victoria Garcia
2014-12-01
The molecular dynamics of solutions of di-propylene glycol methylether (2PGME) and H2O (or D2O) confined in 28 Å pores of MCM-41 have been studied by quasielastic neutron scattering and differential scanning calorimetry over the concentration range 0-90 wt.% water. This system is of particular interest due to its pronounced non-monotonic concentration dependent dynamics of 2PGME in the corresponding bulk system, showing the important role of hydrogen bonding for the dynamics. In this study we have elucidated how this non-monotonic concentration dependence is affected by the confined geometry. The results show that this behaviour is maintained in the confinement, but the slowest diffusive dynamics of 2PGME is now observed at a considerably higher water concentration; at 75 wt.% water in MCM-41 compared to 30 wt.% water in the corresponding bulk system. This difference can be explained by an improper mixing of the two confined liquids. The results suggest that water up to a concentration of about 20 wt.% is used to hydrate the hydrophilic hydroxyl surface groups of the silica pores, and that it is only at higher water contents the water becomes partly mixed with 2PGME. Hence, due to this partial micro-phase separation of the two liquids larger, and thereby slower relaxing, structural entities of hydrogen bonded water and 2PGME molecules can only be formed at higher water contents than in the bulk system. However, the Q-dependence is unchanged with confinement, showing that the nature of the molecular motions is preserved. Thus, there is no indication of localization of the dynamics at length scales of less than 20 Å. The dynamics of both water and 2PGME is strongly dominated by translational diffusion at a temperature of 280 K.
Energy Technology Data Exchange (ETDEWEB)
Swenson, Jan, E-mail: jan.swenson@chalmers.se; Elamin, Khalid; Chen, Guo [Department of Applied Physics, Chalmers University of Technology, SE-412 96 Göteborg (Sweden); Lohstroh, Wiebke [Heinz Maier-Leibnitz Zentrum (MLZ), Technische Universität München, Lichtenbergstr. 1, 85748 Garching (Germany); Sakai, Victoria Garcia [ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, OX11 0QX Oxfordshire (United Kingdom)
2014-12-07
The molecular dynamics of solutions of di-propylene glycol methylether (2PGME) and H{sub 2}O (or D{sub 2}O) confined in 28 Å pores of MCM-41 have been studied by quasielastic neutron scattering and differential scanning calorimetry over the concentration range 0–90 wt.% water. This system is of particular interest due to its pronounced non-monotonic concentration dependent dynamics of 2PGME in the corresponding bulk system, showing the important role of hydrogen bonding for the dynamics. In this study we have elucidated how this non-monotonic concentration dependence is affected by the confined geometry. The results show that this behaviour is maintained in the confinement, but the slowest diffusive dynamics of 2PGME is now observed at a considerably higher water concentration; at 75 wt.% water in MCM-41 compared to 30 wt.% water in the corresponding bulk system. This difference can be explained by an improper mixing of the two confined liquids. The results suggest that water up to a concentration of about 20 wt.% is used to hydrate the hydrophilic hydroxyl surface groups of the silica pores, and that it is only at higher water contents the water becomes partly mixed with 2PGME. Hence, due to this partial micro-phase separation of the two liquids larger, and thereby slower relaxing, structural entities of hydrogen bonded water and 2PGME molecules can only be formed at higher water contents than in the bulk system. However, the Q-dependence is unchanged with confinement, showing that the nature of the molecular motions is preserved. Thus, there is no indication of localization of the dynamics at length scales of less than 20 Å. The dynamics of both water and 2PGME is strongly dominated by translational diffusion at a temperature of 280 K.
Shcherbakov, Alexandre S; Arellanes, Adan Omar
2017-04-20
We present a principally new acousto-optical cell providing an advanced wideband spectrum analysis of ultra-high frequency radio-wave signals. For the first time, we apply a recently developed approach with the tilt angle to a one-phonon non-collinear anomalous light scattering. In contrast to earlier cases, now one can exploit a regime with the fixed optical wavelength for processing a great number of acoustic frequencies simultaneously in the linear regime. The chosen rutile-crystal combines a moderate acoustic velocity with low acoustic attenuation and allows us wide-band data processing within GHz-frequency acoustic waves. We have created and experimentally tested a 6-cm aperture rutile-made acousto-optical cell providing the central frequency 2.0 GHz, frequency bandwidth ∼0.52 GHz with the frequency resolution about 68.3 kHz, and ∼7620 resolvable spots. A similar cell permits designing an advanced ultra-high-frequency arm within a recently developed multi-band radio-wave acousto-optical spectrometer for astrophysical studies. This spectrometer is intended to operate with a few parallel optical arms for processing the multi-frequency data flows within astrophysical observations. Keeping all the instrument's advantages of the previous schematic arrangement, now one can create the highest-frequency arm using the developed rutile-based acousto-optical cell. It permits optimizing the performances inherent in that arm via regulation of both the central frequency and the frequency bandwidth for spectrum analysis.
Wide Angle Compton Scattering within the SCET factorization Framework
Directory of Open Access Journals (Sweden)
Kivel Nikolay
2016-01-01
Full Text Available Existing data for the electromagnetic proton form factors and for the cross section of the wide angle Compton scattering (WACS show that the hard two-gluon exchange mechanism (collinear factorization is still not applicable in the kinematical region where Mandelstam variables s ~ −t ~ −u are about few GeV2. On the other hand these observables can be described in phenomenological models where spectator quarks are soft which assumes a large contribution due to the soft-overlap mechanism. It turns out that the simple QCD factorization picture is not complete and must also include the soft-overlap contribution which can be described as a certain matrix element in the soft collinear effective theory (SCET. Then the leading power contribution to WACS amplitude is described as a sum of the hard- and soft-spectator contributions. The existing experimental data allows one to check certain conclusions based on the assumption about dominant role of the soft-spectator mechanism.
A Note on Soft Factors for Closed String Scattering
Schwab, Burkhard U W
2014-01-01
In this note, it is shown that closed string graviton scattering amplitudes obey the same subleading soft limit as field theory graviton scattering amplitudes. The result is derived using a combination of recent results and methods including the subleading soft expansion for type I open string gluon disk scattering amplitudes, the single value projection for multiple $\\zeta$ values, and the KLT relations in field and string theory.
Electromagnetic Form Factors of the Nucleon and Compton Scattering
Energy Technology Data Exchange (ETDEWEB)
Charles Hyde-Wright; Cornelis De Jager
2004-12-01
We review the experimental and theoretical status of elastic electron scattering and elastic low-energy photon scattering (with both real and virtual photons) from the nucleon. As a consequence of new experimental facilities and new theoretical insights, these subjects are advancing with unprecedented precision. These reactions provide many important insights into the spatial distributions and correlations of quarks in the nucleon.
Determination of pair-structure factor of scattering potential of a collection of particles.
Wang, Tao; Zhao, Daomu
2010-02-01
The method of determination of the pair-structure factor of a collection of particles has been discussed. It is shown that the pair-structure factor of scattering potential of the collection of particles can be determined from the cross-spectral density function of the scattered field.
Analysis of the factors that affect photon counts in Compton scattering.
Luo, Guang; Xiao, Guangyu
2014-10-30
Compton scattering has been applied in a variety of fields. The factors that affect Compton scattering have been studied extensively in the literature. However, the factors that affect the measured photon counts in Compton scattering are rarely considered. In this paper, we make a detailed discussion on those factors. First, Compton scattering experiments of some alloy series and powder mixture series are explored. Second, the electron density is researched in terms of atom and lattice constants. Third, the factor of attenuation coefficient is discussed. And then, the active degree of electrons is discussed based on the DFT theory. Lastly, the conclusions are made, that the factors affecting Compton scattering photon counts include mainly electron number density, attenuation coefficient and active degree of electrons.
Haze-factor maakt plaats voor F-scatter
Swinkels, G.L.A.M.
2014-01-01
Uitgelicht licht & scherming - Wageningen UR Glastuinbouw deed vorig jaar onderzoek naar een methode om de lichtspreiding onder diffuus glas te karakteriseren. dit resulteerde in een nieuwe waarde, de zogenaamde F-scatter voor voorwaartse lichtspreiding. Leveranciers van glas en schermdoekmateri
Lobato, I; Van Dyck, D
2015-08-01
The steadily improving experimental possibilities in instrumental resolution as in sensitivity and quantization of the data recording put increasingly higher demands on the precision of the scattering factors, which are the key ingredients for electron diffraction or high-resolution imaging simulation. In the present study, we will systematically investigate the accuracy of fitting of the main parameterizations of the electron scattering factor for the calculation of electron diffraction intensities. It is shown that the main parameterizations of the electron scattering factor are consistent to calculate electron diffraction intensities for thin specimens and low angle scattering. Parameterizations of the electron scattering factor with the correct asymptotic behavior (Lobato and Dyck [5], Kirkland [4], and Weickenmeier and Kohl [2]) produce similar results for both the undisplaced lattice model and the frozen phonon model, except for certain thicknesses and reflections.
Energy Technology Data Exchange (ETDEWEB)
Sirunyan, Albert M; et al.
2017-08-09
A measurement of vector boson scattering and constraints on anomalous quartic gauge couplings from events with two Z bosons and two jets are presented. The analysis is based on a data sample of proton-proton collisions at sqrt(s) = 13 TeV collected with the CMS detector and corresponding to an integrated luminosity of 35.9 inverse-femtobarns. The search is performed in the fully leptonic final state ZZ to lll'l', where l, l' = e, mu. The electroweak production of two Z bosons in association with two jets is measured with an observed (expected) significance of 2.7 (1.6) standard deviations. A fiducial cross section for the electroweak production is measured to be sigma[EW]( pp -> ZZjj -> lll'l'jj ) = 0.40 -0.16 +0.21 (stat) -0.09 +0.13 (syst) fb, which is consistent with the standard model prediction. Limits on anomalous quartic gauge couplings are determined in terms of the effective field theory operators T0, T1, T2, T8, and T9. This is the first measurement of vector boson scattering in the ZZ channel at the LHC.
Aaboud, Morad; Abbott, Brad; Abdallah, Jalal; Abdinov, Ovsat; Abeloos, Baptiste; Aben, Rosemarie; AbouZeid, Ossama; Abraham, Nicola; Abramowicz, Halina; Abreu, Henso; Abreu, Ricardo; Abulaiti, Yiming; Acharya, Bobby Samir; Adamczyk, Leszek; Adams, David; Adelman, Jahred; Adomeit, Stefanie; Adye, Tim; Affolder, Tony; Agatonovic-Jovin, Tatjana; Agricola, Johannes; Aguilar-Saavedra, Juan Antonio; Ahlen, Steven; Ahmadov, Faig; Aielli, Giulio; Akerstedt, Henrik; Åkesson, Torsten Paul Ake; Akimov, Andrei; Alberghi, Gian Luigi; Albert, Justin; Albrand, Solveig; Alconada Verzini, Maria Josefina; Aleksa, Martin; Aleksandrov, Igor; Alexa, Calin; Alexander, Gideon; Alexopoulos, Theodoros; Alhroob, Muhammad; Ali, Babar; Aliev, Malik; Alimonti, Gianluca; Alison, John; Alkire, Steven Patrick; Allbrooke, Benedict; Allen, Benjamin William; Allport, Phillip; Aloisio, Alberto; Alonso, Alejandro; Alonso, Francisco; Alpigiani, Cristiano; Alstaty, Mahmoud; Alvarez Gonzalez, Barbara; Άlvarez Piqueras, Damián; Alviggi, Mariagrazia; Amadio, Brian Thomas; Amako, Katsuya; Amaral Coutinho, Yara; Amelung, Christoph; Amidei, Dante; Amor Dos Santos, Susana Patricia; Amorim, Antonio; Amoroso, Simone; Amundsen, Glenn; Anastopoulos, Christos; Ancu, Lucian Stefan; Andari, Nansi; Andeen, Timothy; Anders, Christoph Falk; Anders, Gabriel; Anders, John Kenneth; Anderson, Kelby; Andreazza, Attilio; Andrei, George Victor; Angelidakis, Stylianos; Angelozzi, Ivan; Anger, Philipp; Angerami, Aaron; Anghinolfi, Francis; Anisenkov, Alexey; Anjos, Nuno; Annovi, Alberto; Antel, Claire; Antonelli, Mario; Antonov, Alexey; Anulli, Fabio; Aoki, Masato; Aperio Bella, Ludovica; Arabidze, Giorgi; Arai, Yasuo; Araque, Juan Pedro; Arce, Ayana; Arduh, Francisco Anuar; Arguin, Jean-Francois; Argyropoulos, Spyridon; Arik, Metin; Armbruster, Aaron James; Armitage, Lewis James; Arnaez, Olivier; Arnold, Hannah; Arratia, Miguel; Arslan, Ozan; Artamonov, Andrei; Artoni, Giacomo; Artz, Sebastian; Asai, Shoji; Asbah, Nedaa; Ashkenazi, Adi; Åsman, Barbro; Asquith, Lily; Assamagan, Ketevi; Astalos, Robert; Atkinson, Markus; Atlay, Naim Bora; Augsten, Kamil; Avolio, Giuseppe; Axen, Bradley; Ayoub, Mohamad Kassem; Azuelos, Georges; Baak, Max; Baas, Alessandra; Baca, Matthew John; Bachacou, Henri; Bachas, Konstantinos; Backes, Moritz; Backhaus, Malte; Bagiacchi, Paolo; Bagnaia, Paolo; Bai, Yu; Baines, John; Baker, Oliver Keith; Baldin, Evgenii; Balek, Petr; Balestri, Thomas; Balli, Fabrice; Balunas, William Keaton; Banas, Elzbieta; Banerjee, Swagato; Bannoura, Arwa A E; Barak, Liron; Barberio, Elisabetta Luigia; Barberis, Dario; Barbero, Marlon; Barillari, Teresa; Barisits, Martin-Stefan; Barklow, Timothy; Barlow, Nick; Barnes, Sarah Louise; Barnett, Bruce; Barnett, Michael; Barnovska-Blenessy, Zuzana; Baroncelli, Antonio; Barone, Gaetano; Barr, Alan; Barranco Navarro, Laura; Barreiro, Fernando; Barreiro Guimarães da Costa, João; Bartoldus, Rainer; Barton, Adam Edward; Bartos, Pavol; Basalaev, Artem; Bassalat, Ahmed; Bates, Richard; Batista, Santiago Juan; Batley, Richard; Battaglia, Marco; Bauce, Matteo; Bauer, Florian; Bawa, Harinder Singh; Beacham, James; Beattie, Michael David; Beau, Tristan; Beauchemin, Pierre-Hugues; Bechtle, Philip; Beck, Hans~Peter; Becker, Kathrin; Becker, Maurice; Beckingham, Matthew; Becot, Cyril; Beddall, Andrew; Beddall, Ayda; Bednyakov, Vadim; Bedognetti, Matteo; Bee, Christopher; Beemster, Lars; Beermann, Thomas; Begel, Michael; Behr, Janna Katharina; Belanger-Champagne, Camille; Bell, Andrew Stuart; Bella, Gideon; Bellagamba, Lorenzo; Bellerive, Alain; Bellomo, Massimiliano; Belotskiy, Konstantin; Beltramello, Olga; Belyaev, Nikita; Benary, Odette; Benchekroun, Driss; Bender, Michael; Bendtz, Katarina; Benekos, Nektarios; Benhammou, Yan; Benhar Noccioli, Eleonora; Benitez, Jose; Benjamin, Douglas; Bensinger, James; Bentvelsen, Stan; Beresford, Lydia; Beretta, Matteo; Berge, David; Bergeaas Kuutmann, Elin; Berger, Nicolas; Beringer, Jürg; Berlendis, Simon; Bernard, Nathan Rogers; Bernius, Catrin; Bernlochner, Florian Urs; Berry, Tracey; Berta, Peter; Bertella, Claudia; Bertoli, Gabriele; Bertolucci, Federico; Bertram, Iain Alexander; Bertsche, Carolyn; Bertsche, David; Besjes, Geert-Jan; Bessidskaia Bylund, Olga; Bessner, Martin Florian; Besson, Nathalie; Betancourt, Christopher; Bethani, Agni; Bethke, Siegfried; Bevan, Adrian John; Bianchi, Riccardo-Maria; Bianchini, Louis; Bianco, Michele; Biebel, Otmar; Biedermann, Dustin; Bielski, Rafal; Biesuz, Nicolo Vladi; Biglietti, Michela; Bilbao De Mendizabal, Javier
2017-07-28
This paper presents the extended results of measurements of $W^{\\pm}W^{\\pm}jj$ production and limits on anomalous quartic gauge couplings using 20.3 fb$^{-1}$ of proton--proton collision data at $\\sqrt{s}=8$ TeV recorded by the ATLAS detector at the Large Hadron Collider. Events with two leptons ($e$ or $\\mu$) with the same electric charge and at least two jets are analyzed. Production cross-sections are determined in two fiducial regions, with different sensitivities to the electroweak and strong production mechanisms. An additional fiducial region, particularly sensitive to anomalous quartic gauge coupling parameters $\\alpha_4$ and $\\alpha_5$, is introduced, which allows more stringent limits on these parameters compared to the previous ATLAS measurement.
Wang, Hulin; The ATLAS collaboration
2016-01-01
The production of vector boson scattering and triple gauge bosons are studied using $pp$ collisions at $\\sqrt{s}=8$ TeV with the ATLAS detector at the Large Hadron Collider. The vector boson scattering processes of $W^{\\pm}W^{\\pm}(\\rightarrow \\ell^{\\pm}\
Nagai, Yuki; Kato, Yusuke
2010-11-01
We investigate the impurity scattering rates for quasiparticles in vortex cores of sign-reversing s -wave superconductors as a probe to detect the internal phase difference of the order parameters among different Fermi surfaces. The impurity scattering rates and coherence factors are related to quasiparticle interference effect by the scanning tunneling microscopy and spectroscopy technique. With use of the Born and Kramer-Pesch approximations for the Andreev bound states, we show that the sign-reversed forward scatterings are dominant in vortex cores. Owing to the coherence factor in vortex cores of ±s -wave superconductors, the impurity scattering rate of the Andreev bound states has a characteristic distribution on the Fermi surfaces. For comparison, the impurity scattering rates in vortex cores of s -wave and d -wave superconductors are also discussed.
Towards a Better Understanding of the Anomalous Hall Effect
Yue, Di; Jin, Xiaofeng
2017-01-01
Recent experimental efforts to identify the intrinsic and extrinsic contributions in the anomalous Hall effect are reviewed. Benefited from the experimental control of artificial impurity density in single crystalline magnetic thin films, a comprehensive physical picture of the anomalous Hall effect involving multiple competing scattering processes has been established. Some new insights into the microscopic mechanisms of the anomalous Hall effect are discussed.
Anomalous Hall effect in polycrystalline Ni films
Guo, Zaibing
2012-02-01
We systematically studied the anomalous Hall effect in a series of polycrystalline Ni films with thickness ranging from 4 to 200 nm. It is found that both the longitudinal and anomalous Hall resistivity increased greatly as film thickness decreased. This enhancement should be related to the surface scattering. In the ultrathin films (46 nm thick), weak localization corrections to anomalous Hall conductivity were studied. The granular model, taking into account the dominated intergranular tunneling, has been employed to explain this phenomenon, which can explain the weak dependence of anomalous Hall resistivity on longitudinal resistivity as well. © 2011 Elsevier Ltd. All rights reserved.
Four-jet production in kt-factorization: single and double parton scattering
Serino, Mirko
2016-01-01
We present a preliminary study of both Single and Double Parton Scattering contributions to the inclusive 4-jet production in the kt-factorization framework at Leading Order and $E_{CM} = 7$ TeV. We compare our results to collinear results in the literature and to the ATLAS and CMS data at 8 and 7 TeV respectively. We also discuss the importance of double parton scattering for relatively soft cuts on the jet transverse momenta and find out that symmetric cuts do not quite suit well to kt-factorization predictions, because of a kinematic effect suppressing the double parton scattering contribution.
Takebayashi, T; Iwamoto, M; Jikko, A; Matsumura, T; Enomoto-Iwamoto, M; Myoukai, F; Koyama, E; Yamaai, T; Matsumoto, K; Nakamura, T
1995-06-01
Hepatocyte growth factor/scatter factor (HGF/SF) is a multifunctional growth factor that promotes proliferation, motility, and morphogenesis in epithelial cells. Recently the HGF receptor, c-met protooncogene product, has been shown to be expressed in developing limb buds (Sonnenberg, E., D. Meyer, M. Weidner, and C. Birchmeiyer, 1993. J. Cell Biol. 123: 223-235), suggesting that some populations of mesenchymal cells in limb buds respond to HGF/SF. To test the possibility that HGF/SF is involved in regulation of cartilage development, we isolated chondrocytes from knee joints and costal cartilages of 23-d embryonic and 4-wk-old rabbits, and analyzed the effects of HGF/SF on migration and proliferation of these cells. We found that HGF/SF stimulated migration of cultured articular chondrocytes but did not scatter limb mesenchymal fibroblasts or synovial fibroblasts in culture. HGF/SF also stimulated proliferation of chondrocytes; a maximum three-fold stimulation in DNA synthesis was observed at the concentration of 3 ng/ml of HGF/SF. Moreover, HGF/SF had the ability to enhance proteoglycan synthesis in chondrocytes. The responsiveness of chondrocytes to HGF/SF was also supported by the observation that they expressed the HGF/SF receptor. Addition of the neutralizing antibody to rat HGF/SF affected neither DNA synthesis nor proteoglycan synthesis in rat chondrocytes, suggesting a paracine mechanism of action of HGF/SF on these cells. In situ hybridization analysis showed that HGF/SF mRNA was restrictively expressed in the areas of future joint regions in developing limb buds and in the intercostal spaces of developing costal cartilages. These findings suggest that HGF/SF plays important roles in cartilage development through its multiple activities.
1995-01-01
Hepatocyte growth factor/scatter factor (HGF/SF) is a multifunctional growth factor that promotes proliferation, motility, and morphogenesis in epithelial cells. Recently the HGF receptor, c-met protooncogene product, has been shown to be expressed in developing limb buds (Sonnenberg, E., D. Meyer, M. Weidner, and C. Birchmeiyer, 1993. J. Cell Biol. 123: 223-235), suggesting that some populations of mesenchymal cells in limb buds respond to HGF/SF. To test the possibility that HGF/SF is involved in regulation of cartilage development, we isolated chondrocytes from knee joints and costal cartilages of 23-d embryonic and 4-wk-old rabbits, and analyzed the effects of HGF/SF on migration and proliferation of these cells. We found that HGF/SF stimulated migration of cultured articular chondrocytes but did not scatter limb mesenchymal fibroblasts or synovial fibroblasts in culture. HGF/SF also stimulated proliferation of chondrocytes; a maximum three-fold stimulation in DNA synthesis was observed at the concentration of 3 ng/ml of HGF/SF. Moreover, HGF/SF had the ability to enhance proteoglycan synthesis in chondrocytes. The responsiveness of chondrocytes to HGF/SF was also supported by the observation that they expressed the HGF/SF receptor. Addition of the neutralizing antibody to rat HGF/SF affected neither DNA synthesis nor proteoglycan synthesis in rat chondrocytes, suggesting a paracine mechanism of action of HGF/SF on these cells. In situ hybridization analysis showed that HGF/SF mRNA was restrictively expressed in the areas of future joint regions in developing limb buds and in the intercostal spaces of developing costal cartilages. These findings suggest that HGF/SF plays important roles in cartilage development through its multiple activities. PMID:7775584
Nonlocal Anomalous Hall Effect
Zhang, Steven S.-L.; Vignale, Giovanni
2016-04-01
The anomalous Hall (AH) effect is deemed to be a unique transport property of ferromagnetic metals, caused by the concerted action of spin polarization and spin-orbit coupling. Nevertheless, recent experiments have shown that the effect also occurs in a nonmagnetic metal (Pt) in contact with a magnetic insulator [yttrium iron garnet (YIG)], even when precautions are taken to ensure that there is no induced magnetization in the metal. We propose a theory of this effect based on the combined action of spin-dependent scattering from the magnetic interface and the spin-Hall effect in the bulk of the metal. At variance with previous theories, we predict the effect to be of first order in the spin-orbit coupling, just as the conventional anomalous Hall effect—the only difference being the spatial separation of the spin-orbit interaction and the magnetization. For this reason we name this effect the nonlocal anomalous Hall effect and predict that its sign will be determined by the sign of the spin-Hall angle in the metal. The AH conductivity that we calculate from our theory is in order of magnitude agreement with the measured values in Pt /YIG structures.
Nonlocal Anomalous Hall Effect.
Zhang, Steven S-L; Vignale, Giovanni
2016-04-01
The anomalous Hall (AH) effect is deemed to be a unique transport property of ferromagnetic metals, caused by the concerted action of spin polarization and spin-orbit coupling. Nevertheless, recent experiments have shown that the effect also occurs in a nonmagnetic metal (Pt) in contact with a magnetic insulator [yttrium iron garnet (YIG)], even when precautions are taken to ensure that there is no induced magnetization in the metal. We propose a theory of this effect based on the combined action of spin-dependent scattering from the magnetic interface and the spin-Hall effect in the bulk of the metal. At variance with previous theories, we predict the effect to be of first order in the spin-orbit coupling, just as the conventional anomalous Hall effect-the only difference being the spatial separation of the spin-orbit interaction and the magnetization. For this reason we name this effect the nonlocal anomalous Hall effect and predict that its sign will be determined by the sign of the spin-Hall angle in the metal. The AH conductivity that we calculate from our theory is in order of magnitude agreement with the measured values in Pt/YIG structures.
Energy Technology Data Exchange (ETDEWEB)
Lobato, I., E-mail: Ivan.Lobato@uantwerpen.be; Van Dyck, D.
2015-08-15
The steadily improving experimental possibilities in instrumental resolution as in sensitivity and quantization of the data recording put increasingly higher demands on the precision of the scattering factors, which are the key ingredients for electron diffraction or high-resolution imaging simulation. In the present study, we will systematically investigate the accuracy of fitting of the main parameterizations of the electron scattering factor for the calculation of electron diffraction intensities. It is shown that the main parameterizations of the electron scattering factor are consistent to calculate electron diffraction intensities for thin specimens and low angle scattering. Parameterizations of the electron scattering factor with the correct asymptotic behavior (Lobato and Dyck [5], Kirkland [4], and Weickenmeier and Kohl [2]) produce similar results for both the undisplaced lattice model and the frozen phonon model, except for certain thicknesses and reflections. - Highlights: • Parameterizations of the electron scattering factor with the correct asymptotic behavior produce similar electron diffraction intensities. • Peng et al. parameterization is not adequate for calculations that involves higher-order Laue zones reflections. • Electron diffraction calculations of Cu-crystal with and without inclusion of phonons.
The Proton Coulomb Form Factor from Polarized Inclusive e-p Scattering
Energy Technology Data Exchange (ETDEWEB)
Chris Harris
2001-08-01
The proton form factors provide information on the fundamental properties of the proton and provide a test for models based on QCD. In 1998 at Jefferson Lab (JLAB) in Newport News, VA, experiment E93026 measured the inclusive e-p scattering cross section from a polarized ammonia (15NH3) target at a four momentum transfer squared of Q2 = 0.5 (GeV/c)2. Longitudinally polarized electrons were scattered from the polarized target and the scattered electron was detected. Data has been analyzed to obtain the asymmetry from elastically scattered electrons from hydrogen in 15NH3. The asymmetry, Ap, has been used to determine the proton elastic form factor GEp. The result is consistent with the dipole model and data from previous experiments. However, due to the choice of kinematics, the uncertainty in the measurement is large.
Multiphonon resonances in the Debye-Waller factor of atom surface scattering.
Brenig, W
2004-02-06
He atom surface scattering by dispersionless phonons is treated employing coupled channel (CC) calculations. At low energies, they predict a behavior opposite to perturbative Born or "exponentiated" Born approximation: strong resonant phonon stimulated elastic and inhibited inelastic scattering. The corresponding resonances have not been observed in earlier CC results since these have considered only the temperature dependence of the Debye-Waller factor at higher energy or omitted the attractive well. The resonances can be interpreted in terms of bound states in the attractive well with several excited vibrational quanta. They may be observable for, e.g., He scattering by a cold Xe/Cu surface.
Kiselev, M A; Kisselev, A M; Lesieur, P; Aksenov, V L
2003-01-01
Small-angle X-ray scattering (SAXS) experiments have been performed on dimyristoylphosphatidylcholine (DMPC) unilamellar vesicles in 40 % aqueous sucrose solution. Model of separated form factors was applied for the evaluation of SAXS curves from large unilamellar vesicles. For the first time vesicle structure factor, polydispersity, average radius and membrane thickness were calculated simultaneously from the SAXS curves at T=306{\\circ}C for DMPC concentrations in the range from 15 to 75 mM (1-5 % w/w). Structure factor correction to the scattering curve was shown to be negligibly small for the lipid concentration of 15 mM (1 % w/w). It was proved to be necessary to introduce structure factor correction to the scattering curves for lipid concentrations {\\ge}30 mM (2 % w/w).
Palasantzas, G.
2008-01-01
In this work we study the quality factor associated with dissipation due to scattering of shear horizontal surface acoustic waves by random self-affine roughness. It is shown that the quality factor is strongly influenced by both the surface roughness exponent H and the roughness amplitude w to late
Chung, Heeteak; Prado, Karl L; Yi, Byong Yong
2014-02-21
Phantom Scatter Factors, Sp in the Khan formalism (Khan et al 1980 J. Radiat. Oncol. Biol. Phys. 6 745-51) describe medium-induced changes in photon-beam intensity as a function of size of the beam. According to the British Journal of Radiology, Supplement 25, megavoltage phantom scatter factors are invariant as a function of photon-beam energy. However, during the commissioning of an accelerator with flattening filter free (FFF) photon beams (Varian TrueBeam(TM) 6-MV FFF and 10-MV FFF), differences were noted in phantom scatter between the filtered beams and FFF-mode beams. The purpose of this work was to evaluate this difference and provide an analytical formalism to explain the phantom scatter differences between FFF-mode and the filtered mode. An analytical formalism was devised to demonstrate the source of phantom scatter differences between the filtered and the FFF-mode beams. The reason for the differences in the phantom scatter factors between the filtered and the FFF-mode beams is hypothesized to be the non-uniform beam profiles of the FFF-mode beams. The analytical formalism proposed here is based on this idea, taking the product of the filtered phantom scatter factors and the ratio of the off-axis ratio between the FFF-mode and the filtered beams. All measurements were performed using a Varian TrueBeam(TM) linear accelerator with photon energies of 6-MV and 10-MV in both filtered and FFF-modes. For all measurements, a PTW Farmer type chamber and a Scanditronix CC04 cylindrical ionization were used. The in-water measurements were made at depth dose maximum and 100 cm source-to-axis distance. The in-air measurements were done at 100 cm source-to-axis distance with appropriate build-up cap. From these measurements, the phantom scatter factors were derived for the filtered beams and the FFF-mode beams for both energies to be evaluated against the phantoms scatter factors calculated using the proposed algorithm. For 6-MV, the difference between the measured
[Air kerma transmission factors of Scattered X-rays in the maze of a Linac room for lead shield].
Kato, Hideki
2005-01-20
Spectra of scattered X-rays in the maze of a Linac (X-ray energies of 4, 6, and 10 MV) room were estimated by means of the Monte Carlo simulation, and air kerma transmission factors of the X-rays scattered through a lead shield were evaluated based on those spectra. Spectra of scattered X-rays showed a maximum in the energy area below 200 keV. The higher the accelerated electron energy, also, the smaller the scattering angle that tended to spread to the higher energy area of the distribution of spectra. The air kerma transmission factor of 120 degrees scattered X-rays of 4 MV X-rays obtained in this study was larger than the transmission factors of 124 degrees scattered photons of (60)Co gamma rays through a lead shield given in ICRP. The air kerma transmission factors of 120 degrees scattered X-rays of 6 MV X-rays were smaller than the transmission factors of 90 degrees scattered photons of (60)Co gamma rays. The air kerma transmission factors of 120 degrees scattered X-rays of 10 MV X-rays was slightly larger than transmission factors of 90 degrees scattered photons of (60)Co gamma rays. Therefore, in the case of a 4 MV X-ray Linac room, the calculation method given in the "Manual of Practical Shield Calculation of Radiation Facilities (2000)" causes underestimation of leakage doses.
Singh, Rahul; Shukla, K. K.; Kumar, A.; Okram, G. S.; Singh, D.; Ganeshan, V.; Lakhani, Archana; Ghosh, A. K.; Chatterjee, Sandip
2016-09-01
Magnetoresistance (MR), thermo power, magnetization and Hall effect measurements have been performed on Co-doped Bi2Se3 topological insulators. The undoped sample shows that the maximum MR as a destructive interference due to a π-Berry phase leads to a decrease of MR. As the Co is doped, the linearity in MR is increased. The observed MR of Bi2Se3 can be explained with the classical model. The low temperature MR behavior of Co doped samples cannot be explained with the same model, but can be explained with the quantum linear MR model. Magnetization behavior indicates the establishment of ferromagnetic ordering with Co doping. Hall effect data also supports the establishment of ferromagnetic ordering in Co-doped Bi2Se3 samples by showing the anomalous Hall effect. Furthermore, when spectral weight suppression is insignificant, Bi2Se3 behaves as a dilute magnetic semiconductor. Moreover, the maximum power factor is observed when time reversal symmetry (TRS) is maintained. As the TRS is broken the power factor value is decreased, which indicates that with the rise of Dirac cone above the Fermi level the anomalous Hall effect and linearity in MR increase and the power factor decreases.
Singh, Rahul; Shukla, K K; Kumar, A; Okram, G S; Singh, D; Ganeshan, V; Lakhani, Archana; Ghosh, A K; Chatterjee, Sandip
2016-09-21
Magnetoresistance (MR), thermo power, magnetization and Hall effect measurements have been performed on Co-doped Bi2Se3 topological insulators. The undoped sample shows that the maximum MR as a destructive interference due to a π-Berry phase leads to a decrease of MR. As the Co is doped, the linearity in MR is increased. The observed MR of Bi2Se3 can be explained with the classical model. The low temperature MR behavior of Co doped samples cannot be explained with the same model, but can be explained with the quantum linear MR model. Magnetization behavior indicates the establishment of ferromagnetic ordering with Co doping. Hall effect data also supports the establishment of ferromagnetic ordering in Co-doped Bi2Se3 samples by showing the anomalous Hall effect. Furthermore, when spectral weight suppression is insignificant, Bi2Se3 behaves as a dilute magnetic semiconductor. Moreover, the maximum power factor is observed when time reversal symmetry (TRS) is maintained. As the TRS is broken the power factor value is decreased, which indicates that with the rise of Dirac cone above the Fermi level the anomalous Hall effect and linearity in MR increase and the power factor decreases.
Some physical factors influencing the accuracy of convolution scatter correction in SPECT.
Msaki, P; Axelsson, B; Larsson, S A
1989-03-01
Some important physical factors influencing the accuracy of convolution scatter correction techniques in SPECT are presented. In these techniques scatter correction in the projection relies on filter functions, QF, evaluated by Fourier transforms, from measured scatter functions, Qp, obtained from point spread functions. The spatial resolution has a marginal effect on Qp. Thus a single QF can be used in the scatter correction of SPECT measurements acquired with the low energy high resolution or the low energy general purpose collimators and over a wide range of patient-collimator distances. However, it is necessary to examine the details of the shape of point spread functions during evaluation of Qp. QF is completely described by scatter amplitude AF, slope BF and filter sum SF. SF is obtained by summation of the values of QF occupying a 31 x 31 pixels matrix. Regardless of differences in amplitude and slope, two filter functions are shown to be equivalent in terms of scatter correction ability, whenever their sums are equal. On the basis of filter sum, the observed small influence of ellipticity on QF implies that an average function can be used in scatter correcting SPECT measurements conducted with elliptic objects. SF is shown to increase with a decrease in photon energy and with an increase in window size. Thus, scatter correction by convolution may be severely hampered by photon statistics when SPECT imaging is done with low-energy photons. It is pointless to use unnecessarily large discriminator windows, in the hope of improving photon statistics, since most of the extra events acquired will eventually be subtracted during scatter correction. Regardless of the observed moderate reduction in SF when a lung-equivalent material replaces a portion of a water phantom, further studies are needed to develop a technique that is capable of handling attenuation and scatter corrections simultaneously. Whenever superficial and inner radioactive distributions coexist the
On the nucleon–nucleon scattering phase shifts through supersymmetry and factorization
Indian Academy of Sciences (India)
U Laha; J Bhoi
2013-12-01
By exploiting the supersymmetry-inspired factorization method through a judicious use of deuteron ground state wave function, higher partial wave nucleon–nucleon potentials, both energy independent and energy dependent, are generated. We adopt the phase function method to deal with the scattering phase shifts and demonstrate the usefulness of our constructed potentials by means of model calculation.
Light-by-light scattering in the Lamb shift and the bound electron g factor
Czarnecki, Andrzej; Szafron, Robert
2016-12-01
We compute an O ( α2(Zα ) 6) contribution to the hydrogen-atom Lamb shift arising from light-by-light scattering. Analogous diagrams, with one atomic electric field insertion replaced by an external magnetic field, contribute to the gyromagnetic factor of the bound electron at O ( α2(Zα ) 4) . We also calculate the contribution to the gyromagnetic factor from the muon magnetic loop.
Light-by-light scattering in the Lamb shift and the bound electron g factor
Czarnecki, Andrzej
2016-01-01
We compute an $\\mathcal{O}\\left(\\alpha^2(Z\\alpha)^6\\right)$ contribution to the hydrogen-atom Lamb shift arising from the light-by-light scattering. Analogous diagrams, with one atomic electric field insertion replaced by an external magnetic field, contribute to the gyromagnetic factor of the bound electron at $\\mathcal{O}\\left(\\alpha^2(Z\\alpha)^4\\right)$. We also calculate the contribution to the gyromagnetic factor from the muon magnetic loop.
Group-fitted ab initiosingle- and multiple-scattering EXAFS Debye-Waller factors
Dimakis, Nicholas; Bunker, Grant
2002-05-01
X-ray absorption fine structure (XAFS) spectroscopy is one of the few direct probes of the structure of metalloprotein binding that is equally applicable to proteins in crystals, solutions, and membranes. Despite considerable progress in the calculation of the photoelectron scattering aspects of XAFS, calculation of the vibrational aspects has lagged because of the difficulty of the calculations. We report here initial results that express single- and multiple-scattering Debye-Waller factors as polynomial functions of first shell radial distance for metal-peptide complexes, enabling quantitatively accurate full multiple-scattering XAFS data analysis of active sites of unknown structure at arbitrary temperatures without the use of ad hoc assumptions.
Factors influencing repeated seed movements by scatter-hoarding rodents in an alpine forest.
Wang, Bo; Chen, Jin; Corlett, Richard T
2014-04-24
Scatter-hoarding rodents are effective dispersal agents for many plant species. Several studies have shown that rodents repeatedly re-cache seeds. The re-caching process often has a significant impact on final seedling establishment, but the factors determining its occurrence are poorly understood. In this study, we followed the fate of 3564 artificial seeds that varied in size, nutrient content and tannin content. Seeds cached closer to their original releasing plots were more likely to be re-cached, and to a further distance. Larger seeds were more likely to be re-cached than smaller ones, while nutrient and tannin content had little effect. Most plant species that depend on scatter-hoarding rodents for seed dispersal bear relatively large seeds, and large seeds are usually more likely to be dispersed and to establish seedlings, suggesting that the caching preferences of scatter-hoarding rodents may have played an important role in the evolution of large seeds.
Aoyama, T; Kinoshita, T; Nio, M
2012-01-01
This paper reports the tenth-order QED contribution to the lepton g-2 from the gauge-invariant set, called Set III(c), which consists of 390 Feynman vertex diagrams containing an internal fourth-order light-by-light-scattering subdiagram. The mass-independent contribution of Set III(c) to the electron g-2 (a_e) is 4.9210(103) in units of (alpha/pi)^5. The mass-dependent contributions to a_e from diagrams containing a muon loop is 0.00370(37) (alpha/pi)^5. The tau-lepton loop contribution is negligible at present. Altogether the contribution of Set III(c) to a_e is 4.9247 (104) (alpha/pi)^5. We have also evaluated the contribution of the closed electron loop to the muon g-2 (a_mu). The result is 7.435(134) (alpha/pi)^5. The contribution of the tau-lepton loop to a_mu is 0.1999(28)(alpha/pi)^5. The total contribution of variousleptonic loops (electron, muon, and tau-lepton) of Set III(c) to a_mu is 12.556 (135) (alpha/pi)^5.
Prokert, F; Gorbunov, A
2003-01-01
Double layers of Fe-Cr and Co-Cu, respectively, were prepared on oxidized Si substrates by pulsed laser deposition (PLD). The interfacial roughness structure was studied by synchrotron X-ray reflectivity measurements at the absorption K-edges using the contrast enhancement due to resonant scattering. The results are determined from simulations of the measured specular and diffuse scans. Whereas in Fe-Cr double layers the sigma sub r sub m sub s -interface width for Fe deposition on Cr (sigma sub C sub r =0.70+-0.1 nm) is not very different from that of Cr deposition on Fe (sigma sub F sub e =0.85+-0.1 nm), in Co-Cu double layers, in contrast, for Cu deposition on Co, the width (sigma sub C sub o =0.65+-0.1 nm) is much smaller than for Co deposition on Cu (sigma sub C sub u =1.5+-0.15 nm). On the basis of the fractal model to describe the interface roughness morphology, from the off-specular scans the lateral roughness correlation length, xi and the roughness exponent, h, were determined. For both types of dou...
Contemporary Use of Anomalous Diffraction in Biomolecular Structure Analysis
Energy Technology Data Exchange (ETDEWEB)
Liu Q.; Hendrickson, W.
2017-01-01
The normal elastic X-ray scattering that depends only on electron density can be modulated by an ?anomalous? component due to resonance between X-rays and electronic orbitals. Anomalous scattering thereby precisely identifies atomic species, since orbitals distinguish atomic elements, which enables the multi- and single-wavelength anomalous diffraction (MAD and SAD) methods. SAD now predominates in de novo structure determination of biological macromolecules, and we focus here on the prevailing SAD method. We describe the anomalous phasing theory and the periodic table of phasing elements that are available for SAD experiments, differentiating between those readily accessible for at-resonance experiments and those that can be effective away from an edge. We describe procedures for present-day SAD phasing experiments and we discuss optimization of anomalous signals for challenging applications. We also describe methods for using anomalous signals as molecular markers for tracing and element identification. Emerging developments and perspectives are discussed in brief.
The Proton Coulomb Form Factor from Polarized Inclusive e-p Scattering
Energy Technology Data Exchange (ETDEWEB)
Harris, Christopher Matthew [Univ. of Virginia, Charlottesville, VA (United States)
2001-05-01
The proton form factors provide information on the fundamental properties of the proton and provide a test for models based on QCD. In 1998 at Jefferson Lab (JLAB) in Newport News, VA, experiment E93026 measured the inclusive e-p scattering cross section from a polarized ammonia (^{15}NH_{3}) target at a four momentum transfer squared of Q^{2} = 0.5 (GeV/c)^{2}. Longitudinally polarized electrons were scattered from the polarized target and the scattered electron was detected. Data has been analyzed to obtain the asymmetry from elastically scattered electrons from hydrogen in ^{15}NH_{3}. The asymmetry, A_{p}, has been used to determine the proton elastic form factor G_{Ep}. The result is consistent with the dipole model and data from previous experiments. However, due to the choice of kinematics, the uncertainty in the measurement is large.
Baryon scattering at high energies: wave function, impact factor, and gluon radiation
Bartels, J
2007-01-01
The scattering of a baryon consisting of three massive quarks is investigated in the high energy limit of perturbative QCD. A model of a relativistic proton-like wave function, dependent on valence quark longitudinal and transverse momenta and on quark helicities, is proposed, and we derive the baryon impact factors for two, three and four t-channel gluons. We find that the baryonic impact factor can be written as a sum of three pieces: in the first one a subsystem consisting of two of the three quarks behaves very much like the quark-antiquark pair in gamma* scattering, whereas the third quark acts as a spectator. The second term belongs to the odderon, whereas in the third (C-even) piece all three quarks participate in the scattering. This term is new and has no analogue in gamma* scattering. We also study the small x evolution of gluon radiation for each of these three terms. The first term follows the same pattern of gluon radiation as the gamma*-initiated quark-antiquark dipole, and, in particular, it co...
The scatter factor signaling pathways as therapeutic associated target in cancer treatment.
Accornero, P; Pavone, L M; Baratta, M
2010-01-01
Receptor tyrosine kinases (RTKs) are key regulators of critical cellular processes such as proliferation, differentiation, neo-vascularization, and tissue repair. In addition to their importance in the regulation of normal physiology, aberrant expression of certain RTKs has also been associated to the development and progression of many types of cancer. c-Met and RON are two RTKs with closely related sequences, structural homology, and similar functional properties. Both these receptors, once activated by their respective ligands, the Hepatocyte Growth Factor/Scatter Factor (HGF/SF1) and the Macrophage Stimulating Protein/Scatter Factor 2 (MSP/SF2), can induce cell migration, invasion and proliferation. Soon after its discovery in the mid-1980s, c-Met attracted a great interest because of its role in modulating cell motility. Moreover, the causal role for c-Met activating mutations in human cancer propelled an intensive drug discovery effort throughout academic institutions and pharmaceutical companies. While c-Met is now a well-accepted target for anticancer drug design, less is known about the role of RON in cancer and less has been done to target this receptor. In this review we will discuss the biological relevance of c-Met and RON, their deregulation in human cancers and the progress, so far, in identifying c-Met and RON signaling inhibitors. Finally, we will focus on the development of therapeutic strategies and drug efficacy studies based on interfering the scatter factor signaling pathways.
Infrared singularities of scattering amplitudes in perturbative QCD
Energy Technology Data Exchange (ETDEWEB)
Becher, Thomas [Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States); Neubert, Matthias [Johannes Gutenberg-Universitaet Mainz, Mainz (Germany)
2013-11-01
An exact formula is derived for the infrared singularities of dimensionally regularized scattering amplitudes in massless QCD with an arbitrary number of legs, valid at any number of loops. It is based on the conjecture that the anomalous-dimension matrix of n-jet operators in soft-collinear effective theory contains only a single non-trivial color structure, whose coefficient is the cusp anomalous dimension of Wilson loops with light-like segments. Its color-diagonal part is characterized by two anomalous dimensions, which are extracted to three-loop order from known perturbative results for the quark and gluon form factors. This allows us to predict the three-loop coefficients of all 1/epsilon^k poles for an arbitrary n-parton scattering amplitudes, generalizing existing two-loop results.
Energy Technology Data Exchange (ETDEWEB)
Mas, J.; Younes, R.B.; Bellaton, B.; Bidet, R. (Centre Hospitalier Universitaire Jean Minjoz, 25 - Besancon (France). Lab. de Biophysique et de Medecine Nucleaire); Hannequin, P. (Centre d' Imagerie Nucleaire, 74 -Annecy (France))
1990-11-01
A new approach to Compton scatter correction based on factor analysis of dynamic structures (FADS) is presented in this study. The innovation is the use of a constrained photopeak factor. This novel algorithm is evaluated both on planar imaging and SPECT data using Monte Carlo simulations and real phantoms. A comparison with the modified method of Jaszczak is also presented. Different parameters are significantly improved with the authors' recombination method in SPECT studies; particularly after attenuation compensation by the iterative method of Chang. Compared with the subtraction method the contrast is increased by 1.5 for planar Monte Carlo simulations and the scatter fraction is reduced four times with the recombination method. (author).
Pu, Yang; Chen, Jun; Wang, Wubao
2014-02-01
The scattering coefficient, μs, the anisotropy factor, g, the scattering phase function, p(θ), and the angular dependence of scattering intensity distributions of human cancerous and normal prostate tissues were systematically investigated as a function of wavelength, scattering angle and scattering particle size using Mie theory and experimental parameters. The Matlab-based codes using Mie theory for both spherical and cylindrical models were developed and applied for studying the light propagation and the key scattering properties of the prostate tissues. The optical and structural parameters of tissue such as the index of refraction of cytoplasm, size of nuclei, and the diameter of the nucleoli for cancerous and normal human prostate tissues obtained from the previous biological, biomedical and bio-optic studies were used for Mie theory simulation and calculation. The wavelength dependence of scattering coefficient and anisotropy factor were investigated in the wide spectral range from 300 nm to 1200 nm. The scattering particle size dependence of μs, g, and scattering angular distributions were studied for cancerous and normal prostate tissues. The results show that cancerous prostate tissue containing larger size scattering particles has more contribution to the forward scattering in comparison with the normal prostate tissue. In addition to the conventional simulation model that approximately considers the scattering particle as sphere, the cylinder model which is more suitable for fiber-like tissue frame components such as collagen and elastin was used for developing a computation code to study angular dependence of scattering in prostate tissues. To the best of our knowledge, this is the first study to deal with both spherical and cylindrical scattering particles in prostate tissues.
$K_{l4}$ Form-Factors and $\\pi-\\pi$ Scattering
Amorós, G; Talavera, P
2000-01-01
The $F$ and $G$ form-factors of $K_{\\ell4}$ and the quark condensates are calculated to ${\\cal O}(p^6)$ in Chiral Perturbation Theory (CHPT). Full formulas are presented as much as possible. A full refit of most of the ${\\cal O}(p^4)$ CHPT parameters is done with a discussion of all inputs and underlying assumptions. We discuss the consequences for the vacuum expectation values, decay constants, pseudoscalar masses and $\\pi$-$\\pi$ scattering.
Different aspects of the Debye-Waller factor in various atom-surface scattering theories
Gumhalter, Branko
1996-02-01
We discuss differences in the formal appearance, structure and physical origin of the Debye-Waller factor (DWF) obtained in various theoretical treatments of inelastic atom-surface collisions. These differences are illustrated on the example of two most commonly used formalisms for description of inelastic atom scattering by multiple excitation of surface phonons. In the first of these approaches, one starts from the expression for transition rates for the projectile atom which is coupled to the phonon field to all orders in lattice displacements. In first-order Born approximation, which is usually employed to express the corresponding T-matrix in a tractable form, the problem reduces to calculation of the exponentiated lattice displacement correlation function. By using a diagrammatic expansion to represent such correlation function we demonstrate that in this description the DWF occurs as a consequence of atom scattering by zero point motion of the lattice and is therefore expressed through dynamical variables which are not constrained to the energy shell. In the second approach one starts from the expression for the scattering spectrum of the projectile and linear atom-phonon field coupling, which is then treated in a nonperturbative fashion to all orders in the coupling constant. Here the dominant quantum contribution to the DWF arises from the projectile scattering through real uncorrelated multiphonon emission processes, which reduce the scattered beam intensity in the elastic channel. Using analogous diagrammatic expansion we show that the corresponding DWF is expressed in terms of the on-the-energy-shell quantities, which then leads to a normalization of the total scattering spectrum so as to comply with the optical theorem. Only in the limit of fast collision and trajectory approximation for the scattered particle motion the two approaches lead to the same result for the DWF because in this case the on-the-energy-shell features are washed out. We conclude
$J=0$ fixed pole and $D$-term form factor in deeply virtual Compton scattering
Müller, Dieter
2015-01-01
S.~Brodsky, F.~J.~Llanes-Estrada, and A.~Szczepaniak emphasized the importance of the $J=0$ fixed pole manifestation in real and (deeply) virtual Compton scattering measurements and argued that the $J=0$ fixed pole is universal, {\\it i.e.}, independent on the photon virtualities \\cite{Brodsky:2008qu}. In this paper we review the $J=0$ fixed pole issue in deeply virtual Compton scattering. We employ the dispersive approach to derive the sum rule that connects the $J=0$ fixed pole contribution and the subtraction constant, called the $D$-term form factor for deeply virtual Compton scattering. We show that in the Bjorken limit the $J=0$ fixed pole universality hypothesis is equivalent to the conjecture that the $D$-term form factor is given by the inverse moment sum rule for the Compton form factor. This implies that the $D$-term is an inherent part of corresponding generalized parton distribution (GPD). Any supplementary $D$-term added to a GPD results in an additional $J=0$ fixed pole contribution and implies ...
Atomic scattering factor of the ASTRO-H (Hitomi) SXT reflector around the gold's L edges
DEFF Research Database (Denmark)
Kikuchi, Naomichi; Kurashima, Sho; Ishida, Manabu
2016-01-01
-edges in the energy band is a major issue, as it complicates the function of the effective area. In order to model the area, the reflectivity measurements in the 11.2-15.4 keV band with the energy pitch of 0.4-0.7 eV were made in the synchrotron beamline Spring-8 BL01B1. We obtained atomic scattering factors f1 and f......The atomic scattering factor in the energy range of 11.2-15.4 keV for the ASTRO-H Soft X-ray Telescope (SXT) is reported. The large effective area of the SXT makes use of photon spectra above 10 keV viable, unlike most other X-ray satellites with total-reflection mirror optics. Presence of gold's L......2 by the curve fitting to the reflectivities of our witness sample. The edges associated with the L-I, II, and III transitions are identified, of which the depths are found to be roughly 60% shallower than those expected from the Henke's atomic scattering factor....
Effect of the bound nucleon form factors on charged-current neutrino-nucleus scattering
Tsushima, K; Saitô, K; Kim, Hungchong
2003-01-01
We study the effect of bound nucleon form factors on charged-current neutrino-nucleus scattering. The bound nucleon form factors associated with the vector and axial-vector currents are calculated in the quark-meson coupling model. We compute the inclusive $^{12}$C($nu_mu,mu^-$)$X$ differential and total cross sections, which have been measured by the LSND collaboration at Los Alamos, using a relativistic Fermi gas model with the calculated bound nucleon form factors. It is shown that the bound nucleon form factors reduce the total cross section by about 8% relative to that calculated with the free nucleon form factors, where most of the conventional calculations overestimate the total cross section data by about 30% to 100%.
An approximate factorization method for inverse medium scattering with unknown buried objects
Qu, Fenglong; Yang, Jiaqing; Zhang, Bo
2017-03-01
This paper is concerned with the inverse problem of scattering of time-harmonic acoustic waves by an inhomogeneous medium with different kinds of unknown buried objects inside. By constructing a sequence of operators which are small perturbations of the far-field operator in a suitable way, we prove that each operator in this sequence has a factorization satisfying the Range Identity. We then develop an approximate factorization method for recovering the support of the inhomogeneous medium from the far-field data. Finally, numerical examples are provided to illustrate the practicability of the inversion algorithm.
Proton form factors and two-photon exchange in elastic electron-proton scattering
Energy Technology Data Exchange (ETDEWEB)
Nikolenko, D. M., E-mail: D.M.Nikolenko@inp.nsk.su [Russian Academy of Sciences, Budker Institute of Nuclear Physics, Siberian Branch (Russian Federation); Arrington, J. [Argonne National Laboratory (United States); Barkov, L. M. [Russian Academy of Sciences, Budker Institute of Nuclear Physics, Siberian Branch (Russian Federation); Vries, H. de [NIKHEF (Netherlands); Gauzshtein, V. V. [National Research Tomsk Polytechnic University, Physical-Technical Institute (Russian Federation); Golovin, R. A.; Gramolin, A. V.; Dmitriev, V. F.; Zhilich, V. N.; Zevakov, S. A.; Kaminsky, V. V.; Lazarenko, B. A.; Mishnev, S. I.; Muchnoi, N. Yu.; Neufeld, V. V.; Rachek, I. A.; Sadykov, R. Sh. [Russian Academy of Sciences, Budker Institute of Nuclear Physics, Siberian Branch (Russian Federation); Stibunov, V. N. [National Research Tomsk Polytechnic University, Physical-Technical Institute (Russian Federation); Toporkov, D. K. [Russian Academy of Sciences, Budker Institute of Nuclear Physics, Siberian Branch (Russian Federation); Holt, R. J. [Argonne National Laboratory (United States); and others
2015-05-15
Proton electromagnetic form factors are among the most important sources of information about the internal structure of the proton. Two different methods for measuring these form factors, the method proposed by Rosenbluth and the polarization-transfer method, yield contradictory results. It is assumed that this contradiction can be removed upon taking into account the hard part of the contribution of two-photon exchange to the cross section for elastic electron-proton scattering. This contribution can measured experimentally via a precision comparison of the cross sections for the elastic scattering of positrons and electrons on protons. Such a measurement, performed at the VEPP-3 storage ring in Novosibirsk at the beam energies of 1.6 and 1.0 GeV for positron (electron) scattering angles in the ranges of θ{sub e} = 15°–25° and 55°–75° in the first case and in the range of θ{sub e} = 65°–105° in the second case is described in the present article. Preliminary results of this experiment and their comparison with theoretical predictions are described.
Towards a resolution of the proton form factor problem: new electron and positron scattering data
Adikaram, D; Weinstein, L B; Raue, B; Khetarpal, P; Bennett, R P; Arrington, J; Brooks, W K; Adhikari, K P; Afanasev, A V; Amaryan, M J; Anderson, M D; Ball, J; Battaglieri, M; Bedlinskiy, I; Biselli, A S; Bono, J; Boiarinov, S; Briscoe, W J; Burkert, V D; Carman, D S; Celentano, A; Chandavar, S; Charles, G; Colaneri, L; Cole, P L; Contalbrigo, M; D'Angelo, A; Dashyan, N; De Vita, R; De Sanctis, E; Deur, A; Djalali, C; Dodge, G E; Dupre, R; Egiyan, H; Alaoui, A El; Fassi, L El; Eugenio, P; Fedotov, G; Fegan, S; Filippi, A; Fleming, J A; Fradi, A; Gilfoyle, G P; Giovanetti, K L; Girod, F X; Goetz, J T; Gohn, W; Golovatch, E; Gothe, R W; Griffioen, K A; Guidal, M; Guo, L; Hafidi, K; Hakobyan, H; Harrison, N; Hattawy, M; Hicks, K; Holtrop, M; Hughes, S M; Hyde, C E; Ilieva, Y; Ireland, D G; Ishkhanov, B S; Jenkins, D; Jiang, H; Joo, K; Joosten, S; Khandaker, M; Kim, W; Klein, A; Klein, F J; Koirala, S; Kubarovsky, V; Kuhn, S E; Lu, H Y; MacGregor, I J D; Markov, N; Mayer, M; McKinnon, B; Mestayer, M D; Meyer, C A; Mirazita, M; Mokeev, V; Montgomery, R A; Moody, C I; Moutarde, H; Movsisyan, A; Camacho, C Munoz; Nadel-Turonski, P; Niccolai, S; Niculescu, G; Osipenko, M; Ostrovidov, A I; Park, K; Pasyuk, E; Pisano, S; Pogorelko, O; Procureur, S; Prok, Y; Protopopescu, D; Puckett, A J R; Ripani, M; Rizzo, A; Rosner, G; Rossi, P; Sabatié, F; Schott, D; Schumacher, R A; Sharabian, Y G; Simonyan, A; Skorodumina, I; Smith, E S; Smith, G D; Sober, D I; Sparveris, N; Stepanyan, S; Strauch, S; Sytnik, V; Taiuti, M; Tian, Ye; Trivedi, A; Ungaro, M; Voskanyan, H; Voutier, E; Walford, N K; Watts, D P; Wei, X; Wood, M H; Zachariou, N; Zana, L; Zhang, J; Zhao, Z W; Zonta, I
2014-01-01
There is a significant discrepancy between the values of the proton electric form factor, $G_E^p$, extracted using unpolarized and polarized electron scattering. Calculations predict that small two-photon exchange (TPE) contributions can significantly affect the extraction of $G_E^p$ from the unpolarized electron-proton cross sections. We determined the TPE contribution by measuring the ratio of positron-proton to electron-proton elastic scattering cross sections using a simultaneous, tertiary electron-positron beam incident on a liquid hydrogen target and detecting the scattered particles in the Jefferson Lab CLAS detector. This novel technique allowed us to cover a wide range in virtual photon polarization ($\\varepsilon$) and momentum transfer ($Q^2$) simultaneously, as well as to cancel luminosity-related systematic errors. The cross section ratio increases with decreasing $\\varepsilon$ at $Q^2 = 1.45 \\text{ GeV}^2$. This measurement is consistent with the size of the form factor discrepancy at $Q^2\\approx...
Elastic scattering of gamma rays and X-rays
Energy Technology Data Exchange (ETDEWEB)
Kane, P.P. [Physics Department, Indian Institute of Technology, Powai, Mumbai 400076 (India)]. E-mail: ppkane@vsnl.com
2005-12-15
Studies of elastic gamma ray scattering were pursued independently by the groups of Prof. Ghose and the author for several decades in spite of somewhat meagre support. Several techniques for such studies developed by the two groups and some of the results obtained in the energy range from tens of keV to about 1.5 MeV are described briefly. The theoretical background necessary for understanding these results is also outlined. The results showed the importance of Modified Relativistic Form Factor (MRFF) approximation in the explanation of atomic Rayleigh scattering cross sections in the small angle regime and the necessity for an inclusion of real Delbrueck scattering amplitudes at large scattering angles. Dispersion corrections to form factor amplitudes or the so-called anomalous scattering factors are shown to be needed at photon energies close to electron binding energy thresholds. A few promising future extensions of such studies are indicated at the end.
Bootstrapping the QCD soft anomalous dimension arXiv
Almelid, Øyvind; Gardi, Einan; McLeod, Andrew; White, Chris D.
The soft anomalous dimension governs the infrared singularities of scattering amplitudes to all orders in perturbative quantum field theory, and is a crucial ingredient in both formal and phenomenological applications of non-abelian gauge theories. It has recently been computed at three-loop order for massless partons by explicit evaluation of all relevant Feynman diagrams. In this paper, we show how the same result can be obtained, up to an overall numerical factor, using a bootstrap procedure. We first give a geometrical argument for the fact that the result can be expressed in terms of single-valued harmonic polylogarithms. We then use symmetry considerations as well as known properties of scattering amplitudes in collinear and high-energy (Regge) limits to constrain an ansatz of basis functions. This is a highly non-trivial cross-check of the result, and our methods pave the way for greatly simplified higher-order calculations.
Tribuzy-Neto, I A; Conceição, K G; Siqueira-Souza, F K; Hurd, L E; Freitas, C E C
2017-08-17
The effects of extreme droughts on freshwater fish remain unknown worldwide. In this paper, we estimated the condition factor, a measure of relative fitness based on the relationship of body weight to length, in four fish species representing two trophic levels (omnivores and piscivores) from Amazonian floodplain lakes for three consecutive years: 2004, 2005 (an anomalous drought year), and 2006. The two omnivores, Colossoma macropomum and Mylossoma duriventre, exhibited trends consistent with their life cycles in 2004 and 2006: high values during the hydrologic seasons of high water, receding water, and low water, with a drop following reproduction following the onset of rising water. However during the drought year of 2005 the condition factor was much lower than normal during receding and low water seasons, probably as a result of an abnormal reduction in resource availability in a reduced habitat. The two piscivorous piranhas, Serrasalmus spilopleura and S. elongatus, maintained relatively stable values of condition factor over the hydrologic cycles of all three years, with no apparent effect of the drought, probably because the reduction in habitat is counterbalanced by the resulting increase in relative prey density. We suggest that if predictions of increasing drought in the Amazon are correct, predatory species may benefit, at least in the short run, while omnivores may be negatively affected.
Parity-violating Electron Deuteron Scattering and the Proton's Neutral Weak Axial Vector Form Factor
Ito, T M; Averett, T; Barkhuff, D; Batigne, G; Beck, D H; Beise, E J; Blake, A; Breuer, H; Carr, R; Clasie, B; Covrig, S D; Danagulyan, A S; Dodson, G; Dow, K; Dutta, D; Farkhondeh, M; Filippone, B W; Franklin, W; Furget, C; Gao, H; Gao, J; Gustafsson, K K; Hannelius, L; Hasty, R; Hawthorne-Allen, A M; Herda, M C; Jones, C E; King, P; Korsch, W; Kowalski, S; Kox, S; Krämer, K; Lee, P; Liu, J; Martin, J W; McKeown, R D; Müller, B; Pitt, M L; Plaster, B; Quéméner, G; Real, J S; Ritter, J; Roche, J; Savu, V; Schiavilla, R; Seely, J; Spayde, D T; Suleiman, R; Taylor, S; Tieulent, R; Tipton, B; Tsentalovich, E; Wells, S P; Yang, B; Yuan, J; Yun, J; Zwart, T
2004-01-01
We report on a new measurement of the parity-violating asymmetry in quasielastic electron scattering from the deuteron at backward angles at Q2= 0.038 (GeV/c)2. This quantity provides a determination of the neutral weak axial vector form factor of the nucleon, which can potentially receive large electroweak corrections. The measured asymmetry A=-3.51 +/- 0.57(stat) +/- 0.58(sys)ppm is consistent with theoretical predictions. We also report on updated results of the previous experiment at Q2=0.091 (GeV/c)2, which are also consistent with theoretical predictions.
Factorization of the dijet cross section in electron-positron scattering with jet algorithms
Chay, Junegone; Kim, Inchol
2015-01-01
We analyze the effects of jet algorithms on each factorized part of the dijet cross sections in $e^+ e^-$ scattering using the soft-collinear effective theory. The jet function and the soft function with a cone-type jet algorithm and the Sterman-Weinberg jet algorithm are computed to next-to-leading order in $\\alpha_s$, and are shown to be infrared finite using the dimensional regularization. The integrated and unintegrated jet functions are presented, and compared with other types of jet functions.
Derivation of factors for estimating the scatter of diagnostic x-rays from walls and ceiling slabs.
Martin, C J; Sutton, D G; Magee, J; McVey, S; Williams, J R; Peet, D
2012-12-01
Computed tomography (CT) scanning rooms and interventional x-ray facilities with heavy workloads may require the installation of shielding to protect against radiation scattered from walls or ceiling slabs. This is particularly important for the protection of those operating x-ray equipment from within control cubicles who may be exposed to radiation scattered from the ceiling over the top of the protective barrier and round the side if a cubicle door is not included. Data available on the magnitude of this tertiary scatter from concrete slabs are limited. Moreover, there is no way in which tertiary scatter levels can be estimated easily for specific facilities. There is a need for a suitable method for quantification of tertiary scatter because of the increases in workloads of complex x-ray facilities. In this study diagnostic x-ray air kerma levels scattered from concrete and brick walls have been measured to verify scatter factors. The results have been used in a simulation of tertiary scatter for x-ray facilities involving summation of scatter contributions from elements across concrete ceiling slabs. The majority of the ceiling scatter air kerma to which staff behind a barrier will be exposed arises from the area between the patient/x-ray tube and the staff. The level depends primarily on the heights of the ceiling and protective barrier. A method has been developed to allow tertiary scatter levels to be calculated using a simple equation based on a standard arrangement for rooms with different ceiling and barrier heights. Coefficients have been derived for a CT facility and an interventional suite to predict tertiary scatter levels from the workload, so that consideration can be given to the protection options available.
Institute of Scientific and Technical Information of China (English)
Wu Fuxian; Wen Weidong
2016-01-01
Classic maximum entropy quantile function method (CMEQFM) based on the probabil-ity weighted moments (PWMs) can accurately estimate the quantile function of random variable on small samples, but inaccurately on the very small samples. To overcome this weakness, least square maximum entropy quantile function method (LSMEQFM) and that with constraint condition (LSMEQFMCC) are proposed. To improve the confidence level of quantile function estimation, scatter factor method is combined with maximum entropy method to estimate the confidence inter-val of quantile function. From the comparisons of these methods about two common probability distributions and one engineering application, it is showed that CMEQFM can estimate the quan-tile function accurately on the small samples but inaccurately on the very small samples (10 sam-ples); LSMEQFM and LSMEQFMCC can be successfully applied to the very small samples;with consideration of the constraint condition on quantile function, LSMEQFMCC is more stable and computationally accurate than LSMEQFM; scatter factor confidence interval estimation method based on LSMEQFM or LSMEQFMCC has good estimation accuracy on the confidence interval of quantile function, and that based on LSMEQFMCC is the most stable and accurate method on the very small samples (10 samples).
Quasi-elastic electron-deuteron scattering and the electric form factor of the neutron
Energy Technology Data Exchange (ETDEWEB)
Arenhoevel, H.; Kim, Y.E. (Mainz Univ. (Germany, F.R.). Inst. fuer Kernphysik); Craver, B.A. (Purdue Univ., Lafayette, IN (USA). Dept. of Physics); Fabian, W. (State Univ. of New York, Stony Brook (USA). Dept. of Physics); Saylor, D.P. (Worcester Polytechnic Inst., MA (USA). Dept. of Physics)
1978-09-02
The possibility of extracting accurately the neutron electric form factor from electron-neutron coincidence measurements in quasi-elastic electron-deuteron scattering is investigated for squared three-momentum transfers q/sup 2/<=30 fm/sup -2/ using the Reid soft-core, Hamada-Johnston and Bryan-Gersten potentials. It is found that contributions of the electric form factor of the neutron to the quasi-elastic cross section can be as large as 5.4% at q/sup 2/ approximately equal to 1 fm/sup -2/ (approximately 3% at q/sup 2/ approximately equal to 10 approximately 20 fm/sup 2/). Potential model dependence and corrections due to meson exchange currents and isobar configurations are found to be small (< or approximately 1%).
Roden, C. A.; Bond, T. C.; Conway, S.; Osorto Pinel, B.; Maccarty, N.
2006-12-01
In a three-year study of field and laboratory emissions of traditional and improved biofuel cookstoves, we found that field measured particulate emissions of actual cooking events average 2.5 times those of reproduced lab emissions. Emission factors are highly dependent on the care and skill of the operator, and the resulting combustion; these do not appear to be accurately reproduced in the lab. The single scatter albedo (SSA) of the emissions is very low in both lab and field measurements, averaging about 0.3 for lab tests and around 0.5 for field tests, indicating that the primary particles are climate warming. In Honduras, improved stoves generally had lower emission factors than traditional stoves. Over the course of 3 summers we have measured field emissions from traditional cookstoves, relatively-new improved cookstoves, and "broken-in" improved cookstoves. For improved stoves, the presence of a chimney generally resulted in lower emission factors but left the SSA unaffected. Traditional cookstoves had an average PM emission factor of 8.5 g/kg significantly larger than previous studies. Particulate emission factors for improved cookstoves without and with chimneys averaged about 5.7 g/kg and 3.5 g/kg respectively. The elemental carbon (EC) fraction of PM varied significantly between individual tests, but averaged about 25% for each of the categories. Wood type affects on the PM emission factor, the SSA of the emissions and EC fraction. During our 2006 field measurements, we performed multiple emission measurements on the same stove while varying the fuel. Pine wood generally produced more PM than oak per kilogram of fuel. Additionally, Ocote, a resinous pitch pine often used in Central America for lighting fires, produces emissions which have a very low SSA and high EC fraction. We present the elemental carbon fraction and mass emission factors for different type of stoves and testing conditions. We summarize the characteristics of the particles emitted
Theory of the Muon Anomalous Magnetic Moment
Melnikov, Kirill
2006-01-01
The theory of the muon anomalous magnetic moment is "particle physics in a nutshell" and as such is interesting, exciting and difficult. The current precision of the experimental value for this quantity, improved significantly in the past several years due to experiment E821 at Brookhaven National Laboratory, is so high that a large number of subtle effects not relevant previously, become important for the interpretation of the experimental result. The theory of the muon anomalous magnetic moment is at the cutting edge of current research in particle physics and includes multiloop calculations in both QED and electroweak theory, precision low-energy hadron physics, isospin violations and scattering of light by light. Any deviation between the theoretical prediction and the experimental value might be interpreted as a signal of an as-yet-unknown new physics. This book provides a comprehensive review of the theory of the muon anomalous magnetic moment.
[Determination of head scatter factors released from a scanning-type therapeutic accelerator].
Sato, Tomoharu
2003-07-01
The MM50 is a racetrack microtron capable of taking out photon beams and electron beams with energies of up to 50 MeV. It flattens the beam by the beam-scanning method, while the microtron MM22 utilizes a flattening filter. The head-scatter factors (hereafter called S(h)), which are important for evaluating the output of the photon beam of the MM50 and MM22, were measured using a mini-phantom and build-up cap. S(h) measured with the build-up cap showed the influence of contaminated electrons, whereas S(h) measured with the mini-phantom showed less influence, even for 50 MV photon beams. Compared with the MM22, the MM50 showed less change in S(h) according to field size and energy. The reason for this seemed to be that the MM50 has a smaller extra-focal region than other accelerators equipped with flattening filters and, therefore, can essentially be considered a point source by using the beam-scanning method without a flattening filter. This study demonstrated that photons scattered by the flattening filter used for beam flattening in typical medical accelerators mainly contribute to S(h).
Nucleon momentum distributions and elastic electron scattering form factors for some 1p-shell nuclei
Indian Academy of Sciences (India)
A K Hamoudi; M A Hasan; A R Ridha
2012-05-01
The nucleon momentum distributions (NMD) and elastic electron scattering form factors of the ground state for 1p-shell nuclei with = (such as 6Li, 10B, 12C and 14N nuclei) have been calculated in the framework of the coherent density ﬂuctuation model (CDFM) and expressed in terms of the weight function $|f(x)|^2$. The weight function has been expressed in terms of nucleon density distribution (NDD) of the nuclei and determined from the theory and the experiment. The feature of the long-tail behaviour at high-momentum region of the NMDs has been obtained by both the theoretical and experimental weight functions. The experimental form factors $F(q)$ of all the considered nuclei are very well reproduced by the present calculations for all values of momentum transfer . It is found that the contributions of the quadrupole form factors $F_{C2}(q)$ in 10B and 14N nuclei, which are described by the undeformed p-shell model, are essential for obtaining a remarkable agreement between the theoretical and experimental form factors.
Inelastic magnetic electron scattering form factors of the 26Mg nucleus
Indian Academy of Sciences (India)
Khalid S Jassim; Raad A Radhi; Najlla M Hussain
2016-01-01
Magnetic electron scattering (3) form factors with core polarization effects, energy levels and (3) values to 3+ states of the 26Mg nucleus have been studied using shell model calculations. The universal sd of the Wildenthal interaction, universal sd-shell interaction A, universal sd-shell interaction B, are used for the sd-shell orbits. Core polarization effects according to microscopic theory are taken into account by the excitations of nucleons from the (11/2 13/2 11/2) core and also from valence 15/2 21/2 13/2 orbits into higher shells, with $4\\hbar \\omega$ excitation. In form factor calculations, the universal sd-shell interaction B for the sd-shell is used with the Michigan three-range Yakawa effective NN interaction as a residual interaction for the core polarization calculations. The wave functions of the radial single-particle matrix elements have been calculated using harmonic oscillator potentials. The level schemes are compared with the experimental data up to 9.902 MeV. In this study, very good agreements are obtained for all nuclei. Results from 3 form factor calculations with the inclusion of core polarization and new -factors give good agreement with the experimental data.
Resonant X-ray scattering study on the filled skutterudite PrFe{sub 4}P{sub 12}
Energy Technology Data Exchange (ETDEWEB)
Ishii, K.; Inami, T.; Murakami, Y.; Hao, L.; Iwasa, K.; Kohgi, M.; Aoki, Y.; Sugawara, H.; Sato, H.; Imada, S.; Nakao, H.; Sawa, H.; Wakabayashi, Y
2003-05-01
Resonant X-ray scattering study was carried out to investigate an anomalous ordered state (T{sub A}=6.5 K) in the filled skutterudite PrFe{sub 4}P{sub 12}. At the Pr-L{sub III} absorption edge, we observed resonant features in h+k+l=odd reflections, which are forbidden in the BCC structure above T{sub A}. Because these reflections contain the difference of anomalous scattering factor between two Pr atoms in the BCC unit cell, and the ordered state is attributed to the ordering of two different electronic states of Pr.
Factorizations in special relativity and quantum scattering on the line II
Brezov, Danail S.; Mladenova, Clementina D.; Mladenov, Ivaïlo M.
2016-12-01
The present paper may be regarded as a continuation of both [1] and [2]: we discuss the same physical context as in the former, while applying a specific decomposition technique initially proposed in the latter. The method used in [1], however, is completely different (based on repetitive conjugation) and has more in common with the familiar Wigner decomposition [3]. Here we obtain in a dynamical manner a compact two-factor decomposition, which in the Euclidean case allows for convenient parametrizations in rigid body kinematics and quantum-mechanical angular momenta. Applied to the group Spin(2, 1) ≅ SL(2, ℝ), this technique yields numerous applications in hyperbolic geometry and 2 + 1 dimensional special relativity. However, we choose to illustrate it with a particular problem arising in quantum mechanical scattering theory. The extension to SO(3, 1) and SO(2, 2) is discussed as well and numerical examples are provided in the former case.
Cassini observation of Jovian anomalous continuum radiation
Ye, Sheng-Yi; Gurnett, D. A.; Menietti, J. D.; Kurth, W. S.; Fischer, G.; Schippers, P.; Hospodarsky, G. B.
2012-04-01
Jovian anomalous continuum is a narrowband electromagnetic radiation near 10 kHz that can escape from Jupiter's magnetosphere to interplanetary space. One possible source mechanism is the magnetosheath re-radiation of the Jovian low frequency radio emissions such as the quasiperiodic (QP) radio emissions, broadband kilometric radiation (bKOM) and non-thermal continuum. Jovian anomalous continuum was consistently observed by the Cassini Radio and Plasma Wave Science instrument from 2000 to 2004, right before the Saturn orbit insertion, which means the radiation can be detected as far as 8 AU away from Jupiter. An analysis of intensity versus radial distance shows that the Jovian anomalous continuum has a line source rather than a point source, consistent with the theory that the emission is radiated by the whole length of the magnetotail. The emissions are modulated at the system III period of Jupiter and are unpolarized. Since the lower cutoff frequency of the anomalous continuum is related to the plasma frequency in the magnetosheath of Jupiter, which is a function of solar wind density, the recurrent variations of the lower cutoff frequency can be used as a remote diagnostic of the solar wind condition at Jupiter. We propose that the frequency dispersion, a unique characteristic of the anomalous continuum, is likely a comprehensive effect of both the slow group velocity near the local plasma frequency and the refraction/scattering of the waves by density structures as they propagate in the magnetosheath.
Mohammadi, S. M.; Tavakoli-Anbaran, H.; Zeinali, H. Z.
2017-02-01
The parallel-plate free-air ionization chamber termed FAC-IR-300 was designed at the Atomic Energy Organization of Iran, AEOI. This chamber is used for low and medium X-ray dosimetry on the primary standard level. In order to evaluate the air-kerma, some correction factors such as electron-loss correction factor (ke) and photon scattering correction factor (ksc) are needed. ke factor corrects the charge loss from the collecting volume and ksc factor corrects the scattering of photons into collecting volume. In this work ke and ksc were estimated by Monte Carlo simulation. These correction factors are calculated for mono-energy photon. As a result of the simulation data, the ke and ksc values for FAC-IR-300 ionization chamber are 1.0704 and 0.9982, respectively.
Three types of anomalous nickel-iron magnetic films characterized by hysteresigraph and torque-magnetometer measurements; bitter-pattern observations; reprint from ’ Journal of Applied Physics .’
Energy Technology Data Exchange (ETDEWEB)
Amarantov, S. V., E-mail: amarantov_s@mail.ru [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation); Naletova, I. N. [Moscow State University, Belozerskii Institute of Molecular Biology and Bioorganic Chemistry (Russian Federation); Kurochkina, L. P. [Russian Academy of Sciences, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry (Russian Federation)
2011-08-15
The inverse scattering problem has been solved for protein complexes whose surfaces can be described by a set of the simplest doubly connected surfaces in the uniform approximation (a scattering potential inside the molecule is a constant). Solutions of two proteins-well-known GroEL bacterial chaperonin and poor-studied bacteriophage chaperonin, which is a product of 146 gene (gp146)-were taken for the experiment. The shapes of protein complexes have been efficiently reconstructed from the experimental scattering curves. The shell method, the method of the rotation of amino acid sequences with the use of the form factor of an amino acid, and the method of seeking the model parameters of a protein complex with the preliminarily obtained form factor of the model have been used to reconstruct the shape of these particles.
Parity-Violating Electron Scattering from 4He and the Strange Electric Form Factor of the Nucleon
Airapetian, A; Akopov, Z; Amarian, M; Ammosov, V V; Andrus, A; Aschenauer, E C; Augustyniak, W; Avakian, R; Avetisian, A; Avetissian, E; Bailey, P; Balin, D; Baturin, V; Beckmann, M; Belostotskii, S; Bernreuther, S; Bianchi, N; Blok, H P; Böttcher, Helmut B; Borisov, A; Borysenko, A; Bouwhuis, M; Brack, J; Brüll, A; Bryzgalov, V; Capitani, G P; Chen, T; Chiang, H C; Ciullo, G; Contalbrigo, M; Dalpiaz, P F; De Leo, R; Demey, M; De Nardo, L; De Sanctis, E; Devitsin, E G; Di Nezza, P; Dreschler, J; Düren, M; Ehrenfried, M; Elalaoui-Moulay, A; Elbakian, G; Ellinghaus, F; Elschenbroich, U; Fabbri, R; Fantoni, A; Feshchenko, A; Felawka, L; Fox, B; Frullani, S; Gapienko, G; Gapienko, V; Garibaldi, F; Garrow, K; Garutti, E; Gaskell, D; Gavrilov, G; Karibian, V; Graw, G; Grebenyuk, O; Greeniaus, L G; Gregor, I M; Hafidi, K; Hartig, M; Hasch, D; Heesbeen, D; Henoch, M; Hertenberger, R; Hesselink, W H A; Hillenbrand, A; Hoek, M; Holler, Y; Hommez, B; Iarygin, G; Ivanilov, A; Izotov, A; Jackson, H E; Jgoun, A; Kaiser, R; Kinney, E; Kiselev, A; Kopytin, M; Korotkov, V; Kozlov, V; Krauss, B; Krivokhizhin, V G; Lagamba, L; Lapikas, L; Laziev, A; Lenisa, P; Liebing, P; Linden-Levy, L A; Lipka, K; Lorenzon, W; Lü, H; Lü, J; Lu, S; Ma, B Q; Maiheu, B; Makins, N C R; Mao, Y; Marianski, B; Marukyan, H; Masoli, F; Mexner, V; Meyners, N; Miklukho, O; Miller, C A; Miyachi, Y; Muccifora, V; Nagaitsev, A; Nappi, E; Naryshkin, Yu; Nass, A; Negodaev, M; Nowak, Wolf-Dieter; Oganessyan, K; Ohsuga, H; Pickert, N; Potashov, S Yu; Potterveld, D H; Raithel, M; Reggiani, D; Reimer, P E; Reischl, A; Reolon, A R; Riedl, C; Rith, K; Rosner, G; Rostomyan, A; Rubacek, L; Rubin, J; Ryckbosch, D; Salomatin, Y; Sanjiev, I; Savin, I; Schäfer, A; Schill, C; Schnell, G; Schüler, K P; Seele, J; Seidl, R; Seitz, B; Shanidze, R; Shearer, C; Shibata, T A; Shutov, V; Simani, M C; Sinram, K; Stancari, M; Statera, M; Steffens, E; Steijger, J J M; Stenzel, H; Stewart, J; Stinzing, F; Stösslein, U; Tait, P; Tanaka, H; Taroian, S P; Tchuiko, B; Terkulov, A R; Tkabladze, A; Trzcinski, A; Tytgat, M; Vandenbroucke, A; Van der Nat, P B; van der Steenhoven, G; Vetterli, M C; Vikhrov, V; Vincter, M G; Vogel, C; Vogt, M; Volmer, J; Weiskopf, C; Wendland, J; Wilbert, J; Ye, Y; Ye, Z; Yen, S; Zihlmann, B; Zupranski, P; Aniol, K A; Armstrong, D S; Averett, T; Benaoum, H; Bertin, P Y; Burtin, E; Cahoon, J; Cates, G D; Chang, C C; Chao Yu Chiu; Chen, J P; Seonho Choi; Chudakov, E; Craver, B; Cusanno, F; Decowski, P; Deepa, D; Ferdi, C; Feuerbach, R J; Finn, J M; Fuoti, K; Gilman, R; Glamazdin, A; Gorbenko, V; Grames, J M; Hansknecht, J; Higinbotham, D W; Holmes, R; Holmstrom, T; Humensky, T B; Ibrahim, H; De Jager, C W; Jiang, X; Kaufman, L J; Kelleher, A; Kolarkar, A; Kowalski, S; Kumar, K S; Lambert, D; La Violette, P; Le Rose, J; Lhuillier, D; Liyanage, N; Margaziotis, D J; Mazouz, M; McCormick, K; Meekins, D G; Meziani, Z E; Michaels, R; Moffit, B; Monaghan, P; Munoz-Camacho, C; Nanda, S; Nelyubin, V V; Neyret, D; Paschke, K D; Poelker, M; Pomatsalyuk, R I; Qiang, Y; Reitz, B; Roche, J; Saha, A; Singh, J; Snyder, R; Souder, P A; Subedi, R; Suleiman, R; Sulkosky, V; Tobias, W A; Urciuoli, G M; Vacheret, A; Voutier, E; Wang, K; Wilson, R; Wojtsekhowski, B; Zheng, X
2006-01-01
We have measured the parity-violating electroweak asymmetry in the elastic scattering of polarized electrons from ^4He at an average scattering angle = 5.7 degrees and a four-momentum transfer Q^2 = 0.091 GeV^2. From these data, for the first time, the strange electric form factor of the nucleon G^s_E can be isolated. The measured asymmetry of A_PV = (6.72 +/- 0.84 (stat) +/- 0.21 (syst) parts per million yields a value of G^s_E = -0.038 +/- 0.042 (stat) +/- 0.010 (syst), consistent with zero.
Kutak, Krzysztof; Serino, Mirko; Szczurek, Antoni; van Hameren, Andreas
2016-01-01
In the present paper we discuss how to maximize the double-parton scattering (DPS) contribution in four-jet production. Here both single-parton and double-parton scattering effects are calculated in the $k_t$-factorization approach, following our recent developments of relevant methods and tools. Several differential distributions are shown and discussed in the context of future searches for DPS effects, such as rapidity of jets, rapidity distance, and azimuthal correlations between jets. The dependences of the relative DPS amount is studied as function of those observables. The regions with an enhanced DPS contribution are identified. Future experimental explorations could extract more precise values of $\\sigma_{eff}$.
Covariant Spectator Theory of np scattering: Deuteron magnetic moment and form factors
Energy Technology Data Exchange (ETDEWEB)
Gross, Franz L. [JLAB
2014-06-01
The deuteron magnetic moment is calculated using two model wave functions obtained from 2007 high precision fits to $np$ scattering data. Included in the calculation are a new class of isoscalar $np$ interaction currents which are automatically generated by the nuclear force model used in these fits. After normalizing the wave functions, nearly identical predictions are obtained: model WJC-1, with larger relativistic P-state components, gives 0.863(2), while model WJC-2 with very small $P$-state components gives 0.864(2) These are about 1\\% larger than the measured value of the moment, 0.857 n.m., giving a new prediction for the size of the $\\rho\\pi\\gamma$ exchange, and other purely transverse interaction currents that are largely unconstrained by the nuclear dynamics. The physical significance of these results is discussed, and general formulae for the deuteron form factors, expressed in terms of deuteron wave functions and a new class of interaction current wave functions, are given.
Scattering of $^{7}$Be and $^{8}$B and the astrophysical S$_{17}$ factor
Tabacaru, G; Brinkley, J; Burjan, V; Cãrstoiu, F; Fu, C; Gagliardi, C A; Kroha, V; Mukhamedzhanov, A M; Tang, X; Trache, L; Tribble, R E; Zhou, S
2006-01-01
Measurements of scattering of $^{7}$Be at 87 MeV on a melamine (C$_{3}$N$ _{6}$H$_{6}$) target and of $^{8}$B at 95 MeV on C were performed. For $^{7}$Be the angular range was extended over previous measurements and monitoring of the intensity of the radioactive beam was improved. The measurements allowed us to check and improve the optical model potentials used in the incoming and outgoing channels for the analysis of existing data on the proton transfer reaction $^{14}$N($^{7}$Be,$^{8}$B)$^{13}$C. The resultslead to an updated determination of the asymptotic normalization coefficient for the virtual decay $^{8}$B $\\to$ $^{7}$Be + $p$. We find a slightly larger value, $C_{tot}^{2}(^{8}B)=0.466\\pm 0.047$ fm$^{-1}$, for the melamine target. This implies an astrophysical factor, $S_{17}(0)=18.0\\pm 1.8$ eV$\\cdot$b, for the solar neutrino generating reaction $^{7}$Be($p$,$\\gamma $)$^{8}$B.
Anomalous Hall Effect in a 2D Rashba Ferromagnet.
Ado, I A; Dmitriev, I A; Ostrovsky, P M; Titov, M
2016-07-22
Skew scattering on rare impurity configurations is shown to dominate the anomalous Hall effect in a 2D Rashba ferromagnet. The mechanism originates in scattering on rare impurity pairs separated by distances of the order of the Fermi wavelength. The corresponding theoretical description goes beyond the conventional noncrossing approximation. The mechanism provides the only contribution to the anomalous Hall conductivity in the most relevant metallic regime and strongly modifies previously obtained results for lower energies in the leading order with respect to impurity strength.
Coddens, Gerrit
2016-01-01
We discuss the algebra and the interpretation of the anomalous Zeeman effect and the spin-orbit coupling within the Dirac theory. Whereas the algebra for the anomalous Zeeman effect is impeccable and therefore in excellent agreement with experiment, the physical interpretation of that algebra uses images that are based on macroscopic intuition but do not correspond to the meaning of this algebra. The interpretation violates the Lorentz symmetry. We give an alternative intuitive description of the meaning of this effect, which respects the symmetry and is exact. It can be summarized by stating that a magnetic field makes any charged particle spin. We show also that the traditional discussion about magnetic monopoles confuses two issues, viz. the symmetry of the Maxwell equations and the quantization of charge. These two issues define each a different concept of magnetic monopole. They cannot be merged together into a unique all-encompassing issue. We also generalize the minimal substitution for a charged parti...
Lapas, Luciano C; Ferreira, Rogelma M S; Rubí, J Miguel; Oliveira, Fernando A
2015-03-14
We analyze the temperature relaxation phenomena of systems in contact with a thermal reservoir that undergoes a non-Markovian diffusion process. From a generalized Langevin equation, we show that the temperature is governed by a law of cooling of the Newton's law type in which the relaxation time depends on the velocity autocorrelation and is then characterized by the memory function. The analysis of the temperature decay reveals the existence of an anomalous cooling in which the temperature may oscillate. Despite this anomalous behavior, we show that the variation of entropy remains always positive in accordance with the second law of thermodynamics.
Lapas, Luciano C.; Ferreira, Rogelma M. S.; Rubí, J. Miguel; Oliveira, Fernando A.
2015-03-01
We analyze the temperature relaxation phenomena of systems in contact with a thermal reservoir that undergoes a non-Markovian diffusion process. From a generalized Langevin equation, we show that the temperature is governed by a law of cooling of the Newton's law type in which the relaxation time depends on the velocity autocorrelation and is then characterized by the memory function. The analysis of the temperature decay reveals the existence of an anomalous cooling in which the temperature may oscillate. Despite this anomalous behavior, we show that the variation of entropy remains always positive in accordance with the second law of thermodynamics.
Anomalous chiral superfluidity
Energy Technology Data Exchange (ETDEWEB)
Lublinsky, Michael, E-mail: lublinsky@phys.uconn.ed [Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794 (United States); Physics Department, Ben-Gurion University, Beer Sheva 84105 (Israel); Zahed, Ismail [Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794 (United States)
2010-02-08
We discuss both the anomalous Cartan currents and the energy-momentum tensor in a left chiral theory with flavor anomalies as an effective theory for flavored chiral phonons in a chiral superfluid with the gauged Wess-Zumino-Witten term. In the mean-field (leading tadpole) approximation the anomalous Cartan currents and the energy-momentum tensor take the form of constitutive currents in the chiral superfluid state. The pertinence of higher order corrections and the Adler-Bardeen theorem is briefly noted.
Anomalous pion decay revisited
Battistel, O A; Nemes, M C; Hiller, B
1999-01-01
An implicit four dimensional regularization is applied to calculate the axial-vector-vector anomalous amplitude. The present technique always complies with results of Dimensional Regularization and can be easily applied to processes involving odd numbers of $\\gamma_5$ matrices. This is illustrated explicitely in the example of this letter.
Near-edge elastic photon scattering in amorphous systems
Energy Technology Data Exchange (ETDEWEB)
Hugtenburg, R.P. [School of Physics and Astronomy, University of Birmingham, B15 2TT (United Kingdom); Queen Elizabeth Medical Centre, University Hospital Birmingham, B15 2TH (United Kingdom)], E-mail: r.p.hugtenburg@bham.ac.uk; England, D.W. [Queen Elizabeth Medical Centre, University Hospital Birmingham, B15 2TH (United Kingdom); Bradley, D.A. [Department of Physics, School of Electronics and Physical Sciences, University of Surrey, GU2 7XH (United Kingdom)
2007-10-15
The structure of valence and unoccupied electron orbitals and the neighbouring electron density distribution of atoms and ions in amorphous systems can be examined through use of resonance in the elastic photon scattering-cross-section in the vicinity of core atomic orbital energies. So-called anomalous X-ray scattering (AXS) is a mode of analysis that offers similar information to that of EXAFS but can be obtained concurrently with diffraction mode imaging. Of interest is whether the dilute-ion aqueous system provides an environment suitable for testing independent particle approximation (IPA) predictions. With the aqueous environment as the reference system for calibrating relative cross-sections, particular challenges include photons scattered by the medium being subsequently absorbed by the ion, limiting the thickness of the attenuating medium and motivating use of bright synchrotron photon sources where tunable X-rays are obtained at sub-eV resolution using a Si 111 monochromator. Measured scattering intensities and fluorescent yields were compared and shown to agree qualitatively with Monte Carlo calculations utilising amplitudes calculated from modified form-factors with anomalous scatter factors at a resolution of several eV determined from the Dirac-Slater exchange potential. Experimentally determined form-factors for pure water were used to calibrate fluorescent yield and elastic scattering intensities for measurement of the energy dependent variation of these quantities near edge and XRF imaging of the Zn concentration in wax mounted, formalin fixed, breast tumour samples. Results indicate the distribution of Zn at higher resolution than sampling dimensions used in previous studies. Shifts in the position and profile of K-edge absorption and elastic scattering features in aqeuous Zn, Zn doped sol-gel glass and Zn in tissue are shown to reflect changes in the atomic charge state and environment and offer support for the presence of non-nutrient Zn bearing
Near-edge elastic photon scattering in amorphous systems
Hugtenburg, R. P.; England, D. W.; Bradley, D. A.
2007-10-01
The structure of valence and unoccupied electron orbitals and the neighbouring electron density distribution of atoms and ions in amorphous systems can be examined through use of resonance in the elastic photon scattering-cross-section in the vicinity of core atomic orbital energies. So-called anomalous X-ray scattering (AXS) is a mode of analysis that offers similar information to that of EXAFS but can be obtained concurrently with diffraction mode imaging. Of interest is whether the dilute-ion aqueous system provides an environment suitable for testing independent particle approximation (IPA) predictions. With the aqueous environment as the reference system for calibrating relative cross-sections, particular challenges include photons scattered by the medium being subsequently absorbed by the ion, limiting the thickness of the attenuating medium and motivating use of bright synchrotron photon sources where tunable X-rays are obtained at sub-eV resolution using a Si 111 monochromator. Measured scattering intensities and fluorescent yields were compared and shown to agree qualitatively with Monte Carlo calculations utilising amplitudes calculated from modified form-factors with anomalous scatter factors at a resolution of several eV determined from the Dirac-Slater exchange potential. Experimentally determined form-factors for pure water were used to calibrate fluorescent yield and elastic scattering intensities for measurement of the energy dependent variation of these quantities near edge and XRF imaging of the Zn concentration in wax mounted, formalin fixed, breast tumour samples. Results indicate the distribution of Zn at higher resolution than sampling dimensions used in previous studies. Shifts in the position and profile of K-edge absorption and elastic scattering features in aqeuous Zn, Zn doped sol-gel glass and Zn in tissue are shown to reflect changes in the atomic charge state and environment and offer support for the presence of non-nutrient Zn bearing
Kojima, Tomo; Sasaki, Koji
2009-09-20
In the monitor unit verification for high-energy radiation therapy, we evaluated methods of calculation of collimator scatter factors (S(c)) in a linear accelerator equipped with MLC instead of lower collimators. Routinely,S(c) is calculated from rectangular fields shaped by upper and lower jaws in the linear accelerator. However, this calculation method should not be used for the linear accelerator equipped with MLC instead of lower collimators. Consequently, we used a backprojected field at the flattening filter plane projected by calculation point's eye view on each MLC. We then attempted to deviseS(c) by using Clarkson's integration for these backprojected irregular fields. This method makes it possible to calculate collimator scatter factors in error of less than +/-0.3% in all of sixteen measured irregular fields.
Batley, J Richard; Kalmus, George Ernest; Lazzeroni, C; Munday, D J; Slater, M W; Wotton, S A; Arcidiacono, R; Bocquet, G; Cabibbo, Nicola; Ceccucci, A; Cundy, Donald C; Falaleev, V; Fidecaro, Maria; Gatignon, L; Gonidec, A; Kubischta, Werner; Norton, A; Maier, A; Patel, M; Peters, A; Balev, S; Frabetti, P L; Goudzovski, E; Khristov, P Z; Kekelidze, V; Kozhuharov, V; Litov, L; Madigozhin, D T; Marinova, E; Molokanova, N; Polenkevich, I; Potrebenikov, Yu; Stoynev, S; Zinchenko, A; Monnier, E; Swallow, E; Winston, R; Rubin, P; Walker, A; Baldini, W; Cotta-Ramusino, A; Dalpiaz, P; Damiani, C; Fiorini, M; Gianoli, A; Martini, M; Petrucci, F; Savrié, M; Scarpa, M; Wahle, H; Bizzeti, A; Calvetti, M; Celeghini, E; Iacopini, E; Lenti, M; Martelli, F; Ruggiero, G; Veltri, M; Behler, M; Eppard, K; Kleinknecht, K; Marouelli, P; Masetti, L; Moosbrugger, U; Morales-Morales, C; Renk, B; Wache, M; Wanke, R; Winhart, A; Coward, D; Dabrowski, A; Fonseca-Martin, T; Shieh, M; Szleper, M; Velasco, M; Wood, M D; Anzivino, Giuseppina; Cenci, P; Imbergamo, E; Nappi, A; Pepé, M; Petrucci, M C; Piccini, M; Raggi, M; Valdata-Nappi, M; Cerri, C; Collazuol, G; Costantini, F; Di Lella, L; Doble, N; Fantechi, R; Fiorini, L; Giudici, S; Lamanna, G; Mannelli, I; Michetti, A; Pierazzini, G; Sozzi, M; Bloch-Devaux, B; Cheshkov, C; Chèze, J B; De Beer, M; Derré, J; Marel, Gérard; Mazzucato, E; Peyaud, B; Vallage, B; Holder, M; Ziolkowski, M; Bifani, S; Biino, C; Cartiglia, N; Clemencic, M; Goy-Lopez, S; Marchetto, F; Dibon, Heinz; Jeitler, Manfred; Markytan, Manfred; Mikulec, I; Neuhofer, G; Widhalm, L
2008-01-01
We report results from a new measurement of the K_{e4} decay K^{+-} -> \\pi^+ \\pi^- e^{+-} v by the NA48/2 collaboration at the CERN SPS, based on a partial sample of more than 670000 Ke4 decays in both charged modes collected in 2003. The form factors of the hadronic current (F, G, H) and pi pi scattering phase shift delta00-delta11 have been measured using a model-independent method and their variation with the pi pi mass has been investigated. Thanks to a sizeable acceptance at large pi pi mass, a low background and a very good resolution, an improved accuracy (+- 0.006 stat +- 0.002 syst), a factor two better than in the previous measurement, is reached when extracting the pi pi scattering length a00.
Zhang, Zuyin; Song, Guofeng
2017-02-01
Coherent anti-Stokes Raman scattering spectroscopy (CARS) is a well-known detecting tool in biosensing and nonlinear spectroscopy. It can provide a non-invasive alternative without the need for exogenous labels, while the enhancement factor for surface plasmon resonances (SPR) are extensively used to increase the local field close to the oscillators and which can obtain high enhancement. In this work, we investigate the enhancement factor of our structure for surface-enhanced coherent anti-Stokes Raman scattering. The absorption spectrum of the structure has been studied, a wide range of absorption has been realized. The enhancement can be as high as 10{16} over standard CARS. Our design is very useful for improving the enhancement factor of surface-enhanced coherent anti-Stokes Raman scattering. Project supported by the National Key Research Program of China (No. 2011ZX01015-001) and the National Basic Research Program of China (Nos. 2011CBA00608, 2012CB619203, 2015CB351902, 2015CB932402).
Occurrence of normal and anomalous diffusion in polygonal billiard channels.
Sanders, David P; Larralde, Hernán
2006-02-01
From extensive numerical simulations, we find that periodic polygonal billiard channels with angles which are irrational multiples of pi generically exhibit normal diffusion (linear growth of the mean squared displacement) when they have a finite horizon, i.e., when no particle can travel arbitrarily far without colliding. For the infinite horizon case we present numerical tests showing that the mean squared displacement instead grows asymptotically as t ln t. When the unit cell contains accessible parallel scatterers, however, we always find anomalous super-diffusion, i.e., power-law growth with an exponent larger than . This behavior cannot be accounted for quantitatively by a simple continuous-time random walk model. Instead, we argue that anomalous diffusion correlates with the existence of families of propagating periodic orbits. Finally we show that when a configuration with parallel scatterers is approached there is a crossover from normal to anomalous diffusion, with the diffusion coefficient exhibiting a power-law divergence.
Ploquin, N.; Kertzscher, G.; Vandervoort, E.; Cygler, J. E.; Andersen, C. E.; Francescon, P.
2015-01-01
A dosimetry system based on Al2O3:C radioluminescence (RL), and RADPOS, a novel 4D dosimetry system using microMOSFETs, were used to measure total scatter factors, ≤ft({{S}c,p}\\right)\\text{det}{{f\\text{clin}}}, for the CyberKnife robotic radiosugery system. New Monte Carlo calculated correction factors are presented and applied for the RL detector response for the 5, 7.5 and 10 mm collimators in order to correct for the detector geometry and increased photoelectric cross section of Al2O3:C relative to water. For comparison, measurements were also carried out using a micro MOSFET, PTW60012 diode and GAFCHROMIC® film (EBT and EBT2). Uncorrected ≤ft({{S}c,p}\\right)\\text{det}{{f\\text{clin}}}, were obtained by taking the ratio of the detector response for each collimator to that for the 60 mm diameter reference field. Published Monte Carlo calculated correction factors were applied to the RADPOS, microMOSFET and diode detector measurements to yield corrected field factors, Ω {{Q\\text{clin}},{{Q}\\text{msr}}}{{f\\text{clin}},{{f}\\text{msr}}}, following the terminology of a recent formalism introduced for small and composite field relative dosimetry. With corrections, the RL measured Ω {{Q\\text{clin}},{{Q}\\text{msr}}}{{f\\text{clin}},{{f}\\text{msr}}}, were 0.656 ± 0.002, 0.815 ± 0.002 and 0.865 ± 0.003 for the 5, 7.5 and 10 mm collimators, respectively. This was in good agreement with RADPOS corrected field factors of 0.650 ± 0.010, 0.816 ± 0.024 and 0.867 ± 0.010 for the 5, 7.5 and 10 mm collimators, respectively. Both RL and RADPOS total scatter factors agreed within approximately two standard deviations of the GAFCHROMIC film values (average of EBT and EBT2) of 0.640 ± 0.006, 0.806 ± 0.007 and 0.859 ± 0.09. Corrected total scatter factors for all dosimetry systems agreed within one standard deviation for collimator sizes 10-60 mm. Our study suggests that the micro
Ploquin, N; Kertzscher, G; Vandervoort, E; Cygler, J E; Andersen, C E; Francescon, P
2015-01-07
A dosimetry system based on Al2O3:C radioluminescence (RL), and RADPOS, a novel 4D dosimetry system using microMOSFETs, were used to measure total scatter factors, (S(c,p))(f(clin))(det), for the CyberKnife robotic radiosugery system. New Monte Carlo calculated correction factors are presented and applied for the RL detector response for the 5, 7.5 and 10 mm collimators in order to correct for the detector geometry and increased photoelectric cross section of Al2O3:C relative to water. For comparison, measurements were also carried out using a micro MOSFET, PTW60012 diode and GAFCHROMIC(®) film (EBT and EBT2). Uncorrected (S(c,p))(f(clin))(det) were obtained by taking the ratio of the detector response for each collimator to that for the 60 mm diameter reference field. Published Monte Carlo calculated correction factors were applied to the RADPOS, microMOSFET and diode detector measurements to yield corrected field factors, Ω(f(clin),f(msr))(Q(clin),Q(msr)), following the terminology of a recent formalism introduced for small and composite field relative dosimetry. With corrections, the RL measured Ω(f(clin),f(msr))(Q(clin),Q(msr)) were 0.656 ± 0.002, 0.815 ± 0.002 and 0.865 ± 0.003 for the 5, 7.5 and 10 mm collimators, respectively. This was in good agreement with RADPOS corrected field factors of 0.650 ± 0.010, 0.816 ± 0.024 and 0.867 ± 0.010 for the 5, 7.5 and 10 mm collimators, respectively. Both RL and RADPOS total scatter factors agreed within approximately two standard deviations of the GAFCHROMIC film values (average of EBT and EBT2) of 0.640 ± 0.006, 0.806 ± 0.007 and 0.859 ± 0.09. Corrected total scatter factors for all dosimetry systems agreed within one standard deviation for collimator sizes 10-60 mm. Our study suggests that the microMOSFET/RADPOS and optical fibre-coupled RL dosimetry system are well suited for total scatter factor measurements over the entire range of field
The anomalous magnetic moment of the muon
Jegerlehner, Friedrich
2017-01-01
This research monograph covers extensively the theory of the muon anomalous magnetic moment and provides estimates of the theoretical uncertainties. The muon anomalous magnetic moment is one of the most precisely measured quantities in elementary particle physics and provides one of the most stringent tests of relativistic quantum field theory as a fundamental theoretical framework. It allows for an extremely precise check of the standard model of elementary particles and of its limitations. This book reviews the present state of knowledge of the anomalous magnetic moment a=(g-2)/2 of the muon. Recent experiments at the Brookhaven National Laboratory now reach the unbelievable precision of 0.5 parts per million, improving the accuracy of previous g-2 experiments at CERN by a factor of 14. In addition, quantum electrodynamics and electroweak and hadronic effects are reviewed. Since non-perturbative hadronic effects play a key role for the precision test, their evaluation is described in detail. Perspectives fo...
Steurer, W; Apfolter, A; Koch, M; Ernst, W E; Søndergård, E; Manson, J R; Holst, B
2008-04-04
We present helium atom scattering measurements of the boson peak at the surface of vitreous silica between 127.0 and 368.5 K. The most probable energy shows a strong temperature dependence and increases linearly with temperature in the measured range. The observed blueshift of the surface boson peak (shift rate 0.008+/-0.002 meV/K) is a factor of 4 to 10 times stronger than shift rates measured in the bulk by inelastic neutron and Raman scattering. We suggest that the anomalous shift direction of the boson peak to higher energies with increasing temperature has the same origin as the unusual temperature dependence of the bulk modulus of silica glass.
Anomalous diffusion of epicentres
Sotolongo-Costa, Oscar; Posadas, A; Luzon, F
2007-01-01
The classification of earthquakes in main shocks and aftershocks by a method recently proposed by M. Baiesi and M. Paczuski allows to the generation of a complex network composed of clusters that group the most correlated events. The spatial distribution of epicentres inside these structures corresponding to the catalogue of earthquakes in the eastern region of Cuba shows anomalous anti-diffusive behaviour evidencing the attractive nature of the main shock and the possible description in terms of fractional kinetics.
Lapas, Luciano C.; Ferreira, Rogelma M. S.; Oliveira, Fernando A.; Rubí, J. Miguel
2014-01-01
We analyze the temperature relaxation phenomena of systems in contact with a thermal reservoir that undergo a non-Markovian diffusion process. From a generalized Langevin equation, we show that the temperature is governed by a law of cooling of the Newton's law type in which the relaxation time depends on the velocity autocorrelation and is then characterized by the memory function. The analysis of the temperature decay reveals the existence of an anomalous cooling in which the temperature ma...
Energy Technology Data Exchange (ETDEWEB)
Aniol, Konrad; Armstrong, David; Averett, Todd; Benaoum, Hachemi; Bertin, Pierre; Burtin, Etienne; Cahoon, Jason; Cates, Gordon; Chang, C; Chao, Yu-Chiu; Chen, Jian-Ping; Choi, Seonho; Chudakov, Eugene; Craver, Brandon; Cusanno, Francesco; Decowski, Piotr; Deepa, Deepa; Ferdi, Catherine; Feuerbach, Robert; Finn, John; Frullani, Salvatore; Fuoti, Kirsten; Garibaldi, Franco; Gilman, Ronald; Glamazdin, Oleksandr; Gorbenko, V; Grames, Joseph; Hansknecht, John; Higinbotham, Douglas; Holmes, Richard; Holmstrom, Timothy; Humensky, Thomas; Ibrahim, Hassan; Jager, Cornelis De; Jiang, Xiaodong; Kaufman, Lisa; Kelleher, Aidan; Kolarkar, Ameya; Kowalski, Stanley; Kumar, Krishna; Lambert, Daniel; Laviolette, Peter; LeRose, John; Lhuillier, David; Liyanage, Nilanga; Margaziotis, Demetrius; Mazouz, Malek; McCormick, Kathy; Meekins, David; Meziani, Zein-Eddine; Michaels, Robert; Moffit, Bryan; Monaghan, Peter; Camacho, Carlos Munoz; Nanda, Sirish; Nelyubin, Vladimir; Neyret, Damien; Paschke, Kent; Poelker, Benard; Pomatsalyuk, Roman; Qiang, Yi; Reitz, Bodo; Roche, Julie; Saha, Arunava; Singh, Jaideep; Snyder, Ryan; Souder, Paul; Subedi, Ramesh; Suleiman, Riad; Sulkosky, Vincent; Tobias, William; Urciuoli, Guido; Vacheret, Antonin; Voutier, Eric; Wang, Kebin; Wilson, R; Wojtsekhowski, Bogdan; Zheng, Xiaochao
2005-06-01
We have measured the parity-violating electroweak asymmetry in the elastic scattering of polarized electrons from {sup 4}He at an average scattering angle {theta}{sub lab} = 5.7 degrees and a four-momentum transfer Q{sup 2} = 0.091 GeV{sup 2}. From these data, for the first time, the strange electric form factor of the nucleon G{sub E}{sup s} can be isolated. The measured asymmetry of A{sub PV} = 6.72 {+-} 0.84 (stat) {+-} 0.21 (syst) parts per million yields a value of G{sub E}{sup s} = -0.038 {+-} 0.042 (stat) {+-} 0.010 (syst), consistent with zero.
Inelastic x-ray scattering studies on dynamic structure factor of polymeric liquid Se under pressure
Energy Technology Data Exchange (ETDEWEB)
Inui, Masanori; Kajihara, Yukio [Graduate School of Integrated Arts and Sciences, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8521 (Japan); Kimura, Koji; Matsuda, Kazuhiro [Department of Physics, Kyoto University, Sakyoku, Kyoto 606-8502 (Japan); Ohara, Koji; Tsutsui, Satoshi; Ishikawa, Daisuke [Japan Synchrotron Radiation Research Institute/SPring-8, Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan); Baron, Alfred Q. [RIKEN HARIMA BRANCH, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Japan Synchrotron Radiation Research Institute/SPring-8, Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan)
2015-08-17
Inelastic X-ray scattering measurements at 25 MPa using synchrotron radiation were carried out for semiconducting liquid Se at high temperatures up to 1673 K. The excitation energy of the acoustic mode disperses approximately 10-50 % faster than the ultrasonic sound velocity in the observed temperature range while the ultrasonic sound rapidly slows down with increasing temperature. We carried out X-ray scattering measurements and found that the average coordination number at 1673 K is 1.3, indicating that the high temperature liquid consists of short chain molecules. These results suggest that weakening of the interatomic interaction is correlated with breaking of polymeric chain molecules.
Institute of Scientific and Technical Information of China (English)
S. H. Kim
2006-01-01
We calculate the scattering cross section of an electron with respect to the spontaneously produced laser radiation in the first free-electron laser (FEL) with quantum-wiggler electrodynamics (QWD). The cross section is 1016 times the Thomson cross section, confirming the result obtained by a previous analysis of the experimental data. A QWD calculation show that spontaneous emission in an FEL using only an electric wiggler can be very strong while amplification through net stimulated emission is practically negligible.
Anomalous Evidence, Confidence Change, and Theory Change.
Hemmerich, Joshua A; Van Voorhis, Kellie; Wiley, Jennifer
2016-08-01
A novel experimental paradigm that measured theory change and confidence in participants' theories was used in three experiments to test the effects of anomalous evidence. Experiment 1 varied the amount of anomalous evidence to see if "dose size" made incremental changes in confidence toward theory change. Experiment 2 varied whether anomalous evidence was convergent (of multiple types) or replicating (similar finding repeated). Experiment 3 varied whether participants were provided with an alternative theory that explained the anomalous evidence. All experiments showed that participants' confidence changes were commensurate with the amount of anomalous evidence presented, and that larger decreases in confidence predicted theory changes. Convergent evidence and the presentation of an alternative theory led to larger confidence change. Convergent evidence also caused more theory changes. Even when people do not change theories, factors pertinent to the evidence and alternative theories decrease their confidence in their current theory and move them incrementally closer to theory change.
Observation of photonic anomalous Floquet topological insulators
Maczewsky, Lukas J.; Zeuner, Julia M.; Nolte, Stefan; Szameit, Alexander
2017-01-01
Topological insulators are a new class of materials that exhibit robust and scatter-free transport along their edges -- independently of the fine details of the system and of the edge -- due to topological protection. To classify the topological character of two-dimensional systems without additional symmetries, one commonly uses Chern numbers, as their sum computed from all bands below a specific bandgap is equal to the net number of chiral edge modes traversing this gap. However, this is strictly valid only in settings with static Hamiltonians. The Chern numbers do not give a full characterization of the topological properties of periodically driven systems. In our work, we implement a system where chiral edge modes exist although the Chern numbers of all bands are zero. We employ periodically driven photonic waveguide lattices and demonstrate topologically protected scatter-free edge transport in such anomalous Floquet topological insulators.
Directory of Open Access Journals (Sweden)
Andreas van Hameren
2015-09-01
Full Text Available We present first results for the 2→4 single-parton scattering gg→cc¯cc¯ subprocess for the first time fully within the kt-factorization approach. In this calculation we have used the Kimber–Martin–Ryskin unintegrated gluon distribution which effectively includes some class of higher-order gluon emissions, and an off-shell matrix element squared calculated using recently developed techniques. The results are compared with our earlier result obtained within the collinear-factorization approach. Only slightly larger cross sections are obtained than in the case of the collinear approach. Inclusion of transverse momenta of gluons entering the hard process leads to a much stronger azimuthal decorrelation between cc and c¯c¯ than in the collinear-factorization approach. A comparison to predictions of double parton scattering (DPS results and the LHCb data strongly suggests that the assumption of two fully independent DPS (gg→cc¯⊗gg→cc¯ may be too approximate.
Energy Technology Data Exchange (ETDEWEB)
Song, Mi-Young; Yoon, Jung-Sik [Plasma Technology Research Center, National Fusion Research Institute, 814-2 Osikdo-Dong, Gunsan-City, Jeollabuk-Do 573-540 (Korea, Republic of); Jung, Young-Dae, E-mail: ydjung@hanyang.ac.kr [Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, 110 8th Street, Troy, New York 12180-3590 (United States); Department of Applied Physics and Department of Bionanotechnology, Hanyang University, Ansan, Kyunggi-Do 426-791 (Korea, Republic of)
2015-03-15
The electron-neutral collision effects on the Compton scattering process are investigated in warm collisional plasmas. The Compton scattering cross section in warm collisional plasmas is obtained by the Salpeter structure factor with the fluctuation-dissipation theorem and the plasma dielectric function as a function of the electron-neutral collision frequency, Debye length, and wave number. It is shown that the influence of electron-neutral collision strongly suppresses the Compton scattering cross section in warm collisional plasmas. It is also found that the electron-neutral collision effect on the differential Compton scattering cross section is more significant in forward scattering directions. We show that the differential Compton scattering cross section has a maximum at the scattering angle φ=π/2. In addition, we find that the electron-neutral collision effect on the total Compton scattering cross section increases with increasing Debye length and wave number. The variation of the Compton scattering cross section due to the change of collision frequency and plasma parameters is also discussed.
Anomalous Dimensions of Conformal Baryons
DEFF Research Database (Denmark)
Pica, Claudio; Sannino, Francesco
2016-01-01
We determine the anomalous dimensions of baryon operators for the three color theory as function of the number of massless flavours within the conformal window to the maximum known order in perturbation theory. We show that the anomalous dimension of the baryon is controllably small, within...... the $\\delta$-expansion, for a wide range of number of flavours. We also find that this is always smaller than the anomalous dimension of the fermion mass operator. These findings challenge the partial compositeness paradigm....
Beta Function and Anomalous Dimensions
Pica, Claudio
2010-01-01
We demonstrate that it is possible to determine the coefficients of an all-order beta function linear in the anomalous dimensions using as data the two-loop coefficients together with the first one of the anomalous dimensions which are universal. The beta function allows to determine the anomalous dimension of the fermion masses at the infrared fixed point, and the resulting values compare well with the lattice determinations.
Anomalous Dimensions of Conformal Baryons
Pica, Claudio
2016-01-01
We determine the anomalous dimensions of baryon operators for the three color theory as function of the number of massless flavours within the conformal window to the maximum known order in perturbation theory. We show that the anomalous dimension of the baryon is controllably small for a wide range of number of flavours. We also find that this is always smaller than the anomalous dimension of the fermion mass operator. These findings challenge the partial compositeness paradigm.
Anomalous radiative transitions
Ishikawa, Kenzo; Tobita, Yutaka
2014-01-01
Anomalous transitions involving photons derived by many-body interaction of the form, $\\partial_{\\mu} G^{\\mu}$, in the standard model are studied. This does not affect the equation of motion in the bulk, but makes wave functions modified, and causes the unusual transition characterized by the time-independent probability. In the transition probability at a time-interval T expressed generally in the form $P=T \\Gamma_0 +P^{(d)}$, now with $\\Gamma_0=0, P^{(d)} \
Directory of Open Access Journals (Sweden)
V. V. Rozanov
2010-06-01
Full Text Available The Differential Optical Absorption Spectroscopy (DOAS technique is widely used to retrieve amounts of atmospheric species from measurements of the direct solar light transmitted through the Earth's atmosphere as well as of the solar light scattered in the atmosphere or reflected from the Earth's surface. For the transmitted direct solar light the theoretical basis of the DOAS technique represented by the Beer-Lambert law is well studied. In contrast, scarcely investigated is the theoretical basis and validity range of the DOAS method for those cases where the contribution of the multiple scattering processes is not negligible. Our study is intended to fill this gap by means of a theoretical investigation of the applicability of the DOAS technique for the retrieval of amounts of atmospheric species from observations of the scattered solar light with a non-negligible contribution of the multiple scattering.
Starting from the expansion of the intensity logarithm in the functional Taylor series we formulate the general form of the DOAS equation. The thereby introduced variational derivative of the intensity logarithm with respect to the variation of the gaseous absorption coefficient, which is often referred to as the weighting function, is demonstrated to be closely related to the air mass factor. Employing some approximations we show that the general DOAS equation can be rewritten in the form of the weighting function (WFDOAS, the modified (MDOAS, and the standard DOAS equations. For each of these forms a specific equation for the air mass factor follows which, in general, is not suitable for other forms of the DOAS equation. Furthermore, the validity range of the standard DOAS equation is quantitatively investigated using a suggested criterion of a weak absorption.
The results presented in this study are intended to provide a basis for a better understanding of the applicability range of different forms of the DOAS equation as
Fickian dispersion is anomalous
Cushman, John H.; O'Malley, Dan
2015-12-01
The thesis put forward here is that the occurrence of Fickian dispersion in geophysical settings is a rare event and consequently should be labeled as anomalous. What people classically call anomalous is really the norm. In a Lagrangian setting, a process with mean square displacement which is proportional to time is generally labeled as Fickian dispersion. With a number of counter examples we show why this definition is fraught with difficulty. In a related discussion, we show an infinite second moment does not necessarily imply the process is super dispersive. By employing a rigorous mathematical definition of Fickian dispersion we illustrate why it is so hard to find a Fickian process. We go on to employ a number of renormalization group approaches to classify non-Fickian dispersive behavior. Scaling laws for the probability density function for a dispersive process, the distribution for the first passage times, the mean first passage time, and the finite-size Lyapunov exponent are presented for fixed points of both deterministic and stochastic renormalization group operators. The fixed points of the renormalization group operators are p-self-similar processes. A generalized renormalization group operator is introduced whose fixed points form a set of generalized self-similar processes. Power-law clocks are introduced to examine multi-scaling behavior. Several examples of these ideas are presented and discussed.
Kogut, A J
1999-01-01
Improved knowledge of diffuse Galactic emission is important to maximize the scientific return from scheduled CMB anisotropy missions. Cross-correlation of microwave maps with maps of the far-IR dust continuum show a ubiquitous microwave emission component whose spatial distribution is traced by far-IR dust emission. The spectral index of this emission, beta_{radio} = -2.2 (+0.5 -0.7) is suggestive of free-free emission but does not preclude other candidates. Comparison of H-alpha and microwave results show that both data sets have positive correlations with the far-IR dust emission. Microwave data, however, are consistently brighter than can be explained solely from free-free emission traced by H-alpha. This ``anomalous'' microwave emission can be explained as electric dipole radiation from small spinning dust grains. The anomalous component at 53 GHz is 2.5 times as bright as the free-free emission traced by H-alpha, providing an approximate normalization for models with significant spinning dust emission.
Energy Technology Data Exchange (ETDEWEB)
Podgorsak, E.B.; Pla, C.; Evans, M.D.C.; Pla, M.
1985-09-01
Machine outputs, peak scatter factors, and central axis percentage depth dose distributions were measured for various phantom sizes in large radiation fields produced at extended distances by cobalt, 6-MV, and 10-MV photon beams. The results can be applied to practical total body irradiation procedures which usually involve treatment volumes smaller than the actual field sizes in order to provide a uniform total body exposure to radiation. Our study addresses the question of the appropriate phantom dimension to be used in the calibration of photon beams employed in total body irradiations. The measurements show that the machine outputs are only slightly dependent on phantom size; the percentage depth dose distributions, however, are strongly dependent on the phantom size, suggesting that machine data for total body irradiations should be measured in phantoms whose dimensions approximate the patient during the total body irradiation. Peak scatter factors measured in large-field/small-phantom configurations link up well with the published small-field/large-phantom data. The finite patient thickness lowers the dose to points close to the beam exit surface by a few percent, when compared to dose measured at the same depths in infinitely thick phantoms. The surface doses in large radiation fields are essentially independent of phantom cross sections and range from 40% for the 10-MV beam, to 65% for the 6-MV beam and 80% for the cobalt beam.
Aniol, K A; Averett, T; Baylac, M O; Burtin, E; Calarco, J R; Cates, G D; Cavata, C; Chai, Z; Chang, C C; Chen, J P; Chudakov, E A; Cisbani, E; Coman, M; Dale, D; Deur, A; Djawotho, P; Epstein, M B; Escoffier, S; Ewell, L A; Falletto, N; Finn, J M; Fleck, A; Frois, Bernard; Frullani, S; Gao, J; Garibaldi, F; Gasparian, A; Gerstner, G M; Gilman, R; Glamazdin, A V; Gómez, J; Gorbenko, V G; Hansen, O; Hersman, F W; Higinbotham, D W; Holmes, R; Holtrop, M; Humensky, B; Incerti, S; Iodice, M; De Jager, C W; Jardillier, J; Jiang, X; Jones, M K; Jorda, J P; Jutier, C; Kahl, W E; Kelly, J J; Kim, D H; Kim, M J; Kim, M S; Kominis, I; Kooijman, E; Krämer, K; Kumar, K S; Kuss, M W; Le Rose, J J; De Leo, R; Leuschner, M B; Lhuillier, D; Liang, M; Liyanage, N K; Lourie, R W; Madey, R; Malov, S; Margaziotis, D J; Marie, F; Markowitz, P; Martino, J; Mastromarino, P; McCormick, K; McIntyre, J; Meziani, Z E; Michaels, R; Milbrath, B D; Miller, G W; Mitchell, J; Morand, L; Neyret, D; Petratos, G G; Pomatsalyuk, R I; Price, J S; Prout, D L; Pussieux, T; Quéméner, G; Ransome, R D; Relyea, D; Roblin, Y; Roche, J; Rutledge, G A; Rutt, P M; Rvachev, M M; Sabatié, F; Saha, A; Souder, P A; Spradlin, M; Strauch, S; Suleiman, R; Templon, J A; Teresawa, T; Thompson, J; Tieulent, R; Todor, L; Tonguc, B T; Ulmer, P E; Urciuoli, G M; Vlahovic, B; Wijesooriya, K; Wilson, R; Wojtsekhowski, B B; Woo, R; Xu, W; Younus, I; Zhang, C
2001-01-01
We have measured the parity-violating electroweak asymmetry in the elastic scattering of polarized electrons from the proton. The result is A = -14.60 +- 0.94(stat) +- 0.54(syst) ppm at the kinematic point theta_lab = 12.3 degrees and Q^2 = 0.477 (GeV/c)^2. The measurement implies that the value for the strange form factor (G_E^s + 0.392 G_M^s)/(G_M^p/\\mu_p) = 0.091 +- 0.054 +- 0.039, where the first error is experimental and the second arises from the uncertainties in electromagnetic form factors. This measurement is the first fixed-target parity violation experiment that used either a `strained' GaAs photocathode to produce highly polarized electrons or a Compton polarimeter to continuously monitor the electron beam polarization.
Anomalous Dimensions of Conformal Baryons
DEFF Research Database (Denmark)
Pica, Claudio; Sannino, Francesco
2016-01-01
We determine the anomalous dimensions of baryon operators for the three color theory as function of the number of massless flavours within the conformal window to the maximum known order in perturbation theory. We show that the anomalous dimension of the baryon is controllably small, within...
Anomalous Dimensions of Conformal Baryons
DEFF Research Database (Denmark)
Pica, Claudio; Sannino, Francesco
2016-01-01
We determine the anomalous dimensions of baryon operators for the three color theory as function of the number of massless flavours within the conformal window to the maximum known order in perturbation theory. We show that the anomalous dimension of the baryon is controllably small, within the $...
Beta Function and Anomalous Dimensions
DEFF Research Database (Denmark)
Pica, Claudio; Sannino, Francesco
2011-01-01
We demonstrate that it is possible to determine the coefficients of an all-order beta function linear in the anomalous dimensions using as data the two-loop coefficients together with the first one of the anomalous dimensions which are universal. The beta function allows to determine the anomalou...
Fractal model of anomalous diffusion.
Gmachowski, Lech
2015-12-01
An equation of motion is derived from fractal analysis of the Brownian particle trajectory in which the asymptotic fractal dimension of the trajectory has a required value. The formula makes it possible to calculate the time dependence of the mean square displacement for both short and long periods when the molecule diffuses anomalously. The anomalous diffusion which occurs after long periods is characterized by two variables, the transport coefficient and the anomalous diffusion exponent. An explicit formula is derived for the transport coefficient, which is related to the diffusion constant, as dependent on the Brownian step time, and the anomalous diffusion exponent. The model makes it possible to deduce anomalous diffusion properties from experimental data obtained even for short time periods and to estimate the transport coefficient in systems for which the diffusion behavior has been investigated. The results were confirmed for both sub and super-diffusion.
Energy Technology Data Exchange (ETDEWEB)
Ferragut, Erik M.; Laska, Jason A.; Bridges, Robert A.
2016-06-07
A system is described for receiving a stream of events and scoring the events based on anomalousness and maliciousness (or other classification). The system can include a plurality of anomaly detectors that together implement an algorithm to identify low-probability events and detect atypical traffic patterns. The anomaly detector provides for comparability of disparate sources of data (e.g., network flow data and firewall logs.) Additionally, the anomaly detector allows for regulatability, meaning that the algorithm can be user configurable to adjust a number of false alerts. The anomaly detector can be used for a variety of probability density functions, including normal Gaussian distributions, irregular distributions, as well as functions associated with continuous or discrete variables.
Shtukenberg, Alexander; Kahr, Bart
2007-01-01
Optical anomalies in crystals are puzzles that collectively constituted the greatest unsolved problems in crystallography in the 19th Century. The most common anomaly is a discrepancy between a crystal’s symmetry as determined by its shape or by X-ray analysis, and that determined by monitoring the polarization state of traversing light. These discrepancies were perceived as a great impediment to the development of the sciences of crystals on the basis of Curie’s Symmetry Principle, the grand organizing idea in the physical sciences to emerge in the latter half of the 19th Century. Optically Anomalous Crystals begins with an historical introduction covering the contributions of Brewster, Biot, Mallard, Brauns, Tamman, and many other distinguished crystallographers. From this follows a tutorial in crystal optics. Further chapters discuss the two main mechanisms of optical dissymmetry: 1. the piezo-optic effect, and 2. the kinetic ordering of atoms. The text then tackles complex, inhomogeneous crystals, and...
Anomalous Magnetic Excitations of Cooperative Tetrahedral Spin Clusters
DEFF Research Database (Denmark)
Prsa, K.; Rønnow, H.M.; Zaharko, O.;
2009-01-01
An inelastic neutron scattering study of Cu2Te2O5X2 (X=Cl, Br) shows strong dispersive modes with large energy gaps persisting far above T-N, notably in Cu2Te2O5Br2. The anomalous features: a coexisting unusually weak Goldstone-like mode observed in Cu2Te2O5Cl2 and the size of the energy gaps can...
Anomalous pressure dependence of the torsional levels in solid nitromethane
Cavagnat, D.; Magerl, A.; Vettier, C.; Anderson, I. S.; Trevino, S. F.
1985-01-01
Inelastic neutron-scattering measurement of the torsional levels of CH3NO2 and CD3NO2 are presented as functions of pressure and temperature. In contrast to all previously observed pressure dependence of hindered rotors, the ground-state tunnel splitting increases and the energies of the bound torsional levels decrease with pressure. A potential which reproduces these anomalous effects is found and the source of the anomaly explained.
Titantah, J. T.; Lamoen, D.; Schowalter, M.; Rosenauer, A.
2010-02-01
The atomic scattering amplitudes of the various atoms of the systems Ga1-xInxAs, GaAs1-xNx and InAs1-xNx are calculated using the density functional theory (DFT) approach. The scattering amplitudes of N, Ga, As and In in the model systems are compared with the frequently used Doyle and Turner values. Deviation from the latter values is found for small scattering vectors (sMASAs) for small scattering vectors (sMASAs are exploited within zero pressure classical Metropolis Monte Carlo (MC), finite temperature calculations to investigate the effect of quantum well size on the electron {002} structure factor (SF) of Ga1-xInxAs quantum wells.
Anomalous transport in low-dimensional systems with correlated disorder
Energy Technology Data Exchange (ETDEWEB)
Izrailev, F M [Instituto de Fisica, Universidad Autonoma de Puebla, Apartado Postal J-48, Puebla, Pue., 72570 (Mexico); Makarov, N M [Instituto de Ciencias, Universidad Autonoma de Puebla, Priv. 17 Norte No 3417, Col. San Miguel Hueyotlipan, Puebla, Pue., 72050 (Mexico)
2005-12-09
We review recent results on the anomalous transport in one-dimensional and quasi-one-dimensional systems with bulk and surface disorder. Principal attention is paid to the role of long-range correlations in random potentials for the bulk scattering and in corrugated profiles for the surface scattering. It is shown that with the proper type of correlations one can construct such a disorder that results in a selective transport with given properties. Of particular interest is the possibility to arrange windows of a complete transparency (or reflection) with dependence on the wave number of incoming classical waves or electrons.
Directory of Open Access Journals (Sweden)
Nathan D. Israelsen
2015-01-01
Full Text Available Raman spectroscopy has enabled researchers to map the specific chemical makeup of surfaces, solutions, and even cells. However, the inherent insensitivity of the technique makes it difficult to use and statistically complicated. When Raman active molecules are near gold or silver nanoparticles, the Raman intensity is significantly amplified. This phenomenon is referred to as surface-enhanced Raman spectroscopy (SERS. The extent of SERS enhancement is due to a variety of factors such as nanoparticle size, shape, material, and configuration. The choice of Raman reporters and protective coatings will also influence SERS enhancement. This review provides an introduction to how these factors influence signal enhancement and how to optimize them during synthesis of SERS nanoparticles.
Communication: Probing anomalous diffusion in frequency space
Energy Technology Data Exchange (ETDEWEB)
Stachura, Sławomir [Centre de Biophys. Moléculaire, CNRS, Rue Charles Sadron, 45071 Orléans (France); Synchrotron Soleil, L’Orme de Merisiers, 91192 Gif-sur-Yvette (France); Kneller, Gerald R., E-mail: gerald.kneller@cnrs-orleans.fr [Centre de Biophys. Moléculaire, CNRS, Rue Charles Sadron, 45071 Orléans (France); Synchrotron Soleil, L’Orme de Merisiers, 91192 Gif-sur-Yvette (France); Université d’Orléans, Chateau de la Source-Av. du Parc Floral, 45067 Orléans (France)
2015-11-21
Anomalous diffusion processes are usually detected by analyzing the time-dependent mean square displacement of the diffusing particles. The latter evolves asymptotically as W(t) ∼ 2D{sub α}t{sup α}, where D{sub α} is the fractional diffusion constant and 0 < α < 2. In this article we show that both D{sub α} and α can also be extracted from the low-frequency Fourier spectrum of the corresponding velocity autocorrelation function. This offers a simple method for the interpretation of quasielastic neutron scattering spectra from complex (bio)molecular systems, in which subdiffusive transport is frequently encountered. The approach is illustrated and validated by analyzing molecular dynamics simulations of molecular diffusion in a lipid POPC bilayer.
Anomalous anisotropic magnetoresistance effects in graphene
Directory of Open Access Journals (Sweden)
Yiwei Liu
2014-09-01
Full Text Available We investigate the effect of external stimulus (temperature, magnetic field, and gases adsorptions on anisotropic magnetoresistance (AMR in multilayer graphene. The graphene sample shows superlinear magnetoresistance when magnetic field is perpendicular to the plane of graphene. A non-saturated AMR with a value of −33% is found at 10 K under a magnetic field of 7 T. It is surprisingly to observe that a two-fold symmetric AMR at high temperature is changed into a one-fold one at low temperature for a sample with an irregular shape. The anomalous AMR behaviors may be understood by considering the anisotropic scattering of carriers from two asymmetric edges and the boundaries of V+(V- electrodes which serve as active adsorption sites for gas molecules at low temperature. Our results indicate that AMR in graphene can be optimized by tuning the adsorptions, sample shape and electrode distribution in the future application.
Localization correction to the anomalous Hall effect in amorphous CoFeB thin films
Institute of Scientific and Technical Information of China (English)
丁进军; 吴少兵; 杨晓非; 朱涛
2015-01-01
An obvious weak localization correction to anomalous Hall conductance (AHC) in very thin CoFeB film is reported. We find that both the weak localization to AHC and the mechanism of anomalous Hall effect are related to the CoFeB thickness. When the film is thicker than 3 nm, the side jump mechanism dominates and the weak localization to AHC vanishes. For very thin CoFeB films, both the side jump and skew scattering mechanisms contribute to the anomalous Hall effect, and the weak localization correction to AHC is observed.
The Anomalous Magnetic Moment of the Muon
Jegerlehner, Friedrich
2008-01-01
This book reviews the present state of knowledge of the anomalous magnetic moment a=(g-2)/2 of the muon. The muon anomalous magnetic moment amy is one of the most precisely measured quantities in elementary particle physics and provides one of the most stringent tests of relativistic quantum field theory as a fundamental theoretical framework. It allows for an extremely precise check of the standard model of elementary particles and of its limitations. Recent experiments at the Brookhaven National Laboratory now reach the unbelievable precision of 0.5 parts per million, improving the accuracy of previous g-2 experiments at CERN by a factor of 14. A major part of the book is devoted to the theory of the anomalous magnetic moment and to estimates of the theoretical uncertainties. Quantum electrodynamics and electroweak and hadronic effects are reviewed. Since non-perturbative hadronic effects play a key role for the precision test, their evaluation is described in detail. After the overview of theory, the exper...
The anomalous magnetic moment of the muon
Energy Technology Data Exchange (ETDEWEB)
Jegerlehner, F. [Humboldt-Universitaet, Berlin (Germany). Theorie der Elementarteilchen
2008-07-01
The muon anomalous magnetic moment is one of the most precisely measured quantities in elementary particle physics and provides one of the most stringent tests of relativistic quantum field theory as a fundamental theoretical framework. It allows for an extremely precise check of the standard model of elementary particles and of its limitations. This book reviews the present state of knowledge of the anomalous magnetic moment a=(g-2)/2 of the muon. Recent experiments at the Brookhaven National Laboratory now reach the unbelievable precision of 0.5 parts per million, improving the accuracy of previous g-2 experiments at CERN by a factor of 14. A major part of the book is devoted to the theory of the anomalous magnetic moment and to estimates of the theoretical uncertainties. In addition, quantum electrodynamics and electroweak and hadronic effects are reviewed. Since non-perturbative hadronic effects play a key role for the precision test, their evaluation is described in detail. Perspectives for future improvements of the theoretical and experimental precision are considered. This reference text requires some basic knowledge of relativistic quantum field theory and elementary particle theory. (orig.)
Light scattering by a rough surface of human skin. 1. The luminance factor of reflected light
Energy Technology Data Exchange (ETDEWEB)
Barun, V V [Belarusian State University of Informatics and Radioelectronics, Minsk (Belarus); Ivanov, A P [B.I.Stepanov Institute of Physics, National Academy of Sciences of Belarus, Minsk (Belarus)
2013-08-31
Based on the analytical solution of Maxwell's equations, we have studied the angular structure of the luminance factor of light reflected by the rough skin surface with large-scale relief elements, illuminated by a directed radiation beam incident at an arbitrary angle inside or outside the medium. The parameters of the surface inhomogeneities are typical of human skin. The calculated angular dependences are interpreted from the point of view of the angular distribution function of micro areas. The results obtained can be used for solving direct and inverse problems in biomedical optics, in particular for determining the depth of light penetration into a biological tissue, for studying the light action spectra on tissue chromophores under the in vivo conditions, for developing diagnostic methods of structural and biophysical parameters of a medium, and for optimising the mechanisms of interaction of light with biological tissues under their noninvasive irradiation through skin. (biomedical optics)
Light scattering by a rough surface of human skin. 1. The luminance factor of reflected light
Barun, V. V.; Ivanov, A. P.
2013-08-01
Based on the analytical solution of Maxwell's equations, we have studied the angular structure of the luminance factor of light reflected by the rough skin surface with large-scale relief elements, illuminated by a directed radiation beam incident at an arbitrary angle inside or outside the medium. The parameters of the surface inhomogeneities are typical of human skin. The calculated angular dependences are interpreted from the point of view of the angular distribution function of micro areas. The results obtained can be used for solving direct and inverse problems in biomedical optics, in particular for determining the depth of light penetration into a biological tissue, for studying the light action spectra on tissue chromophores under the in vivo conditions, for developing diagnostic methods of structural and biophysical parameters of a medium, and for optimising the mechanisms of interaction of light with biological tissues under their noninvasive irradiation through skin.
Energy Technology Data Exchange (ETDEWEB)
Konrad Aniol; David Armstrong; Todd Averett; Maud Baylac; Etienne Burtin; John Calarco; Gordon Cates; Christian Cavata; Zhengwei Chai; C. Chang; Jian-Ping Chen; Eugene Chudakov; Evaristo Cisbani; Marius Coman; Daniel Dale; Alexandre Deur; Pibero Djawotho; Martin Epstein; Stephanie Escoffier; Lars Ewell; Nicolas Falletto; John Finn; A. Fleck; Bernard Frois; Salvatore Frullani; Juncai Gao; Franco Garibaldi; Ashot Gasparian; G. M. Gerstner; Ronald Gilman; Oleksandr Glamazdin; Javier Gomez; Viktor Gorbenko; Jens-ole Hansen; F. Hersman; Douglas Higinbotham; Richard Holmes; Maurik Holtrop; Thomas Humensky; Sebastien Incerti; Mauro Iodice; Cornelis De Jager; Johann Jardillier; Xiaodong Jiang; Mark Jones; J. Jorda; Christophe Jutier; W. Kahl; James Kelly; Donghee Kim; M. -J. Kim; Minsuk Kim; Ioannis Kominis; Edgar Kooijman; Kevin Kramer; Krishna Kumar; Michael Kuss; John LeRose; Raffaele De Leo; M. Leuschner; David Lhuillier; Meihua Liang; Nilanga Liyanage; R. Lourie; Richard Madey; Sergey Malov; Demetrius Margaziotis; Frederic Marie; Pete Markowitz; Jacques Martino; Peter Mastromarino; Kathy McCormick; Justin McIntyre; Zein-Eddine Meziani; Robert Michaels; Brian Milbrath; Gerald Miller; Joseph Mitchell; Ludyvine Morand; Damien Neyret; Gerassimos Petratos; Roman Pomatsalyuk; John Price; David Prout; Thierry Pussieux; Gilles Quemener; Ronald Ransome; David Relyea; Yves Roblin; Julie Roche; Gary Rutledge; Paul Rutt; Marat Rvachev; Franck Sabatie; Arunava Saha; Paul Souder; Marcus Spradlin; Steffen Strauch; Riad Suleiman; Jeffrey Templon; T. Teresawa; James Thompson; Raphael Tieulent; Luminita Todor; Baris Tonguc; Paul Ulmer; Guido Urciuoli; Branislav Vlahovic; Krishni Wijesooriya; R. Wilson; Bogdan Wojtsekhowski; Rhett Woo; Wang Xu; Imran Younus; C. Zhang
2001-06-01
We have measured the parity-violating electroweak asymmetry in the elastic scattering of polarized electrons from the proton. The result is A = -15.05 +- 0.98(stat) {+-} 0.56(syst) ppm at the kinematic point theta{sub lab} = 12.3 degrees and Q{sup 2} = 0.477 (GeV/c){sup 2}. The measurement implies that the value for the strange form factor (G{sub E}{sup s} + 0.392 G{sub M}{sup s})/(G{sub M}{sup p} {mu}{sub p}) = 0.069 +- 0.056 +- 0.039, where the first error is experimental and the second arises from the uncertainties in electromagnetic form factors. This measurement is the first fixed-target parity violation experiment that used either a ''strained'' GaAs photocathode to produce highly polarized electrons or a Compton polarimeter to continuously monitor the electron beam polarization.
Petrology of Anomalous Eucrites
Mittlefehldt, D. W.; Peng, Z. X.; Ross, D. K.
2015-01-01
Most mafic achondrites can be broadly categorized as being "eucritic", that is, they are composed of a ferroan low-Ca clinopyroxene, high-Ca plagioclase and a silica phase. They are petrologically distinct from angritic basalts, which are composed of high-Ca, Al-Ti-rich clinopyroxene, Carich olivine, nearly pure anorthite and kirschsteinite, or from what might be called brachinitic basalts, which are composed of ferroan orthopyroxene and high-Ca clinopyroxene, intermediate-Ca plagioclase and ferroan olivine. Because of their similar mineralogy and composition, eucrite-like mafic achondrites formed on compositionally similar asteroids under similar conditions of temperature, pressure and oxygen fugacity. Some of them have distinctive isotopic compositions and petrologic characteristics that demonstrate formation on asteroids different from the parent of the HED clan (e.g., Ibitira, Northwest Africa (NWA) 011). Others show smaller oxygen isotopic distinctions but are otherwise petrologically and compositionally indistinguishable from basaltic eucrites (e.g., Pasamonte, Pecora Escarpment (PCA) 91007). The degree of uniformity in delta O-17 of eucrites and diogenites is one piece of evidence considered to favor of a magma-ocean scenario for their petrogenesis. Given that the O isotopic differences separating Pasamonte and PCA 91007 from other eucrites are small, and that there is an absence of other distinguishing characteristics, a legitimate question is: Did the HED parent asteroid fail to homogenize via a magma-ocean stage, thus explaining outliers like Pasamonte? We are initiating a program of study of anomalous eucrite-like achondrites as one part of our effort to seek a resolution of this issue. Here we present preliminary petrologic information on Asuka (A-) 881394, Elephant Moraine (EET) 87520 and EET 87542. We will have studied several more by conference time.
Erokhin, N S; Rycroft, M J; Nunn, D G
1996-01-01
The influence of wave frequency variation on the anomalous cyclotron resonance $\\omega=\\omega_{Be}+kv_{\\|}$ interaction (ACRI) of energetic electrons with a ducted finite amplitude whistler-mode wave propagating through the so-called transient plasma layer (TPL) in the magnetosphere or in the ionosphere is studied both analytically and numerically. The anomalous cyclotron resonance interaction takes place in the case when the whistler-mode wave amplitude $B_{W}$ is consistent with the gradient of magnetic field interacting energetic electrons (synchronous particles) is determined. The efficiencies of both the pitch-angle scattering of resonant electrons and their transverse acceleration are studied and the efficiencies dependence on the magnitude and sign of the wave frequency drift is considered. It has been shown that in the case of ACRI occuring under conditions relevant to VLF-emission in the magnetosphere, the energy and pitch-angle changes of synchronous electrons may be enchanced by a factor $10^2 \\div...
Structure determination of thin CoFe films by anomalous x-ray diffraction
Energy Technology Data Exchange (ETDEWEB)
Gloskovskii, Andrei; Stryganyuk, Gregory; Ouardi, Siham [Institut fuer Anorganische und Analytische Chemie, Johannes Gutenberg-Universitaet, 55099 Mainz (Germany); Fecher, Gerhard H.; Felser, Claudia [Institut fuer Anorganische und Analytische Chemie, Johannes Gutenberg-Universitaet, 55099 Mainz (Germany); Max Planck Institute for Chemical Physics of Solids, D-01187 Dresden (Germany); Hamrle, Jaroslav; Pistora, Jaromir [Department of Physics and Nanotechnology Centre, VSB-Technical University of Ostrava, 70833 Ostrava (Czech Republic); Bosu, Subrojati; Saito, Kesami; Sakuraba, Yuya; Takanashi, Koki [Institute for Materials Research (IMR), Tohoku University, Sendai 980-8577 (Japan)
2012-10-01
This work reports on the investigation of structure-property relationships in thin CoFe films grown on MgO. Because of the very similar scattering factors of Fe and Co, it is not possible to distinguish the random A2 (W-type) structure from the ordered B2 (CsCl-type) structure with commonly used x-ray sources. Synchrotron radiation based anomalous x-ray diffraction overcomes this problem. It is shown that as grown thin films and 300 K post annealed films exhibit the A2 structure with a random distribution of Co and Fe. In contrast, films annealed at 400 K adopt the ordered B2 structure.
Ainslie, M.A.; Leighton, T.G.
2011-01-01
Perhaps the most familiar concepts when discussing acoustic scattering by bubbles are the resonance frequency for bubble pulsation, the bubbles' damping, and their scattering and extinction cross-sections, all of which are used routinely in oceanography, sonochemistry, and biomedicine. The apparent
Energy Technology Data Exchange (ETDEWEB)
Dimakis, N; Mion, T [Department of Physics and Geology, University of Texas-Pan American, Edinburg, TX 78539 (United States); Bunker, G, E-mail: dimakis@utpa.ed [Department of Biological Chemical and Physical Sciences, Illinois Institute of Technology, Chicago, IL 60616 (United States)
2009-11-15
We present an accurate and efficient technique for calculating thermal X-ray absorption fine structure (XAFS) Debye-Waller factors (DWFs) applicable to crystalline materials. Using Density Functional Theory on a 3x3x3 supercell pattern of MnO structure, under the nonlocal hybrid B3LYP functional paired with Gaussian local basis sets, we obtain the normal mode eigenfrequencies and eigenvectors; these parameters are in turn used to calculate single and multiple scattering XAFS DWFs. The DWFs obtained via this technique are temperature dependent expressions and can be used to substantially reduce the number of fitting parameters, when experimental spectra are fitted with a hypothetical structure. The size of the supercell size limits the R-space range that these parameters could be used. Therefore corresponding DWFs for paths outside of this range are calculated using the correlated Debye model. Our method is compared with prior cluster calculations and with corresponding values obtained from fitting experimental XAFS spectra on manganosite with simulated spectra.
Kondratyuk, S
2000-01-01
Pion-loop corrections for Compton scattering are calculated in a novel approach based on the use of dispersion relations in a formalism obeying unitarity. The basic framework is presented, including an application to Compton scattering. In the approach the effects of the non-pole contribution arising from pion dressing are expressed in terms of (half-off-shell) form factors and the nucleon self-energy. These quantities are constructed through the application of dispersion integrals to the pole contribution of loop diagrams, the same as those included in the calculation of the amplitudes through a K-matrix formalism. The prescription of minimal substitution is used to restore gauge invariance. The resulting relativistic-covariant model combines constraints from unitarity, causality, and crossing symmetry.
The anomalous magnetic moment of the muon
Hughes, V W; Earle, W; Efstathiadis, E F; Hare, M; Hazen, E S; Krienen, F; Miller, J P; Rind, O; Roberts, B L; Sulak, Lawrence R; Trofimov, A V; Brown, H N; Bunce, G M; Danby, G T; Larsen, R; Lee, Y Y; Meng, W; Mi, J L; Morse, W M; Pai, C; Prigl, R; Sanders, R; Semertzidis, Y K; Tanaka, M; Warburton, D; Orlov, Yu F; Winn, D; Grossmann, A; Jungmann, Klaus; zu Putlitz, Gisbert; Debevec, P T; Deninger, W; Hertzog, D W; Polly, C; Sedykh, S; Urner, D; Haeberlen, U; Cushman, P B; Duong, L; Giron, S; Kindem, J; McNabb, R; Miller, D; Timmermans, C; Zimmerman, D; Druzhinin, V P; Fedotovich, G V; Khazin, B I; Logashenko, I B; Ryskulov, N M; Serednyakov, S I; Shatunov, Yu M; Solodov, E P; Yamamoto, A; Iwasaki, M; Kawamura, M; Deng, H; Dhawan, S K; Farley, Francis J M; Grosse-Perdekamp, M; Hughes, V W; Kawall, D; Redin, S I; Steinmetz, A
1998-01-01
A new experiment is underway at Brookhaven National Laboratory to measure the g-2 value of the muon to a precision of 0.35 ppm, which would improve our present knowledge by a factor of 20. In its initial run the muon anomalous g-value was found to be a/sub mu //sup + /=1165925(15)*10/sup -9/ [13 ppm], in good agreement with the previous CERN measurements and with approximately the same uncertainty. The current scientific motivations for this experiment are discussed, and the experiment is described. (30 refs).
Venus Highland Anomalous Reflectivity
Simpson, Richard A.; Tyler, G. L.; Häusler, B.; Mattei, R.; Patzold, M.
2009-09-01
Maxwell Montes was one of several unusually bright areas identified from early Venus radar backscatter observations. Pioneer Venus' orbiting radar associated low emissivity with the bright areas and established a correlation between reflectivity and altitude. Magellan, using an oblique bistatic geometry, showed that the bright surface dielectric constant was not only large but also imaginary -- i.e., the material was conducting, at least near Cleopatra Patera (Pettengill et al., Science, 272, 1996). Venus Express (VEX) repeated Magellan's bistatic observations over Maxwell, using the more conventional circular polarization carried by most spacecraft. Although VEX signal-to-noise ratio was lower than Magellan's, echoes were sufficiently strong to verify the Magellan conclusions near Cleopatra (see J. Geophys. Res., 114, E00B41, doi:10.1029/2008JE003156). Only about 40% of the surface at Cleopatra scatters specularly, opening the Fresnel (specular) interpretation model to question. Elsewhere in Maxwell, the specular percentage may be even lower. Nonetheless, the echo polarization is reversed throughout Maxwell, a result that is consistent with large dielectric constants and difficult to explain without resorting qualitatively (if not quantitatively) to specular models. VEX was scheduled to explore other high altitude regions when its S-Band (13-cm wavelength) radio system failed in late 2006, so further probing of high altitude targets awaits arrival of a new spacecraft.
Anomalous Dimensions of Heavy Operators from Magnon Energies
Koch, Robert de Mello; Mathwin, Christopher
2015-01-01
We study spin chains with boundaries that are dual to open strings suspended between systems of giant gravitons and dual giant gravitons. The anomalous dimensions computed in the gauge theory are in complete quantitative agreement with energies computed in the dual string theory. The comparison makes use of a description in terms of magnons, generalizing results for a single maximal giant graviton. The symmetries of the problem determine the structure of the magnon boundary reflection/scattering matrix up to a phase. We compute a reflection/scattering matrix element at weak coupling and verify that it is consistent with the answer determined by symmetry. We find the reflection/scattering matrix does not satisfy the boundary Yang-Baxter equation so that the boundary condition on the open spin chain spoils integrability. We also explain the interpretation of the double coset ansatz in the magnon language.
Directory of Open Access Journals (Sweden)
Steven Weigand
2016-03-01
Full Text Available Here we describe the treatment of the small-angle X-ray Scattering (SAXS data used during SpeG quaternary structure study as part of the research article “Substrate induced allosteric change in the quaternary structure of the spermidine N-acetyltransferase SpeG” published in Journal of Molecular Biology [1]. These data were collected on two separate area detectors as separate dilution series of the SpeG and the SpeG with spermine samples along with data from their companion buffers. The data were radially integrated, corrected for incident beam variation, and scaled to absolute units. After subtraction of volume-fraction scaled buffer scattering and division by the SpeG concentration, multiple scattering curves free of an inter-molecular structure factor were derived from the dilution series. Rather than extrapolating to infinite dilution, the structure factor contribution was estimated by fitting to the full set of data provided by dividing the scattering curves of a dilution series by the curve from the most dilute sample in that series.
Anomalous magnetic moment of anyons
Gat, G; Gat, Gil; Ray, Rashmi
1994-01-01
The anomalous magnetic moment of anyons is calculated to leading order in a 1/N expansion. It is shown that the gyromagnetic ratio g remains 2 to the leading order in 1/N. This result strongly supports that obtained in \\cite{poly}, namely that g=2 is in fact exact.
Guo, Han; Liu, Yang; Hu, Jun; Michielssen, Eric
2017-09-01
A butterfly-based direct combined-field integral equation (CFIE) solver for analyzing scattering from electrically large, perfect electrically conducting objects is presented. The proposed solver leverages the butterfly scheme to compress blocks of the hierarchical LU-factorized discretized CFIE operator and uses randomized butterfly reconstruction schemes to expedite the factorization. The memory requirements and computational cost of the direct butterfly-CFIE solver scale as $O(N\\mathrm{log}^2N)$ and $O(N^{1.5}\\mathrm{log}N)$, respectively. These scaling estimates permit significant memory and CPU savings when compared to those realized by low-rank (LR) decomposition-based solvers. The efficacy and accuracy of the proposed solver are demonstrated through its application to the analysis of scattering from canonical and realistic objects involving up to 14 million unknowns.
Anomalous Hall effect in Fe/Au multilayers
Zhang, Q.
2016-07-22
To understand the interfacial scattering effect on the anomalous Hall effect (AHE), we prepared multilayers of (Fe(36/n)nm/Au(12/n)nm)n using an e-beam evaporator. This structure design allowed us to investigate the effect of interfacial scattering on the AHE, while keeping the samples\\' thickness and composition unchanged. We measured the (magneto)transport properties of the samples in a wide temperature range (10–310 K) with magnetic fields up to 50 kOe. We found that the scaling between the anomalous Hall resistivity (ρAHE) and longitudinal resistivity (ρxx) can be roughly described by ρAHE∼ργxx with γ=2.65±0.10 and 1.90 ± 0.04 for samples from n=1 to n=4 and samples from n=4 to n=12, respectively. Our quantitative analysis results showed that the interfacial scattering suppresses the contribution of the intrinsic mechanism and gives rise to a side-jump contribution.
Anomalous dimensions of higher spin currents in large N CFTs
Hikida, Yasuaki
2016-01-01
We examine anomalous dimensions of higher spin currents in the critical O(N) scalar model and the Gross-Neveu model in arbitrary d dimensions. These two models are proposed to be dual to the type A and type B Vasiliev theories, respectively. We reproduce the known results on the anomalous dimensions to the leading order in 1/N by using conformal perturbation theory. This work can be regarded as an extension of previous work on the critical O(N) scalars in 3 dimensions, where it was shown that the bulk computation for the masses of higher spin fields on AdS_4 can be mapped to the boundary one in conformal perturbation theory. The anomalous dimensions of the both theories agree with each other up to an overall factor depending only on d, and the coincidence is explained for d=3 by making use of N=2 supersymmetry.
Indetermination of particle sizing by laser diffraction in the anomalous size ranges
Pan, Linchao; Ge, Baozhen; Zhang, Fugen
2017-09-01
The laser diffraction method is widely used to measure particle size distributions. It is generally accepted that the scattering angle becomes smaller and the angles to the location of the main peak of scattered energy distributions in laser diffraction instruments shift to smaller values with increasing particle size. This specific principle forms the foundation of the laser diffraction method. However, this principle is not entirely correct for non-absorbing particles in certain size ranges and these particle size ranges are called anomalous size ranges. Here, we derive the analytical formulae for the bounds of the anomalous size ranges and discuss the influence of the width of the size segments on the signature of the Mie scattering kernel. This anomalous signature of the Mie scattering kernel will result in an indetermination of the particle size distribution when measured by laser diffraction instruments in the anomalous size ranges. By using the singular-value decomposition method we interpret the mechanism of occurrence of this indetermination in detail and then validate its existence by using inversion simulations.
Titantah, J. T.; Lamoen, D.; Schowalter, M.; Rosenauer, A.
2009-04-01
The modified atomic scattering amplitudes (MASAs) of mixed Ga1-xInxAs, GaAs1-xNx, and InAs1-xNx are calculated using the density functional theory approach and the results are compared with those of the binary counterparts. The MASAs of N, Ga, As, and In for various scattering vectors in various chemical environments and in the zinc-blende structure are compared with the frequently used Doyle and Turner values. Deviation from the Doyle and Turner results is found for small scattering vectors (s MASAs are found to be sensitive to the orientation of the scattering vector and on the chemical environment. The chemical environment sensitive MASAs are used within zero pressure classical Metropolis Monte Carlo, finite temperature calculations to investigate the effect of well size on the electron 002 and 220 structure factors (SFs). The implications of the use of the 002 (200) spot for the quantification of nanostructured Ga1-xInxAs systems are examined while the 220 SF across the well is evaluated and is found to be very sensitive to the in-plane static displacements.
First Numerical Simulations of Anomalous Hydrodynamics
Hongo, Masaru; Hirano, Tetsufumi
2013-01-01
Anomalous hydrodynamics is a low-energy effective theory that captures effects of quantum anomalies. We develop a numerical code of anomalous hydrodynamics and apply it to dynamics of heavy-ion collisions, where anomalous transports are expected to occur. This is the first attempt to perform fully non-linear numerical simulations of anomalous hydrodynamics. We discuss implications of the simulations for possible experimental observations of anomalous transport effects. From analyses of the charge-dependent elliptic flow parameters ($v_2^\\pm$) as a function of the net charge asymmetry $A_\\pm$, we quantitatively verify that the linear dependence of $\\Delta v_2 \\equiv v_2^- - v_2^+$ on the net charge asymmetry $A_\\pm$ cannot be regarded as a sensitive signal of anomalous transports, contrary to previous studies. We, however, find that the intercept $\\Delta v_2(A_\\pm=0)$ is sensitive to anomalous transport effects.
Origin of anomalous anharmonic lattice dynamics of lead telluride
Shiga, Takuma; Hori, Takuma; Delaire, Olivier; Shiomi, Junichiro
2015-01-01
The origin of the anomalous anharmonic lattice dynamics of lead telluride is investigated using molecular dynamics simulations with interatomic force constants (IFCs) up to quartic terms obtained from first principles. The calculations reproduce the peak asymmetry of the radial distribution functions and the double peaks of transverse optical phonon previously observed with neutron diffraction and scattering experiments. They are identified to be due to the extremely large nearest-neighbor cubic IFCs in the [100] direction. The outstanding strength of the nearest-neighbor cubic IFCs relative to the longer-range ones explains the reason why the distortion in the radial distribution function is local.
Limits on anomalous WWγ and WWZ couplings
Abbott, B.; Abolins, M.; Acharya, B. S.; Adam, I.; Adams, D. L.; Adams, M.; Ahn, S.; Aihara, H.; Alves, G. A.; Amos, N.; Anderson, E. W.; Astur, R.; Baarmand, M. M.; Babukhadia, L.; Baden, A.; Balamurali, V.; Balderston, J.; Baldin, B.; Banerjee, S.; Bantly, J.; Barberis, E.; Bartlett, J. F.; Belyaev, A.; Beri, S. B.; Bertram, I.; Bezzubov, V. A.; Bhat, P. C.; Bhatnagar, V.; Bhattacharjee, M.; Biswas, N.; Blazey, G.; Blessing, S.; Bloom, P.; Boehnlein, A.; Bojko, N. I.; Borcherding, F.; Boswell, C.; Brandt, A.; Brock, R.; Bross, A.; Buchholz, D.; Burtovoi, V. S.; Butler, J. M.; Carvalho, W.; Casey, D.; Casilum, Z.; Castilla-Valdez, H.; Chakraborty, D.; Chang, S.-M.; Chekulaev, S. V.; Chen, L.-P.; Chen, W.; Choi, S.; Chopra, S.; Choudhary, B. C.; Christenson, J. H.; Chung, M.; Claes, D.; Clark, A. R.; Cobau, W. G.; Cochran, J.; Coney, L.; Cooper, W. E.; Cretsinger, C.; Cullen-Vidal, D.; Cummings, M. A.; Cutts, D.; Dahl, O. I.; Davis, K.; de, K.; del Signore, K.; Demarteau, M.; Denisov, D.; Denisov, S. P.; Diehl, H. T.; Diesburg, M.; di Loreto, G.; Draper, P.; Ducros, Y.; Dudko, L. V.; Dugad, S. R.; Edmunds, D.; Ellison, J.; Elvira, V. D.; Engelmann, R.; Eno, S.; Eppley, G.; Ermolov, P.; Eroshin, O. V.; Evdokimov, V. N.; Fahland, T.; Fatyga, M. K.; Feher, S.; Fein, D.; Ferbel, T.; Finocchiaro, G.; Fisk, H. E.; Fisyak, Y.; Flattum, E.; Forden, G. E.; Fortner, M.; Frame, K. C.; Fuess, S.; Gallas, E.; Galyaev, A. N.; Gartung, P.; Gavrilov, V.; Geld, T. L.; Genik, R. J.; Genser, K.; Gerber, C. E.; Gershtein, Y.; Gibbard, B.; Glenn, S.; Gobbi, B.; Goldschmidt, A.; Gómez, B.; Gómez, G.; Goncharov, P. I.; González Solís, J. L.; Gordon, H.; Goss, L. T.; Gounder, K.; Goussiou, A.; Graf, N.; Grannis, P. D.; Green, D. R.; Greenlee, H.; Grinstein, S.; Grudberg, P.; Grünendahl, S.; Guglielmo, G.; Guida, J. A.; Guida, J. M.; Gupta, A.; Gurzhiev, S. N.; Gutierrez, G.; Gutierrez, P.; Hadley, N. J.; Haggerty, H.; Hagopian, S.; Hagopian, V.; Hahn, K. S.; Hall, R. E.; Hanlet, P.; Hansen, S.; Hauptman, J. M.; Hedin, D.; Heinson, A. P.; Heintz, U.; Hernández-Montoya, R.; Heuring, T.; Hirosky, R.; Hobbs, J. D.; Hoeneisen, B.; Hoftun, J. S.; Hsieh, F.; Hu, Ting; Hu, Tong; Huehn, T.; Ito, A. S.; James, E.; Jaques, J.; Jerger, S. A.; Jesik, R.; Jiang, J. Z.-Y.; Joffe-Minor, T.; Johns, K.; Johnson, M.; Jonckheere, A.; Jones, M.; Jöstlein, H.; Jun, S. Y.; Jung, C. K.; Kahn, S.; Kalbfleisch, G.; Kang, J. S.; Karmanov, D.; Karmgard, D.; Kehoe, R.; Kelly, M. L.; Kim, C. L.; Kim, S. K.; Klima, B.; Klopfenstein, C.; Kohli, J. M.; Koltick, D.; Kostritskiy, A. V.; Kotcher, J.; Kotwal, A. V.; Kourlas, J.; Kozelov, A. V.; Kozlovsky, E. A.; Krane, J.; Krishnaswamy, M. R.; Krzywdzinski, S.; Kuleshov, S.; Kunori, S.; Landry, F.; Landsberg, G.; Lauer, B.; Leflat, A.; Li, H.; Li, J.; Li-Demarteau, Q. Z.; Lima, J. G.; Lincoln, D.; Linn, S. L.; Linnemann, J.; Lipton, R.; Liu, Y. C.; Lobkowicz, F.; Loken, S. C.; Lökös, S.; Lueking, L.; Lyon, A. L.; Maciel, A. K.; Madaras, R. J.; Madden, R.; Magaña-Mendoza, L.; Manankov, V.; Mani, S.; Mao, H. S.; Markeloff, R.; Marshall, T.; Martin, M. I.; Mauritz, K. M.; May, B.; Mayorov, A. A.; McCarthy, R.; McDonald, J.; McKibben, T.; McKinley, J.; McMahon, T.; Melanson, H. L.; Merkin, M.; Merritt, K. W.; Miettinen, H.; Mincer, A.; Mishra, C. S.; Mokhov, N.; Mondal, N. K.; Montgomery, H. E.; Mooney, P.; da Motta, H.; Murphy, C.; Nang, F.; Narain, M.; Narasimham, V. S.; Narayanan, A.; Neal, H. A.; Negret, J. P.; Nemethy, P.; Norman, D.; Oesch, L.; Oguri, V.; Oliveira, E.; Oltman, E.; Oshima, N.; Owen, D.; Padley, P.; Para, A.; Park, Y. M.; Partridge, R.; Parua, N.; Paterno, M.; Pawlik, B.; Perkins, J.; Peters, M.; Piegaia, R.; Piekarz, H.; Pischalnikov, Y.; Pope, B. G.; Prosper, H. B.; Protopopescu, S.; Qian, J.; Quintas, P. Z.; Raja, R.; Rajagopalan, S.; Ramirez, O.; Rasmussen, L.; Reucroft, S.; Rijssenbeek, M.; Rockwell, T.; Roco, M.; Rubinov, P.; Ruchti, R.; Rutherfoord, J.; Sánchez-Hernández, A.; Santoro, A.; Sawyer, L.; Schamberger, R. D.; Schellman, H.; Sculli, J.; Shabalina, E.; Shaffer, C.; Shankar, H. C.; Shivpuri, R. K.; Shupe, M.; Singh, H.; Singh, J. B.; Sirotenko, V.; Smart, W.; Smith, E.; Smith, R. P.; Snihur, R.; Snow, G. R.; Snow, J.; Snyder, S.; Solomon, J.; Sosebee, M.; Sotnikova, N.; Souza, M.; Spadafora, A. L.; Steinbrück, G.; Stephens, R. W.; Stevenson, M. L.; Stewart, D.; Stichelbaut, F.; Stoker, D.; Stolin, V.; Stoyanova, D. A.; Strauss, M.; Streets, K.; Strovink, M.; Sznajder, A.; Tamburello, P.; Tarazi, J.; Tartaglia, M.; Thomas, T. L.; Thompson, J.; Trippe, T. G.; Tuts, P. M.; Varelas, N.; Varnes, E. W.; Vititoe, D.; Volkov, A. A.; Vorobiev, A. P.; Wahl, H. D.; Wang, G.; Warchol, J.; Watts, G.; Wayne, M.; Weerts, H.; White, A.; White, J. T.; Wightman, J. A.; Willis, S.; Wimpenny, S. J.; Wirjawan, J. V.; Womersley, J.; Won, E.; Wood, D. R.; Xu, H.; Yamada, R.; Yamin, P.; Yang, J.; Yasuda, T.; Yepes, P.; Yoshikawa, C.; Youssef, S.; Yu, J.; Yu, Y.; Zhou, Z.; Zhu, Z. H.; Zieminska, D.; Zieminski, A.; Zverev, E. G.; Zylberstejn, A.
1998-08-01
Limits on the anomalous WWγ and WWZ couplings are presented from a simultaneous fit to the data samples of three gauge boson pair final states in pp¯ collisions at s=1.8 TeV: Wγ production with the W boson decaying to eν or μν, W boson pair production with both of the W bosons decaying to eν or μν, and WW or WZ production with one W boson decaying to eν and the other W boson or the Z boson decaying to two jets. Assuming identical WWγ and WWZ couplings, 95% C.L. limits on the anomalous couplings of -0.30<Δκ<0.43 (λ=0) and -0.20<λ<0.20 (Δκ=0) are obtained using a form factor scale Λ=2.0 TeV. Limits found under other assumptions on the relationship between the WWγ and WWZ couplings are also presented.
Anomalous Thermalization in Ergodic Systems
Luitz, David J.; Bar Lev, Yevgeny
2016-10-01
It is commonly believed that quantum isolated systems satisfying the eigenstate thermalization hypothesis (ETH) are diffusive. We show that this assumption is too restrictive since there are systems that are asymptotically in a thermal state yet exhibit anomalous, subdiffusive thermalization. We show that such systems satisfy a modified version of the ETH ansatz and derive a general connection between the scaling of the variance of the off-diagonal matrix elements of local operators, written in the eigenbasis of the Hamiltonian, and the dynamical exponent. We find that for subdiffusively thermalizing systems the variance scales more slowly with system size than expected for diffusive systems. We corroborate our findings by numerically studying the distribution of the coefficients of the eigenfunctions and the off-diagonal matrix elements of local operators of the random field Heisenberg chain, which has anomalous transport in its thermal phase. Surprisingly, this system also has non-Gaussian distributions of the eigenfunctions, thus, directly violating Berry's conjecture.
Faraday anomalous dispersion optical tuners
Wanninger, P.; Valdez, E. C.; Shay, T. M.
1992-01-01
Common methods for frequency stabilizing diode lasers systems employ gratings, etalons, optical electric double feedback, atomic resonance, and a Faraday cell with low magnetic field. Our method, the Faraday Anomalous Dispersion Optical Transmitter (FADOT) laser locking, is much simpler than other schemes. The FADOT uses commercial laser diodes with no antireflection coatings, an atomic Faraday cell with a single polarizer, and an output coupler to form a compound cavity. This method is vibration insensitive, thermal expansion effects are minimal, and the system has a frequency pull in range of 443.2 GHz (9A). Our technique is based on the Faraday anomalous dispersion optical filter. This method has potential applications in optical communication, remote sensing, and pumping laser excited optical filters. We present the first theoretical model for the FADOT and compare the calculations to our experimental results.
Faraday anomalous dispersion optical filters
Shay, T. M.; Yin, B.; Alvarez, L. S.
1993-01-01
The effect of Faraday anomalous dispersion optical filters on infrared and blue transitions of some alkali atoms is calculated. A composite system is designed to further increase the background noise rejection. The measured results of the solar background rejection and image quality through the filter are presented. The results show that the filter may provide high transmission and high background noise rejection with excellent image quality.
Energy Technology Data Exchange (ETDEWEB)
Kostorz, G. [Eidgenoessische Technische Hochschule, Angewandte Physik, Zurich (Switzerland)
1996-12-31
While Bragg scattering is characteristic for the average structure of crystals, static local deviations from the average lattice lead to diffuse elastic scattering around and between Bragg peaks. This scattering thus contains information on the occupation of lattice sites by different atomic species and on static local displacements, even in a macroscopically homogeneous crystalline sample. The various diffuse scattering effects, including those around the incident beam (small-angle scattering), are introduced and illustrated by typical results obtained for some Ni alloys. (author) 7 figs., 41 refs.
Kato, Hideki; Minami, Kazuyuki; Asada, Yasuki; Suzuki, Shoichi
2016-05-01
To obtain patient entrance surface dose in X-ray photography, a calculation method based on measured exposure or air kerma radiated from X-ray tube is generally used. Two factors are necessary for this calculation: (1) exposure/air kerma to absorb dose conversion factor and (2) back-scatter factor (BSF) based on X-ray quality and on field size. These BSFs are commonly obtained by interpolation from existent data which were given for a water phantom whose entrance surface is flat. Since patient's surface in X-ray photograph is not flat, some error may occur when existent BSF is used in this calculation. In this article, BSF for water phantom with cylindrical surface and elliptic cylinder surface were calculated by means of the Monte Carlo simulation. And these BSFs were compared with BSF for flat surface phantom. As a result (1) radius of curvature of cylindrical phantom or horizontal axis of elliptic cylinder phantom is smaller, (2) half value layer of X-ray is larger, (3) field size is larger, difference of these BSF with that for flat surface phantom tends to be larger. Maximum difference by calculation condition assumed in this article was more than 10%. The cause of this difference is because scattering volume in irradiated body of cylindrical or elliptic cylinder phantom is smaller than flat surface phantom. To obtain patient entrance surface dose more precisely, it is necessary to use BSF respectively calculated for phantom resembling patient's body such as cylindrical or elliptic cylinder phantom by means of the Monte Carlo simulation.
Ashokkumar, Sigamani; Nambi Raj, N Arunai; Sinha, Sujit Nath; Yadav, Girigesh; Thiyagarajan, Rajesh; Raman, Kothanda; Mishra, Manindra Bhushan
2014-07-01
To measure and compare the head scatter factor for flattened (FB) and unflattened (FFF) of 6MV and 10MV photon beam using indigenously designed mini phantom. A columnar mini phantom was designed as recommended by AAPM Task Group 74 with low and high atomic number materials at 10 cm (mini phantom) and at approximately twice the depth of maximum dose water equivalent thickness (brass build-up cap). Scatter in the accelerator (Sc) values of 6MV-FFF photon beams are lesser than that of the 6MV-FB photon beams (0.66-2.8%; Clinac iX, 2300CD) and (0.47-1.74%; True beam) for field sizes ranging from 10 × 10 cm(2) to 40 × 40 cm(2). Sc values of 10MV-FFF photon beams are lesser (0.61-2.19%; True beam) than that of the 10MV-FB photons beams for field sizes ranging from 10 × 10 cm(2) to 40 × 40 cm(2). The SSD had no influence on head scatter for both flattened and unflattened beams and irrespective of head design of the different linear accelerators. The presence of field shaping device influences the Sc values. The collimator exchange effect reveals that the opening of the upper jaw increases Sc irrespective of FB or FFF photon beams and different linear accelerators, and it is less significant in FFF beams. Sc values of 6MV-FB square field were in good agreement with that of AAPM, TG-74 published data for Varian (Clinac iX, 2300CD) accelerator. Our results confirm that the removal of flattening filter decreases in the head scatter factor compared to flattened beam. This could reduce the out-of-field dose in advanced treatment delivery techniques.
Lin, Jian; Liu, Jiaming; Zhang, Hao; Li, Wenxiu; Zhao, Lu; Jin, Junjie; Huang, Anping; Zhang, Xiaofu; Xiao, Zhisong
2016-12-01
Rigorous expressions of resonant frequency shift (RFS) in anomalous dispersion enhanced resonant optical gyroscopes (ADEROGs) are deduced without making approximation, which provides a precise theoretical guidance to achieve ultra-sensitive ADEROGs. A refractive index related modification factor is introduced when considering special theory of relativity (STR). We demonstrate that the RFS will not be ”infinitely large” by using critical anomalous dispersion (CAD) and negative modification does not exist, which make the mechanism of anomalous dispersion enhancement clear and coherent. Although step change of RFS will happen when the anomalous dispersion condition varies, the amplification of RFS is limited by attainable variation of refractive index in practice. Moreover, it is shown that the properties of anomalous dispersion will influence not only the amplification of RFS, but also the detection range of ADEROGs.
Surface enhanced Raman scattering
Furtak, Thomas
1982-01-01
In the course of the development of surface science, advances have been identified with the introduction of new diagnostic probes for analytical characterization of the adsorbates and microscopic structure of surfaces and interfaces. Among the most recently de veloped techniques, and one around which a storm of controversy has developed, is what has now been earmarked as surface enhanced Raman scattering (SERS). Within this phenomenon, molecules adsorbed onto metal surfaces under certain conditions exhibit an anomalously large interaction cross section for the Raman effect. This makes it possible to observe the detailed vibrational signature of the adsorbate in the ambient phase with an energy resolution much higher than that which is presently available in electron energy loss spectroscopy and when the surface is in contact with a much larger amount of material than that which can be tolerated in infrared absorption experiments. The ability to perform vibrational spectroscopy under these conditions would l...
Anomalous polarization conversion in arrays of ultrathin ferromagnetic nanowires
Stashkevich, Andrey A.; Roussigné, Yves; Poddubny, Alexander N.; Chérif, S.-M.; Zheng, Y.; Vidal, Franck; Yagupov, Ilya V.; Slobozhanyuk, Alexei P.; Belov, Pavel A.; Kivshar, Yuri S.
2015-12-01
We study the optical properties of arrays of ultrathin cobalt nanowires by means of the Brillouin scattering of light on magnons. We employ the Stokes/anti-Stokes scattering asymmetry to probe the circular polarization of a local electric field induced inside nanowires by linearly polarized light waves. We observe the anomalous polarization conversion of the opposite sign than that in a bulk medium or thick nanowires with a great enhancement of the degree of circular polarization attributed to the unconventional refraction in a nanowire medium. A rigorous simulation of the electric field polarization as a function of the wire diameter and spacing reveals the reversed polarization for a thin sparse wire array, in full quantitative agreement with experimental results.
Viscoelastic hydrodynamic interactions and anomalous CM diffusion in polymer melts
Meyer, Hendrik
We have recently discovered that anomalous center-of-mass (CM) diffusion occurring on intermediate time scales in polymer melts can be explained by the interplay of viscoelastic and hydrodynamic interactions (VHI). The theory has been solved for unentangled melts in 3D and 2D and excellent agreement between theory and simulation is found, also for alkanes with a force field optimized from neutron scattering. The physical mechanism considers that hydrodynamic interactions are not screened: they are time dependent because of increasing viscosity before the terminal relaxation time. The VHI are generally active in melts of any topology. They are most important at early times well before the terminal relaxation time and thus affect the nanosecond time range typically observable in dynamic neutron scattering experiments. We illustrate the effects with recent molecular dynamics simulations of linear, ring and star polymers. Work performed with A.N. Semenov and J. Farago.
Influence of disorder on anomalous Hall effect for Heusler compounds
Vilanova Vidal, E.; Schneider, H.; Jakob, G.
2011-05-01
The anomalous Hall effect (AHE) is a long known but still not fully understood transport effect. Most theory papers focus on the influence of one particular contribution to the AHE. Actual measured experimental data, however, often are not in accord with idealized assumptions. In this work we discuss the data analysis for materials with low residual resistivity ratios. As prototypical materials we study half metallic Heusler compounds. Here the influence of defects and disorder is apparent in a material with a complex topology of the Fermi surface. Using films of different degree of disorder, we show how different scattering mechanisms can be separated. For Co2FeSi0.6Al0.4 and Co2FeGa0.5Ge0.5 the AHE induced by B2-type disorder and temperature-dependent scattering is positive, while DO3-type disorder and possible intrinsic contributions possess a negative sign.
Energy Technology Data Exchange (ETDEWEB)
Kelleher, Aidan [College of William and Mary, Williamsburg, VA (United States)
2010-02-01
Knowledge of the electric and magnetic elastic form factors of the nucleon is essential for an understanding of nucleon structure. Of the form factors, the electric form factor of the neutron has been measured over the smallest range in Q^{2} and with the lowest precision. Jefferson Lab experiment 02-013 used a novel new polarized ^{3} He target to nearly double the range of momentum transfer in which the neutron form factor has been studied and to measure it with much higher precision. Polarized electrons were scattered off this target, and both the scattered electron and neutron were detected. G^{n} _{E} was measured to be 0.0242 ± 0.0020(stat) ± 0.0061(sys) and 0.0247 ± 0.0029(stat) ± 0.0031(sys) at Q^{2} = 1.7 and 2.5 GeV^{2} , respectively.
Energy Technology Data Exchange (ETDEWEB)
Wokoma, S; Yoon, J; Jung, J [East Carolina University, Greenville, NC (United States); Lee, S [Rhode Island Hospital / Warren Alpert Medical, Providence, RI (United States)
2014-06-01
Purpose: To investigate the impact of custom-made build-up caps for a diode detector in robotic radiosurgery radiation fields with variable collimator (IRIS) for collimator scatter factor (Sc) calculation. Methods: An acrylic cap was custom-made to fit our SFD (IBA Dosimetry, Germany) diode detector. The cap has thickness of 5 cm, corresponding to a depth beyond electron contamination. IAEA phase space data was used for beam modeling and DOSRZnrc code was used to model the detector. The detector was positioned at 80 cm source-to-detector distance. Calculations were performed with the SFD, with and without the build-up cap, for clinical IRIS settings ranging from 7.5 to 60 mm. Results: The collimator scatter factors were calculated with and without 5 cm build-up cap. They were agreed within 3% difference except 15 mm cone. The Sc factor for 15 mm cone without buildup was 13.2% lower than that with buildup. Conclusion: Sc data is a critical component in advanced algorithms for treatment planning in order to calculate the dose accurately. After incorporating build-up cap, we discovered differences of up to 13.2 % in Sc factors in the SFD detector, when compared against in-air measurements without build-up caps.
More Modular Invariant Anomalous U(1) Breaking
Gaillard, Mary Katherin; Gaillard, Mary K.; Giedt, Joel
2002-01-01
We consider the case of several scalar fields, charged under a number of U(1) factors, acquiring vacuum expectation values due to an anomalous U(1). We demonstrate how to make redefinitions at the superfield level in order to account for tree-level exchange of vector supermultiplets in the effective supergravity theory of the light fields in the supersymmetric vacuum phase. Our approach builds upon previous results that we obtained in a more elementary case. We find that the modular weights of light fields are typically shifted from their original values, allowing an interpretation in terms of the preservation of modular invariance in the effective theory. We address various subtleties in defining unitary gauge that are associated with the noncanonical Kahler potential of modular invariant supergravity, the vacuum degeneracy, and the role of the dilaton field. We discuss the effective superpotential for the light fields and note how proton decay operators may be obtained when the heavy fields are integrated o...
Local orbitals approach to the anomalous Hall and Nernst effects in itinerant ferromagnets
Directory of Open Access Journals (Sweden)
Středa Pavel
2014-07-01
Full Text Available Linear response of the orbital momentum to the gradient of the chemical potential is used to obtain anomalous Hall conductivity. Transition from the ideal Bloch system for which the conductivity is determined by the Berry phase curvatures to the case of strong disorder for which the conductivity becomes dependent on the relaxation time is analysed. Presented tight-binding model reproduces experimentally observed qualitative features of the anomalous Hall conductivity and the transverse Peltier coefficient in the so called bad-metal and scattering-independent regimes.
Slama, Betty Nicole
The 'phase problem' is central to X-ray crystallography, and multiwavelength anomalous diffraction (MAD) provides an elegant and broadly accessible solution. In the first part, the use of MAD at the xenon L3 edge is explored, as an alternative to the well established selenium K-edge phasing. In the second part, the structure of the bacterial protein Vibrio cholerae LuxQ, part of a two component signaling system involved in quorum sensing, is solved and analyzed. Keywords: anomalous scattering, x-ray diffraction, phasing, protein structure.
Anomalous Transport Foundations and Applications
Klages, Rainer; Sokolov, Igor M
2008-01-01
This multi-author reference work provides a unique introduction to the currently emerging, highly interdisciplinary field of those transport processes that cannot be described by using standard methods of statistical mechanics. It comprehensively summarizes topics ranging from mathematical foundations of anomalous dynamics to the most recent experiments in this field. In so doing, this monograph extracts and emphasizes common principles and methods from many different disciplines while providing up-to-date coverage of this new field of research, considering such diverse applications as plasma
Energy Technology Data Exchange (ETDEWEB)
Buehring, W.
1983-03-01
Non-relativistic scattering phase shifts, bound state energies, and wave function normalization factors for a screened Coulomb potential of the Hulthen type are presented in the form of relatively simple analytic expressions. These formulae have been obtained by a suitable renormalization procedure applied to the quantities derived from an approximate Schroedinger equation which contains the exact Hulthen potential together with an approximate angular momentum term. When the screening exponent vanishes, our formulae reduce to the exact Coulomb expresions. The interrelation between our formulae and Pratt's analytic perturbation theory for screened Coulomb potentials' is discussed.
DEFF Research Database (Denmark)
Rygaard, K; Nakamura, T; Spang-Thomsen, M
1993-01-01
We examined a panel of 25 small cell lung cancer (SCLC) cell lines and nude mouse xenografts for expression of the proto-oncogenes c-met and c-kit, and for expression of the corresponding ligands, hepatocyte growth factor (HGF) (also known as scatter factor (SF)), and stem cell factor (SCF......), respectively. Expression of mRNA was detected by Northern blotting, and c-met and c-kit protein expression was detected by Western blotting and immunocytochemistry. c-met and c-kit mRNA was expressed in 22 of the examined cell lines or xenografts, and coexpression of the two proto-oncogenes was observed in 20...... tumours. Expression of c-met and c-kit protein paralleled in the mRNA expression. HGF/SF mRNA was expressed in two of the examined tumours, and only one of these also expressed the c-met proto-oncogene. SCF mRNA was expressed in 19 of the examined tumours, and in 18 of these coexpression of c-kit and SCF...
Long-distance singularities in multi-leg scattering amplitudes
Gardi, Einan; Duhr, Claude
2016-01-01
We report on the recent completion of the three-loop calculation of the soft anomalous dimension in massless gauge-theory scattering amplitudes. This brings the state-of-the-art knowledge of long-distance singularities in multi-leg QCD amplitudes with any number of massless particles to three loops. The result displays some novel features: this is the first time non-dipole corrections appear, which directly correlate the colour and kinematic degrees of freedom of four coloured partons. We find that non-dipole corrections appear at three loops also for three coloured partons, but these are independent of the kinematics. The final result is remarkably simple when expressed in terms of single-valued harmonic polylogarithms, and it satisfies several non-trivial constraints. In particular, it is consistent with the high-energy limit behaviour and it satisfies the expected factorization properties in two-particle collinear limits.
Skar-Gislinge, Nicholas; Arleth, Lise
2011-02-28
Nanodiscs™ consist of small phospholipid bilayer discs surrounded and stabilized by amphiphilic protein belts. Nanodiscs and their confinement and stabilization of nanometer sized pieces of phospholipid bilayer are highly interesting from a membrane physics point of view. We demonstrate how the detailed structure of Di-Lauroyl-Phosphatidyl Choline (DLPC) nanodiscs may be determined by simultaneous fitting of a structural model to small-angle scattering data from the nanodiscs as investigated in three different contrast situations, respectively two SANS contrasts and one SAXS contrast. The article gives a detailed account of the underlying structural model for the nanodiscs and describe how additional chemical and biophysical information can be incorporated in the model in terms of molecular constraints. We discuss and quantify the contribution from the different elements of the structural model and provide very strong experimental support for the nanodiscs as having an elliptical cross-section and with poly-histidine tags protruding out from the rim of the protein belt. The analysis also provides unprecedented information about the structural conformation of the phospholipids when these are localized in the nanodiscs. The model paves the first part of the way in order to reach our long term goal of using the nanodiscs as a platform for small-angle scattering based structural investigations of membrane proteins in solution.
DEFF Research Database (Denmark)
Mosbæk, Charlotte Rode; Nolan, David; Persson, Egon
2010-01-01
Blood coagulation factor VIIa (FVIIa) is used in the treatment of replacement therapy resistant hemophilia patients, and FVIIa is normally activated upon complex formation with tissue factor (TF), potentially in context with structural rearrangements. The solution behavior of uncomplexed FVIIa...
Huang, Baohua; Deng, Shuo; Loo, Ser Yue; Datta, Arpita; Yap, Yan Lin; Yan, Benedict; Ooi, Chia Huey; Dinh, Thuy Duong; Zhuo, Jingli; Tochhawng, Lalchhandami; Gopinadhan, Suma; Jegadeesan, Tamilarasi; Tan, Patrick; Salto-Tellez, Manuel; Yong, Wei Peng; Soong, Richie; Yeoh, Khay Guan; Goh, Yaw Chong; Lobie, Peter E; Yang, Henry; Kumar, Alan Prem; Maciver, Sutherland K; So, Jimmy B Y; Yap, Celestial T
2016-05-01
In gastric cancer (GC), the main subtypes (diffuse and intestinal types) differ in pathological characteristics, with diffuse GC exhibiting early disseminative and invasive behaviour. A distinctive feature of diffuse GC is loss of intercellular adhesion. Although widely attributed to mutations in the CDH1 gene encoding E-cadherin, a significant percentage of diffuse GC do not harbor CDH1 mutations. We found that the expression of the actin-modulating cytoskeletal protein, gelsolin, is significantly higher in diffuse-type compared to intestinal-type GCs, using immunohistochemical and microarray analysis. Furthermore, in GCs with wild-type CDH1, gelsolin expression correlated inversely with CDH1 gene expression. Downregulating gelsolin using siRNA in GC cells enhanced intercellular adhesion and E-cadherin expression, and reduced invasive capacity. Interestingly, hepatocyte growth factor (HGF) induced increased gelsolin expression, and gelsolin was essential for HGF-medicated cell scattering and E-cadherin transcriptional repression through Snail, Twist and Zeb2. The HGF-dependent effect on E-cadherin was found to be mediated by interactions between gelsolin and PI3K-Akt signaling. This study reveals for the first time a function of gelsolin in the HGF/cMet oncogenic pathway, which leads to E-cadherin repression and cell scattering in gastric cancer. Our study highlights gelsolin as an important pro-disseminative factor contributing to the aggressive phenotype of diffuse GC.
Huang, Baohua; Deng, Shuo; Loo, Ser Yue; Datta, Arpita; Yap, Yan Lin; Yan, Benedict; Ooi, Chia Huey; Dinh, Thuy Duong; Zhuo, Jingli; Tochhawng, Lalchhandami; Gopinadhan, Suma; Jegadeesan, Tamilarasi; Tan, Patrick; Salto-Tellez, Manuel; Yong, Wei Peng; Soong, Richie; Yeoh, Khay Guan; Goh, Yaw Chong; Lobie, Peter E.; Yang, Henry; Kumar, Alan Prem; Maciver, Sutherland K.; So, Jimmy B.Y.; Yap, Celestial T.
2016-01-01
In gastric cancer (GC), the main subtypes (diffuse and intestinal types) differ in pathological characteristics, with diffuse GC exhibiting early disseminative and invasive behaviour. A distinctive feature of diffuse GC is loss of intercellular adhesion. Although widely attributed to mutations in the CDH1 gene encoding E-cadherin, a significant percentage of diffuse GC do not harbor CDH1 mutations. We found that the expression of the actin-modulating cytoskeletal protein, gelsolin, is significantly higher in diffuse-type compared to intestinal-type GCs, using immunohistochemical and microarray analysis. Furthermore, in GCs with wild-type CDH1, gelsolin expression correlated inversely with CDH1 gene expression. Downregulating gelsolin using siRNA in GC cells enhanced intercellular adhesion and E-cadherin expression, and reduced invasive capacity. Interestingly, hepatocyte growth factor (HGF) induced increased gelsolin expression, and gelsolin was essential for HGF-medicated cell scattering and E-cadherin transcriptional repression through Snail, Twist and Zeb2. The HGF-dependent effect on E-cadherin was found to be mediated by interactions between gelsolin and PI3K-Akt signaling. This study reveals for the first time a function of gelsolin in the HGF/cMet oncogenic pathway, which leads to E-cadherin repression and cell scattering in gastric cancer. Our study highlights gelsolin as an important pro-disseminative factor contributing to the aggressive phenotype of diffuse GC. PMID:27058427
Anomalous osmosis resulting from preferential absorption
Staverman, A.J.; Kruissink, C.A.; Pals, D.T.F.
1965-01-01
An explanation of the anomalous osmosis described in the preceding paper is given in terms of friction coefficients in the glass membrane. It is shown that anomalous osmosis may be expected when the friction coefficients are constant and positive provided that the membrane absorbs solute strongly an
Anomalous osmosis resulting from preferential absorption
Staverman, A.J.; Kruissink, C.A.; Pals, D.T.F.
1965-01-01
An explanation of the anomalous osmosis described in the preceding paper is given in terms of friction coefficients in the glass membrane. It is shown that anomalous osmosis may be expected when the friction coefficients are constant and positive provided that the membrane absorbs solute strongly an
Seo, Jaetae; Kim, Wanjoong; Jung, Sungsoo
2009-05-01
Surface-enhanced Raman spectroscopy (SERS) of molecules on nanometals has been intensively studied for technical application of bio-chemical sensing. Among physical origins of SERS enhancement, the electromagnetic effect is the most fundamental contribution of SERS enhancement. Relevant REF of C-C stretching mode of Rh6G near 1511 cm-1 was shown two-order enhancement with 5-nm Au colloidal nanoparticles. The REF was greatly enhanced up to ˜six orders with ˜35 nm Au particles, and was enhanced ˜five orders with 40-nm Au nanoparticles. The reduction of REF with smaller sizes is possibly due to the scattering of conduction electrons on particles surfaces; that with larger sizes is probably due to tips or complex structures. This work at Hampton University was supported by the National Science Foundation (HRD-0734635, HRD-0630372, and ESI-0426328/002) and the U.S. Army Research Office (W911NF-07-1-0608).
Li, Liang; Huang, Ting-Zhu; Jing, Yan-Fei; Zhang, Yong
2010-02-01
The incomplete Cholesky (IC) factorization preconditioning technique is applied to the Krylov subspace methods for solving large systems of linear equations resulted from the use of edge-based finite element method (FEM). The construction of the preconditioner is based on the fact that the coefficient matrix is represented in an upper triangular compressed sparse row (CSR) form. An efficient implementation of the IC factorization is described in detail for complex symmetric matrices. With some ordering schemes our IC algorithm can greatly reduce the memory requirement as well as the iteration numbers. Numerical tests on harmonic analysis for plane wave scattering from a metallic plate and a metallic sphere coated by a lossy dielectric layer show the efficiency of this method.
Risk factors for mortality of total anomalous pulmonary venous connection%影响完全性肺静脉异位引流术病死率的危险因素
Institute of Scientific and Technical Information of China (English)
徐红亮; 范顺阳; 王峰峰; 杨玉齐; 范太兵
2013-01-01
Objective To analyze the outcomes of the surgery repair for total anomalous pulmonary venous connection(TAPVC),and to investigate the risk factors which influence the mortality of the operation.Methods Comparative analysis was performed in the children with TAPVC who were treated operatively from Sep.2001 to Sep.2011 in the Third Affiliated Hospital of Zhengzhou University,Henan Diagnosis & Treatment Center of Congenital Heart Disease.The children included 37 male and 20 female,aged from 15 days to 6.5 years[(4.27 ± 8.63) months],with body weight 4.0-21.0 (6.33 ± 2.70) kg,and the clinical records in hospital including echocardiogram operation records were collected.The clinical data including the age on operation,body weight,diagnosis,anatomic type of TAPVC,the emergency event before operation,cardiopulmonary bypass time,aortic crossclamping time,were analyzed by chisquared test and Logistic multivariable regression analysis.The risk factors influencing the early mortality of TAPVC were analyzed.Results Fifty-seven children underwent the operation,and 7 (12.2％)cases died during the operation.The univariate analysis on outcomes indicated that the risk factors influencing the mortality of the operation included body weight(P =0.035),anatomic type of TAPVC (P =0.037),the emergency event before operation (P =0.021),and aortic crossclamping time(P =0.046).The Logistic multivariable regression analysis indicated that the emergency events before operation was the independent risk factor for the mortality of TAPVC(P =0.003).Conclusion TAPVC children with preoperative emergency events have higher postoperative mortality.%目的 分析完全性肺静脉异位引流(TAPVC)纠治术的手术结果,探讨影响其病死率的危险因素.方法 对比分析郑州大学第三附属医院河南省小儿先心病诊疗中心2001年9月至2011年9月收集的TAPVC患儿临床资料.其中男37例,女20例；年龄15 d～6.5岁[(4.27±8.63)个月]；体质量4.0 ～21.0(6.33 ±2
Anomalous diffraction in hyperbolic materials
Alberucci, Alessandro; Boardman, Allan D; Assanto, Gaetano
2016-01-01
We demonstrate that light is subject to anomalous (i.e., negative) diffraction when propagating in the presence of hyperbolic dispersion. We show that light propagation in hyperbolic media resembles the dynamics of a quantum particle of negative mass moving in a two-dimensional potential. The negative effective mass implies time reversal if the medium is homogeneous. Such property paves the way to diffraction compensation, spatial analogue of dispersion compensating fibers in the temporal domain. At variance with materials exhibiting standard elliptic dispersion, in inhomogeneous hyperbolic materials light waves are pulled towards regions with a lower refractive index. In the presence of a Kerr-like optical response, bright (dark) solitons are supported by a negative (positive) nonlinearity.
Anomalous diffraction in hyperbolic materials
Alberucci, Alessandro; Jisha, Chandroth P.; Boardman, Allan D.; Assanto, Gaetano
2016-09-01
We demonstrate that light is subject to anomalous (i.e., negative) diffraction when propagating in the presence of hyperbolic dispersion. We show that light propagation in hyperbolic media resembles the dynamics of a quantum particle of negative mass moving in a two-dimensional potential. The negative effective mass implies time reversal if the medium is homogeneous. Such property paves the way to diffraction compensation, i.e., spatial analog of dispersion compensating fibers in the temporal domain. At variance with materials exhibiting standard elliptic dispersion, in inhomogeneous hyperbolic materials light waves are pulled towards regions with a lower refractive index. In the presence of a Kerr-like optical response, bright (dark) solitons are supported by a negative (positive) nonlinearity.
Anomalous origin of the left coronary artery from the pulmonary artery: case report and review
Sandhu, K; Barron, D.; Jones, H.; Clift, P. (Peter); Thorne, S.; BUTLER, R.
2016-01-01
Anomalous origin of the left coronary artery from the pulmonary artery is a rare congenital condition that proves to be fatal in most individuals during childhood due to significant left ventricular ischaemia. However, there are case reports of individuals surviving into adulthood that have varying presenting symptoms. We report a case of a young male, who presented to our cardiology clinic with typical ischaemic cardiac pain, with no established risk factors, and was found to have anomalous ...
Scaling of the anomalous Hall current in Fe100−x(SiO2)x films
Xu, W. J.
2011-05-20
To study the origin of the anomalous Hall effect, Fe100−x(SiO2)x granular films with a volume fraction of SiO2 (0 ⩽ x ⩽ 40.51) were fabricated using cosputtering. Hall and longitudinal resistivities were measured in the temperature range of 5–350 K with magnetic fields up to 5 T. As x increased from 0 to 40.51, the anomalous Hall resistivity and longitudinal resistivity increased by about four and three orders in magnitude, respectively. Analysis of the results revealed that the normalized anomalous Hall conductivity is a constant for all of the samples, which may suggest a scattering-independent anomalous Hall conductivity in Fe.
Anomalous mechanical behavior and crack growth of oxide glasses
Seaman, Jared Hilliard
This thesis is concerned with analytically describing anomalous mechanical behaviors of glass. A new slow crack growth model is presented that considers a semi-elliptical crack in a cylindrical glass rod subjected to 4-point bending that is both loaded statically and under a time-dependent load. This model is used to explain a suppression of the loading-rate dependency of ion-exchanged strengthened glass. The stress relaxation behavior of an ion-exchanged strengthened glass is then analyzed in view of a newly observed water-assisted surface stress relaxation mechanism. By making refinements to a time-dependent Maxwell material model for stress buildup and relaxation, the anomalous subsurface compressive stress peak in ion-exchanged strengthened glass is explained. The notion of water-assisted stress relaxation is extended to the crack tip, where high tensile stresses exist. A toughening effect has historically been observed for cracks aged at subcritical stress intensity factors, where crack tip stress relaxation is hypothesized. A simple fracture mechanics model is developed that estimates a shielding stress intensity factor that is then superimposed with the far-field stress intensity factor. The model is used to estimate anomalous "restart" times for aged cracks. The same model predicts a non-linear crack growth rate for cracks loaded near the static fatigue limit. Double cantilever beam slow crack growth experiments were performed and new slow crack growth data for soda-lime silicate glass was collected. Interpretation of this new experimental slow crack growth data suggests that the origin of the static fatigue limit in glass is due to water-assisted stress relaxation. This thesis combines a number of studies that offer a new unified understanding of historical anomalous mechanical behaviors of glass. These anomalies are interpreted as simply the consequence of slow crack growth and water-assisted surface stress relaxation.
Energy Technology Data Exchange (ETDEWEB)
Stirling, W.G. [Liverpool Univ., Dep. of Physics, Liverpool (United Kingdom); Perry, S.C. [Keele Univ. (United Kingdom). Dept. of Physics
1996-12-31
We outline the theoretical and experimental background to neutron scattering studies of critical phenomena at magnetic and structural phase transitions. The displacive phase transition of SrTiO{sub 3} is discussed, along with examples from recent work on magnetic materials from the rare-earth (Ho, Dy) and actinide (NpAs, NpSb, USb) classes. The impact of synchrotron X-ray scattering is discussed in conclusion. (author) 13 figs., 18 refs.
Anomalous human behavior detection: an adaptive approach
van Leeuwen, Coen; Halma, Arvid; Schutte, Klamer
2013-05-01
Detection of anomalies (outliers or abnormal instances) is an important element in a range of applications such as fault, fraud, suspicious behavior detection and knowledge discovery. In this article we propose a new method for anomaly detection and performed tested its ability to detect anomalous behavior in videos from DARPA's Mind's Eye program, containing a variety of human activities. In this semi-unsupervised task a set of normal instances is provided for training, after which unknown abnormal behavior has to be detected in a test set. The features extracted from the video data have high dimensionality, are sparse and inhomogeneously distributed in the feature space making it a challenging task. Given these characteristics a distance-based method is preferred, but choosing a threshold to classify instances as (ab)normal is non-trivial. Our novel aproach, the Adaptive Outlier Distance (AOD) is able to detect outliers in these conditions based on local distance ratios. The underlying assumption is that the local maximum distance between labeled examples is a good indicator of the variation in that neighborhood, and therefore a local threshold will result in more robust outlier detection. We compare our method to existing state-of-art methods such as the Local Outlier Factor (LOF) and the Local Distance-based Outlier Factor (LDOF). The results of the experiments show that our novel approach improves the quality of the anomaly detection.
DEFF Research Database (Denmark)
Callisen, Thomas Hønger; Mortensen, Kell; Ipsen, John Hjorth
1994-01-01
Small-angle neutron scattering is used to determine the temperature dependence of the lamellar repeat distance in an aqueous multilamellar solution of phospholipid bilayers. A thermal anomaly in the swelling behavior is observed at the bilayer phase transition. The anomalous behavior can be suppr......Small-angle neutron scattering is used to determine the temperature dependence of the lamellar repeat distance in an aqueous multilamellar solution of phospholipid bilayers. A thermal anomaly in the swelling behavior is observed at the bilayer phase transition. The anomalous behavior can...... be suppressed by varying the lipid acyl-chain length or by alloying with a molecular stiffening agent. The experimental results are explained in terms of renormalization of the bilayer curvature elasticity and by using a theory of repulsive interlamellar undulation forces....
Silva de Almeida, Francylaine; Bussler, Larissa; Marcio Lima, Sandro; Fiorucci, Antonio Rogério; da Cunha Andrade, Luis Humberto
2016-07-01
In this work, low-cost substrates with rough silver surfaces were prepared from commercial copper foil-covered phenolic board (CPB) and an aqueous solution of AgNO3, and were used for surface-enhanced Raman scattering (SERS) and surface-enhanced resonance Raman scattering (SERRS) measurements. A maximum SERS amplification factor of 1.2 × 10(7) was obtained for Rhodamine 6G (R6G), and use of the CPB resulted in a detection limit for Thiram pesticide of 0.5 µmol L(-1) The minimum detection level was limited by residual traces of phenolic groups that originated from the substrate resin, which became solubilized in the aqueous Ag(+) solution. It was found that the bands corresponding to the impurities had less influence in the Thiram analysis, which could be explained by the high affinity of sulfur for Ag surfaces. The influence of impurities in the SERS analyses therefore depended on the linkage between the rough silver surface and the analyte. The findings demonstrated the ease and effectiveness of using CPB to prepare a nanostructured surface for SERS. © The Author(s) 2016.
Scattering and coherence in EUVL
Milster, Tomas D.; Beaudry, Neil A.
1998-06-01
We illustrate the importance of considering scattering from the illuminator in extreme UV lithography systems. Our results indicate that a significant amount of amplitude modulation noise is present in the aerial image if scatter is present in a Koehler illuminator. The effect depends on the spatial frequency of the pattern on the mask, the numerical aperture of the projection camera, the coherence factor, and placement of the plane in the illuminator where the scattering occurs.
Anomalous dimensions of heavy operators from magnon energies
Energy Technology Data Exchange (ETDEWEB)
Koch, Robert de Mello; Tahiridimbisoa, Nirina Hasina; Mathwin, Christopher [National Institute for Theoretical Physics,School of Physics and Mandelstam Institute for Theoretical Physics, University of Witwatersrand,Wits, 2050 (South Africa)
2016-03-22
We study spin chains with boundaries that are dual to open strings suspended between systems of giant gravitons and dual giant gravitons. Motivated by a geometrical interpretation of the central charges of su(2|2), we propose a simple and minimal all loop expression that interpolates between the anomalous dimensions computed in the gauge theory and energies computed in the dual string theory. The discussion makes use of a description in terms of magnons, generalizing results for a single maximal giant graviton. The symmetries of the problem determine the structure of the magnon boundary reflection/scattering matrix up to a phase. We compute a reflection/scattering matrix element at weak coupling and verify that it is consistent with the answer determined by symmetry. We find the reflection/scattering matrix does not satisfy the boundary Yang-Baxter equation so that the boundary condition on the open spin chain spoils integrability. We also explain the interpretation of the double coset ansatz in the magnon language.
Anomalous dimensions of heavy operators from magnon energies
de Mello Koch, Robert; Tahiridimbisoa, Nirina Hasina; Mathwin, Christopher
2016-03-01
We study spin chains with boundaries that are dual to open strings suspended between systems of giant gravitons and dual giant gravitons. Motivated by a geometrical interpretation of the central charges of su(2|2), we propose a simple and minimal all loop expression that interpolates between the anomalous dimensions computed in the gauge theory and energies computed in the dual string theory. The discussion makes use of a description in terms of magnons, generalizing results for a single maximal giant graviton. The symmetries of the problem determine the structure of the magnon boundary reflection/scattering matrix up to a phase. We compute a reflection/scattering matrix element at weak coupling and verify that it is consistent with the answer determined by symmetry. We find the reflection/scattering matrix does not satisfy the boundary Yang-Baxter equation so that the boundary condition on the open spin chain spoils integrability. We also explain the interpretation of the double coset ansatz in the magnon language.
Buchanan, P
2001-01-01
NDIS technique alone. The structure of liquid FeTe sub 2 was determined at the total structure factor level using neutron diffraction in order to estimate the effect of chalcogenide ion size on the structure. The results demonstrate the feasibility of the additional structural determination techniques for disordered materials made possible through the development of third generation X-ray synchrotron sources. A study of the applicability of modern X-ray and neutron scattering techniques to the study of the structure of liquid semiconductors and glasses has been made. The results demonstrate how neutron scattering with isotopic substitution (NDIS), anomalous X-ray scattering and Extended X-ray Absorption Fine Structure (EXAFS) can be successfully used to elucidate the structure of materials that cannot be studied by NDIS alone. The local coordination structure of Ag sub 2 Se in its room temperature, superionic and liquid phases has been determined using the EXAFS technique. This EXAFS data have been combined w...
Energy Technology Data Exchange (ETDEWEB)
Titantah, J T; Lamoen, D [EMAT, Universiteit Antwerpen, Groenenborgerlaan 171, 2020 Antwerpen (Belgium); Schowalter, M; Rosenauer, A, E-mail: john.titantah@ua.ac.b [Institut fuer Festkoerperphysik, Universitaet Bremen, D 28359 Bremen (Germany)
2010-02-01
The atomic scattering amplitudes of the various atoms of the systems Ga{sub 1-x}In{sub x}As, GaAs{sub 1-x}N{sub x} and InAs{sub 1-x}N{sub x} are calculated using the density functional theory (DFT) approach. The scattering amplitudes of N, Ga, As and In in the model systems are compared with the frequently used Doyle and Turner values. Deviation from the latter values is found for small scattering vectors (s<0.3A{sup -1}) and for these scattering vectors dependence on the orientation of the scattering vector and the chemical environment is reported. We suggest a parametrization of these modified scattering amplitudes (MASAs) for small scattering vectors (s<1.0A{sup -1}). The MASAs are exploited within zero pressure classical Metropolis Monte Carlo (MC), finite temperature calculations to investigate the effect of quantum well size on the electron {l_brace}002{r_brace} structure factor (SF) of Ga{sub 1-x}In{sub x}As quantum wells.
Neutron Scattering from fcc Pr and Pr3Tl
DEFF Research Database (Denmark)
Birgeneau, R. J.; Als-Nielsen, Jens Aage; Bucher, E.
1972-01-01
Elastic-neutron-scattering measurements on the singlet-ground-state ferromagnets fcc Pr and Pr3 Tl are reported. Both exhibit magnetic phase transitions, possibly to a simple ferromagnetic state at 20 and 11.6 °K, respectively. The transitions appear to be of second order although that in fcc Pr...... is clearly anomalous. Additional information on the inelastic scattering studies of the Γ1-Γ4 excitons in these systems is presented. dhcp Pr is also briefly discussed....
Garnier, A.; Pelon, J.; Vaughan, M. A.; Winker, D. M.; Trepte, C. R.; Dubuisson, P.
2015-07-01
Cirrus cloud absorption optical depths retrieved at 12.05 μm are compared to extinction optical depths retrieved at 0.532 μm from perfectly co-located observations of single-layered semi-transparent cirrus over ocean made by the Imaging Infrared Radiometer (IIR) and the Cloud and Aerosol Lidar with Orthogonal Polarization (CALIOP) flying on board the CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations) satellite. IIR infrared absorption optical depths are compared to CALIOP visible extinction optical depths when the latter can be directly derived from the measured apparent two-way transmittance through the cloud. An evaluation of the CALIOP multiple scattering factor is inferred from these comparisons after assessing and correcting biases in IIR and CALIOP optical depths reported in version 3 data products. In particular, the blackbody radiance taken in the IIR version 3 algorithm is evaluated, and IIR retrievals are corrected accordingly. Numerical simulations and IIR retrievals of ice crystal sizes suggest that the ratios of CALIOP extinction and IIR absorption optical depths should remain roughly constant with respect to temperature. Instead, these ratios are found to increase quasi-linearly by about 40 % as the temperature at the layer centroid altitude decreases from 240 to 200 K. It is discussed that this behavior can be explained by variations of the multiple scattering factor ηT applied to correct the measured apparent two-way transmittance for contribution of forward-scattering. While the CALIOP version 3 retrievals hold ηT fixed at 0.6, this study shows that ηT varies with temperature (and hence cloud particle size) from ηT = 0.8 at 200 K to ηT = 0.5 at 240 K for single-layered semi-transparent cirrus clouds with optical depth larger than 0.3. The revised parameterization of ηT introduces a concomitant temperature dependence in the simultaneously derived CALIOP lidar ratios that is consistent with observed changes in CALIOP
Aslam, M; Perkins, S J
2001-06-22
Factor H (FH) is a regulatory cofactor for the protease factor I in the breakdown of C3b in the complement system of immune defence, and binds to heparin and other polyanionic substrates. FH is composed of 20 short consensus/complement repeat (SCR) domains, for which the overall arrangement in solution is unknown. As previous studies had shown that FH can form monomeric or dimeric structures, X-ray and neutron scattering was accordingly performed with FH in the concentration range between 0.7 and 14 mg ml(-1). The radius of gyration of FH was determined to be 11.1-11.3 nm by both methods, and the radii of gyration of the cross-section were 4.4 nm and 1.7 nm. The distance distribution function P(r) showed that the overall length of FH was 38 nm. The neutron data showed that FH was monomeric with a molecular mass of 165,000(+/-17,000) Da. Analytical ultracentrifugation data confirmed this, where sedimentation equilibrium curve fits gave a mean molecular mass of 155,000(+/-3,000) Da. Sedimentation velocity experiments using the g*(s) derivative method showed that FH was monodisperse and had a sedimentation coefficient of 5.3(+/-0.1) S. In order to construct a full model of FH for scattering curve and sedimentation coefficient fits, homology models were constructed for 17 of the 20 SCR domains using knowledge of the NMR structures for FH SCR-5, SCR-15 and SCR-16, and vaccinia coat protein SCR-3 and SCR-4. Molecular dynamics simulations were used to generate a large conformational library for each of the 19 SCR-SCR linker peptides. Peptides from these libraries were combined with the 20 SCR structures in order to generate stereochemically complete models for the FH structure. Using an automated constrained fit procedure, the analysis of 16,752 possible FH models showed that only those models in which the 20 SCR domains were bent back upon themselves were able to account for the scattering and sedimentation data. The best-fit models showed that FH had an overall length
Large anomalous Hall effect in a half-Heusler antiferromagnet
Suzuki, T.; Chisnell, R.; Devarakonda, A.; Liu, Y.-T.; Feng, W.; Xiao, D.; Lynn, J. W.; Checkelsky, J. G.
2016-12-01
The quantum mechanical (Berry) phase of the electronic wavefunction plays a critical role in the anomalous and spin Hall effects, including their quantized limits. While progress has been made in understanding these effects in ferromagnets, less is known in antiferromagnetic systems. Here we present a study of antiferromagnet GdPtBi, whose electronic structure is similar to that of the topologically non-trivial HgTe (refs ,,), and where the Gd ions offer the possibility to tune the Berry phase via control of the spin texture. We show that this system supports an anomalous Hall angle ΘAH > 0.1, comparable to the largest observed in bulk ferromagnets and significantly larger than in other antiferromagnets. Neutron scattering measurements and electronic structure calculations suggest that this effect originates from avoided crossing or Weyl points that develop near the Fermi level due to a breaking of combined time-reversal and lattice symmetries. Berry phase effects associated with such symmetry breaking have recently been explored in kagome networks; our results extend this to half-Heusler systems with non-trivial band topology. The magnetic textures indicated here may also provide pathways towards realizing the topological insulating and semimetallic states predicted in this material class.
Experimental demonstration of anomalous Floquet topological insulator for sound
Peng, Yu-Gui; Qin, Cheng-Zhi; Zhao, De-Gang; Shen, Ya-Xi; Xu, Xiang-Yuan; Bao, Ming; Jia, Han; Zhu, Xue-Feng
2016-11-01
Time-reversal invariant topological insulator is widely recognized as one of the fundamental discoveries in condensed matter physics, for which the most fascinating hallmark is perhaps a spin-based topological protection, the absence of scattering of conduction electrons with certain spins on matter surface. Recently, it has created a paradigm shift for topological insulators, from electronics to photonics, phononics and mechanics as well, bringing about not only involved new physics but also potential applications in robust wave transport. Despite the growing interests in topologically protected acoustic wave transport, T-invariant acoustic topological insulator has not yet been achieved. Here we report experimental demonstration of anomalous Floquet topological insulator for sound: a strongly coupled metamaterial ring lattice that supports one-way propagation of pseudo-spin-dependent edge states under T-symmetry. We also demonstrate the formation of pseudo-spin-dependent interface states due to lattice dislocations and investigate the properties of pass band and band gap states.
The charmonium dissociation in an "anomalous wind"
Sadofyev, Andrey V
2016-01-01
We study the charmonium dissociation in a strongly coupled chiral plasma in the presence of magnetic field and axial charge imbalance. This type of plasma carries ``anomalous flow" induced by the chiral anomaly and exhibits novel transport phenomena such as chiral magnetic effect. We found that the ``anomalous flow" would modify the charmonium color screening length by using the gauge/gravity correspondence. We derive an analytical expression quantifying the ``anomalous flow" experienced by a charmonium for a large class of chiral plasma with a gravity dual. We elaborate on the similarity and {\\it qualitative} difference between anomalous effects on the charmonium color screening length which are {\\it model-dependent} and those on the heavy quark drag force which are fixed by the second law of thermodynamics. We speculate on the possible charmonium dissociation induced by chiral anomaly in heavy ion collisions.
Anomalous magnetic moment with heavy virtual leptons
Energy Technology Data Exchange (ETDEWEB)
Kurz, Alexander [Institut für Theoretische Teilchenphysik, Karlsruhe Institute of Technology (KIT), 76128 Karlsruhe (Germany); Deutsches Elektronen Synchrotron (DESY), 15738 Zeuthen (Germany); Liu, Tao [Institut für Theoretische Teilchenphysik, Karlsruhe Institute of Technology (KIT), 76128 Karlsruhe (Germany); Marquard, Peter [Deutsches Elektronen Synchrotron (DESY), 15738 Zeuthen (Germany); Steinhauser, Matthias [Institut für Theoretische Teilchenphysik, Karlsruhe Institute of Technology (KIT), 76128 Karlsruhe (Germany)
2014-02-15
We compute the contributions to the electron and muon anomalous magnetic moment induced by heavy leptons up to four-loop order. Asymptotic expansion is applied to obtain three analytic expansion terms which show rapid convergence.
Anomalous magnetic moment with heavy virtual leptons
Kurz, Alexander; Marquard, Peter; Steinhauser, Matthias
2013-01-01
We compute the contributions to the electron and muon anomalous magnetic moment induced by heavy leptons up to four-loop order. Asymptotic expansion is applied to obtain three analytic expansion terms which show rapid convergence.
Anomalous Fractional Diffusion Equation for Transport Phenomena
Institute of Scientific and Technical Information of China (English)
QiuhuaZENG; HouqiangLI; 等
1999-01-01
We derive the standard diffusion equation from the continuity equation and by discussing the defectiveness of earlier proposed equations,we get the generalized fractional diffusion equation for anomalous diffusion.
Anomalous magnetic moment with heavy virtual leptons
Energy Technology Data Exchange (ETDEWEB)
Kurz, Alexander [Karlsruher Institut fuer Technologie (Germany). Inst. fuer Theoretische Teilchenphysik; Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Liu, Tao; Steinhauser, Matthias [Karlsruher Institut fuer Technologie (Germany). Inst. fuer Theoretische Teilchenphysik; Marquard, Peter [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany)
2013-11-15
We compute the contributions to the electron and muon anomalous magnetic moment induced by heavy leptons up to four-loop order. Asymptotic expansion is applied to obtain three analytic expansion terms which show rapid convergence.
Schowalter, M; Müller, K; Rosenauer, A
2012-01-01
Modified atomic scattering amplitudes (MASAs), taking into account the redistribution of charge due to bonds, and the respective correction factors considering the effect of static atomic displacements were computed for the chemically sensitive 002 reflection for ternary III-V and II-VI semiconductors. MASAs were derived from computations within the density functional theory formalism. Binary eight-atom unit cells were strained according to each strain state s (thin, intermediate, thick and fully relaxed electron microscopic specimen) and each concentration (x = 0, …, 1 in 0.01 steps), where the lattice parameters for composition x in strain state s were calculated using continuum elasticity theory. The concentration dependence was derived by computing MASAs for each of these binary cells. Correction factors for static atomic displacements were computed from relaxed atom positions by generating 50 × 50 × 50 supercells using the lattice parameter of the eight-atom unit cells. Atoms were randomly distributed according to the required composition. Polynomials were fitted to the composition dependence of the MASAs and the correction factors for the different strain states. Fit parameters are given in the paper.
Signal velocity for anomalous dispersive waves
Energy Technology Data Exchange (ETDEWEB)
Mainardi, F. (Bologna Univ. (Italy))
1983-03-11
The concept of signal velocity for dispersive waves is usually identified with that of group velocity. When the dispersion is anomalous, this interpretation is not correct since the group velocity can assume nonphysical values. In this note, by using the steepest descent method first introduced by Brillouin, the phase velocity is shown to be the signal velocity when the dispersion is anomalous in the full range of frequencies.
Anomalous transport due to scale anomaly
Chernodub, M N
2016-01-01
We show that the scale anomaly in field theories leads to new anomalous transport effects that emerge in external electromagnetic field in inhomogeneous gravitational background. In inflating geometry the QED scale anomaly generates electric current which flows in opposite direction with respect to background electric field. In static spatially inhomogeneous gravitational background the dissipationless electric current flows transversely both to the magnetic field axis and to the gradient of the inhomogeneity. The anomalous currents are proportional to the beta function of the theory.
Neutron Scattering from 36Ar and 4He Films
DEFF Research Database (Denmark)
Carneiro, K.
1977-01-01
Scale factors for neutron diffraction and neutron inelastic scattering are presented for common adsorbates, and the feasibility of experiments is discussed together with the information gained by each type of experiment. Diffraction, coherent inelastic scattering, and incoherent scattering are tr...
Large angle elastic and inelastic scattering of 14.93 keV photons
Energy Technology Data Exchange (ETDEWEB)
Singh, P.; Mehta, D.; Kumar, S.; Sharma, M.; Puri, S.; Shahi, J.S.; Singh, N. E-mail: nsingh@pu.ac.in
2004-07-01
Elastic and inelastic scattering cross-sections for the 14.93 keV photons (Y-K{alpha} X-rays) were measured at an angle of 141 deg. in the elements with 6 {<=} Z {<=} 92 and 1 {<=} Z {<=} 50, respectively. A reflection mode geometrical arrangement involving a Y-foil excited by the 59.54 keV {gamma}-rays from the {sup 241}Am radioisotope as photon source and an HPGe/Si(Li) detector was used. The measurements were performed under vacuum {approx}10{sup -2} Torr. Special care was taken in determination of the incident photon intensity and geometrical factors and to check effects due to occurrence of Bragg diffraction from the target lattice. The measured elastic scattering cross-sections have been compared with predictions from the form-factor formalism and relativistic second-order S-matrix calculations. The modified form-factor (MF) cross-sections are higher up to 50% than the measured ones in the case of elements with the electron binding energy (BE) in vicinity of the incident photon energy and are lower up to 20% for the other elements. These deviations are smoothed by incorporating the Anomalous Scattering Factors (ASFs) to the MF values [Acta Cryst. A 46 (1990) 170]. The S-matrix values exhibit general agreement with the measured cross-sections. The measured inelastic scattering cross-sections are found to be in good agreement with those calculated using the Klein-Nishina cross-section incorporating the Hartree-Fock incoherent scattering function (ISF)
Navigation by anomalous random walks on complex networks
Weng, Tongfeng; Khajehnejad, Moein; Small, Michael; Zheng, Rui; Hui, Pan
2016-01-01
Anomalous random walks having long-range jumps are a critical branch of dynamical processes on networks, which can model a number of search and transport processes. However, traditional measurements based on mean first passage time are not useful as they fail to characterize the cost associated with each jump. Here we introduce a new concept of mean first traverse distance (MFTD) to characterize anomalous random walks that represents the expected traverse distance taken by walkers searching from source node to target node, and we provide a procedure for calculating the MFTD between two nodes. We use Levy walks on networks as an example, and demonstrate that the proposed approach can unravel the interplay between diffusion dynamics of Levy walks and the underlying network structure. Interestingly, applying our framework to the famous PageRank search, we can explain why its damping factor empirically chosen to be around 0.85. The framework for analyzing anomalous random walks on complex networks offers a new us...
Institute of Scientific and Technical Information of China (English)
N. Ghahramany; M. Vaez zadeh Asadi; G.R. Boroun
2003-01-01
Electric and Magnetic form factors of neutron are calculated via electron-deuteron scattering at 1.511 ～5.507 GeV energy using SLAC group data. Our results show that the neutron electric form factor is not equal to zero;rather it has a small value, indicating that in spite of the fact that total charge is almost neutral, there is a nonuniformcharge distribution within the neutron, and that magnetic form factor follows the dipole fit.
Anomalous magnetism in hydrogenated graphene
García-Martínez, N. A.; Lado, J. L.; Jacob, D.; Fernández-Rossier, J.
2017-07-01
We revisit the problem of local moment formation in graphene due to chemisorption of individual atomic hydrogen or other analogous sp 3 covalent functionalizations. We describe graphene with the single-orbital Hubbard model, so that the H chemisorption is equivalent to a vacancy in the honeycomb lattice. To circumvent artifacts related to periodic unit cells, we use either huge simulation cells of up to 8 ×105 sites, or an embedding scheme that allows the modeling of a single vacancy in an otherwise pristine infinite honeycomb lattice. We find three results that stress the anomalous nature of the magnetic moment (m ) in this system. First, in the noninteracting (U =0 ) zero-temperature (T =0 ) case, the m (B ) is a continuous smooth curve with divergent susceptibility, different from the stepwise constant function found for single unpaired spins in a gapped system. Second, for U =0 and T >0 , the linear susceptibility follows a power law ∝T-α with an exponent of α =0.77 different from the conventional Curie law. For U >0 , in the mean-field approximation, the integrated moment is smaller than m =1 μB , in contrast with results using periodic unit cells. These three results highlight the fact that the magnetic response of the local moment induced by sp 3 functionalizations in graphene is different from that of local moments in gapped systems, for which the magnetic moment is quantized and follows a Curie law, and from Pauli paramagnetism in conductors, for which linear susceptibility can be defined at T =0 .
DEFF Research Database (Denmark)
Ploquin, N.; Kertzscher, Gustavo; Vandervoort, E.
2015-01-01
for the RL detector response for the 5, 7.5 and 10 mm collimators in order to correct for the detector geometry and increased photoelectric cross section of Al2O3:C relative to water. For comparison, measurements were also carried out using a micro MOSFET, PTW60012 diode and GAFCHROMIC® film (EBT and EBT2......). Uncorrected (Sc,p)fclindet, were obtained by taking the ratio of the detector response for each collimator to that for the 60 mm diameter reference field. Published Monte Carlo calculated correction factors were applied to the RADPOS, microMOSFET and diode detector measurements to yield corrected field...... factors, Ωfclin,fmsrQclin,Qmsrfollowing the terminology of a recent formalism introduced for small and composite field relative dosimetry. With corrections, the RL measured Ωfclin,fmsrQclin,Qmsr were 0.656 ± 0.002, 0.815 ± 0.002 and 0.865 ± 0.003 for the 5, 7.5 and 10 mm collimators, respectively...
Yu, Hsiu-Yu
2014-09-15
© the Partner Organisations 2014. We investigate the static structure factor S(q) of solvent-free nanoparticle-organic hybrid materials consisting of silica nanocores and space-filling polyethylene glycol coronas using a density-functional theory and small angle X-ray scattering measurements. The theory considers a bidisperse suspension of hard spheres with different radii and tethered bead-spring oligomers with different grafting densities to approximate the polydispersity effects in experiments. The experimental systems studied include pure samples with different silica core volume fractions and the associated mean corona grafting densities, and blends with different mixing ratios of the pure samples, in order to introduce varying polydispersity of corona grafting density. Our scattering experiments and theory show that, compared to the hard-sphere suspension with the same core volume fraction, S(q) for pure samples exhibit both substantially smaller values at small q and stronger particle correlations corresponding to a larger effective hard core at large q, indicating that the tethered incompressible oligomers enforce a more uniform particle distribution, and the densely grafted brush gives rise to an additional exclusionary effect between the nanoparticles. According to the theory, polydispersity in the oligomer grafting density controls the deviation of S(q) from the monodisperse system at smaller q, and the interplay of the enhanced effective core size and the entropic attraction among the particles is responsible for complex variations in the particle correlations at larger q. The successful comparison between the predictions and the measurements for the blends further suggests that S(q) can be used to assess the uniformity of grafting density in polymer-grafted nanoparticle materials. This journal is
Small angle neutron scattering
Directory of Open Access Journals (Sweden)
Cousin Fabrice
2015-01-01
Full Text Available Small Angle Neutron Scattering (SANS is a technique that enables to probe the 3-D structure of materials on a typical size range lying from ∼ 1 nm up to ∼ a few 100 nm, the obtained information being statistically averaged on a sample whose volume is ∼ 1 cm3. This very rich technique enables to make a full structural characterization of a given object of nanometric dimensions (radius of gyration, shape, volume or mass, fractal dimension, specific area… through the determination of the form factor as well as the determination of the way objects are organized within in a continuous media, and therefore to describe interactions between them, through the determination of the structure factor. The specific properties of neutrons (possibility of tuning the scattering intensity by using the isotopic substitution, sensitivity to magnetism, negligible absorption, low energy of the incident neutrons make it particularly interesting in the fields of soft matter, biophysics, magnetic materials and metallurgy. In particular, the contrast variation methods allow to extract some informations that cannot be obtained by any other experimental techniques. This course is divided in two parts. The first one is devoted to the description of the principle of SANS: basics (formalism, coherent scattering/incoherent scattering, notion of elementary scatterer, form factor analysis (I(q→0, Guinier regime, intermediate regime, Porod regime, polydisperse system, structure factor analysis (2nd Virial coefficient, integral equations, characterization of aggregates, and contrast variation methods (how to create contrast in an homogeneous system, matching in ternary systems, extrapolation to zero concentration, Zero Averaged Contrast. It is illustrated by some representative examples. The second one describes the experimental aspects of SANS to guide user in its future experiments: description of SANS spectrometer, resolution of the spectrometer, optimization of
Towards a data-driven analysis of hadronic light-by-light scattering
Colangelo, Gilberto; Kubis, Bastian; Procura, Massimiliano; Stoffer, Peter
2014-01-01
The hadronic light-by-light contribution to the anomalous magnetic moment of the muon was recently analyzed in the framework of dispersion theory, providing a systematic formalism where all input quantities are expressed in terms of on-shell form factors and scattering amplitudes that are in principle accessible in experiment. We briefly review the main ideas behind this framework and discuss the various experimental ingredients needed for the evaluation of one- and two-pion intermediate states. In particular, we identify processes that in the absence of data for doubly-virtual pion-photon interactions can help constrain parameters in the dispersive reconstruction of the relevant input quantities, the pion transition form factor and the helicity partial waves for $\\gamma^*\\gamma^*\\to\\pi\\pi$.
Rodriguez, I D
2003-01-01
The process $e^+e^- \\to \\tau \\bar\\tau \\gamma$ contains configurations of the four-momenta for which the scattering amplitude vanishes (Radiation Zeros or Null Zone). These Radiation Zeros only occur for couplings given by a gauge theory, in particular the standard model. Therefore they are sensitive to physics beyond the standard model as the anomalous magnetic and weak moment of the $\\tau$ lepton. In this article we compute the effect of these anomalous interactions on the Radiation Zeros in the above mentioned process.
ON THE SOURCE OF ASTROMETRIC ANOMALOUS REFRACTION
Energy Technology Data Exchange (ETDEWEB)
Taylor, M. Suzanne [Department of Natural and Environmental Sciences, Western State Colorado University, 128 Hurst Hall, Gunnison, CO 81230 (United States); McGraw, John T.; Zimmer, Peter C. [Department of Physics and Astronomy, University of New Mexico, MSC07 4220, Albuquerque, NM 87131 (United States); Pier, Jeffrey R., E-mail: mstaylor@western.edu [Division of Astronomical Sciences, NSF 4201 Wilson Blvd, Arlington, VA 22230 (United States)
2013-03-15
More than a century ago, astronomers using transit telescopes to determine precise stellar positions were hampered by an unexplained periodic shifting of the stars they were observing. With the advent of CCD transit telescopes in the past three decades, this unexplained motion, termed 'anomalous refraction' by these early astronomers, is again being observed. Anomalous refraction is described as a low-frequency, large angular scale ({approx}2 Degree-Sign ) motion of the entire image plane with respect to the celestial coordinate system as observed and defined by astrometric catalogs. These motions, of typically several tenths of an arcsecond amplitude with timescales on the order of 10 minutes, are ubiquitous to ground-based drift-scan astrometric measurements regardless of location or telescopes used and have been attributed to the effect of tilting of equal-density layers of the atmosphere. The cause of this tilting has often been attributed to atmospheric gravity waves, but this cause has never been confirmed. Although theoretical models of atmospheric refraction show that atmospheric gravity waves are a plausible cause of anomalous refraction, an observational campaign specifically directed at defining this relationship provides clear evidence that anomalous refraction is not consistent with the passage of atmospheric gravity waves. The source of anomalous refraction is found to be meter-scale, slowly evolving quasi-coherent dynamical structures in the boundary layer below 60 m above ground level.
On the Source of Astrometric Anomalous Refraction
Taylor, M. Suzanne; McGraw, John T.; Zimmer, Peter C.; Pier, Jeffrey R.
2013-03-01
More than a century ago, astronomers using transit telescopes to determine precise stellar positions were hampered by an unexplained periodic shifting of the stars they were observing. With the advent of CCD transit telescopes in the past three decades, this unexplained motion, termed "anomalous refraction" by these early astronomers, is again being observed. Anomalous refraction is described as a low-frequency, large angular scale (~2°) motion of the entire image plane with respect to the celestial coordinate system as observed and defined by astrometric catalogs. These motions, of typically several tenths of an arcsecond amplitude with timescales on the order of 10 minutes, are ubiquitous to ground-based drift-scan astrometric measurements regardless of location or telescopes used and have been attributed to the effect of tilting of equal-density layers of the atmosphere. The cause of this tilting has often been attributed to atmospheric gravity waves, but this cause has never been confirmed. Although theoretical models of atmospheric refraction show that atmospheric gravity waves are a plausible cause of anomalous refraction, an observational campaign specifically directed at defining this relationship provides clear evidence that anomalous refraction is not consistent with the passage of atmospheric gravity waves. The source of anomalous refraction is found to be meter-scale, slowly evolving quasi-coherent dynamical structures in the boundary layer below 60 m above ground level.
Energy Technology Data Exchange (ETDEWEB)
Friedrich, Harald [Technische Univ. Muenchen, Garching (Germany). Physik-Department
2013-08-01
Written by the author of the widely acclaimed textbook. Theoretical Atomic Physics Includes sections on quantum reflection, tunable Feshbach resonances and Efimov states. Useful for advanced students and researchers. This book presents a concise and modern coverage of scattering theory. It is motivated by the fact that experimental advances have shifted and broadened the scope of applications where concepts from scattering theory are used, e.g. to the field of ultracold atoms and molecules, which has been experiencing enormous growth in recent years, largely triggered by the successful realization of Bose-Einstein condensates of dilute atomic gases in 1995. In the present treatment, special attention is given to the role played by the long-range behaviour of the projectile-target interaction, and a theory is developed, which is well suited to describe near-threshold bound and continuum states in realistic binary systems such as diatomic molecules or molecular ions. The level of abstraction is kept as low as at all possible, and deeper questions related to mathematical foundations of scattering theory are passed by. The book should be understandable for anyone with a basic knowledge of nonrelativistic quantum mechanics. It is intended for advanced students and researchers, and it is hoped that it will be useful for theorists and experimentalists alike.
Friedrich, Harald
2016-01-01
This corrected and updated second edition of "Scattering Theory" presents a concise and modern coverage of the subject. In the present treatment, special attention is given to the role played by the long-range behaviour of the projectile-target interaction, and a theory is developed, which is well suited to describe near-threshold bound and continuum states in realistic binary systems such as diatomic molecules or molecular ions. It is motivated by the fact that experimental advances have shifted and broadened the scope of applications where concepts from scattering theory are used, e.g. to the field of ultracold atoms and molecules, which has been experiencing enormous growth in recent years, largely triggered by the successful realization of Bose-Einstein condensates of dilute atomic gases in 1995. The book contains sections on special topics such as near-threshold quantization, quantum reflection, Feshbach resonances and the quantum description of scattering in two dimensions. The level of abstraction is k...
Scattering by two spheres: Theory and experiment
DEFF Research Database (Denmark)
Bjørnø, Irina; Jensen, Leif Bjørnø
1998-01-01
on three issues: (1) to develop a simplified theory for scattering by two elastical spheres; (2) to measure the scattering by two spheres in a water tank, and (3) to compare the theoretical/numerical results with the measured data. A number of factors influencing multiple scattering, including...
Leading logarithms in the anomalous sector of two-flavour QCD
Energy Technology Data Exchange (ETDEWEB)
Bijnens, Johan [Department of Astronomy and Theoretical Physics, Lund University, Soelvegatan 14A, S 223 62 Lund (Sweden); Kampf, Karol [Institute of Particle and Nuclear Physics, Faculty of Mathematics and Physics, Charles University, 18000 Prague (Czech Republic); Department of Astronomy and Theoretical Physics, Lund University, Soelvegatan 14A, S 223 62 Lund (Sweden); Lanz, Stefan, E-mail: stefan.lanz@thep.lu.se [Department of Astronomy and Theoretical Physics, Lund University, Soelvegatan 14A, S 223 62 Lund (Sweden)
2012-07-11
We add the Wess-Zumino-Witten term to the N=3 massive nonlinear sigma model and study the leading logarithms in the anomalous sector. We obtain the leading logarithms to six loops for {pi}{sup 0}{yields}{gamma}{sup Low-Asterisk }{gamma}{sup Low-Asterisk} and to five loops for {gamma}{sup Low-Asterisk }{pi}{pi}{pi}. In addition we extend the earlier work on the mass and decay constant to six loops and the vector form factor to five loops. We present numerical results for the anomalous processes and the vector form factor. In all cases the series are found to converge rapidly.
Universal Higher Order QED Corrections to Polarized Lepton Scattering
Blümlein, J; Bl\\"umlein, Johannes; Kawamura, Hiroyuki
2004-01-01
We calculate the universal radiative QED corrections to polarized lepton scattering for general scattering cross sections in analytic form. The flavor non--singlet and singlet radiation functions are calculated to $O((\\alpha {\\rm L})^5)$. The resummation of the non--singlet and singlet contributions to the QED--anomalous dimensions $\\propto(\\alpha \\ln^2(x))^k$ is performed to all orders. Numerical results are presented for the individual radiation functions. Applications to polarized deeply inelastic lepton--nucleon scattering are given.
Dynamo and anomalous transport in the reversed field pinch
Energy Technology Data Exchange (ETDEWEB)
Prager, S.C.
1998-08-01
The reversed field pinch is an effective tool to study the macroscopic consequences of magnetic fluctuations, such as the dynamo effect and anomalous transport. Several explanations exist for the dynamo (the self-generation of plasma current)--the MHD dynamo, the kinetic dynamo, and the diamagnetic dynamo. There is some experimental evidence for each, particularly from measurements of ion velocity and electron pressure fluctuations. Magnetic fluctuations are known to produce energy and particle flux in the RFP core. Current profile control is able to decrease fluctuation-induced transport by a factor of five. Improved confinement regimes are also obtained at deep reversal and, possibly, with flow shear.
Minimal flavour violation and anomalous top decays
Energy Technology Data Exchange (ETDEWEB)
Faller, Sven; Mannel, Thomas [Theoretische Physik 1, Department Physik, Universitaet Siegen, D-57068 Siegen (Germany); Gadatsch, Stefan [Nikhef, National Institute for Subatomatic Physics, P.O. Box 41882, 1009 Amsterdam (Netherlands)
2013-07-01
Any experimental evidence of anomalous top-quark couplings will open a window to study physics beyond the standard model (SM). However, all current flavour data indicate that nature is close to ''minimal flavour violation'', i.e. the pattern of flavour violation is given by the CKM matrix, including the hierarchy of parameters. In this talk we present results of the conceptual test of minimal flavour violation for the anomalous charged as well as flavour changing top-quark couplings. Our analysis is embedded in two-Higgs doublet model of type II (2HDM-II). Including renormalization effects, we calculate the top decay rates taking into account anomalous couplings constrained by minimal flavour violation.
Electroweak Baryogenesis with Anomalous Higgs Couplings
Kobakhidze, Archil; Yue, Jason
2015-01-01
We investigate feasibility of efficient baryogenesis at the electroweak scale within the effective field theory framework based on a non-linear realisation of the electroweak gauge symmetry. In this framework the LHC Higgs boson is described by a singlet scalar field, which, therefore, admits new interactions. Assuming that Higgs couplings with the eletroweak gauge bosons are as in the Standard Model, we demonstrate that the Higgs cubic coupling and the CP-violating Higgs-top quark anomalous couplings alone may drive the a strongly first-order phase transition. The distinguished feature of this transition is that the anomalous Higgs vacuum expectation value is generally non-zero in both phases. We identify a range of anomalous couplings, consistent with current experimental data, where sphaleron rates are sufficiently fast in the 'symmetric' phase and are suppressed in the 'broken' phase and demonstrate that the desired baryon asymmetry can indeed be generated in this framework. This range of the Higgs anomal...
Anomalous magnetohydrodynamics in the extreme relativistic domain
Giovannini, Massimo
2016-01-01
The evolution equations of anomalous magnetohydrodynamics are derived in the extreme relativistic regime and contrasted with the treatment of hydromagnetic nonlinearities pioneered by Lichnerowicz in the absence of anomalous currents. In particular we explore the situation where the conventional vector currents are complemented by the axial-vector currents arising either from the pseudo Nambu-Goldstone bosons of a spontaneously broken symmetry or because of finite fermionic density effects. After expanding the generally covariant equations in inverse powers of the conductivity, the relativistic analog of the magnetic diffusivity equation is derived in the presence of vortical and magnetic currents. While the anomalous contributions are generally suppressed by the diffusivity, they are shown to disappear in the perfectly conducting limit. When the flow is irrotational, boost-invariant and with vanishing four-acceleration the corresponding evolution equations are explicitly integrated so that the various physic...
Neoclassical Viscosities and Anomalous Flows in Stellarators
Ware, A. S.; Spong, D. A.; Breyfogle, M.; Marine, T.
2009-05-01
We present initial work to use neoclassical viscosities calculated with the PENTA code [1] in a transport model that includes Reynolds stress generation of flows [2]. The PENTA code uses a drift kinetic equation solver to calculate neoclassical viscosities and flows in general three-dimensional geometries over a range of collisionalities. The predicted neoclassical viscosities predicted by PENTA can be flux-surfaced average and applied in a 1-D transport model that includes anomalous flow generation. This combination of codes can be used to test the impact of stellarator geometry on anomalous flow generation. As a test case, we apply the code to modeling flows in the HSX stellarator. Due to variations in the neoclassical viscosities, HSX can have strong neoclassical flows in the core region. In turn, these neoclassical flows can provide a seed for anomalous flow generation. [1] D. A. Spong, Phys. Plasmas 12, 056114 (2005). [2] D. E. Newman, et al., Phys. Plasmas 5, 938 (1998).
Penante, Brenda
2016-01-01
Planar maximally supersymmetric Yang-Mills theory (N=4 SYM) is a special quantum field theory. A few of its remarkable features are conformal symmetry at the quantum level, evidence of integrability and, moreover, it is a prime example of the AdS/CFT duality. Triggered by Witten's twistor string theory, the past 15 years have witnessed enormous progress in reformulating this theory to make as many of these special features manifest, from the choice of convenient variables to recursion relations that allowed new mathematical structures to appear, like the Grassmannian. These methods are collectively referred to as on-shell methods. The ultimate hope is that, by understanding N=4 SYM in depth, one can learn about other, more realistic quantum field theories. The overarching theme of this thesis is the investigation of how on-shell methods can aid the computation of quantities other than scattering amplitudes. In this spirit we study form factors and correlation functions, said to be partially and completely off...
Anomalous mass dimension in multiflavor QCD
Doff, A.; Natale, A. A.
2016-10-01
Models of strongly interacting theories with a large mass anomalous dimension (γm) provide an interesting possibility for the dynamical origin of the electroweak symmetry breaking. A laboratory for these models is QCD with many flavors, which may present a nontrivial fixed point associated to a conformal region. Studies based on conformal field theories and on Schwinger-Dyson equations have suggested the existence of bounds on the mass anomalous dimension at the fixed points of these models. In this note we discuss γm values of multiflavor QCD exhibiting a nontrivial fixed point and affected by relevant four-fermion interactions.
Anomalous Feeding of the Left Upper Lobe.
Hazzard, Christopher; Itagaki, Shinobu; Lajam, Fouad; Flores, Raja M
2016-09-01
We report the case of a 53-year-old woman who presented with massive hemoptysis. Computed tomographic angiography revealed an anomalous vessel arising from the abdominal aorta, coursing anteriorly and through the diaphragm, and feeding the left upper lobe. At operation the vessel was found to anastomose to the left upper lobe lingula, which contained multiple vascular abnormalities and arteriovenous fistulas. The vessel was ligated, and the affected portion of the left upper lobe was resected. Anomalous systemic arterial supply of an upper lobe is an especially rare form of a Pryce type 1 abnormality. Recognition of these unusual anatomic variants is crucial to successful treatment and avoidance of adverse events.
A potassium Faraday anomalous dispersion optical filter
Yin, B.; Shay, T. M.
1992-01-01
The characteristics of a potassium Faraday anomalous dispersion optical filter operating on the blue and near infrared transitions are calculated. The results show that the filter can be designed to provide high transmission, very narrow pass bandwidth, and low equivalent noise bandwidth. The Faraday anomalous dispersion optical filter (FADOF) provides a narrow pass bandwidth (about GHz) optical filter for laser communications, remote sensing, and lidar. The general theoretical model for the FADOF has been established in our previous paper. In this paper, we have identified the optimum operational conditions for a potassium FADOF operating on the blue and infrared transitions. The signal transmission, bandwidth, and equivalent noise bandwidth (ENBW) are also calculated.
Wang, Qi; Sun, Shanshan; Zhang, Xiao; Pang, Fei; Lei, Hechang
2016-08-01
The anomalous Hall effect (AHE) is investigated for a ferromagnetic Fe3Sn2 single crystal with a geometrically frustrated kagome bilayer of Fe. The scaling behavior between anomalous Hall resistivity ρxy A and longitudinal resistivity ρx x is quadratic and further analysis implies that the AHE in the Fe3Sn2 single crystal should be dominated by the intrinsic Karplus-Luttinger mechanism rather than extrinsic skew-scattering or side-jump mechanisms. Moreover, there is a sudden jump of anomalous Hall conductivity σxy A appearing at about 100 K where the spin-reorientation transition from the c axis to the a b plane is completed. This change of σxy A might be related to the evolution of the Fermi surface induced by the spin-reorientation transition.
Superradiant Forward Scattering in Multiple Scattering
Chabe, Julien; Bienaime, Tom; Bachelard, Romain; Piovella, Nicola; Kaiser, Robin
2012-01-01
We report on an interference effect in multiple scattering by resonant scatterers resulting in enhanced forward scattering, violating Ohm's law for photons. The underlying mechanism of this wave effect is superradiance, which we have investigated using cold atoms as a toy model. We present numerical and experimental evidences for this superradiant forward scattering, which is robust against disorder and configuration averaging.
Latest results on anomalous gauge boson couplings with the ATLAS experiment
Schnoor, Ulrike; The ATLAS collaboration
2015-01-01
Contributions from new physics in the electroweak sector can be described in a model-independent way by anomalous gauge boson couplings in the framework of an effective field theory. Measurements of these parameters allow for the exclusion or discovery of contributions beyond the Standard Model. Experimentally, electroweak triple gauge boson couplings have been accessible in di-boson production at the LHC and at previous colliders. More recently, the first measurements of triple gauge boson couplings in vector boson production through vector boson fusion have been achieved. The first observations of vector boson scattering and triple boson production processes have been made recently at the LHC, giving the possibility to measure quartic gauge boson interactions of electroweak vector bosons. These proceedings describe measurements at the ATLAS detector at the LHC in various channels which allow to set limits on anomalous triple and quartic gauge boson couplings. All measurements show good agreement with the pr...
Enhancement of perpendicular magnetic anisotropy and anomalous hall effect in Co/Ni multilayers
Liu, Yiwei; Zhang, Jingyan; Jiang, Shaolong; Liu, Qianqian; Li, Xujing; Yu, Guanghua
2016-12-01
The perpendicular magnetic anisotropy (PMA) and the anomalous Hall effect (AHE) in Co/Ni multilayer were optimized by manipulating its interface structure (inducing HfO2 capping layer and Pt insertion) and post-annealing treatment. A strong PMA can be obtained in Co/Ni multilayers with HfO2 capping layer even after annealing at 400 °C. The heavy metal Hf may improve the interfacial spin-orbit coupling, which responsible for the enhanced PMA and high annealing stability. Moreover, the multilayer containing HfO2 capping layer also exhibited high saturation anomalous Hall resistivity through post-annealing, which is 0.85 μΩ cm after annealing at 375 °C, 211% larger than in the sample at deposited state which is only 0.27 μΩ cm. The enhancement of AHE is mainly attributed to the interface scattering through post-annealing treatment.
Scattering analysis of LOFAR pulsar observations
Geyer, M.; Karastergiou, A.; Kondratiev, V. I.; Zagkouris, K.; Kramer, M.; Stappers, B. W.; Grießmeier, J.-M.; Hessels, J. W. T.; Michilli, D.; Pilia, M.; Sobey, C.
2017-09-01
We measure the effects of interstellar scattering on average pulse profiles from 13 radio pulsars with simple pulse shapes. We use data from the LOFAR High Band Antennas, at frequencies between 110 and 190 MHz. We apply a forward fitting technique, and simultaneously determine the intrinsic pulse shape, assuming single Gaussian component profiles. We find that the constant τ, associated with scattering by a single thin screen, has a power-law dependence on frequency τ ∝ ν-α, with indices ranging from α = 1.50 to 4.0, despite simplest theoretical models predicting α = 4.0 or 4.4. Modelling the screen as an isotropic or extremely anisotropic scatterer, we find anisotropic scattering fits lead to larger power-law indices, often in better agreement with theoretically expected values. We compare the scattering models based on the inferred, frequency-dependent parameters of the intrinsic pulse, and the resulting correction to the dispersion measure (DM). We highlight the cases in which fits of extreme anisotropic scattering are appealing, while stressing that the data do not strictly favour either model for any of the 13 pulsars. The pulsars show anomalous scattering properties that are consistent with finite scattering screens and/or anisotropy, but these data alone do not provide the means for an unambiguous characterization of the screens. We revisit the empirical τ versus DM relation and consider how our results support a frequency dependence of α. Very long baseline interferometry, and observations of the scattering and scintillation properties of these sources at higher frequencies, will provide further evidence.
Total least squares for anomalous change detection
Energy Technology Data Exchange (ETDEWEB)
Theiler, James P [Los Alamos National Laboratory; Matsekh, Anna M [Los Alamos National Laboratory
2010-01-01
A family of difference-based anomalous change detection algorithms is derived from a total least squares (TLSQ) framework. This provides an alternative to the well-known chronochrome algorithm, which is derived from ordinary least squares. In both cases, the most anomalous changes are identified with the pixels that exhibit the largest residuals with respect to the regression of the two images against each other. The family of TLSQ-based anomalous change detectors is shown to be equivalent to the subspace RX formulation for straight anomaly detection, but applied to the stacked space. However, this family is not invariant to linear coordinate transforms. On the other hand, whitened TLSQ is coordinate invariant, and furthermore it is shown to be equivalent to the optimized covariance equalization algorithm. What whitened TLSQ offers, in addition to connecting with a common language the derivations of two of the most popular anomalous change detection algorithms - chronochrome and covariance equalization - is a generalization of these algorithms with the potential for better performance.
Anomalous human behavior detection: An Adaptive approach
Leeuwen, C. van; Halma, A.; Schutte, K.
2013-01-01
Detection of anomalies (outliers or abnormal instances) is an important element in a range of applications such as fault, fraud, suspicious behavior detection and knowledge discovery. In this article we propose a new method for anomaly detection and performed tested its ability to detect anomalous
Anomalous Hall Effect for chiral fermions
Zhang, P -M
2014-01-01
Semiclassical chiral fermions manifest the anomalous spin-Hall effect: when put into a pure electric field, they suffer a side jump, analogous to what happens to their massive counterparts in non-commutative mechanics. The transverse shift is consistent with the conservation of the angular momentum. In a pure magnetic field a cork-screw-like, spiraling motion is found.
ACS SBC Recovery from Anomalous Shutdown
Wheeler, Thomas
2013-10-01
This proposal is designed to permit a safe and orderly recovery of the SBC {FUV MAMA} detector after an anomalous shutdown. This is accomplished by using slower-than-normal MCP high-voltage ramp-ups and diagnostics. Anomalous shutdowns can occur because of bright object violations, which trigger the Global Hardware Monitor or the Global Software Monitor. Anomalous shutdowns can also occur because of MAMA hardware anomalies or failures. The cause of the shutdown should be thoroughly investigated and understood prior to recovery. Twenty-four hour wait intervals are required after each test for MCP gas desorption and data analysis. Event flag 2 is used to prevent inadvertent MAMA usage. The recovery procedure consists of four separate tests {i.e. visits} to check the MAMA's health after an anomalous shutdown: 1} signal processing electronics check, 2} slow, high-voltage ramp-up to an intermediate voltage, 3} a slow high-voltage ramp-up to the nominal operating HV, and 4} fold analysis test. Each must be completed successfully before proceeding onto the next. During the two high-voltage ramp-ups, dark ACCUM exposures are taken. At high voltage, dark ACCUM exposures and diagnostics are taken. This proposal is based on Proposal 13163 from Cycle 20. For additional MAMA recovery information, see STIS ISR 98-02R.
Anomalous human behavior detection: An Adaptive approach
Leeuwen, C. van; Halma, A.; Schutte, K.
2013-01-01
Detection of anomalies (outliers or abnormal instances) is an important element in a range of applications such as fault, fraud, suspicious behavior detection and knowledge discovery. In this article we propose a new method for anomaly detection and performed tested its ability to detect anomalous b
Anomalous pulmonary venous return: A case report
Energy Technology Data Exchange (ETDEWEB)
Park, Gyeong Min; Kang, MinJin; Lee, Han Bee; Bae, Kyung Eun; Lee, Jaehe; Kim, Jae Hyung; Jeong, Myeong Ja; Kang, Tae Kyung [Sanggye Paik Hospital, Inje University College of Medicine, Seoul (Korea, Republic of)
2013-10-15
Partial anomalous pulmonary venous return is a type of congenital pulmonary venous anomaly. We present a rare type of partial pulmonary venous return, subaortic vertical vein drains left lung to superior vena cava, accompanying hypoplasia of the ipsilateral lung and pulmonary artery. We also review the previous report and relationship of these structures.
Anomalous atomic volume of alpha-Pu
DEFF Research Database (Denmark)
Kollar, J.; Vitos, Levente; Skriver, Hans Lomholt
1997-01-01
.3%. The comparison between the LDA and GGA results show that the anomalously large atomic volume of alpha-Pu relative to alpha-Np can be ascribed to exchange-correlation effects connected with the presence of low coordinated sites in the structure where the f electrons are close to the onset of localization...
Anomalous solutions to the strong CP problem.
Hook, Anson
2015-04-10
We present a new mechanism for solving the strong CP problem using a Z_{2} discrete symmetry and an anomalous U(1) symmetry. A Z_{2} symmetry is used so that two gauge groups have the same theta angle. An anomalous U(1) symmetry makes the difference between the two theta angles physical and the sum unphysical. Two models are presented where the anomalous symmetry manifests itself in the IR in different ways. In the first model, there are massless bifundamental quarks, a solution reminiscent of the massless up quark solution. In the IR of this model, the η^{'} boson relaxes the QCD theta angle to the difference between the two theta angles-in this case zero. In the second model, the anomalous U(1) symmetry is realized in the IR as a dynamically generated mass term that has exactly the phase needed to cancel the theta angle. Both of these models make the extremely concrete prediction that there exist new colored particles at the TeV scale.
Anomalous transports in a time-delayed system subjected to anomalous diffusion
Chen, Ru-Yin; Tong, Lu-Mei; Nie, Lin-Ru; Wang, Chaojie; Pan, Wanli
2017-02-01
We investigate anomalous transports of an inertial Brownian particle in a time-delayed periodic potential subjected to an external time-periodic force, a constant bias force, and the Lévy noise. By means of numerical calculations, effect of the time delay and the Lévy noise on its mean velocity are discussed. The results indicate that: (i) The time delay can induce both multiple current reversals (CRs) and absolute negative mobility (ANM) phenomena in the system; (ii) The CRs and ANM phenomena only take place in the region of superdiffusion, while disappear in the regions of normal diffusion; (iii) The time delay can cause state transition of the system from anomalous →normal →anomalous →normal →anomalous →normal transport in the case of superdiffusion.
Anomalous collisional absorption of laser pulses in underdense plasma at low temperature
Kundu, M.
2015-04-01
In a previous paper [M. Kundu, Phys. Plasmas 21, 013302 (2014), 10.1063/1.4862038], fractional collisional absorption (α ) of laser light in underdense plasma was studied by using a classical scattering model of electron-ion collision frequency νei, where total velocity v =√{vth2+v02 } (with vth and v0 as the thermal and the ponderomotive velocity of an electron) dependent Coulomb logarithm lnΛ (v ) was shown to be responsible for the anomalous (unconventional) increase of νei and α (∝νei ) with the laser intensity I0 up to a maximum value about an intensity Ic in the low temperature (TeIc . One may object that the anomalous increase in νei and α were partly due to the artifact introduced in lnΛ through the maximum cutoff distance bmax∝v . In this work, we show similar anomalous increase in νei and α versus I0 (in the low temperature and underdense density regime) with more accurate quantum and classical kinetic models of νei without using lnΛ , but with a proper choice of the total velocity dependent inverse cutoff length kmax∝v2 (classical) or kmax∝v (quantum). For a given I0<5 ×1014Wcm -2 , νei versus Te also exhibits so far unnoticed identical anomalous increase as νei versus I0, even if the conventional kmax∝vth2 or kmax∝vth (without v0) is chosen. The total velocity dependent kmax in the kinetic models, as proposed here, is found to explain the anomalous increase of α with I0 measured in some earlier laser-plasma experiments.
Phase rotation symmetry and the topology of oriented scattering networks
Delplace, Pierre; Fruchart, Michel; Tauber, Clément
2017-05-01
We investigate the topological properties of dynamical states evolving on periodic oriented graphs. This evolution, which encodes the scattering processes occurring at the nodes of the graph, is described by a single-step global operator, in the spirit of the Ho-Chalker model. When the successive scattering events follow a cyclic sequence, the corresponding scattering network can be equivalently described by a discrete time-periodic unitary evolution, in line with Floquet systems. Such systems may present anomalous topological phases where all the first Chern numbers are vanishing, but where protected edge states appear in a finite geometry. To investigate the origin of such anomalous phases, we introduce the phase rotation symmetry, a generalization of usual symmetries which only occurs in unitary systems (as opposed to Hamiltonian systems). Equipped with this new tool, we explore a possible explanation of the pervasiveness of anomalous phases in scattering network models, and we define bulk topological invariants suited to both equivalent descriptions of the network model, which fully capture the topology of the system. We finally show that the two invariants coincide, again through a phase rotation symmetry arising from the particular structure of the network model.
Directory of Open Access Journals (Sweden)
A. Garnier
2015-02-01
Full Text Available This paper provides a detailed evaluation of cloud absorption optical depths retrieved at 12.05 μm and comparisons to extinction optical depths retrieved at 0.532 μm from perfectly co-located observations of single-layered semi-transparent cirrus over ocean made by the Imaging Infrared Radiometer (IIR and the Cloud and Aerosol Lidar with Orthogonal Polarization (CALIOP flying on-board the CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations satellite. The blackbody radiance taken in the IIR Version 3 algorithm is evaluated, and IIR retrievals are corrected accordingly. IIR infrared absorption optical depths are then compared to CALIOP visible extinction optical depths when the latter can be directly derived from the measured apparent 2-way transmittance through the cloud. Numerical simulations and IIR retrievals of ice crystal sizes suggest that the ratios of CALIOP extinction and IIR absorption optical depths should remain roughly constant with respect to temperature. Instead, these ratios are found to increase quasi-linearly by about 40% as the temperature at the layer centroid altitude decreases from 240 to 200 K. This behavior is explained by variations of the multiple scattering factor ηT to be applied to correct the measured transmittance, which is taken equal to 0.6 in the CALIOP Version 3 algorithm, and which is found here to vary with temperature (and hence cloud particle size from ηT = 0.8 at 200 K to ηT = 0.5 at 240 K for clouds with optical depth larger than 0.3. The revised parameterization of ηT introduces a concomitant temperature dependence in the simultaneously derived CALIOP lidar ratios that is consistent with observed changes in CALIOP depolarization ratios and particle habits derived from IIR measurements.
Semiclassical wave packet study of anomalous isotope effect in ozone formation.
Vetoshkin, Evgeny; Babikov, Dmitri
2007-10-21
We applied the semiclassical initial value representation method to calculate energies, lifetimes, and wave functions of scattering resonances in a two-dimensional potential for O+O2 collision. Such scattering states represent the metastable O3* species and play a central role in the process of ozone formation. Autocorrelation functions for scattering states were computed and then analyzed using the Prony method, which permits one to extract accurate energies and widths of the resonances. We found that the results of the semiclassical wave packet propagation agree well with fully quantum results. The focus was on the 16O16O18O isotopomer and the anomalous isotope effect associated with formation of this molecule, either through the 16O16O+18O or the 16O+16O18O channels. An interesting correlation between the local vibration mode character of the metastable states and their lifetimes was observed and explained. New insight is obtained into the mechanism by which the long-lived resonances in the delta zero-point energy part of spectrum produce the anomalously large isotope effect.
Anomalous scaling and super-roughness in the growth of CdTe polycrystalline films
Mata, Angélica S.; Ferreira, Silvio C., Jr.; Ribeiro, Igor R. B.; Ferreira, Sukarno O.
2008-09-01
CdTe films grown on glass substrates covered by fluorine-doped tin oxide by hot-wall epitaxy were studied through the interface dynamical scaling theory. Direct measures of the dynamical exponent revealed an intrinsically anomalous scaling characterized by a global roughness exponent α , distinct from the local one (the Hurst exponent H ) previously reported by Ferreira [Appl. Phys. Lett.88, 244103 (2006)]. A variety of scaling behaviors was obtained with varying substrate temperature. In particular, a transition from an intrinsically anomalous scaling regime with H≠αrough regime with H≠α>1 at high temperatures was observed. The temperature is a growth parameter that controls both the interface roughness and dynamical scaling exponents. Nonlocal effects are pointed out as the factors ruling the anomalous scaling behavior.
Scattering fidelity in elastodynamics
Gorin, T.; Seligman, T. H.; Weaver, R. L.
2006-01-01
The recent introduction of the concept of scattering fidelity causes us to revisit the experiment by Lobkis and Weaver [Phys. Rev. Lett. 90, 254302 (2003)]. There, the “distortion” of the coda of an acoustic signal is measured under temperature changes. This quantity is, in fact, the negative logarithm of scattering fidelity. We reanalyze their experimental data for two samples, and we find good agreement with random matrix predictions for the standard fidelity. Usually, one may expect such an agreement for chaotic systems, only. While the first sample may indeed be assumed chaotic, for the second sample, a perfect cuboid, such an agreement is surprising. For the first sample, the random matrix analysis yields perturbation strengths compatible with semiclassical predictions. For the cuboid, the measured perturbation strengths are by a common factor of (5)/(3) too large. Apart from that, the experimental curves for the distortion are well reproduced.
Comparison of anomalous Doppler resonance effects with molybdenum and graphite limiters on HT-7.
Wang, Y M; Gao, X; Ling, B L; Liu, Y; Zhang, S B; Han, X; Ti, A; Li, E Z
2012-03-01
The material of limiter in HT-7 tokamak was changed from graphite to molybdenum in the last experimental campaign. The pitch angle scattering of runaway electrons due to anomalous Doppler resonance effects was observed. The experimental results agree very well with the stable boundary condition expected from the linear resistive theory but only agree with that from the nonlinear evolutionary of runaway-electron distribution theory in low electric field region. The current carried by runaway electrons is the same under different limiter conditions.
Single meson contributions to the muon's anomalous magnetic moment
Energy Technology Data Exchange (ETDEWEB)
Pauk, Vladyslav [Johannes Gutenberg-Universitaet, Institut fuer Kernphysik, Mainz (Germany); Johannes Gutenberg-Universitaet, PRISMA Cluster of Excellence, Mainz (Germany); Taras Shevchenko National University of Kyiv, Department of Physics, Kyiv (Ukraine); Vanderhaeghen, Marc [Johannes Gutenberg-Universitaet, Institut fuer Kernphysik, Mainz (Germany); Johannes Gutenberg-Universitaet, PRISMA Cluster of Excellence, Mainz (Germany)
2014-08-15
We develop the formalism to provide an improved estimate for the hadronic light-by-light correction to the muon's anomalous magnetic moment a{sub μ}, by considering single meson contributions beyond the leading pseudoscalar mesons. We incorporate available experimental input as well as constraints from light-by-light scattering sum rules to estimate the effects of axial-vector, scalar, and tensor mesons. We give numerical evaluations for the hadronic light-by-light contribution of these states to a{sub μ}. The presented formalism allows one to further improve on these estimates, once new data for such meson states will become available. (orig.)
Origin of enhanced anomalous Hall effect in ultrathin Pt/permalloy bilayers
Directory of Open Access Journals (Sweden)
Y. Q. Zhang
2016-02-01
Full Text Available There are two mechanisms which could enhance spin-dependent scattering in a low dimensional Pt/Ferromagnetic metal structure. One is magnetic proximity effect. The other is spin orbit coupling proximity effect which was suggested recently. This work demonstrates that, through a series of experiments on anomalous Hall effect, the spin orbit coupling proximity effect dominates the enhancement in very thin Pt/Permalloy bilayers. It may help to find a way to optimize magnetic transport property of spintronics devices in which the spin orbit coupling is deeply involved.
Institute of Scientific and Technical Information of China (English)
段弯弯; 杨红
2015-01-01
为促进我国肉羊产业发展提供参考，基于2006—2012年肉羊生产相关数据，运用随机前沿分析法对河北、黑龙江、山东、河南、陕西和新疆的肉羊散养成本效率进行测算，分析其变化趋势，探讨其影响因素。结果表明：河北、黑龙江、山东、河南、陕西和新疆的肉羊散养成本效率总体呈波动上升趋势，存在不同程度的成本非效率情况，距离最优效率水平仍有一定差距，尚有较大的提升空间。料肉比与成本效率呈负相关，降低料肉比能够提高成本效率；疫病是导致成本效率低下的主要因素。%The cost efficiency of scatter-fed mutton sheep of Hebei, Heilongjiang, Shangdong, Henan,Shaanxi and Xinjiang was calculated,then the variation trend of cost efficiency of scatter-fed mutton sheep was analyzed by stochastic frontier analysis, and finally the factors to influence cost efficiency of scatter-fed mutton sheep were discussed to provide a reference for development of mutton sheep industry in China.The results showed that the cost efficiency of scatter-fed mutton sheep of Hebei, Heilongjiang,Shangdong,Henan,Shaanxi and Xinjiang presents a fluctuant rising trend overall and because there is a cost non-efficiency condition to varying degrees,the cost efficiency of scatter-fed mutton sheep does not reach the optimum efficiency,which indicates there is a great promotion space in cost efficiency of scatter-fed mutton sheep.The feed/meat ratio is negatively related to the cost efficiency and reducing feed/meat ratio can improve cost efficiency.Epidemic disease is the main factor to influence cost efficiency of scatter-fed mutton sheep.
Brown, Adrian J
2013-01-01
Scattering by particles significantly smaller than the wavelength is an important physical process in the rocky bodies in our solar system and beyond. A number of observations of spectral bluing (referred to in those papers as "Rayleigh scattering") on planetary surfaces have been recently reported, however, the necessary mathematical modeling of this phenomenon has not yet achieved maturity. This paper is a first step to this effect, by examining the effect of grain size and optical index on the albedo of small conservative and absorbing particles as a function of wavelength. The basic conditions necessary for spectral bluing or reddening to be observed in real-world situations are identified. We find that any sufficiently monomodal size distribution of scattering particles will cause spectral bluing in some part of the EM spectrum regardless of its optical index.
Anomalous Coronary Artery: Run of a Lifetime.
Green, Michael Stuart; Sehgal, Sankalp; Smukler, Naomi; Suber, LaDouglas Jarod; Saththasivam, Pooven
2016-09-01
The anatomy of the coronary circulation is well described with incidence of congenital anomalies of approximately 0.3% to 1.0%. Although often incidental, 20% are life-threatening. A 25-year-old woman with syncopal episodes collapsed following a 10-km run. Coronary anatomy evaluation showed an anomalous left main coronary artery originating from the right sinus of valsalva and following a course between the aorta and the pulmonary outflow tract. Percutaneous coronary intervention was followed by eventual surgical revascularization. Abnormal course of coronary arteries plays a role in the pathogenesis of sudden death on exertion. Origin of the left main coronary from the right sinus of valsalva is a rare congenital anomaly. The expansion of the roots of the aorta and pulmonary trunk with exertion lead to compression of the coronary artery and syncope. Our patient raises awareness of a potentially fatal coronary artery path. Intraoperative identification of anomalous coronaries by utilizing intraoperative transesophageal echocardiography was critical.
Anomalous interactions at a linear collider
Indian Academy of Sciences (India)
Sudhansu S Biswal; Debajyoti Choudhury; Rohini M Godbole; Ritesh K Singh
2007-11-01
We examine, in a model independent way, the sensitivity of a linear collider to the couplings of a light Higgs boson to a pair of gauge bosons, including the possibility of CP violation. We construct several observables that probe the various possible anomalous couplings. For an intermediate mass Higgs, a collider operating at a center of mass energy of 500 GeV and with an integrated luminosity of 500 fb-1 is shown to be able to constrain the vertex at the few per cent level, with even higher sensitivity for some of the couplings. However, lack of sufficient number of observables as well as contamination from the vertex limits the precision to which anomalous part of the coupling can be probed.
Anomalous electromagnetism of pions and magnons
Energy Technology Data Exchange (ETDEWEB)
Wiese, U.-J. [Institute for Theoretical Physics, Bern University Sidlerstrasse 5, CH-3012 Bern (Switzerland)
2005-04-15
Pions and magnons - the Goldstone bosons of the strong interactions and of magnetism - share a number of common features. Pion and magnon fields couple anomalously to electromagnetism through the conserved Goldstone-Wilczek current of their topological Skyrmion excitations. In the pion case, this coupling gives rise to the decay of the neutral pion into two photons. In the magnon case, the anomalous coupling leads to photonmagnon conversion in an external magnetic field. A measurement of the conversion rate in quantum Hall ferromagnets determines the anyon statistics angle of baby-Skyrmions. If photon-magnon conversion also occurs in antiferromagnets, baby-Skyrmions carry electric charge and may represent the Cooper-pairs of high-temperature superconductors.
Remote sensing and characterization of anomalous debris
Sridharan, R.; Beavers, W.; Lambour, R.; Gaposchkin, E. M.; Kansky, J.; Stansbery, E.
1997-01-01
The analysis of orbital debris data shows a band of anomalously high debris concentration in the altitude range between 800 and 1000 km. Analysis indicates that the origin is the leaking coolant fluid from nuclear power sources that powered a now defunct Soviet space-based series of ocean surveillance satellites. A project carried out to detect, track and characterize a sample of the anomalous debris is reported. The nature of the size and shape of the sample set, and the possibility of inferring the composition of the droplets were assessed. The technique used to detect, track and characterize the sample set is described and the results of the characterization analysis are presented. It is concluded that the nature of the debris is consistent with leaked Na-K fluid, although this cannot be proved with the remote sensing techniques used.
Anomalous feedback and negative domain wall resistance
Cheng, Ran; Zhu, Jian-Gang; Xiao, Di
2016-11-01
Magnetic induction can be regarded as a negative feedback effect, where the motive-force opposes the change of magnetic flux that generates the motive-force. In artificial electromagnetics emerging from spintronics, however, this is not necessarily the case. By studying the current-induced domain wall dynamics in a cylindrical nanowire, we show that the spin motive-force exerting on electrons can either oppose or support the applied current that drives the domain wall. The switching into the anomalous feedback regime occurs when the strength of the dissipative torque β is about twice the value of the Gilbert damping constant α. The anomalous feedback manifests as a negative domain wall resistance, which has an analogy with the water turbine.
Asano, M; Bliokh, Y P; Kofman, A G; Zhao, G; Ikuta, R; Yamamoto, T; Kivshar, Y S; Yang, L; Imoto, N; Ozdemir, S K; Nori, F
2016-01-01
We study inelastic resonant scattering of a Gaussian pulse with the parameters close to a zero of the complex scattering coefficient. We demonstrate, both theoretically and experimentally, that such near-zero scattering can result in anomalously-large time delays and frequency shifts of the scattered pulse. Furthermore, we reveal a close analogy of these anomalous shifts with the spatial and angular Goos-Hanchen optical beam shifts, which are amplified via quantum weak measurements. However, in contrast to other beam-shift and weak-measurement systems, we deal with a one-dimensional scalar wave without any intrinsic degrees of freedom. It is the non-Hermitian nature of the system that produces its rich and non-trivial behaviour. Our results are generic for any scattering problem, either quantum or classical. As an example, we consider the transmission of an optical pulse through a nano-fiber with a side-coupled toroidal micro-resonator. The zero of the transmission coefficient corresponds to the critical coup...
On scattered subword complexity
Kása, Zoltán
2011-01-01
Special scattered subwords, in which the gaps are of length from a given set, are defined. The scattered subword complexity, which is the number of such scattered subwords, is computed for rainbow words.
Anomalous enthalpy relaxation in vitreous silica
DEFF Research Database (Denmark)
Yue, Yuanzheng
2015-01-01
scans. It is known that the liquid fragility (i.e., the speed of the viscous slow-down of a supercooled liquid at its Tg during cooling) has impact on enthalpy relaxation in glass. Here, we find that vitreous silica (as a strong system) exhibits striking anomalies in both glass transition and enthalpy...... the fragile ones do in a structurally independent fashion. We discuss the origin of the anomalous enthalpy relaxation in the HQ vitreous silica....
Anomalous Symmetry Fractionalization and Surface Topological Order
Directory of Open Access Journals (Sweden)
Xie Chen
2015-10-01
Full Text Available In addition to possessing fractional statistics, anyon excitations of a 2D topologically ordered state can realize symmetry in distinct ways, leading to a variety of symmetry-enriched topological (SET phases. While the symmetry fractionalization must be consistent with the fusion and braiding rules of the anyons, not all ostensibly consistent symmetry fractionalizations can be realized in 2D systems. Instead, certain “anomalous” SETs can only occur on the surface of a 3D symmetry-protected topological (SPT phase. In this paper, we describe a procedure for determining whether a SET of a discrete, on-site, unitary symmetry group G is anomalous or not. The basic idea is to gauge the symmetry and expose the anomaly as an obstruction to a consistent topological theory combining both the original anyons and the gauge fluxes. Utilizing a result of Etingof, Nikshych, and Ostrik, we point out that a class of obstructions is captured by the fourth cohomology group H^{4}(G,U(1, which also precisely labels the set of 3D SPT phases, with symmetry group G. An explicit procedure for calculating the cohomology data from a SET is given, with the corresponding physical intuition explained. We thus establish a general bulk-boundary correspondence between the anomalous SET and the 3D bulk SPT whose surface termination realizes it. We illustrate this idea using the chiral spin liquid [U(1_{2}] topological order with a reduced symmetry Z_{2}×Z_{2}⊂SO(3, which can act on the semion quasiparticle in an anomalous way. We construct exactly solved 3D SPT models realizing the anomalous surface terminations and demonstrate that they are nontrivial by computing three-loop braiding statistics. Possible extensions to antiunitary symmetries are also discussed.
Blow up Analysis for Anomalous Granular Gases
Rey, Thomas
2012-01-01
20 p.; International audience; We investigate in this article the long-time behaviour of the solutions to the energy-dependant, spatially-homogeneous, inelastic Boltzmann equation for hard spheres. This model describes a diluted gas composed of hard spheres under statistical description, that dissipates energy during collisions. We assume that the gas is ''anomalous'', in the sense that energy dissipation increases when temperature decreases. This allows the gas to cool down in finite time. W...
Anomalous Mirror Symmetry Generated by Optical Illusion
Directory of Open Access Journals (Sweden)
Kokichi Sugihara
2016-04-01
Full Text Available This paper introduces a new concept of mirror symmetry, called “anomalous mirror symmetry”, which is physically impossible but can be perceived by human vision systems because of optical illusion. This symmetry is characterized geometrically and a method for creating cylindrical surfaces that create this symmetry is constructed. Examples of solid objects constructed by a 3D printer are also shown.
Anomalous CMB polarization and gravitational chirality
Contaldi, Carlo R.; Magueijo, Joao; Smolin, Lee
2008-01-01
We consider the possibility that gravity breaks parity, with left and right handed gravitons coupling to matter with a different Newton's constant and show that this would affect their zero-point vacuum fluctuations during inflation. Should there be a cosmic background of gravity waves, the effect would translate into anomalous CMB polarization. Non-vanishing TB (and EB) polarization components emerge, revealing interesting experimental targets. Indeed if reasonable chirality is present a TB ...
The Discovery of Anomalous Microwave Emission
Leitch, Erik M.; Readhead, A. C. R.
2013-01-01
We discuss the first detection of anomalous microwave emission, in the Owens Valley RING5M experiment, and its interpretation in the context of the ground-based cosmic microwave background (CMB) experiments of the early 1990s. The RING5M experiment was one of the first attempts to constrain the anisotropy power on sub-horizon scales, by observing a set of -size fields around the North Celestial Pole (NCP). Fields were selected close to the NCP to allow continuous integrati...
Anomalous dominance, immune parameters, and spatial ability.
Hassler, M
1993-02-01
In a sample of male and female subjects in late adolescence, we investigated the relationship of spatial abilities to anomalous dominance and immune parameters as suggested by Geschwind's model of cerebral lateralization (Geschwind & Galaburda, 1985) In addition to the behavioral markers asthma/allergies, migraine, and myopia, we measured IgE and Ig total in blood serum. Atypical handedness, atypical language dominance, and atypical visuospatial dominance were found to be connected with spatial giftedness, and atypical handedness was related to immune vulnerability in males. This outcome provided some support for the Geschwind model in men. In women, spatial giftedness was related to immune vulnerability, but no indicator of anomalous dominance was connected with either giftedness, or immune parameters. Thus, the central thesis of the Geschwind model, i.e., elevated prenatal testosterone effects on the developing brain cause anomalous dominance and, as side effects, spatial giftedness and immune vulnerability, and all these consequences should be related to each other, was not confirmed by our data for females.
Neoclassical and anomalous flows in stellarators
Ware, A. S.; Marine, T.; Spong, D. A.
2009-11-01
The impact of magnetic geometry and plasma profiles on flows and viscosities in stellarators is investigated. This work examines both neoclassical and anomalous flows for a number of configurations including a particular focus on the Helically Symmetric Experiment (HSX) and other quasi-symmetric configurations. Neoclassical flows and viscosities are calculated using the PENTA code [1]. For anomalous flows, the neoclassical viscosities from PENTA are used in a transport code that includes Reynolds stress flow generation [2]. This is done for the standard quasi-helically symmetric configuration of HSX, a symmetry-breaking mirror configuration and a hill configuration. The impact of these changes in the magnetic geometry on neoclassical viscosities and flows in HSX are discussed. Due to variations in neoclassical viscosities, HSX can have strong neoclassical flows in the core region. In turn, these neoclassical flows can provide a seed for anomalous flow generation. These effects are shown to vary as the ratio of electron to ion temperature varies. In particular, as the ion temperature increases relative to the electron flow shear is shown to increase. [1] D. A. Spong, Phys. Plasmas 12, 056114 (2005). [2] D. E. Newman, et al., Phys. Plasmas 5, 938 (1998).
Anomalous dissolution of metals and chemical corrosion
Directory of Open Access Journals (Sweden)
DRAGUTIN M. DRAZIC
2005-03-01
Full Text Available An overview is given of the anomalous behavior of some metals, in particular Fe and Cr, in acidic aqueous solutions during anodic dissolution. The anomaly is recognizable by the fact that during anodic dissolutionmore material dissolves than would be expected from the Faraday law with the use of the expected valence of the formed ions. Mechanical disintegration, gas bubble blocking, hydrogen embrittlement, passive layer cracking and other possible reasons for such behavior have been discussed. It was shown, as suggested by Kolotyrkin and coworkers, that the reason can be, also, the chemical reaction in which H2O molecules with the metal form metal ions and gaseous H2 in a potential independent process. It occurs simultaneously with the electrochemical corrosion process, but the electrochemical process controls the corrosion potential. On the example of Cr in acid solution itwas shown that the reason for the anomalous behavior is dominantly chemical dissolution, which is considerably faster than the electrochemical corrosion, and that the increasing temperature favors chemical reaction, while the other possible reasons for the anomalous behavior are of negligible effect. This effect is much smaller in the case of Fe, but exists. The possible role of the chemical dissolution reacton and hydrogen evolution during pitting of steels and Al and stress corrosion cracking or corrosion fatigue are discussed.
Bidirectional optical scattering facility
Federal Laboratory Consortium — Goniometric optical scatter instrument (GOSI)The bidirectional reflectance distribution function (BRDF) quantifies the angular distribution of light scattered from a...
Bidirectional optical scattering facility
Federal Laboratory Consortium — Goniometric optical scatter instrument (GOSI) The bidirectional reflectance distribution function (BRDF) quantifies the angular distribution of light scattered from...
Experimental demonstration of anomalous Floquet topological insulator for sound
Peng, Yu-Gui; Qin, Cheng-Zhi; Zhao, De-Gang; Shen, Ya-Xi; Xu, Xiang-Yuan; Bao, Ming; Jia, Han; Zhu, Xue-Feng
2016-01-01
Time-reversal invariant topological insulator is widely recognized as one of the fundamental discoveries in condensed matter physics, for which the most fascinating hallmark is perhaps a spin-based topological protection, the absence of scattering of conduction electrons with certain spins on matter surface. Recently, it has created a paradigm shift for topological insulators, from electronics to photonics, phononics and mechanics as well, bringing about not only involved new physics but also potential applications in robust wave transport. Despite the growing interests in topologically protected acoustic wave transport, T-invariant acoustic topological insulator has not yet been achieved. Here we report experimental demonstration of anomalous Floquet topological insulator for sound: a strongly coupled metamaterial ring lattice that supports one-way propagation of pseudo-spin-dependent edge states under T-symmetry. We also demonstrate the formation of pseudo-spin-dependent interface states due to lattice dislocations and investigate the properties of pass band and band gap states. PMID:27834375
Pavel, Ioana E.; Alnajjar, Khadijeh S.; Monahan, Jennifer L.; Stahler, Adam; Hunter, Nora E.; Weaver, Kent M.; Baker, Joshua D.; Meyerhoefer, Allie J.; Dolson, David A.
2012-01-01
A novel laboratory experiment was successfully implemented for undergraduate and graduate students in physical chemistry and nanotechnology. The main goal of the experiment was to rigorously determine the surface-enhanced Raman scattering (SERS)-based sensing capabilities of colloidal silver nanoparticles (AgNPs). These were quantified by…
Large-angle elastic scattering of 88.03-keV photons by elements with 30{<=}Z{<=}92
Energy Technology Data Exchange (ETDEWEB)
Kumar, Ajay; Shahi, J.S.; Garg, M.L.; Puri, Sanjiv; Mehta, D.; Singh, Nirmal E-mail: nsingh@panjabuniv.chd.nic.in
2001-10-01
Elastic-scattering differential cross-sections for 88.03-keV photons have been measured at an angle of 125 deg. for 17 elements in the atomic region 30{<=}Z{<=}92. The measured elastic-scattering cross-sections have been compared with those obtained in the independent-particle approximation through calculations of the modified-relativistic form factors (MFs), a combination of the MFs and angle-independent 'anomalous' scattering factors (ASFs), and the relativistic second-order S-matrix. The S-matrix cross-sections, in general, represent the trend of the measured data over the whole atomic region under investigation. However, these values are, on an average, lower by 10% than the measured ones. The MF cross-sections, in general, exhibit considerable deviations ({approx}30%) from the measured values. In the case of Bi with K-shell binding energy, E{sub K}(Bi)=90.526 keV, just above the incident photon energy (E{sub inc}) of 88.03 keV, the MF cross-section is found to be enormously ({approx}5 times) higher than the measured value. The MF cross-sections in combination with ASFs are in good agreement with the measured values for all the elements except for Pb (E{sub K}(Pb)=88.004 keV) and Bi, where these values are enormously ({approx}28 times) smaller and higher by 31%, respectively.
Coherent control of double deflected anomalous modes in ultrathin trapezoid-shaped slit metasurface
Zhu, Z.; Liu, H.; Wang, D.; Li, Y. X.; Guan, C. Y.; Zhang, H.; Shi, J. H.
2016-11-01
Coherent light-matter interaction in ultrathin metamaterials has been demonstrated to dynamically modulate intensity, polarization and propagation direction of light. The gradient metasurface with a transverse phase variation usually exhibits an anomalous refracted beam of light dictated by so-called generalized Snell’s law. However, less attention has been paid to coherent control of the metasurface with multiple anomalous refracted beams. Here we propose an ultrathin gradient metasurface with single trapezoid-shaped slot antenna as its building block that allows one normal and two deflected transmitted beams. It is numerically demonstrated that such metasurface with multiple scattering modes can be coherently controlled to modulate output intensities by changing the relative phase difference between two counterpropagating coherent beams. Each mode can be coherently switched on/off and two deflected anomalous beams can be synchronously dictated by the phase difference. The coherent control effect in the trapezoid-shaped slit metasurface will offer a promising opportunity for multichannel signals modulation, multichannel sensing and wave front shaping.
Energy Technology Data Exchange (ETDEWEB)
Zhu, Hongguo [Univ. of Virginia, Charlottesville, VA (United States)
2000-08-01
The form factors of the neutron give information on fundamental properties of the nucleons and provide a critical testing ground for models based on QCD. In late 1998, Jefferson Lab (JLAB) experiment E93-026 measured the spin-dependent part of the exclusive (e, e'n) scattering cross section from a polarized deuterated ammonia (^{15}ND_{3}) target at a four momentum transfer squared of Q^{2} = 0.5 (GeV/c)_{2}. A longitudinally polarized electron beam was scattered from the polarized target and the quasi-elastically scattered electron was detected in coincidence with the knocked-out neutron. The data have been analyzed in terms of the spin-correlation parameter, or the electron-deuteron vector asymmetry (A$V\\atop{ed}$), of (e, e'n) to determine the neutron electric form factor G$n\\atop{E}$. The result is consistent with data from existing experiments and shows a good agreement with the Galster parameterization of G$n\\atop{E}$ within experimental uncertainty.
Energy Technology Data Exchange (ETDEWEB)
Hongguo Zhu
2000-08-01
The form factors of the neutron give information on fundamental properties of the nucleons and provide a critical testing ground for models based on QCD. In late 1998, Jefferson Lab (JLAB) experiment E93-026 measured the spin-dependent part of the exclusive (e, e'n) scattering cross section from a polarized deuterated ammonia ({sup 15}ND{sub 3}) target at a four momentum transfer squared of Q{sup 2} = 0.5 (GeV/c){sub 2}. A longitudinally polarized electron beam was scattered from the polarized target and the quasi-elastically scattered electron was detected in coincidence with the knocked-out neutron. The data have been analyzed in terms of the spin-correlation parameter, or the electron-deuteron vector asymmetry (A{sub ed}{sup V}), of (e, e'n) to determine the neutron electric form factor G{sub E}{sup n}. The result is consistent with data from existing experiments and shows a good agreement with the Galster parameterization of G{sub E}{sup n} within experimental uncertainty.
An improved algorithm for cloud multiple scattering
Institute of Scientific and Technical Information of China (English)
Guibin Yuan; Xiaogang Sun; Jingmin Dai
2006-01-01
@@ Clouds' radiation characteristics are very important in clouds scene simulation, weather forecasting, pattern recognition, and other fields. Radiation of a cloud mainly comes from its multiple scattering. A new algorithm to calculate multiple scattering, called build-up factor algorithm, is proposed in this paper. In this algorithm, a modified gamma distribution is assumed to describe droplets distribution inside a cloud, then the radiation transport equation is calculated to get the solution of single scattering, and finally, a build-up factor is defined to estimate the multiple scattering contributions. This algorithm considers both single scattered radiance and multiple scattered radiance and needs shorter computing time. It can be used in real time simulations.
Scaling of Anomalous Hall Effects in Facing-Target Reactively Sputtered Fe4N Films
Zhang, Yan
2015-05-13
Anomalous Hall effect (AHE) in the reactively sputtered epitaxial and polycrystalline γ′-Fe4N films is investigated systematically. The Hall resistivity is positive in the entire temperature range. The magnetization, carrier density and grain boundaries scattering have a major impact on the AHE scaling law. The scaling exponent γ in the conventional scaling of is larger than 2 in both the epitaxial and polycrystalline γ′-Fe4N films. Although γ>2 has been found in heterogeneous systems due to the effects of the surface and interface scattering on AHE, γ>2 is not expected in homogenous epitaxial systems. We demonstrated that γ>2 results from residual resistivity (ρxx0) in γ′-Fe4N films. Furthermore, the side-jump and intrinsic mechanisms are dominant in both epitaxial and polycrystalline samples according to the proper scaling relation.
Soejima, Y; Sugiyama, M; Annaka, M; Nakamura, A; Hiramatsu, N; Hara, K
2003-01-01
The structure of copper ion clusters in dehydrated N-isopropylacrylamide/sodium acrylate (NIPA/SA) gel has been studied by means of small angle X-ray scattering (SAXS) method. In order to distinguish the intensity scattered by Cu ions, the X-ray anomalous dispersion effect around the Cu K absorption edge has been coupled with SAXS. It is found that the dispersion effect dependent on the incident X-ray energy is remarkable only at the momentum transfer q = 0.031 A sup - sup 1 , where a SAXS peak is observed. The results indicate that copper ions form clusters in the dehydrated gel, and that the mean size of clusters is the same as that of SA clusters produced by microphase separation. It is therefore naturally presumed that copper ions are adsorbed into the SA molecules. On the basis of the presumption, a mechanism is proposed for microphase-separation and clustering of Cu ions.
Theory for the anomalous electron transport in Hall effect thrusters. II. Kinetic model
Lafleur, T.; Baalrud, S. D.; Chabert, P.
2016-05-01
In Paper I [T. Lafleur et al., Phys. Plasmas 23, 053502 (2016)], we demonstrated (using particle-in-cell simulations) the definite correlation between an anomalously high cross-field electron transport in Hall effect thrusters (HETs), and the presence of azimuthal electrostatic instabilities leading to enhanced electron scattering. Here, we present a kinetic theory that predicts the enhanced scattering rate and provides an electron cross-field mobility that is in good agreement with experiment. The large azimuthal electron drift velocity in HETs drives a strong instability that quickly saturates due to a combination of ion-wave trapping and wave-convection, leading to an enhanced mobility many orders of magnitude larger than that expected from classical diffusion theory. In addition to the magnetic field strength, B0, this enhanced mobility is a strong function of the plasma properties (such as the plasma density) and therefore does not, in general, follow simple 1 /B02 or 1 /B0 scaling laws.
Anomalous Hall effect and magnetoresistance behavior in Co/Pd1−xAgx multilayers
Guo, Z. B.
2013-02-13
In this paper, we report anomalous Hall effect (AHE) correlated with the magnetoresistance behavior in [Co/Pd1-xAg x]n multilayers. For the multilayers with n = 6, the increase in Ag content from x = 0 to 0.52 induces the change in AHE sign from negative surface scattering-dominated AHE to positive interface scattering-dominated AHE, which is accompanied with the transition from anisotropy magnetoresistance (AMR) dominated transport to giant magnetoresistance (GMR) dominated transport. For n = 80, scaling analysis with Rs ∝ρ xx γ yields γ ∼ 3.44 for x = 0.52 which presents GMR-type transport, in contrast to γ ∼ 5.7 for x = 0 which presents AMR-type transport. © 2013 American Institute of Physics.
Inelastic neutron scattering and lattice dynamics of minerals
Indian Academy of Sciences (India)
Narayani Choudhury; S L Chaplot
2008-10-01
We review current research on minerals using inelastic neutron scattering and lattice dynamics calculations. Inelastic neutron scattering studies in combination with first principles and atomistic calculations provide a detailed understanding of the phonon dispersion relations, density of states and their manifestations in various thermodynamic properties. The role of theoretical lattice dynamics calculations in the planning, interpretation and analysis of neutron experiments are discussed. These studies provide important insights in understanding various anomalous behaviour including pressure-induced amorphization, phonon and elastic instabilities, prediction of novel high pressure phase transitions, high pressure{temperature melting, etc.
X-Ray Absorption and Scattering by Interstellar Grains
Hoffman, John A
2015-01-01
Interstellar abundance determinations from fits to X-ray absorption edges often rely on the following false assumptions: (1) the grains are "optically thin" at the observed X-ray wavelengths, and (2) scattering is insignificant and can be ignored. We show instead that scattering contributes significantly to the attenuation of X-rays for realistic dust grain size distributions and substantially modifies the spectrum near absorption edges of elements present in grains. The dust attenuation modules used in major X-ray spectral fitting programs do not take this into account. We show that the consequences of neglecting scattering on the determination of interstellar elemental abundances are modest; however, scattering (along with uncertainties in the grain size distribution) must be taken into account when near-edge extinction fine structure is used to infer dust mineralogy. We advertise the benefits and accuracy of anomalous diffraction theory for both X-ray halo analysis and near edge absorption studies. An open...
Correlations and anomalous transport effects related to stochastic instability
Energy Technology Data Exchange (ETDEWEB)
Bakunin, O G [Department of Physics and Astronomy, University of Kansas, Malott Hall, 1251 Wescoe Hall Drive, Lawrence, KS 66044 (United States); Nuclear Fusion Institute, RRC ' Kurchatov Institute' , pl. Kurchatova 1, Moscow, 123182 (Russian Federation); FOM Instituut voor Plasmafysica ' Rijnhuizen' , Associate Euroatom-FOM, 3430 BE Nieuwegein (Netherlands)
2005-11-15
In this paper, we analyse turbulent transport in the framework of the correlation approach to obtain the effective diffusion coefficient and characteristic increment in the scaling form. Such factors as anisotropy, seed diffusion mechanisms and reconstruction of flow topology significantly have an impact on the effective diffusivity. We consider the different aspects of stochastic instability such as the decorrelation mechanism to estimate characteristic correlation times and correlation scales in the framework of the scaling approach. The topics to be discussed include the Rechester-Rosenbluth correlation scalings, percolation transport in time dependent flows, anisotropic MHD spectra and a multi-scale approach to the analysis of anomalous transport. To treat long-range correlation effects, the percolation renormalization is analysed in time-dependent regimes. In the framework of the multiscale approach, a scaling for an increment of the stochastic instability in two-dimensional random flow is suggested.
Intraosseous anomalous drainage: a rare case of pretibial varicose vein.
Moraes, Frederico Barra de; Camelo, Carolina Parreira Ribeiro; Brandão, Marcelo Luiz; Fávaro, Pedro Ivo; Barbosa, Tercília Almeida; Barbosa, Raul Carlos
2016-01-01
Valve failure with reflux and post-thrombotic syndrome are the factors most commonly correlated with varicose disease. Other rare etiologies can be put forward when these two main causes are ruled out. We report a case in which a young man presented chronic pain in the left tibia, varicose veins in the lower limbs and frequent occurrences of erysipelas. During investigation of the etiology of the varicose veins, radiographs and magnetic resonance imaging of the left leg were requested. These showed images suggestive of an osteolytic lesion in the tibia, but led us to the diagnosis of an intraosseous vein with anomalous drainage. This was confirmed through vascular examinations comprising Doppler venous flow measurement and phlebography. Recognition of this rare intraosseous anomaly is fundamental for proper patient management, but an intraosseous surgical approach is unnecessary.
Anomalous behavior of nearly-entire visible band manipulated with degenerated image dipole array
Zhang, Lei; Hao, Jiaming; Qiu, Min; Zouhdi, Said; Yang, Joel Kwang Wei; Qiu, Cheng-Wei
2014-10-01
Recently, the control of anomalous light bending via flat gradient-phase metasurfaces has enabled many unprecedented applications. However, either low manipulation efficiency or challenging difficulties in fabrication hinders their practical applications, in particular in the visible range. Therefore, a concept of degenerated image dipole array is reported to realize anomalous light bending with high efficiency. A continuous phase delay varying rather than a discrete one, along with an in-plane wave vector is utilized to achieve anomalous light bending, by controlling and manipulating the mutual coupling between dipole array and the dipole array of its image. The anomalous light bending covers almost the entire visible range with broad incident angles, accompanied with preserved well-defined planar wavefront. In addition, this design is feasible to be fabricated with recent nanofabrication techniques due to its planarized surface configuration. The concept of imperfect image dipole array degenerated from ideal metamaterial absorbers surprisingly empowers significant enhancement in light manipulation efficiency for visible light in a distinct fashion.Recently, the control of anomalous light bending via flat gradient-phase metasurfaces has enabled many unprecedented applications. However, either low manipulation efficiency or challenging difficulties in fabrication hinders their practical applications, in particular in the visible range. Therefore, a concept of degenerated image dipole array is reported to realize anomalous light bending with high efficiency. A continuous phase delay varying rather than a discrete one, along with an in-plane wave vector is utilized to achieve anomalous light bending, by controlling and manipulating the mutual coupling between dipole array and the dipole array of its image. The anomalous light bending covers almost the entire visible range with broad incident angles, accompanied with preserved well-defined planar wavefront. In
SCATTERING FROM RAMIFIED POLYMERIC SYSTEMS
Directory of Open Access Journals (Sweden)
M.Benhamou
2004-01-01
Full Text Available Here, of great interest to us is a quantitative study of the scattering properties from ramified polymeric systems of arbitrary topology. We consider three types of systems, namely ramified polymers in solution, ramified polymer blends, or ternary mixtures made of two ramified polymers of different chemical nature immersed in a good solvent. To achieve the goal of the study, use is made of the Random Phase Approximation. First we determine the exact expression of the form factor of an ideal ramified polymer of any topology, from which we extract the exact expression of its gyration radius. Using the classical Zimm's formulae and the exact form factor, we determine all scattering properties of these three types of ramified polymeric systems. The main conclusion is that ramification of the chains induces drastic changes of the scattering properties.
Energy Technology Data Exchange (ETDEWEB)
Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner (eds.)
2010-07-01
The following topics are dealt with: Neutron sources, symmetry of crystals, diffraction, nanostructures investigated by small-angle neutron scattering, the structure of macromolecules, spin dependent and magnetic scattering, structural analysis, neutron reflectometry, magnetic nanostructures, inelastic scattering, strongly correlated electrons, dynamics of macromolecules, applications of neutron scattering. (HSI)
Berger, D
2000-01-01
scanning electron microscope is examined. By means of the scattering at mono-crystalline samples the influence of channeling (anomalous absorption and transmission) on backscattered electron spectra is shown. Captions are given in English language. This work presents high resolution measurements of the energy and complete angular distribution of the scattering of 20 keV electrons (energy resolution 0.55%). The examinations include take-off angles close to the target surface and non-perpendicular incidences of electrons partly for the first time. The results are of interest for the understanding of fundamental scattering processes, the interpretation of signals and new detector systems in electron microscopy and electron spectroscopy. Furthermore, they are used for the verification of electron scattering models and simulations. The applied compact electrostatic spectrometers with spherical and toroidal geometries are characterized and compared. High resolution spectra are obtained by deconvolution of the measu...
Conformal Sigma Models with Anomalous Dimensions and Ricci Solitons
Nitta, M
2004-01-01
We present new non-Ricci-flat Kahler metrics with U(N) and O(N) isometries as target manifolds of conformally invariant sigma models with an anomalous dimension. They are so-called Ricci solitons, special solutions to a Ricci-flow equation. These metrics explicitly contain the anomalous dimension and reduce to Ricci-flat Kahler metrics on the canonical line bundles over certain coset spaces in the limit of vanishing anomalous dimension.
The anomalous exchange bias effect in core-shell Co/CoO nanoparticles
Feygenson, Mikhail; Yuen, Yiu; Kim, Kisub; Aronson, Meigan
2008-03-01
We study the anomalous exchange bias effect in Co/CoO nanoparticles by means of neutron and x-ray scattering and magnetic experiments. The Co nanoparticles were prepared in oleic acid by thermal decomposition of Co2(CO)8 and were subsequently oxidized. Co core- CoO shell nanoparticles with differing core and shell dimensions were obtained. The magnetic measurements indicated that there is an optimal ratio of the core and shell dimensions which maximizes the exchange bias field. Anomalous small angle x-ray scattering experiments using core-shell contrast and energy analysis provide high accuracy measurements of the core and shell, and their respective size distributions. Neutron diffraction measurements find that oxidation introduces a new modulation wave vector for the magnetization, leading to the increasing magnetic decompensation of the core-shell interface. It is our proposal that this interface moment enhances the exchange coupling of the core and shell, and leads to the extraordinarily large exchange bias effect.
Hic Sunt Leones: Anomalous Scaling In Rainfall
Ferraris, L.; Gabellani, S.; Provenzale, A.; Rebora, N.
In recent years the spatio-temporal intermittency of precipitation fields has often been quantified in terms of scaling and/or multifractal behaviour. In this work we anal- yse the spatial scaling properties of precipitation intensity fields measured during the GATE radar experiment, and compare the results with those obtained from surrogate data generated by nonlinearly filtered, linear stochastic processes and from random shuffling of the original data. The results of the study suggest a spurious nature of the spatial multifractal behaviour of the GATE fields and indicate that claims of multifrac- tality and anomalous scaling in rainfall may have to be reconsidered.
Anomalous Hall Effect in a Kagome Ferromagnet
Ye, Linda; Wicker, Christina; Suzuki, Takehito; Checkelsky, Joseph; Joseph Checkelsky Team
The ferromagnetic kagome lattice is theoretically known to possess topological band structures. We have synthesized large single crystals of a kagome ferromagnet Fe3Sn2 which orders ferromagnetically well above room temperature. We have studied the electrical and magnetic properties of these crystals over a broad temperature and magnetic field range. Both the scaling relation of anomalous Hall effect and anisotropic magnetic susceptibility show that the ferromagnetism of Fe3Sn2 is unconventional. We discuss these results in the context of magnetism in kagome systems and relevance to the predicted topological properties in this class of compounds. This research is supported by DMR-1231319.
Anomalous CMB polarization and gravitational chirality
Contaldi, Carlo R; Smolin, Lee
2008-01-01
We consider the possibility that gravity breaks parity, with left and right handed gravitons coupling to matter with a different Newton's constant and show that this would affect their zero-point vacuum fluctuations during inflation. Should there be a cosmic background of gravity waves, the effect would translate into anomalous CMB polarization. Non-vanishing TB (and EB) polarization components emerge, revealing interesting experimental targets. Indeed if reasonable chirality is present a TB measurement would provide the easiest way to detect a gravitational wave background. We speculate on the theoretical implications of such an observation.
Anomalous Redshift of Some Galactic Objects
Zheng, Yi-Jia
2013-01-01
Anomalous redshifts of some galactic objects such as binary stars, early-type stars in the solar neighborhood, and O stars in a star clusters are discussed. It is shown that all these phenomena have a common characteristic, that is, the redshifts of stars increase as the temperature rises. This characteristic cannot be explained by means of the Doppler Effect but can by means of the soft-photon process proposed by Yijia Zheng (arXiv:1305.0427 [astro-ph.HE]).
Energy Technology Data Exchange (ETDEWEB)
Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner (eds.)
2010-07-01
The following topics are dealt with: Neutron sources, neutron properties and elastic scattering, correlation functions measured by scattering experiments, symmetry of crystals, applications of neutron scattering, polarized-neutron scattering and polarization analysis, structural analysis, magnetic and lattice excitation studied by inelastic neutron scattering, macromolecules and self-assembly, dynamics of macromolecules, correlated electrons in complex transition-metal oxides, surfaces, interfaces, and thin films investigated by neutron reflectometry, nanomagnetism. (HSI)
Imaging with Scattered Neutrons
Ballhausen, H.; Abele, H.; Gaehler, R.; Trapp, M.; Van Overberghe, A.
2006-01-01
We describe a novel experimental technique for neutron imaging with scattered neutrons. These scattered neutrons are of interest for condensed matter physics, because they permit to reveal the local distribution of incoherent and coherent scattering within a sample. In contrast to standard attenuation based imaging, scattered neutron imaging distinguishes between the scattering cross section and the total attenuation cross section including absorption. First successful low-noise millimeter-re...
Optical scattering in glass ceramics
Mattarelli, M.; Montagna, M.; Verrocchio, P.
2008-01-01
The transparency of glass ceramics with nanocrystals is generally higher than that expected from the theory of Rayleigh scattering. We attribute this ultra-transparency to the spatial correlation of the nanoparticles. The structure factor is calculated for a simple model system, the random sequentia
What is Double Parton Scattering?
Manohar, Aneesh V
2012-01-01
Processes such as double Drell-Yan and same-sign WW production have contributions from double parton scattering, which are not well-defined because of a delta(z_\\perp=0) singularity that is generated by QCD evolution. We study the single and double parton contributions to these processes, and show how to handle the singularity using factorization and operator renormalization.
Radiative corrections to electron-proton scattering
Maximon, LC; Tjon, JA
2000-01-01
The radiative corrections to elastic electron-proton scattering are analyzed in a hadronic model including the finite size of the nucleon. For initial electron energies above 8 GeV and large scattering angles, the proton vertex correction in this model increases by at least 2% of the overall factor
Growth of CdTe on (100) GaAs and analysis using ion scattering spectrometry
Energy Technology Data Exchange (ETDEWEB)
Mitrovic, B.; King, B.V. [Newcastle Univ., NSW (Australia). Dept. of Physics
1993-12-31
A brief review of Coaxial Impact collision Ion Scattering Spectroscopy (CAICISS) has been presented as well as its advantages in studies of semiconductor surfaces and interfaces. The results that we have gained using fast computer code - SABRE are graphically presented as an incident angular spectrum. The plausible interpretation for the large anomalous peak at 60 deg is given. 14 refs., 1 fig.
Students' Progression in Monitoring Anomalous Results Obtained in Inquiry-Based Laboratory Tasks
Crujeiras-Pérez, Beatriz; Jiménez-Aleixandre, Maria Pilar
2017-07-01
This paper examines students' engagement in monitoring anomalous results across a 2-year longitudinal study with 9th and 10th graders (14-15 and 15-16 years of age). The context is a set of five inquiry-based laboratory tasks, requiring students to plan and carry out investigations. The study seeks to examine students' interpretation of data, in particular anomalous results generated by them during the process of solving the tasks, and their ability to monitor them. Data collected include video and audio recordings as well as students' written products. For the analysis, two rubrics were developed drawing on Chinn and Brewer (Cognition and Instruction, 19, 323-393, 2001) and Hmelo-Silver et al. (Science Education, 86, 219-243, 2002). The findings point to a pattern of progress in students' responses across the 2 years: (a) responses revealing a low capacity of monitoring due to not recognizing the data as anomalous or recognizing it as anomalous but being unable to explain their causes are more frequent in the first tasks and (b) responses revealing an improved capacity of monitoring are more frequent in the last tasks. The factors influencing students' regulation of their performances, as the requirement of planning, and specific scaffolding based on activity theory are discussed.
Antonov; Lanotte; Mazzino
2000-06-01
The problem of anomalous scaling in magnetohydrodynamics turbulence is considered within the framework of the kinematic approximation, in the presence of a large-scale background magnetic field. The velocity field is Gaussian, delta-correlated in time, and scales with a positive exponent xi. Explicit inertial-range expressions for the magnetic correlation functions are obtained; they are represented by superpositions of power laws with nonuniversal amplitudes and universal (independent of the anisotropy and forcing) anomalous exponents. The complete set of anomalous exponents for the pair correlation function is found nonperturbatively, in any space dimension d, using the zero-mode technique. For higher-order correlation functions, the anomalous exponents are calculated to O(xi) using the renormalization group. The exponents exhibit a hierarchy related to the degree of anisotropy; the leading contributions to the even correlation functions are given by the exponents from the isotropic shell, in agreement with the idea of restored small-scale isotropy. Conversely, the small-scale anisotropy reveals itself in the odd correlation functions: the skewness factor is slowly decreasing going down to small scales and higher odd dimensionless ratios (hyperskewness, etc.) dramatically increase, thus diverging in the r-->0 limit.
Automatically identifying scatter in fluorescence data using robust techniques
DEFF Research Database (Denmark)
Engelen, S.; Frosch, Stina; Hubert, M.
2007-01-01
is developed based on robust statistical methods. The method does not demand any visual inspection of the data prior to modeling, and can handle first and second order Rayleigh scatter as well as Raman scatter in various types of EEM data. The results of the automated scatter identification method were used......First and second order Rayleigh and Raman scatter is a common problem when fitting Parallel Factor Analysis (PARAFAC) to fluorescence excitation-emission data (EEM). The scatter does not contain any relevant chemical information and does not conform to the low-rank trilinear model. The scatter...... as input data for three different PARAFAC methods. Firstly inserting missing values in the scatter regions are tested, secondly an interpolation of the scatter regions is performed and finally the scatter regions are down-weighted. These results show that the PARAFAC method to choose after scatter...
Diffraction Anomalous Near-Edge Structure
Moltaji, Habib O., Jr.
1995-11-01
To determine the atomic structure about atom of an element in a sample of a condensed multicomponent single crystal, contrast radiation is proposed with the use of Diffraction Anomalous Near-Edge Structure (DANES), which combines the long-range order sensitivity of the x-ray diffraction and short-range order of the x-ray absorption near-edge techniques. This is achieved by modulating the photon energy of the x-ray beam incident on the sample over a range of energies near an absorption edge of the selected element. Due to anomalous dispersion, x-ray diffraction, and x-ray absorption, the DANES intensity with respect to the selected element is obtained in a single experiment. I demonstrate that synchrotron DANES measurements for the single crystal of thin film and the powder samples and provide the same local atomic structural information as the x-ray absorption near-edge with diffraction condition and can be used to provide enhanced site selectivity. I demonstrate calculations of DAFS intensity and measurements of polarized DANES and XANES intensity.
Anomalous Enthalpy Relaxation in Vitreous Silica
Directory of Open Access Journals (Sweden)
Yuanzheng eYue
2015-08-01
Full Text Available It is a challenge to calorimetrically determine the glass transition temperature (Tg of vitreous silica. Here we demonstrate that this challenge mainly arises from the extreme sensitivity of the Tg to the hydroxyl content in vitreous silica, but also from the irreversibility of its glass transition when repeating the calorimetric scans. It is known that the liquid fragility (i.e., the speed of the viscous slow-down of a supercooled liquid at its Tg during cooling has impact on enthalpy relaxation in glass. Here we find that vitreous silica (as a strong system exhibits striking anomalies in both glass transition and enthalpy relaxation compared to fragile oxide systems. The anomalous enthalpy relaxation of vitreous silica is discovered by performing the hperquenching-annealing-calorimetry experiments. We argue that the strong systems like vitreous silica and vitreous Germania relax in a structurally cooperative manner, whereas the fragile ones do in a structurally independent fashion. We discuss the origin of the anomalous enthalpy relaxation in the HQ vitreous silica.
Hydrodynamic Waves in an Anomalous Charged Fluid
Abbasi, Navid; Rezaei, Zahra
2015-01-01
We study the collective excitations in a relativistic fluid with an anomalous conserved charge. In $3+1$ dimensions, in addition to two ordinary sound modes we find two propagating modes in presence of an external magnetic field: one with a velocity proportional to the coefficient of gauge-gravitational anomaly coefficient and the other with a velocity which depends on both chiral anomaly and the gauge gravitational anomaly coefficients. While the former is the Chiral Alfv\\'en wave recently found in arXiv:1505.05444, the latter is a new type of collective excitations originated from the density fluctuations. We refer to these modes as the Type-M and Type-D chiral Alfv\\'en waves respectively. We show that the Type-M Chiral Alfv\\'en mode is split into two chiral Alfv\\'en modes when taking into account the effect of dissipation processes in the fluid. In 1+1 dimensions we find only one propagating mode associated with the anomalous effects. We explicitly compute the velocity of this wave and show that in contras...
Anomalous Dispersion in a Sand Bed River
Bradley, D. N.; Tucker, G. E.; Benson, D. M.
2009-04-01
There has been a recent surge of interest in non-local, heavy-tailed models of sediment transport and dispersion that are governed by fractional order differential equations. These models have a firm mathematical foundation and have been successfully applied in a variety of transport systems, but their use in geomorphology has been minimal because the data required to validate the models is difficult to acquire. We use data from a nearly 50-year-old tracer experiment to test a fluvial bed load transport model with a two unique features. First, the model uses a heavy-tailed particle velocity distribution with a divergent second moment to reproduce the anomalously high fraction of tracer mass observed in the downstream tail of the spatial distribution. Second, the model partitions mass into a detectable mobile phase and an undetectable, immobile phase. This two-phase transport model predicts two other features observed in the data: a decrease in the amount of detected tracer mass over the course of the experiment and the high initial velocity of the tracer plume. Because our model uses a heavy-tailed velocity distribution with a divergent second moment it is non-local and non-Fickian and able to reproduce aspects of the data that a local, Fickian model cannot. The model's successful prediction of the observed concentration profiles provides some of the first evidence of anomalous dispersion of bed load in a natural river.
Minimal flavor violation and anomalous top decays
Faller, Sven; Mannel, Thomas; Gadatsch, Stefan
2013-08-01
Top-quark physics at the LHC may open a window to physics beyond the Standard Model and even lead us to an understanding of the phenomenon of “flavor.” However, current flavor data is a strong hint that no “new physics” with a generic flavor structure can be expected at the TeV scale. In turn, if there is “new physics” at the TeV scale, it must be “minimally flavor violating.” This has become a widely accepted assumption for “new physics” models. In this paper we propose a model-independent scheme to test minimal flavor violation for the anomalous charged Wtq, q∈{d,s,b} and flavor-changing Vtq, q∈{u,c} and V∈{Z,γ,g} couplings within an effective field theory framework, i.e., in a model-independent way. We perform a spurion analysis of our effective field theory approach and calculate the decay rates for the anomalous top-quark decays in terms of the effective couplings for different helicities by using a two-Higgs doublet model of type II, under the assumption that the top-quark is produced at a high-energy collision and decays as a quasi-free particle.
Minimal Flavour Violation and Anomalous Top Decays
Faller, Sven; Mannel, Thomas
2013-01-01
Top quark physics at the LHC may open a window to physics beyond the standard model and even lead us to an understanding of the phenomenon "flavour". However, current flavour data is a strong hint that no "new physics" with a generic flavour structure can be expected in the TeV scale. In turn, if there is "new physics" at the TeV scale, it must be "minimally flavour violating". This has become a widely accepted assumption for "new physics" models. In this paper we propose a way to test the concept of minimal flavour violation for the anomalous charged $Wtq$, $q\\in\\{d,s,b\\}$, and flavour-changing $Vtq$, $q\\in\\{u,c\\}$ and $V\\in\\{Z,\\gamma,g\\}$, couplings within an effective field theory framework, i.e. in a model independent way. We perform a spurion analysis of our effective field theory approach and calculate the decay rates for the anomalous top-quark decays in terms of the effective couplings for different helicities by using a two-Higgs doublet model of type II (2HDM-II), under the assumption that the top-q...
Discovering anomalous events from urban informatics data
Jayarajah, Kasthuri; Subbaraju, Vigneshwaran; Weerakoon, Dulanga; Misra, Archan; Tam, La Thanh; Athaide, Noel
2017-05-01
Singapore's "smart city" agenda is driving the government to provide public access to a broader variety of urban informatics sources, such as images from traffic cameras and information about buses servicing different bus stops. Such informatics data serves as probes of evolving conditions at different spatiotemporal scales. This paper explores how such multi-modal informatics data can be used to establish the normal operating conditions at different city locations, and then apply appropriate outlier-based analysis techniques to identify anomalous events at these selected locations. We will introduce the overall architecture of sociophysical analytics, where such infrastructural data sources can be combined with social media analytics to not only detect such anomalous events, but also localize and explain them. Using the annual Formula-1 race as our candidate event, we demonstrate a key difference between the discriminative capabilities of different sensing modes: while social media streams provide discriminative signals during or prior to the occurrence of such an event, urban informatics data can often reveal patterns that have higher persistence, including before and after the event. In particular, we shall demonstrate how combining data from (i) publicly available Tweets, (ii) crowd levels aboard buses, and (iii) traffic cameras can help identify the Formula-1 driven anomalies, across different spatiotemporal boundaries.
Scattering Solar Thermal Concentrators
Energy Technology Data Exchange (ETDEWEB)
Giebink, Noel C. [Pennsylvania State Univ., State College, PA (United States)
2015-01-31
concentrator optical efficiency was found to decrease significantly with increasing aperture width beyond 0.5 m due to parasitic waveguide out-coupling loss and low-level absorption that become dominant at larger scale. A heat transfer model was subsequently implemented to predict collector fluid heat gain and outlet temperature as a function of flow rate using the optical model as a flux input. It was found that the aperture width size limitation imposed by the optical efficiency characteristics of the waveguide limits the absolute optical power delivered to the heat transfer element per unit length. As compared to state-of-the-art parabolic trough CPV system aperture widths approaching 5 m, this limitation leads to an approximate factor of order of magnitude increase in heat transfer tube length to achieve the same heat transfer fluid outlet temperature. The conclusion of this work is that scattering solar thermal concentration cannot be implemented at the scale and efficiency required to compete with the performance of current parabolic trough CSP systems. Applied within the alternate context of CPV, however, the results of this work have likely opened up a transformative new path that enables quasi-static, high efficiency CPV to be implemented on rooftops in the form factor of traditional fixed-panel photovoltaics.
Anomalous time delays and quantum weak measurements in optical micro-resonators
Asano, M.; Bliokh, K. Y.; Bliokh, Y. P.; Kofman, A. G.; Ikuta, R.; Yamamoto, T.; Kivshar, Y. S.; Yang, L.; Imoto, N.; Özdemir, Ş. K.; Nori, F.
2016-11-01
Quantum weak measurements, wavepacket shifts and optical vortices are universal wave phenomena, which originate from fine interference of multiple plane waves. These effects have attracted considerable attention in both classical and quantum wave systems. Here we report on a phenomenon that brings together all the above topics in a simple one-dimensional scalar wave system. We consider inelastic scattering of Gaussian wave packets with parameters close to a zero of the complex scattering coefficient. We demonstrate that the scattered wave packets experience anomalously large time and frequency shifts in such near-zero scattering. These shifts reveal close analogies with the Goos-Hänchen beam shifts and quantum weak measurements of the momentum in a vortex wavefunction. We verify our general theory by an optical experiment using the near-zero transmission (near-critical coupling) of Gaussian pulses propagating through a nano-fibre with a side-coupled toroidal micro-resonator. Measurements demonstrate the amplification of the time delays from the typical inverse-resonator-linewidth scale to the pulse-duration scale.
Scattering behaviour of Janus particles
Kaya, H
2002-01-01
Recent advances in polymer synthesis has produced so-called Janus micelles: tailor-made copolymer structures in which the blocks constitute separate moieties. We present expressions for the form factors, P(Q), and the radii of gyration, R sub g , of Janus particles with spherical and cylindrical morphology and check their validity by comparison to simulated scattering data, calculated from Monte Carlo generations of the pair-distance distribution function, p(r). The effect of block incompatibilities on the scattering is briefly discussed. (orig.)
An upper limit on the anomalous magnetic moment of the $\\tau$ lepton
Ackerstaff, K.; Allison, John; Altekamp, N.; Anderson, K.J.; Anderson, S.; Arcelli, S.; Asai, S.; Ashby, S.F.; Axen, D.; Azuelos, G.; Ball, A.H.; Barberio, E.; Barlow, Roger J.; Bartoldus, R.; Batley, J.R.; Baumann, S.; Bechtluft, J.; Behnke, T.; Bell, Kenneth Watson; Bella, G.; Bentvelsen, S.; Bethke, S.; Betts, S.; Biebel, O.; Biguzzi, A.; Bird, S.D.; Blobel, V.; Bloodworth, I.J.; Bobinski, M.; Bock, P.; Bonacorsi, D.; Boutemeur, M.; Braibant, S.; Brigliadori, L.; Brown, Robert M.; Burckhart, H.J.; Burgard, C.; Burgin, R.; Capiluppi, P.; Carnegie, R.K.; Carter, A.A.; Carter, J.R.; Chang, C.Y.; Charlton, David G.; Chrisman, D.; Clarke, P.E.L.; Cohen, I.; Conboy, J.E.; Cooke, O.C.; Couyoumtzelis, C.; Coxe, R.L.; Cuffiani, M.; Dado, S.; Dallapiccola, C.; Dallavalle, G.Marco; Davis, R.; De Jong, S.; del Pozo, L.A.; de Roeck, A.; Desch, K.; Dienes, B.; Dixit, M.S.; Doucet, M.; Duchovni, E.; Duckeck, G.; Duerdoth, I.P.; Eatough, D.; Estabrooks, P.G.; Etzion, E.; Evans, H.G.; Evans, M.; Fabbri, F.; Fanfani, A.; Fanti, M.; Faust, A.A.; Feld, L.; Fiedler, F.; Fierro, M.; Fischer, H.M.; Fleck, I.; Folman, R.; Fong, D.G.; Foucher, M.; Furtjes, A.; Futyan, D.I.; Gagnon, P.; Gary, J.W.; Gascon, J.; Gascon-Shotkin, S.M.; Geddes, N.I.; Geich-Gimbel, C.; Geralis, T.; Giacomelli, G.; Giacomelli, P.; Giacomelli, R.; Gibson, V.; Gibson, W.R.; Gingrich, D.M.; Glenzinski, D.; Goldberg, J.; Goodrick, M.J.; Gorn, W.; Grandi, C.; Gross, E.; Grunhaus, J.; Gruwe, M.; Hajdu, C.; Hanson, G.G.; Hansroul, M.; Hapke, M.; Hargrove, C.K.; Hart, P.A.; Hartmann, C.; Hauschild, M.; Hawkes, C.M.; Hawkings, R.; Hemingway, R.J.; Herndon, M.; Herten, G.; Heuer, R.D.; Hildreth, M.D.; Hill, J.C.; Hillier, S.J.; Hobson, P.R.; Hocker, James Andrew; Homer, R.J.; Honma, A.K.; Horvath, D.; Hossain, K.R.; Howard, R.; Huntemeyer, P.; Hutchcroft, D.E.; Igo-Kemenes, P.; Imrie, D.C.; Ishii, K.; Jawahery, A.; Jeffreys, P.W.; Jeremie, H.; Jimack, M.; Joly, A.; Jones, C.R.; Jones, M.; Jost, U.; Jovanovic, P.; Junk, T.R.; Kanzaki, J.; Karlen, D.; Kartvelishvili, V.; Kawagoe, K.; Kawamoto, T.; Kayal, P.I.; Keeler, R.K.; Kellogg, R.G.; Kennedy, B.W.; Kirk, J.; Klier, A.; Kluth, S.; Kobayashi, T.; Kobel, M.; Koetke, D.S.; Kokott, T.P.; Kolrep, M.; Komamiya, S.; Kowalewski, Robert V.; Kress, T.; Krieger, P.; von Krogh, J.; Kyberd, P.; Lafferty, G.D.; Lahmann, R.; Lai, W.P.; Lanske, D.; Lauber, J.; Lautenschlager, S.R.; Lawson, I.; Layter, J.G.; Lazic, D.; Lee, A.M.; Lefebvre, E.; Lellouch, D.; Letts, J.; Levinson, L.; List, B.; Lloyd, S.L.; Loebinger, F.K.; Long, G.D.; Losty, M.J.; Ludwig, J.; Lui, D.; Macchiolo, A.; Macpherson, A.; Mannelli, M.; Marcellini, S.; Markopoulos, C.; Markus, C.; Martin, A.J.; Martin, J.P.; Martinez, G.; Mashimo, T.; Mattig, Peter; McDonald, W.John; McKenna, J.; Mckigney, E.A.; McMahon, T.J.; McPherson, R.A.; Meijers, F.; Menke, S.; Merritt, F.S.; Mes, H.; Meyer, J.; Michelini, A.; Mihara, S.; Mikenberg, G.; Miller, D.J.; Mincer, A.; Mir, R.; Mohr, W.; Montanari, A.; Mori, T.; Nagai, K.; Nakamura, I.; Neal, H.A.; Nellen, B.; Nisius, R.; O'Neale, S.W.; Oakham, F.G.; Odorici, F.; Ogren, H.O.; Oh, A.; Oldershaw, N.J.; Oreglia, M.J.; Orito, S.; Palinkas, J.; Pasztor, G.; Pater, J.R.; Patrick, G.N.; Patt, J.; Perez-Ochoa, R.; Petzold, S.; Pfeifenschneider, P.; Pilcher, J.E.; Pinfold, J.; Plane, David E.; Poffenberger, P.; Poli, B.; Posthaus, A.; Rembser, C.; Robertson, S.; Robins, S.A.; Rodning, N.; Roney, J.M.; Rooke, A.; Rossi, A.M.; Routenburg, P.; Rozen, Y.; Runge, K.; Runolfsson, O.; Ruppel, U.; Rust, D.R.; Sachs, K.; Saeki, T.; Sahr, O.; Sang, W.M.; Sarkisian, E.K.G.; Sbarra, C.; Schaile, A.D.; Schaile, O.; Scharf, F.; Scharff-Hansen, P.; Schieck, J.; Schleper, P.; Schmitt, B.; Schmitt, S.; Schoning, A.; Schroder, Matthias; Schumacher, M.; Schwick, C.; Scott, W.G.; Shears, T.G.; Shen, B.C.; Shepherd-Themistocleous, C.H.; Sherwood, P.; Siroli, G.P.; Sittler, A.; Skillman, A.; Skuja, A.; Smith, A.M.; Snow, G.A.; Sobie, R.; Soldner-Rembold, S.; Springer, Robert Wayne; Sproston, M.; Stephens, K.; Steuerer, J.; Stockhausen, B.; Stoll, K.; Strom, David M.; Strohmer, R.; Szymanski, P.; Tafirout, R.; Talbot, S.D.; Taras, P.; Tarem, S.; Teuscher, R.; Thiergen, M.; Thomson, M.A.; von Torne, E.; Torrence, E.; Towers, S.; Trigger, I.; Trocsanyi, Z.; Tsur, E.; Turcot, A.S.; Turner-Watson, M.F.; Ueda, I.; Utzat, P.; Van Kooten, Rick J.; Vannerem, P.; Verzocchi, M.; Vikas, P.; Vokurka, E.H.; Voss, H.; Wackerle, F.; Wagner, A.; Ward, C.P.; Ward, D.R.; Watkins, P.M.; Watson, A.T.; Watson, N.K.; Wells, P.S.; Wermes, N.; White, J.S.; Wilson, G.W.; Wilson, J.A.; Wyatt, T.R.; Yamashita, S.; Yekutieli, G.; Zacek, V.; Zer-Zion, D.
1998-01-01
Using radiative Z^0 -> \\tau^+ \\tau^- \\gamma events collected with the OPAL detector at LEP at \\sqrt{s}=M_Z during 1990-95, a direct study of the electromagnetic current at the \\tau\\gamma vertex has been performed in terms of the anomalous magnetic form factor F_2 of the \\tau lepton. The analysis is based on a data sample of 1429 e^+ e^- -> \\tau^+ \\tau^- \\gamma events which are examined for a deviation from the expectation with F_2 = 0. From the non-observation of anomalous \\tau^+ \\tau^- \\gamma production a limit of -0.068 < F_2 < 0.065 is obtained. This can also be interpreted as a limit on the electric dipole form factor F_3 as -3.8 x 10^-16 e-cm < eF_3 < 3.6 x 10^-16 e-cm. The above ranges are valid at the 95% confidence level.
Energy Technology Data Exchange (ETDEWEB)
Kumar, S.; Sharma, V.; Shahi, J.S.; Mehta, D.; Singha, N. [Panjab Univ., Dept. of Physics (India)
2009-10-15
Differential cross sections for elastic scattering of the 59.54 keV {gamma}-rays in elements with 22 {<=} Z {<=} 92 have been measured over the angular range 10-160 degrees corresponding to the momentum transfer 0.4 {<=} x {<=} 4.7 Angstrom{sup -1}. The measurements at forward and backward angles were performed using the {sup 241}Am radioactive point-source, target and the Ge detectors in the transmission and reflection arrangements, respectively. The measured differential scattering cross sections are compared with those based on the form-factor (FF) formalism and state-of-the-art S-matrix calculations to differentiate between their relative efficacies and to check angular-dependence of the anomalous scattering factors (ASF) incorporated as correction to the modified form-factor (MF). The S-matrix values exhibit agreement with the measured data at backward angles and differences about 10% at forward angles. The scattering cross sections based on the MF including ASF's are in general lower at various angles by up to 20% for medium- and high-Z elements. The observed deviations being higher at the forward angles infer possibility of angular-dependence of ASF's. (authors)
[Anomalous Properties of Water and Aqueous Solutions at Low Temperatures].
Matsumoto, Masakazu
2015-01-01
Water has many anomalous properties below the room temperature. The temperature range overlaps with that of the Earth's atmosphere and also with that natural life forms favor. We review the origin of the anomalous properties of water and aqueous solutions in association with the hypothetical second critical point and liquid-liquid phase separation of water hidden in the supercooled state of liquid water.
Bootstrapping Rapidity Anomalous Dimensions for Transverse-Momentum Resummation
Energy Technology Data Exchange (ETDEWEB)
Li, Ye; Zhu, Hua Xing
2017-01-01
Soft function relevant for transverse-momentum resummation for Drell-Yan or Higgs production at hadron colliders are computed through to three loops in the expansion of strong coupling, with the help of bootstrap technique and supersymmetric decomposition. The corresponding rapidity anomalous dimension is extracted. An intriguing relation between anomalous dimensions for transverse-momentum resummation and threshold resummation is found.
Bootstrapping Rapidity Anomalous Dimension for Transverse-Momentum Resummation
Energy Technology Data Exchange (ETDEWEB)
Li, Ye [Fermilab; Zhu, Hua Xing [MIT, Cambridge, CTP
2016-04-05
Soft function relevant for transverse-momentum resummation for Drell-Yan or Higgs production at hadron colliders are computed through to three loops in the expansion of strong coupling, with the help of bootstrap technique and supersymmetric decomposition. The corresponding rapidity anomalous dimension is extracted. An intriguing relation between anomalous dimensions for transverse-momentum resummation and threshold resummation is found.
An algorithm for DLP on anomalous elliptic curves over Fp
Institute of Scientific and Technical Information of China (English)
祝跃飞; 裴定一
2002-01-01
This paper improves the method of discrete logarithm on anomalous elliptic curves, and establishes an isomorphism from E(Fp) to Fp which can be more easily implemented. Fruthermore, we give an optimized algorithm for discrete logarithm on anomalous elliptic curves E(Fp).
Strange and charm quark spins from the anomalous Ward identity
Gong, Ming; Yang, Yi-Bo; Liang, Jian; Alexandru, Andrei; Draper, Terrence; Liu, Keh-Fei; χQCD Collaboration
2017-06-01
We present a calculation of the strange and charm quark contributions to the nucleon spin from the anomalous Ward identity (AWI). This is performed with overlap valence quarks on 2 +1 -flavor domain-wall fermion gauge configurations on a 2 43×64 lattice with lattice spacing a-1=1.73 GeV and the light sea mass at mπ=330 MeV . To satisfy the AWI, the overlap fermion for the pseudoscalar density and the overlap Dirac operator for the topological density, which do not have multiplicative renormalization, are used to normalize the form factor of the local axial-vector current at finite q2. For the charm quark, we find that the negative pseudoscalar term almost cancels the positive topological term. For the strange quark, the pseudoscalar term is less negative than that of the charm. By imposing the AWI, the strange gA(q2) at q2=0 is obtained by a global fit of the pseudoscalar and the topological form factors, together with gA(q2) and the induced pseudoscalar form factor hA(q2) at finite q2. The chiral extrapolation to the physical pion mass gives Δ s +Δ s ¯=-0.0403 (44 )(78 ).
Liquid 1-propanol studied by neutron scattering, near-infrared, and dielectric spectroscopy
Energy Technology Data Exchange (ETDEWEB)
Sillrén, P.; Matic, A.; Karlsson, M. [Department of Applied Physics, Chalmers University of Technology, SE-412 96 Göteborg (Sweden); Koza, M.; Maccarini, M.; Fouquet, P. [Institut Laue Langevin, 6, rue Jules Horowitz, BP 156, 38042 Grenoble Cedex 9 (France); Götz, M.; Bauer, Th.; Gulich, R.; Lunkenheimer, P.; Loidl, A. [Experimental Physics V, University of Augsburg, 86135 Augsburg (Germany); Mattsson, J. [School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT (United Kingdom); Gainaru, C.; Vynokur, E.; Schildmann, S.; Bauer, S.; Böhmer, R. [Fakultät für Physik, Technische Universität Dortmund, 44221 Dortmund (Germany)
2014-03-28
Liquid monohydroxy alcohols exhibit unusual dynamics related to their hydrogen bonding induced structures. The connection between structure and dynamics is studied for liquid 1-propanol using quasi-elastic neutron scattering, combining time-of-flight and neutron spin-echo techniques, with a focus on the dynamics at length scales corresponding to the main peak and the pre-peak of the structure factor. At the main peak, the structural relaxation times are probed. These correspond well to mechanical relaxation times calculated from literature data. At the pre-peak, corresponding to length scales related to H-bonded structures, the relaxation times are almost an order of magnitude longer. According to previous work [C. Gainaru, R. Meier, S. Schildmann, C. Lederle, W. Hiller, E. Rössler, and R. Böhmer, Phys. Rev. Lett. 105, 258303 (2010)] this time scale difference is connected to the average size of H-bonded clusters. The relation between the relaxation times from neutron scattering and those determined from dielectric spectroscopy is discussed on the basis of broad-band permittivity data of 1-propanol. Moreover, in 1-propanol the dielectric relaxation strength as well as the near-infrared absorbance reveal anomalous behavior below ambient temperature. A corresponding feature could not be found in the polyalcohols propylene glycol and glycerol.
Detecting quark anomalous electroweak couplings at the LHC
Zhao, Sheng-Zhi
2015-01-01
We study the dimension-6 quark anomalous electroweak couplings in the formulation of linearly realized effective Lagrangian. We investigate the constraints on these anomalous couplings from the $pp \\rightarrow W^+W^-$ process in detail at the LHC. With additional kinematic cuts, we find that the 14 TeV LHC can provide a test of anomalous couplings of $O(0.1-1)\\,{\\rm TeV}^{-2}$. The $pp \\rightarrow ZZ/Z\\gamma/\\gamma\\gamma$ processes can provide a good complement as they are sensitive to those anomalous couplings which do not affect the $pp \\rightarrow W^+W^-$ process. Those processes that only contain anomalous triple vertices, like $p p \\to W^* \\to l \
di Francia, Giuliano Toraldo
1973-01-01
The art of deriving information about an object from the radiation it scatters was once limited to visible light. Now due to new techniques, much of the modern physical science research utilizes radiation scattering. (DF)
Neutron scattering from fractals
DEFF Research Database (Denmark)
Kjems, Jørgen; Freltoft, T.; Richter, D.
1986-01-01
The scattering formalism for fractal structures is presented. Volume fractals are exemplified by silica particle clusters formed either from colloidal suspensions or by flame hydrolysis. The determination of the fractional dimensionality through scattering experiments is reviewed, and recent small...
Directory of Open Access Journals (Sweden)
Zhong Shi
2016-01-01
Full Text Available The anomalous Hall effect (AHE and magneto-crystalline anisotropy (MCA are investigated in epitaxial NixFe1−x thin films grown on MgO (001 substrates. The scattering independent term b of anomalous Hall conductivity shows obvious correlation with cubic magneto-crystalline anisotropy K1. When nickel content x decreasing, both b and K1 vary continuously from negative to positive, changing sign at about x = 0.85. Ab initio calculations indicate NixFe1−x has more abundant band structures than pure Ni due to the tuning of valence electrons (band fillings, resulting in the increased b and K1. This remarkable correlation between b and K1 can be attributed to the effect of band filling near the Fermi surface.
Jiang, Shao-Jian; Zhou, Fei
2015-07-01
The stability of Bose gases near resonance has been a puzzling problem in recent years. In this article, we demonstrate that in addition to generating thermal pressure, thermal atoms enhance the repulsiveness of the scale-dependent interactions between condensed atoms due to a renormalization effect and further stabilize the Bose gases. Consequently, we find that, as a precursor of instability, the compressibility develops an anomalous structure as a function of scattering length and is drastically reduced compared with the mean-field value. Furthermore, the density profile of a Bose gas in a harmonic trap is found to develop a flat top near the center. This is due to the anomalous behavior of compressibility and can be a potential smoking gun for probing such an effect.
Zhang, Ying-Tao; Deng, Xinzhou; Sun, Qing-Feng; Qiao, Zhenhua
2015-01-01
The quantum entanglement between two qubits is crucial for applications in the quantum communication. After the entanglement of photons was experimentally realized, much effort has been taken to exploit the entangled electrons in solid-state systems. Here, we propose a Cooper-pair splitter, which can generate spatially-separated but entangled electrons, in a quantum anomalous Hall insulator proximity-coupled with a superconductor. After coupling with a superconductor, the chiral edge states of the quantum anomalous Hall insulator can still survive, making the backscattering impossible. Thus, the local Andreev reflection becomes vanishing, while the crossed Andreev reflection becomes dominant in the scattering process. This indicates that our device can serve as an extremely high-efficiency Cooper-pair splitter. Furthermore, because of the chiral characteristic, our Cooper-pair splitter is robust against disorders and can work in a wide range of system parameters. Particularly, it can still function even if the system length exceeds the superconducting coherence length.
Energy Technology Data Exchange (ETDEWEB)
Shi, Zhong; Jiang, Hang-Yu; Zhou, Shi-Ming, E-mail: shiming@tongji.edu.cn [Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology & Pohl Institute of Solid State Physics, School of Physics Science and Engineering, Tongji University, Shanghai 200092 (China); Hou, Yan-Liang; Ye, Quan-Lin [Department of Physics, Hangzhou Normal University, Hangzhou 310036 (China); Su Si, Ming [Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education, Lanzhou University, Lanzhou 730000 (China)
2016-01-15
The anomalous Hall effect (AHE) and magneto-crystalline anisotropy (MCA) are investigated in epitaxial Ni{sub x}Fe{sub 1−x} thin films grown on MgO (001) substrates. The scattering independent term b of anomalous Hall conductivity shows obvious correlation with cubic magneto-crystalline anisotropy K{sub 1}. When nickel content x decreasing, both b and K{sub 1} vary continuously from negative to positive, changing sign at about x = 0.85. Ab initio calculations indicate Ni{sub x}Fe{sub 1−x} has more abundant band structures than pure Ni due to the tuning of valence electrons (band fillings), resulting in the increased b and K{sub 1}. This remarkable correlation between b and K{sub 1} can be attributed to the effect of band filling near the Fermi surface.
The anomalous quadrupole collectivity in Te isotopes
Qi, Chong
2016-01-01
We present systematic calculations on the spectroscopy and transition properties of even-even Te isotopes by using the large-scale configuration interaction shell model approach with a realistic interaction. These nuclei are of particular interest since their yrast spectra show a vibrational-like equally-spaced pattern but the few known E2 transitions show anomalous rotational-like behavior, which cannot be reproduced by collective models. Our calculations reproduce well the equally-spaced spectra of those isotopes as well as the constant behavior of the $B(E2)$ values in $^{114}$Te. The calculated $B(E2)$ values for neutron-deficient and heavier Te isotopes show contrasting different behaviors along the yrast line. The $B(E2)$ of light isotopes can exhibit a nearly constant bevavior upto high spins. We show that this is related to the enhanced neutron-proton correlation when approaching $N=50$.
Anomalous Dynamical Responses in a Driven System
Dutta, Suman
2016-01-01
The interplay between structure and dynamics in non-equilibrium steady-state is far from understood. We address this interplay by tracking Brownian Dynamics trajectories of particles in a binary colloid of opposite charges in an external electric field, undergoing cross-over from homogeneous to lane state, a prototype of heterogeneous structure formation in non-equilibrium systems. We show that the length scale of structural correlations controls heterogeneity in diffusion and consequent anomalous dynamic responses, like the exponential tail in probability distributions of particle displacements and stretched exponential structural relaxation. We generalise our observations using equations for steady state density which may aid to understand microscopic basis of heterogeneous diffusion in condensed matter systems.
Anomalous rectification in a purely electronic memristor
Wang, Jingrui; Pan, Ruobing; Cao, Hongtao; Wang, Yang; Liang, Lingyan; Zhang, Hongliang; Gao, Junhua; Zhuge, Fei
2016-10-01
An anomalous rectification was observed in a purely electronic memristive device Ti/ZnO/Pt. It could be due to (1) an Ohmic or quasi-Ohmic contact at the ZnO/Pt interface and (2) a Schottky contact at the Ti/ZnO interface. The Ohmic contact originates from the reduction of ZnO occurring in the whole film instead of only at the Ti/ZnO interface. The Schottky contact may come from moisture adsorbed in the nanoporous ZnO. The conduction in the electroformed device is controlled by the carrier trapping/detrapping of the trap sites, inducing a poor rectification and high nonlinearity. Furthermore, a complementary resistive switching was achieved.
Anomalous Flavor U(1)_X for Everything
Energy Technology Data Exchange (ETDEWEB)
Dreiner, Herbi K.; Murayama, Hitoshi; Thormeier, Marc
2003-12-01
We present an ambitious model of flavor, based on an anomalous U(1)_X gauge symmetry with one flavon, only two right-handed neutrinos and only two mass scales: M_{grav} and m_{3/2}. In particular, there are no new scales introduced for right-handed neutrino masses. The X-charges of the matter fields are such that R-parity is conserved exactly, higher-dimensional operators are sufficiently suppressed to guarantee a proton lifetime in agreement with experiment, and the phenomenology is viable for quarks, charged leptons, as well as neutrinos. In our model one of the three light neutrinos automatically is massless. The price we have to pay for this very successful model are highly fractional X-charges which can likely be improved with less restrictive phenomenological ansatze for mass matrices.
Chiral magnetic plasmons in anomalous relativistic matter
Gorbar, E V; Shovkovy, I A; Sukhachov, P O
2016-01-01
The chiral plasmon modes of relativistic matter in background magnetic and strain-induced pseudomagnetic fields are studied in detail using the consistent chiral kinetic theory. The results reveal a number of anomalous features of these chiral magnetic and pseudomagnetic plasmons that could be used to identify them in experiment. In a system with nonzero electric (chiral) chemical potential, the background magnetic (pseudomagnetic) fields not only modify the values of the plasmon frequencies in the long wavelength limit, but also affect the qualitative dependence on the wave-vector. Similar modifications can be also induced by the chiral shift parameter in Weyl materials. Interestingly, even in the absence of the chiral shift and external fields, the chiral chemical potential alone leads to a splitting of plasmon energies at linear order in the wave vector.
Blow up Analysis for Anomalous Granular Gases
Rey, Thomas
2011-01-01
We investigate in this article the long-time behaviour of the solutions to the energy-dependent, spatially-homogeneous, inelastic Boltzmann equation for hard spheres. This model describes a diluted gas composed of hard spheres under statistical description, that dissipates energy during collisions. We assume that the gas is "anomalous", in the sense that the energy dissipation increases when the temperature decreases. This allows the gas to cool down in finite time. We study the existence, uniqueness and attractiveness of blow up profiles for this model and the cooling law associated, generalizing the classical Haff's Law for granular gases. To this end, we give some new estimates about the third order moment of the inelastic Boltzmann equation with drift term and we introduce new strongly "non-linear" self-similar variables
Anomalous Abelian symmetry in the standard model
Energy Technology Data Exchange (ETDEWEB)
Ramond, P.
1995-12-31
The observed hierarchy of quark and lepton masses can be parametrized by nonrenormalizable operators with dimensions determined by an anomalous Abelian family symmetry, a gauge extension to the minimal supersymmetric standard model. Such an Abelian symmetry is generic to compactified superstring theories, with its anomalies compensated by the Green-Schwarz mechanism. If we assume these two symmetries to be the same, we find the electroweak mixing angle to be sin {sup 2}{theta}{sub {omega}} = 3/8 at the string scale, just by setting the ratio of the product of down quark to charged lepton masses equal to one at the string scale. This assumes no GUT structure. The generality of the result suggests a superstring origin for the standard model. We generalize our analysis to massive neutrinos, and mixings in the lepton sector.
Anomalous conductances in an ultracold quantum wire
Kanász-Nagy, Márton; Esslinger, Tilman; Demler, Eugene A
2016-01-01
We analyze the recently measured anomalous transport properties of an ultracold gas through a ballistic constriction [S. Krinner et al., PNAS 201601812 (2016)]. The quantized conductance observed at weak interactions increases several-fold as the gas is made strongly interacting, which cannot be explained by the Landauer theory of single-channel transport. We show that this phenomenon is due to the multichannel Andreev reflections at the edges of the constriction, where the interaction and confinement result in a superconducting state. Andreev processes convert atoms of otherwise reflecting channels into the condensate propagating through the constriction, leading to a significant excess conductance. Furthermore, we find the spin conductance being suppressed by superconductivity; the agreement with experiment provides an additional support for our model.
Anomalous magnetoresistance in magnetized topological insulator cylinders
Energy Technology Data Exchange (ETDEWEB)
Siu, Zhuo Bin, E-mail: a0018876@nus.edu.sg [NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore 117456 (Singapore); Data Storage Institute, Agency for Science, Technology and Research, Singapore 117608 (Singapore); Jalil, Mansoor B. A. [NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore 117456 (Singapore)
2015-05-07
The close coupling between the spin and momentum degrees of freedom in topological insulators (TIs) presents the opportunity for the control of one to manipulate the other. The momentum can, for example, be confined on a curved surface and the spin influenced by applying a magnetic field. In this work, we study the surface states of a cylindrical TI magnetized in the x direction perpendicular to the cylindrical axis lying along the z direction. We show that a large magnetization leads to an upwards bending of the energy bands at small |k{sub z}|. The bending leads to an anomalous magnetoresistance where the transmission between two cylinders magnetized in opposite directions is higher than when the cylinders are magnetized at intermediate angles with respect to each other.
The Anomalous Acceleration of the Pioneer Spacecrafts
de Diego, Jose A
2008-01-01
Radiometric data from the Pioneer 10 and 11 spacecrafts have revealed an unexplained constant acceleration of a_A = (8.74 +/- 1.33) x 10^(-10) m s^(-2) towards the Sun, also known as the Pioneer anomaly. Different groups have analyzed the Pioneer data and have got the same results, which rules out computer programming and handling errors. Attempts to explain this phenomenon arguing intrinsic causes on-board the spacecrafts failed or have lead to inconclusive results. Therefore, the Pioneer anomalous acceleration has motivated the interest of researchers to find out explanations that could bring insight upon the forces acting in the outer Solar Systems or a hint to discover new natural laws.
Latest results on $J/$ anomalous suppression
Indian Academy of Sciences (India)
Sérgio Ramos; NA50 Collaboration; B Allessandro; C Alexa; R Arnaldi; M Atayan; C Baglin; A Baldit; M Bedjidian; S Beolè; V Boldea; P Bordalo; S R Borenstein; G Borges; A Bussière; L Capelli; C Castanier; J Castor; B Chaurand; B Cheynis; E Chiavassa; C Cicalo; T Claudino; M P Comets; S Constantinescu; P Cortese; J Cruz; A DeFalco; N DeMarco; G Dellacasa; A Devaux; S Dita; O Drapier; B Espagnon; J Fargeix; P Force; M Gallio; Y K Gavrilov; C Gerschel; P Giubellino; M B Golubeva; M Gonin; A A Grigorian; S Grigorian; J Y Grossiord; F F Guber; A Guichard; H Gulkanyan; R Hakobyan; R Haroutunian; M Idzik; D Jouan; T L Karavitcheva; L Kluberg; A B Kurepin; Y Le Bornée; C Lourenço; P Macciotta; M Mac Cormick; A Marzari-Chiesa; M Masera; A Masoni; M Monteno; A Musso; P Petiau; A Piccotti; J R Pizzi; W L Prado da Silva; F Prino; G Puddu; C Quintans; L Ramello; S Ramos; P Rato Mendes; L Riccati; A Romana; H Santos; P Saturnini; E Scalas; E Scomparin; S Serci; R Shahoyan; F Sigaudo; M Sitta; P Sonderegger; X Tarrago; N S Topilskaya; G L Usai; E Vercellin; L Villatte; N Willis; T Wu
2004-03-01
The NA50 experiment deals with Pb–Pb collisions at 158 GeV/nucleon at the CERN SPS accelerator. The $J/$ production is studied through the muon decay channel, using the Drell–Yan dimuons as a reference. New results based on recent analyses, from data taken with improved experimental conditions and using different centrality estimators, are presented and compared to an update of those already obtained from previous data samples. The stepwise pattern of the anomalous $J/$ suppression as a function of centrality, already present in these previous results, is confirmed. This observation could be a fingerprint of the theoretically predicted melting of charmonia resonances in a deconfined quark–gluon plasma.
Anomalous transport from holography: Part I
Bu, Yanyan; Sharon, Amir
2016-01-01
We revisit the transport properties induced by the chiral anomaly in a charged plasma holographically dual to anomalous $U(1)_V\\times U(1)_A$ Maxwell theory in Schwarzschild-$AdS_5$. Off-shell constitutive relations for vector and axial currents are derived using various approximations generalising most of known in the literature anomaly-induced phenomena and revealing some new ones. In a weak external field approximation, the constitutive relations have all-order derivatives resummed into six momenta-dependent transport coefficient functions: the diffusion, the electric/magnetic conductivity, and three anomaly induced functions. The latter generalise the chiral magnetic and chiral separation effects. Nonlinear transport is studied assuming presence of constant background external fields. The chiral magnetic effect, including all order nonlinearity in magnetic field, is proven to be exact when the magnetic field is the only external field that is turned on. Non-linear corrections to the constitutive relations...
Heterogeneous anomalous diffusion in view of superstatistics
Itto, Yuichi
2014-01-01
It is experimentally known that virus exhibits stochastic motion in cytoplasm of a living cell in the free form as well as the form being contained in the endosome and the exponent of anomalous diffusion of the virus fluctuates depending on localized areas of the cytoplasm. Here, a theory is developed for establishing a generalized fractional kinetics for the infection pathway of the virus in the cytoplasm in view of superstatistics, which offers a general framework for describing nonequilibrium complex systems with two largely separated time scales. In the present theory, the existence of a large time-scale separation in the infection pathway is explicitly taken into account. A comment is also made on scaling nature of the motion of the virus that is suggested by the theory.
Can Anomalous Amplification be Attained Without Postselection?
Martínez-Rincón, Julián; Viza, Gerardo I; Howell, John C
2015-01-01
We present a parameter estimation technique based on performing joint measurements of a weak interaction away from the weak-value-amplification approximation. Two detectors are used to collect full statistics of the correlations between two weakly entangled degrees of freedom. Without the need of postselection, the protocol resembles the anomalous amplification of an imaginary-weak-value-like response. The amplification is induced in the difference signal of both detectors allowing robustness to different sources of technical noise, and offering in addition the advantages of balanced signals for precision metrology. All of the Fisher information about the parameter of interest is collected, and a phase controls the amplification response. We experimentally demonstrate the proposed technique by measuring polarization rotations in a linearly polarized laser pulse. The effective sensitivity and precision of a split detector is increased when compared to a conventional continuous-wave balanced detection technique...
44th Annual Anomalous Absorption Conference
Energy Technology Data Exchange (ETDEWEB)
Beg, Farhat
2014-03-03
Conference Grant Report July 14, 2015 Submitted to the U. S. Department of Energy Attn: Dr. Sean Finnegan By the University of California, San Diego 9500 Gilman Drive La Jolla, California 92093 On behalf of the 44th Annual Anomalous Absorption Conference 8-13 June 2014, in Estes Park, Colorado Support Requested: $10,100 Amount expended: $3,216.14 Performance Period: 1 March 20 14 to 28 February 20 15 Principal Investigator Dr. Farhat Beg Center for Energy Research University of California, San Diego 9500 Gilman Drive La Jolla, California 92093-0417 858-822-1266 (telephone) 858-534-4543 (fax) fbeg@ucsd.edu Administrative Point of Contact: Brandi Pate, 858-534-0851, blpate®ucsd.edu I. Background The forty-fourth Anomalous Absorption Conference was held in Estes Park, Colorado from June 5-8, 2014 (aac2014.ucsd.edu). The first Anomalous Absorption Conference was held in 1971 to assemble experts in the poorly understood area of laser-plasma absorption. The goal of that conference was to address the anomalously large laser absorption seen in plasma experiments with respect to the laser absorption predicted by linear plasma theory. Great progress in this research area has been made in the decades since that first meeting, due in part to the scientific interactions that have occurred annually at this conference. Specifically, this includes the development of nonlinear laser-plasma theory and the simulation of laser interactions with plasmas. Each summer since that first meeting, this week-long conference has been held at unique locations in North America as a scientific forum for intense scientific exchanges relevant to the interaction of laser radiation with plasmas. Responsibility for organizing the conference has traditional rotated each year between the major Inertial Confinement Fusion (ICF) laboratories and universities including LANL, LLNL, LLE, UCLA UC Davis and NRL. As the conference has matured over the past four decades, its technical footprint has expanded
Examination of anomalous self-experience
DEFF Research Database (Denmark)
Raballo, Andrea; Parnas, Josef
2012-01-01
-disorders [SDs]), has been shown to constitute a core feature of both clinically overt and latent (schizotaxic) spectrum phenotypes. However, a major limitation for the translational implementation of this research evidence has been a lack of assessment tools capable of encompassing the clinical richness of SDs....... Here, we present the initial normative data and psychometric properties of a newly developed instrument (Examination of Anomalous Self-experience [EASE]), specifically designed to support the psychopathological exploration of SDs in both research and "real world" clinical settings. Our results support...... the clinical validity of the EASE as a tool for assessing anomalies of self-awareness (SDs) and lend credit to the translational potential of a phenomenological exploration of the subjective experience of vulnerability to schizophrenia....
Powder diffraction studies using anomalous dispersion
Energy Technology Data Exchange (ETDEWEB)
Cox, D.E. [Brookhaven National Lab., Upton, NY (United States); Wilkinson, A.P. [California Univ., Santa Barbara, CA (United States). Dept. of Materials
1993-05-01
With the increasing availability and accessibility of high resolution powder diffractometers at many synchrotron radiation sources throughout the world, there is rapidly-growing interest in the exploitation of anomalous dispersion techniques for structural studies of polycrystalline materials. In conjunction with the Rietveld profile method for structure refinement, such studies are especially useful for the determination of the site distributions of two or more atoms which are near neighbors in the periodic table, or atoms which are distributed among partially occupied sites. Additionally, it is possible to (1) determine the mean-square displacements associated with different kinds of atoms distributed over a single set of sites, (2) distinguish between different oxidation states and coordination geometries of a particular atom in a compound and (3) to determine f` for a wide range of atomic species as a function of energy in the vicinity of an absorption edge. Experimental methods for making anomalous dispersion measurements are described in some detail, including data collection strategies, data analysis and correlation problems, possible systematic errors, and the accuracy of the results. Recent work in the field is reviewed, including cation site-distribution studies (e.g. doped high {Tc} superconductors, ternary alloys, FeCo{sub 2}(PO{sub 4}){sub 3}, FeNi{sub 2}BO{sub 5}), oxidation-state contrast (e.g. YBa{sub 2}Cu{sub 3}O{sub 6+x}, Eu{sub 3}O{sub 4}, GaCl{sub 2}, Fe{sub 2}PO{sub 5}), and the effect of coordination geometry (e.g. Y{sub 3}Ga{sub 5}O{sub l2}).
Powder diffraction studies using anomalous dispersion
Energy Technology Data Exchange (ETDEWEB)
Cox, D.E. (Brookhaven National Lab., Upton, NY (United States)); Wilkinson, A.P. (California Univ., Santa Barbara, CA (United States). Dept. of Materials)
1993-01-01
With the increasing availability and accessibility of high resolution powder diffractometers at many synchrotron radiation sources throughout the world, there is rapidly-growing interest in the exploitation of anomalous dispersion techniques for structural studies of polycrystalline materials. In conjunction with the Rietveld profile method for structure refinement, such studies are especially useful for the determination of the site distributions of two or more atoms which are near neighbors in the periodic table, or atoms which are distributed among partially occupied sites. Additionally, it is possible to (1) determine the mean-square displacements associated with different kinds of atoms distributed over a single set of sites, (2) distinguish between different oxidation states and coordination geometries of a particular atom in a compound and (3) to determine f' for a wide range of atomic species as a function of energy in the vicinity of an absorption edge. Experimental methods for making anomalous dispersion measurements are described in some detail, including data collection strategies, data analysis and correlation problems, possible systematic errors, and the accuracy of the results. Recent work in the field is reviewed, including cation site-distribution studies (e.g. doped high [Tc] superconductors, ternary alloys, FeCo[sub 2](PO[sub 4])[sub 3], FeNi[sub 2]BO[sub 5]), oxidation-state contrast (e.g. YBa[sub 2]Cu[sub 3]O[sub 6+x], Eu[sub 3]O[sub 4], GaCl[sub 2], Fe[sub 2]PO[sub 5]), and the effect of coordination geometry (e.g. Y[sub 3]Ga[sub 5]O[sub l2]).
Anomalous diffusion in geophysical and laboratory turbulence
Directory of Open Access Journals (Sweden)
A. Tsinober
1994-01-01
Full Text Available We present an overview and some new results on anomalous diffusion of passive scalar in turbulent flows (including those used by Richardson in his famous paper in 1926. The obtained results are based on the analysis of the properties of invariant quantities (energy, enstrophy, dissipation, enstrophy generation, helicity density, etc. - i.e. independent of the choice of the system of reference as the most appropriate to describe physical processes - in three different turbulent laboratory flows (grid-flow, jet and boundary layer, see Tsinober et al. (1992 and Kit et al. (1993. The emphasis is made on the relations between the asymptotic properties of the intermittency exponents of higher order moments of different turbulent fields (energy, dissipation, helicity, spontaneous breaking of isotropy and reflexional symmetry and the variability of turbulent diffusion in the atmospheric boundary layer, in the troposphere and in the stratosphere. It is argued that local spontaneous breaking of isotropy of turbulent flow results in anomalous scaling laws for turbulent diffusion (as compared to the scaling law of Richardson which are observed, as a rule, in different atmospheric layers from the atmospheric boundary layer (ABL to the stratosphere. Breaking of rotational symmetry is important in the ABL, whereas reflexional symmetry breaking is dominating in the troposphere locally and in the stratosphere globally. The results are of speculative nature and further analysis is necessary to validate or disprove the claims made, since the correspondence with the experimental results may occur for the wrong reasons as happens from time to time in the field of turbulence.
Andersson, N
2000-01-01
This is a chapter on Black-hole Scattering that was commissioned for an Encyclopaedia on Scattering edited by Pike and Sabatier, to be published by Academic Press. The chapter surveys wave propagation in black-hole spacetimes, diffraction effects in wave scattering, resonances, quasinormal modes and related topics.
Directory of Open Access Journals (Sweden)
Ganesh Narayanasamy
2015-01-01
Full Text Available The purpose of this study is to examine the accuracy of calculated tissue phantom ratio (TPR data with measured TPR values of a 6MV photon beam. TPR was calculated from the measured percent depth dose (PDD values using 2 methods – with and without correcting for the differences in peak scatter fraction (PSF. Mean error less than 1% was observed between the measured and calculated TPR values with the PSF correction, for all clinically relevant field sizes and depths. When not accounting for the PSF correction, mean difference between the measured and calculated TPR values was larger than 1% for square field sizes ranging from 3 cm to 10 cm.
Dynamics of liquid N2 studied by neutron inelastic scattering
DEFF Research Database (Denmark)
Pedersen, Karen Schou; Carneiro, Kim; Hansen, Flemming Yssing
1982-01-01
Neutron inelastic-scattering data from liquid N2 at wave-vector transfer κ between 0.18 and 2.1 Å-1 and temperatures ranging from T=65-77 K are presented. The data are corrected for the contribution from multiple scattering and incoherent scattering. The resulting dynamic structure factor S (κ,ω)...
Multiple exchange and high-energy fixed-angle scattering
Halliday, I G; Orzalesi, C A; Tau, M
1975-01-01
The application of the eikonal ansatz to fermion fermion elastic scattering with Abelian vector gluon exchanges is discussed. The behaviours of the elastic scattering amplitude and the elastic form factor are considered and an important mechanism for fixed angle high energy elastic scattering is identified. (6 refs).
Phonon Scattering Dynamics of Thermophoretic Motion in Carbon Nanotube Oscillators.
Prasad, Matukumilli V D; Bhattacharya, Baidurya
2016-04-13
Using phonon wave packet molecular dynamics simulations, we find that anomalous longitudinal acoustic (LA) mode phonon scattering in low to moderate energy ranges is responsible for initiating thermophoretic motion in carbon nanotube oscillators. The repeated scattering of a single mode LA phonon wave packet near the ends of the inner nanotube provides a net unbalanced force that, if large enough, initiates thermophoresis. By applying a coherent phonon pulse on the outer tube, which generalizes the single mode phonon wave packet, we are able to achieve thermophoresis in a carbon nanotube oscillator. We also find the nature of the unbalanced force on end-atoms to be qualitatively similar to that under an imposed thermal gradient. The thermodiffusion coefficient obtained for a range of thermal gradients and core lengths suggest that LA phonon scattering is the dominant mechanism for thermophoresis in longer cores, whereas for shorter cores, it is the highly diffusive mechanism that provides the effective force.
Tuning anomalous Hall conductivity in L1[sub 0] FePt films by long range chemical ordering
Chen, M.
2011-02-24
For L10 FePt films, the anomalous Hall conductivity σ xy=-a σxx-b, where a=a0f(T), b=b 0f(T), and f (T) is the temperature dependence factor of the spontaneous magnetization. With increasing chemical long range ordering S, a0 changes its sign accompanied by a reduction of its magnitude and b0 increases monotonically. The spin-orbit coupling strength is suggested to increase with increasing S. As an approach, the long range chemical ordering can be used to control the anomalous Hall effect in ferromagnetic alloy films. © 2011 American Institute of Physics.
Enhancement in anomalous Hall resistivity of Co/Pd multilayer and CoPd alloy by Ga+ ion irradiation
Guo, Zaibing
2014-02-01
In this paper, we report the effect of Ga+ ion irradiation on anomalous Hall effect (AHE) and longitudinal resistivity (ρxx) in [Co(3 Å)/Pd(5 Å)]80 multilayer and Co 42Pd58 alloy. 4- and 2-fold increases in anomalous Hall resistivity (ρAH) in the Co/Pd multilayer and CoPd alloy have been observed after irradiations at doses of 2.4 × 1015 and 3.3×10 15 ions/cm2, respectively. Skew scattering and side jump contributions to AHE have been analyzed based on the scaling relationship ρAH = aρxx + bρ2xx. For the Co/Pd multilayer, AHE is mainly affected by ion irradiation-induced interface diffusion and defects. For the CoPd alloy, the increase in doses above 1.5 × 1015 ions/cm2 induces a sign change in skew scattering, followed by the skew scattering contribution to AHE overwhelming the side jump contribution, this phenomenon should be attributed to irradiation-induced defects and modifications in chemical ordering. © Copyright EPLA, 2014.
Enhancement in anomalous Hall resistivity of Co/Pd multilayer and CoPd alloy by Ga+ ion irradiation
Guo, Z. B.; Mi, W. B.; Li, J. Q.; Cheng, Y. C.; Zhang, X. X.
2014-02-01
In this paper, we report the effect of Ga+ ion irradiation on anomalous Hall effect (AHE) and longitudinal resistivity (\\rho_{\\textit{xx}}) in [Co(3 Å)/Pd(5 Å)]80 multilayer and Co42Pd58 alloy. 4- and 2-fold increases in anomalous Hall resistivity (\\rho_{\\textit{AH}}) in the Co/Pd multilayer and CoPd alloy have been observed after irradiations at doses of 2.4\\times 10^{15} and 3.3\\times 10^{15}\\ \\text{ions/cm}^{2} , respectively. Skew scattering and side jump contributions to AHE have been analyzed based on the scaling relationship \\rho_{\\textit{AH}}=a\\rho_{\\textit{xx}}+b\\rho_{\\textit{xx}}^{2} . For the Co/Pd multilayer, AHE is mainly affected by ion irradiation-induced interface diffusion and defects. For the CoPd alloy, the increase in doses above 1.5\\times 10^{15}\\ \\text{ions/cm}^{2} induces a sign change in skew scattering, followed by the skew scattering contribution to AHE overwhelming the side jump contribution, this phenomenon should be attributed to irradiation-induced defects and modifications in chemical ordering.
Metzler, Ralf; Jeon, Jae-Hyung; Cherstvy, Andrey G; Barkai, Eli
2014-11-28
Modern microscopic techniques following the stochastic motion of labelled tracer particles have uncovered significant deviations from the laws of Brownian motion in a variety of animate and inanimate systems. Such anomalous diffusion can have different physical origins, which can be identified from careful data analysis. In particular, single particle tracking provides the entire trajectory of the traced particle, which allows one to evaluate different observables to quantify the dynamics of the system under observation. We here provide an extensive overview over different popular anomalous diffusion models and their properties. We pay special attention to their ergodic properties, highlighting the fact that in several of these models the long time averaged mean squared displacement shows a distinct disparity to the regular, ensemble averaged mean squared displacement. In these cases, data obtained from time averages cannot be interpreted by the standard theoretical results for the ensemble averages. Here we therefore provide a comparison of the main properties of the time averaged mean squared displacement and its statistical behaviour in terms of the scatter of the amplitudes between the time averages obtained from different trajectories. We especially demonstrate how anomalous dynamics may be identified for systems, which, on first sight, appear to be Brownian. Moreover, we discuss the ergodicity breaking parameters for the different anomalous stochastic processes and showcase the physical origins for the various behaviours. This Perspective is intended as a guidebook for both experimentalists and theorists working on systems, which exhibit anomalous diffusion.
Vanishing Str M2 in the presence of anomalous U A(1)
Lopez, Jorge L.; Nanopoulos, D. V.
1996-02-01
We show that the presence of an anomalous U A(1) factor in the gauge group of string-derived models may have the new and important phenomenological consequence of allowing the vanishing of Str M2 in the “shifted” vacuum that results in the process of cancelling the anomalous U A(1). The feasibility of this effect seems to be enhanced by a vanishing vacuum energy, and by a “small” value of Str M2 in the original vacuum. In the class of free-fermionic models with vanishing vacuum energy that we focus on, a necessary condition for this mechanism to be effective is that Str M2 > 0 in the original vacuum. A vanishing Str M2 ameliorates the cosmological constant problem and is a necessary element in the stability of the no-scale mechanism.
Reliable resource-constrained telecardiology via compressive detection of anomalous ECG signals.
Chandra, Bollepalli S; Sastry, Challa S; Jana, Soumya
2015-11-01
Telecardiology is envisaged as a supplement to inadequate local cardiac care, especially, in infrastructure deficient communities. Yet the associated infrastructure constraints are often ignored while designing a traditional telecardiology system that simply records and transmits user electrocardiogram (ECG) signals to a professional diagnostic facility. Against this backdrop, we propose a two-tier telecardiology framework, where constraints on resources, such as power and bandwidth, are met by compressively sampling ECG signals, identifying anomalous signals, and transmitting only the anomalous signals. Specifically, we design practical compressive classifiers based on inherent properties of ECG signals, such as self-similarity and periodicity, and illustrate their efficacy by plotting receiver operating characteristics (ROC). Using such classifiers, we realize a resource-constrained telecardiology system, which, for the PhysioNet databases, allows no more than 0.5% undetected patients even at an average downsampling factor of five, reducing the power requirement by 80% and bandwidth requirement by 83.4% compared to traditional telecardiology.
Limits on anomalous WWγ and WWZ couplings from WW/WZ-->eνjj production
Abbott, B.; Abolins, M.; Abramov, V.; Acharya, B. S.; Adams, D. L.; Adams, M.; Ahn, S.; Akimov, V.; Alves, G. A.; Amos, N.; Anderson, E. W.; Baarmand, M. M.; Babintsev, V. V.; Babukhadia, L.; Baden, A.; Baldin, B.; Banerjee, S.; Bantly, J.; Barberis, E.; Baringer, P.; Bartlett, J. F.; Bassler, U.; Belyaev, A.; Beri, S. B.; Bernardi, G.; Bertram, I.; Bezzubov, V. A.; Bhat, P. C.; Bhatnagar, V.; Bhattacharjee, M.; Blazey, G.; Blessing, S.; Boehnlein, A.; Bojko, N. I.; Borcherding, F.; Brandt, A.; Breedon, R.; Briskin, G.; Brock, R.; Brooijmans, G.; Bross, A.; Buchholz, D.; Buescher, V.; Burtovoi, V. S.; Butler, J. M.; Carvalho, W.; Casey, D.; Casilum, Z.; Castilla-Valdez, H.; Chakraborty, D.; Chan, K. M.; Chekulaev, S. V.; Chen, L.-P.; Chen, W.; Cho, D. K.; Choi, S.; Chopra, S.; Choudhary, B. C.; Christenson, J. H.; Chung, M.; Claes, D.; Clark, A. R.; Cobau, W. G.; Cochran, J.; Coney, L.; Connolly, B.; Cooper, W. E.; Coppage, D.; Cullen-Vidal, D.; Cummings, M. A.; Cutts, D.; Dahl, O. I.; Davis, K.; de, K.; del Signore, K.; Demarteau, M.; Denisov, D.; Denisov, S. P.; Diehl, H. T.; Diesburg, M.; di Loreto, G.; Draper, P.; Ducros, Y.; Dudko, L. V.; Dugad, S. R.; Dyshkant, A.; Edmunds, D.; Ellison, J.; Elvira, V. D.; Engelmann, R.; Eno, S.; Eppley, G.; Ermolov, P.; Eroshin, O. V.; Estrada, J.; Evans, H.; Evdokimov, V. N.; Fahland, T.; Feher, S.; Fein, D.; Ferbel, T.; Fisk, H. E.; Fisyak, Y.; Flattum, E.; Fleuret, F.; Fortner, M.; Frame, K. C.; Fuess, S.; Gallas, E.; Galyaev, A. N.; Gartung, P.; Gavrilov, V.; Genik, R. J.; Genser, K.; Gerber, C. E.; Gershtein, Y.; Gibbard, B.; Gilmartin, R.; Ginther, G.; Gobbi, B.; Gómez, B.; Gómez, G.; Goncharov, P. I.; González Solís, J. L.; Gordon, H.; Goss, L. T.; Gounder, K.; Goussiou, A.; Graf, N.; Grannis, P. D.; Green, D. R.; Green, J. A.; Greenlee, H.; Grinstein, S.; Grudberg, P.; Grünendahl, S.; Guglielmo, G.; Gupta, A.; Gurzhiev, S. N.; Gutierrez, G.; Gutierrez, P.; Hadley, N. J.; Haggerty, H.; Hagopian, S.; Hagopian, V.; Hahn, K. S.; Hall, R. E.; Hanlet, P.; Hansen, S.; Hauptman, J. M.; Hays, C.; Hebert, C.; Hedin, D.; Heinson, A. P.; Heintz, U.; Heuring, T.; Hirosky, R.; Hobbs, J. D.; Hoeneisen, B.; Hoftun, J. S.; Hsieh, F.; Ito, A. S.; Jerger, S. A.; Jesik, R.; Joffe-Minor, T.; Johns, K.; Johnson, M.; Jonckheere, A.; Jones, M.; Jöstlein, H.; Jun, S. Y.; Kahn, S.; Kajfasz, E.; Karmanov, D.; Karmgard, D.; Kehoe, R.; Kim, S. K.; Klima, B.; Klopfenstein, C.; Knuteson, B.; Ko, W.; Kohli, J. M.; Koltick, D.; Kostritskiy, A. V.; Kotcher, J.; Kotwal, A. V.; Kozelov, A. V.; Kozlovsky, E. A.; Krane, J.; Krishnaswamy, M. R.; Krzywdzinski, S.; Kubantsev, M.; Kuleshov, S.; Kulik, Y.; Kunori, S.; Landsberg, G.; Leflat, A.; Lehner, F.; Li, J.; Li, Q. Z.; Lima, J. G.; Lincoln, D.; Linn, S. L.; Linnemann, J.; Lipton, R.; Lu, J. G.; Lucotte, A.; Lueking, L.; Lundstedt, C.; Maciel, A. K.; Madaras, R. J.; Manankov, V.; Mani, S.; Mao, H. S.; Markeloff, R.; Marshall, T.; Martin, M. I.; Martin, R. D.; Mauritz, K. M.; May, B.; Mayorov, A. A.; McCarthy, R.; McDonald, J.; McKibben, T.; McMahon, T.; Melanson, H. L.; Merkin, M.; Merritt, K. W.; Miao, C.; Miettinen, H.; Mincer, A.; Mishra, C. S.; Mokhov, N.; Mondal, N. K.; Montgomery, H. E.; Mostafa, M.; da Motta, H.; Nagy, E.; Nang, F.; Narain, M.; Narasimham, V. S.; Neal, H. A.; Negret, J. P.; Negroni, S.; Norman, D.; Oesch, L.; Oguri, V.; Olivier, B.; Oshima, N.; Owen, D.; Padley, P.; Para, A.; Parashar, N.; Partridge, R.; Parua, N.; Paterno, M.; Patwa, A.; Pawlik, B.; Perkins, J.; Peters, M.; Piegaia, R.; Piekarz, H.; Pischalnikov, Y.; Pope, B. G.; Popkov, E.; Prosper, H. B.; Protopopescu, S.; Qian, J.; Quintas, P. Z.; Raja, R.; Rajagopalan, S.; Reay, N. W.; Reucroft, S.; Rijssenbeek, M.; Rockwell, T.; Roco, M.; Rubinov, P.; Ruchti, R.; Rutherfoord, J.; Sánchez-Hernández, A.; Santoro, A.; Sawyer, L.; Schamberger, R. D.; Schellman, H.; Schwartzman, A.; Sculli, J.; Sen, N.; Shabalina, E.; Shankar, H. C.; Shivpuri, R. K.; Shpakov, D.; Shupe, M.; Sidwell, R. A.; Singh, H.; Singh, J. B.; Sirotenko, V.; Slattery, P.; Smith, E.; Smith, R. P.; Snihur, R.; Snow, G. R.; Snow, J.; Snyder, S.; Solomon, J.; Song, X. F.; Sorín, V.; Sosebee, M.; Sotnikova, N.; Souza, M.; Stanton, N. R.; Steinbrück, G.; Stephens, R. W.; Stevenson, M. L.; Stichelbaut, F.; Stoker, D.; Stolin, V.; Stoyanova, D. A.; Strauss, M.; Streets, K.; Strovink, M.; Stutte, L.; Sznajder, A.; Tarazi, J.; Tartaglia, M.; Thomas, T. L.; Thompson, J.; Toback, D.; Trippe, T. G.; Turcot, A. S.; Tuts, P. M.; van Gemmeren, P.; Vaniev, V.; Varelas, N.; Volkov, A. A.; Vorobiev, A. P.; Wahl, H. D.; Warchol, J.; Watts, G.; Wayne, M.; Weerts, H.; White, A.; White, J. T.; Wightman, J. A.; Willis, S.; Wimpenny, S. J.; Wirjawan, J. V.; Womersley, J.; Wood, D. R.; Yamada, R.; Yamin, P.; Yasuda, T.; Yip, K.; Youssef, S.; Yu, J.; Yu, Y.; Zanabria, M.; Zheng, H.; Zhou, Z.; Zhu, Z. H.; Zielinski, M.; Zieminska, D.; Zieminski, A.; Zutshi, V.; Zverev, E. G.; Zylberstejn, A.
2000-09-01
Limits on anomalous WWγ and WWZ couplings are presented from a study of WW/WZ-->eνjj events produced in pp¯ collisions at s=1.8 TeV. Results from the analysis of data collected using the DØ detector during the 1993-1995 Tevatron collider run at Fermilab are combined with those of an earlier study from the 1992-1993 run. A fit to the transverse momentum spectrum of the W boson yields direct limits on anomalous WWγ and WWZ couplings. With the assumption that the WWγ and WWZ couplings are equal, we obtain -0.34<λ<0.36 (with Δκ=0) and -0.43<Δκ<0.59 (with λ=0) at the 95% confidence level for a form-factor scale Λ=2.0 TeV.
Early inner solar system origin for anomalous sulfur isotopes in differentiated protoplanets.
Antonelli, Michael A; Kim, Sang-Tae; Peters, Marc; Labidi, Jabrane; Cartigny, Pierre; Walker, Richard J; Lyons, James R; Hoek, Joost; Farquhar, James
2014-12-16
Achondrite meteorites have anomalous enrichments in (33)S, relative to chondrites, which have been attributed to photochemistry in the solar nebula. However, the putative photochemical reactions remain elusive, and predicted accompanying (33)S depletions have not previously been found, which could indicate an erroneous assumption regarding the origins of the (33)S anomalies, or of the bulk solar system S-isotope composition. Here, we report well-resolved anomalous (33)S depletions in IIIF iron meteorites (solar system (solar system S-isotope composition was chondritic (consistent with IAB iron meteorites, Earth, Moon, and Mars). The range of mass-independent sulfur isotope compositions may reflect spatial or temporal changes influenced by photochemical processes. A tentative correlation between S isotopes and Hf-W core segregation ages suggests that the two systems may be influenced by common factors, such as nebular location and volatile content.
Design of photonic crystal fibers with anomalous dispersion
Institute of Scientific and Technical Information of China (English)
CHI Hao; ZHANG Xian-min; SHEN Lin-fang
2006-01-01
Photonic crystal fibers (PCFs) with anomalous dispersion in short wavelength region are significant for some applications, such as short wavelength soliton propagation, super continuum generation and short pulse fiber lasing.In this paper,a systematic method for designing PCFs with required anomalous dispersion region is proposed by using a finite difference solver and the scaling transformation of the waveguide dispersion of PCFs.Designed PCF can be anomalously dispersive in the region less than 1.3 μm,which is very difficult to realize in the traditional standard single-mode fibers.The effectiveness of the proposed method is approved by numerical results.
The no-drag frame for anomalous chiral fluid
Stephanov, Mikhail A
2015-01-01
We show that for an anomalous fluid carrying dissipationless chiral magnetic and/or vortical currents there is a frame in which a stationary obstacle experiences no drag, but energy and charge currents do not vanish, resembling superfluidity. However, unlike ordinary superfluid flow, the anomalous chiral currents do transport entropy in this frame. We show that the second law of thermodynamics completely determines the amounts of these anomalous non-dissipative currents in the "no-drag frame" as polynomials in temperature and chemical potential with known anomaly coefficients. These general results are illustrated and confirmed by a calculation in the chiral kinetic theory and quark-gluon plasma at high temperature.
Search for Anomalous Couplings in the Higgs Sector at LEP
Achard, P; Aguilar-Benítez, M; Alcaraz, J; Alemanni, G; Allaby, James V; Aloisio, A; Alviggi, M G; Anderhub, H; Andreev, V P; Anselmo, F; Arefev, A; Azemoon, T; Aziz, T; Bagnaia, P; Bajo, A; Baksay, G; Baksay, L; Baldew, S V; Banerjee, S; Banerjee, Sw; Barczyk, A; Barillère, R; Bartalini, P; Basile, M; Batalova, N; Battiston, R; Bay, A; Becattini, F; Becker, U; Behner, F; Bellucci, L; Berbeco, R; Berdugo, J; Berges, P; Bertucci, B; Betev, B L; Biasini, M; Biglietti, M; Biland, A; Blaising, J J; Blyth, S C; Bobbink, Gerjan J; Böhm, A; Boldizsar, L; Borgia, B; Bottai, S; Bourilkov, D; Bourquin, Maurice; Braccini, S; Branson, J G; Brochu, F; Burger, J D; Burger, W J; Cai, X D; Capell, M; Cara Romeo, G; Carlino, G; Cartacci, A M; Casaus, J; Cavallari, F; Cavallo, N; Cecchi, C; Cerrada, M; Chamizo-Llatas, M; Chang, Y H; Chemarin, M; Chen, A; Chen, G; Chen, G M; Chen, H F; Chen, H S; Chiefari, G; Cifarelli, Luisa; Cindolo, F; Clare, I; Clare, R; Coignet, G; Colino, N; Costantini, S; de la Cruz, B; Cucciarelli, S; van Dalen, J A; De Asmundis, R; Déglon, P L; Debreczeni, J; Degré, A; Dehmelt, K; Deiters, K; Della Volpe, D; Delmeire, E; Denes, P; De Notaristefani, F; De Salvo, A; Diemoz, M; Dierckxsens, M; Dionisi, C; Dittmar, M; Doria, A; Dova, M T; Duchesneau, D; Duda, M; Echenard, B; Eline, A; El-Hage, A; El-Mamouni, H; Engler, A; Eppling, F J; Extermann, P; Falagán, M A; Falciano, S; Favara, A; Fay, J; Fedin, O; Felcini, M; Ferguson, T; Fesefeldt, H S; Fiandrini, E; Field, J H; Filthaut, F; Fisher, P H; Fisher, W; Fisk, I; Forconi, G; Freudenreich, Klaus; Furetta, C; Galaktionov, Yu; Ganguli, S N; García-Abia, P; Gataullin, M; Gentile, S; Giagu, S; Gong, Z F; Grenier, G; Grimm, O; Grünewald, M W; Guida, M; van Gulik, R; Gupta, V K; Gurtu, A; Gutay, L J; Haas, D; Hatzifotiadou, D; Hebbeker, T; Hervé, A; Hirschfelder, J; Hofer, H; Hohlmann, M; Holzner, G; Hou, S R; Hu, Y; Jin, B N; Jones, L W; de Jong, P; Josa-Mutuberria, I; Kaur, M; Kienzle-Focacci, M N; Kim, J K; Kirkby, Jasper; Kittel, E W; Klimentov, A; König, A C; Kopal, M; Koutsenko, V F; Kräber, M H; Krämer, R W; Krüger, A; Kunin, A; Ladrón de Guevara, P; Laktineh, I; Landi, G; Lebeau, M; Lebedev, A; Lebrun, P; Lecomte, P; Lecoq, P; Le Coultre, P; Le Goff, J M; Leiste, R; Levtchenko, M; Levchenko, P M; Li, C; Likhoded, S; Lin, C H; Lin, W T; Linde, Frank L; Lista, L; Liu, Z A; Lohmann, W; Longo, E; Lü, Y S; Luci, C; Luminari, L; Lustermann, W; Ma Wen Gan; Malgeri, L; Malinin, A; Maña, C; Mans, J; Martin, J P; Marzano, F; Mazumdar, K; McNeil, R R; Mele, S; Merola, L; Meschini, M; Metzger, W J; Mihul, A; Milcent, H; Mirabelli, G; Mnich, J; Mohanty, G B; Muanza, G S; Muijs, A J M; Musicar, B; Musy, M; Nagy, S; Natale, S; Napolitano, M; Nessi-Tedaldi, F; Newman, H; Nisati, A; Novák, T; Nowak, H; Ofierzynski, R A; Organtini, G; Pal, I; Palomares, C; Paolucci, P; Paramatti, R; Passaleva, G; Patricelli, S; Paul, T; Pauluzzi, M; Paus, C; Pauss, Felicitas; Pedace, M; Pensotti, S; Perret-Gallix, D; Petersen, B; Piccolo, D; Pierella, F; Pioppi, M; Piroué, P A; Pistolesi, E; Plyaskin, V; Pohl, M; Pozhidaev, V; Pothier, J; Prokofev, D; Prokofiev, D O; Quartieri, J; Rahal-Callot, G; Rahaman, M A; Raics, P; Raja, N; Ramelli, R; Rancoita, P G; Ranieri, R; Raspereza, A V; Razis, P A; Ren, D; Rescigno, M; Reucroft, S; Riemann, S; Riles, K; Roe, B P; Romero, L; Rosca, A; Rosemann, C; Rosenbleck, C; Rosier-Lees, S; Roth, S; Rubio, J A; Ruggiero, G; Rykaczewski, H; Sakharov, A; Saremi, S; Sarkar, S; Salicio, J; Sánchez, E; Schäfer, C; Shchegelskii, V; Schopper, Herwig Franz; Schotanus, D J; Sciacca, C; Servoli, L; Shevchenko, S; Shivarov, N; Shoutko, V; Shumilov, E; Shvorob, A V; Son, D; Souga, C; Spillantini, P; Steuer, M; Stickland, D P; Stoyanov, B; Strässner, A; Sudhakar, K; Sultanov, G G; Sun, L Z; Sushkov, S; Suter, H; Swain, J D; Szillási, Z; Tang, X W; Tarjan, P; Tauscher, Ludwig; Taylor, L; Tellili, B; Teyssier, D; Timmermans, C; Ting, Samuel C C; Ting, S M; Tonwar, S C; Tóth, J; Tully, C; Tung, K L; Ulbricht, J; Valente, E; Van de Walle, R T; Vásquez, R; Veszpremi, V; Vesztergombi, G; Vetlitskii, I; Vicinanza, D; Viertel, Gert M; Villa, S; Vivargent, M; Vlachos, S; Vodopyanov, I; Vogel, H; Vogt, H; Vorobev, I; Vorobyov, A A; Wadhwa, M; Wang, Q; Wang, X L; Wang, Z M; Weber, M; Wilkens, H; Wynhoff, S; Xia, L; Xu, Z Z; Yamamoto, J; Yang, B Z; Yang, C G; Yang, H J; Yang, M; Yeh, S C; Zalite, A; Zalite, Yu; Zhang, Z P; Zhao, J; Zhu, G Y; Zhu, R Y; Zhuang, H L; Zichichi, A; Zimmermann, B; Zöller, M
2004-01-01
Anomalous couplings of the Higgs boson are searched for through the processes e^+ e^- -> H gamma, e^+ e^- -> e^+ e^- H and e^+ e^- -> HZ. The mass range 70 GeV ffbar, H -> gamma gamma, H -> Z\\gamma and H -> WW^(*) are considered and no evidence is found for anomalous Higgs production or decay. Limits on the anomalous couplings d, db, Delta(g1z), Delta(kappa_gamma) and xi^2 are derived as well as limits on the H -> gamma gamma and H -> Z gamma decay rates.
Borah, Bhaskar J; Jobic, H; Yashonath, S
2010-04-14
We report the quasielastic neutron scattering (QENS) and molecular dynamics (MD) investigations into diffusion of pentane isomers in zeolite NaY. The molecular cross section perpendicular to the long molecular axis varies for the three isomers while the mass and the isomer-zeolite interaction remains essentially unchanged. Both QENS and MD results show that the branched isomers neopentane and isopentane have higher self-diffusivities as compared with n-pentane at 300 K in NaY zeolite. This result provides direct experimental evidence for the existence of nonmonotonic, anomalous dependence of self-diffusivity on molecular diameter known as the levitation effect. The energetic barrier at the bottleneck derived from MD simulations exists for n-pentane which lies in the linear regime while no such barrier is seen for neopentane which is located clearly in the anomalous regime. Activation energy is in the order E(a)(n-pentane)>E(a)(isopentane)>E(a)(neopentane) consistent with the predictions of the levitation effect. In the liquid phase, it is seen that D(n-pentane)>D(isopentane)>D(neopentane) and E(a)(n-pentane)
Outcomes of surgery for total anomalous pulmonary venous drainage
Directory of Open Access Journals (Sweden)
Milovanović Vladimir
2014-01-01
Full Text Available Introduction. Total anomalous pulmonary venous connection (TAPVC is a rare congenital heart disease and in some variants represents the only true surgical emergency in congenital heart surgery. Basic anatomical characteristic of this anomaly is an abnormal connection of pulmonary veins with systemic venous circulation. Although the results of TAPVC repair in infancy have been markedly improved in recent years, the recurrent pulmonary venous obstruction (RPVO remains relatively frequent complication of surgical treatment. Objective. The aim of this study was a retrospective evaluation of TAPVC repair at a single institution, identifying the risk factors associated with the increased mortality and morbidity. Methods. Between January 2001 and January 2010, 43 consecutive patients underwent repair of TAPVC at the University Children’s Hospital, with median weight of 3.8 kg (1.8-13 kg. Median age at surgery varied from 5 days to 5 years. Distribution of TAPVC types was as follows: supracardiac 19 (44%, cardiac 12 (28%, infracardiac 9 (21%, and mixed 3 (7%. Eleven patients (26% were emergencies due to obstructed drainage. Results. Early mortality was 9.30% (4/43. An average time of followup/survival for 95% interval of confidence was 101.6±6.7 months. Kaplan-Meier cumulative survival was 83.7±5.7%. Freedom from reintervention after 10 years was 87.2±0.5%. The principal reason for reintervention was RPVO. Conclusion. Preoperative obstruction is not a risk factor of early mortality and RPVO. Low body mass (below 2.5 kg is the only identified risk factor of early mortality. Complex morphology of the confluens, particularly in a mixed type of TAPVR, is the main risk factor of RPVO development.
Light-by-light scattering sum rules in light of new data
Danilkin, Igor
2016-01-01
We evaluate the light-quark meson contributions to three exact light-by-light scattering sum rules in light of new data by the Belle Collaboration, which recently has extracted the transition form factors of the tensor meson $f_2(1270)$ as well as of the scalar meson $f_0(980)$. We confirm a previous finding that the $\\eta, \\eta^\\prime$ and helicity-2 $f_2(1270)$ contributions saturate one of these sum rules up to photon virtualities up to around 1 GeV$^2$. At larger virtualities, our sum rule analysis shows an important contribution of the $f_2(1565)$ meson and provides a first empirical extraction of its helicity-2 transition form factor. Two further sum rules allow us to predict the helicity-0 and helicity-1 transition form factors of the $f_2(1270)$ meson. Furthermore, our analysis also provides an update for the scalar and tensor meson hadronic light-by-light contributions to the muon's anomalous magnetic moment.
Modelling the inelastic scattering of fast electrons
Energy Technology Data Exchange (ETDEWEB)
Allen, L.J., E-mail: lja@unimelb.edu.au [School of Physics, University of Melbourne, Parkville, Victoria 3010 (Australia); D' Alfonso, A.J., E-mail: a.j@dalfonso.com.au [School of Physics, University of Melbourne, Parkville, Victoria 3010 (Australia); Findlay, S.D. [School of Physics, Monash University, Clayton, Victoria 3800 (Australia)
2015-04-15
Imaging at atomic resolution based on the inelastic scattering of electrons has become firmly established in the last three decades. Harald Rose pioneered much of the early theoretical work on this topic, in particular emphasising the role of phase and the importance of a mixed dynamic form factor. In this paper we review how the modelling of inelastic scattering has subsequently developed and how numerical implementation has been achieved. A software package μSTEM is introduced, capable of simulating various imaging modes based on inelastic scattering in both scanning and conventional transmission electron microscopy. - Highlights: • Harald Rose was a pioneer of important work on atomic resolution imaging using inelastic scattering. • We review how the modelling of inelastic scattering has subsequently developed and been applied. • A software package μSTEM is introduced, capable of simulating various inelastic imaging modes.
Anomalous spin waves and the commensurate-incommensurate magnetic phase transition in LiNiPO4
DEFF Research Database (Denmark)
Jensen, Thomas Bagger Stibius; Christensen, Niels Bech; Kenzelmann, M.
2009-01-01
above T-N. A linear spin-wave model based on Heisenberg exchange couplings and single-ion anisotropies accounts for all the observed spin-wave dispersions and intensities. Along the b axis an unusually strong next-nearest-neighbor AF coupling competes with the dominant nearest-neighbor AF exchange......Detailed spin-wave spectra of magnetoelectric LiNiPO4 have been measured by neutron scattering at low temperatures in the commensurate (C) antiferromagnetic (AF) phase below T-N=20.8 K. An anomalous shallow minimum is observed at the modulation vector of the incommensurate (IC) AF phase appearing...
Anomalous X-ray Diffraction Studies for Photovoltaic Applications
Energy Technology Data Exchange (ETDEWEB)
2011-06-22
Anomalous X-ray Diffraction (AXRD) has become a useful technique in characterizing bulk and nanomaterials as it provides specific information about the crystal structure of materials. In this project we present the results of AXRD applied to materials for photovoltaic applications: ZnO loaded with Ga and ZnCo{sub 2}O{sub 4} spinel. The X-ray diffraction data collected for various energies were plotted in Origin software. The peaks were fitted using different functions including Pseudo Voigt, Gaussian, and Lorentzian. This fitting provided the integrated intensity data (peaks area values), which when plotted as a function of X-ray energies determined the material structure. For the first analyzed sample, Ga was not incorporated into the ZnO crystal structure. For the ZnCo{sub 2}O{sub 4} spinel Co was found in one or both tetrahedral and octahedral sites. The use of anomalous X-ray diffraction (AXRD) provides element and site specific information for the crystal structure of a material. This technique lets us correlate the structure to the electronic properties of the materials as it allows us to probe precise locations of cations in the spinel structure. What makes it possible is that in AXRD the diffraction pattern is measured at a number of energies near an X-ray absorption edge of an element of interest. The atomic scattering strength of an element varies near its absorption edge and hence the total intensity of the diffraction peak changes by changing the X-ray energy. Thus AXRD provides element specific structural information. This method can be applied to both crystalline and liquid materials. One of the advantages of AXRD in crystallography experiments is its sensitivity to neighboring elements in the periodic tables. This method is also sensitive to specific crystallographic phases and to a specific site in a phase. The main use of AXRD in this study is for transparent conductors (TCs) analysis. TCs are considered to be important materials because of their
Anomalous Refraction of Acoustic Guided Waves in Solids with Geometrically Tapered Metasurfaces
Zhu, Hongfei; Semperlotti, Fabio
2016-07-01
The concept of a metasurface opens new exciting directions to engineer the refraction properties in both optical and acoustic media. Metasurfaces are typically designed by assembling arrays of subwavelength anisotropic scatterers able to mold incoming wave fronts in rather unconventional ways. The concept of a metasurface was pioneered in photonics and later extended to acoustics while its application to the propagation of elastic waves in solids is still relatively unexplored. We investigate the design of acoustic metasurfaces to control elastic guided waves in thin-walled structural elements. These engineered discontinuities enable the anomalous refraction of guided wave modes according to the generalized Snell's law. The metasurfaces are made out of locally resonant toruslike tapers enabling an accurate phase shift of the incoming wave, which ultimately affects the refraction properties. We show that anomalous refraction can be achieved on transmitted antisymmetric modes (A0) either when using a symmetric (S0) or antisymmetric (A0) incident wave, the former clearly involving mode conversion. The same metasurface design also allows achieving structure embedded planar focal lenses and phase masks for nonparaxial propagation.
Anomalous Refraction of Acoustic Guided Waves in Solids with Geometrically Tapered Metasurfaces.
Zhu, Hongfei; Semperlotti, Fabio
2016-07-15
The concept of a metasurface opens new exciting directions to engineer the refraction properties in both optical and acoustic media. Metasurfaces are typically designed by assembling arrays of subwavelength anisotropic scatterers able to mold incoming wave fronts in rather unconventional ways. The concept of a metasurface was pioneered in photonics and later extended to acoustics while its application to the propagation of elastic waves in solids is still relatively unexplored. We investigate the design of acoustic metasurfaces to control elastic guided waves in thin-walled structural elements. These engineered discontinuities enable the anomalous refraction of guided wave modes according to the generalized Snell's law. The metasurfaces are made out of locally resonant toruslike tapers enabling an accurate phase shift of the incoming wave, which ultimately affects the refraction properties. We show that anomalous refraction can be achieved on transmitted antisymmetric modes (A_{0}) either when using a symmetric (S_{0}) or antisymmetric (A_{0}) incident wave, the former clearly involving mode conversion. The same metasurface design also allows achieving structure embedded planar focal lenses and phase masks for nonparaxial propagation.
Probing anomalous heavy neutral Higgs bosons at the LHC II: LHC signatures
Xia, Ling-Hao; Kuang, Yu-Ping
2014-01-01
In this manuscript, we study the LHC signatures of a non-standard heavy neutral Higgs boson H at the 14 TeV LHC model-independently by taking the anomalous HVV coupling constants in the possible range obtained in our previous paper, Ref.[1]. We suggest WW scattering and VH associated production as two sensitive processes for detecting H, and the latter is more sensitive than the former. The study is at the hadron level with signals and backgrounds carefully calculated. Certain kinematic cuts are proposed to suppress the backgrounds effectively. We take several values of the heavy Higgs masses in the few hundred GeV range as examples. We show that, in VH associated production, the invariant mass distribution M(J_1,J_2) of the final state jets can show a clear peak at M(J_1,J_2)=M_H with reasonable integrated luminosity. Finally, we propose several detectable observables from which the values of the anomalous coupling constants f_W and f_WW can be measured experimentally.
Medvedev, Mikhail V.
2017-01-01
Faraday effect - a common and useful probe of cosmic magnetic fields - is the result of magnetically-induced birefringence in plasmas causing rotation of the polarization plane of a linearly polarized electromagnetic wave. Classically, the rotation angle scales with the wavelength as Δϕ =RMλ2 , where RM is the rotation measure. Although a typical RM in the Milky Way is of the order of a few hundred to a few thousand, a famous Cygnus region shows anomalously small, even negative rotation measures. Moreover, Faraday rotation measurements seem to be inconsistent with the standard λ2-law. We argue that fast micro-turbulence can cause this anomaly. We demonstrate that electromagnetic high-frequency and/or small-scale fluctuations can lead to effective plasma collisionality by scattering electrons over pitch-angle. We show that such quasi-collisionality radically alters Faraday rotation and other radiative transport properties, e.g., absorption, transmission and reflection. Thus, we explain the Cygnus puzzle by anomalous Faraday rotation in a thin ``blanket'' of highly turbulent plasma at the front of an interstellar bubble/shock. Supported by DOE grant DE-SC0016368.
Anomalous transfer of syntax between languages.
Vaughan-Evans, Awel; Kuipers, Jan Rouke; Thierry, Guillaume; Jones, Manon W
2014-06-11
Each human language possesses a set of distinctive syntactic rules. Here, we show that balanced Welsh-English bilinguals reading in English unconsciously apply a morphosyntactic rule that only exists in Welsh. The Welsh soft mutation rule determines whether the initial consonant of a noun changes based on the grammatical context (e.g., the feminine noun cath--"cat" mutates into gath in the phrase y gath--"the cat"). Using event-related brain potentials, we establish that English nouns artificially mutated according to the Welsh mutation rule (e.g., "goncert" instead of "concert") require significantly less processing effort than the same nouns implicitly violating Welsh syntax. Crucially, this effect is found whether or not the mutation affects the same initial consonant in English and Welsh, showing that Welsh syntax is applied to English regardless of phonological overlap between the two languages. Overall, these results demonstrate for the first time that abstract syntactic rules transfer anomalously from one language to the other, even when such rules exist only in one language.
Hydrodynamic waves in an anomalous charged fluid
Abbasi, Navid; Davody, Ali; Hejazi, Kasra; Rezaei, Zahra
2016-11-01
We study the collective excitations in a relativistic fluid with an anomalous U (1) current. In 3 + 1 dimensions at zero chemical potential, in addition to ordinary sound modes we find two propagating modes in presence of an external magnetic field. The first one which is a transverse degenerate mode, propagates with a velocity proportional to the coefficient of gravitational anomaly; this is in fact the Chiral Alfvén wave recently found in [1]. Another one is a wave of density perturbation, namely a chiral magnetic wave (CMW). The velocity dependence of CMW on the chiral anomaly coefficient is well known. We compute the dependence of CMW's velocity on the coefficient of gravitational anomaly as well. We also show that the dissipation splits the degeneracy of CAW. At finite chiral charge density we show that in general there may exist five chiral hydrodynamic waves. Of these five waves, one is the CMW while the other four are mixed Modified Sound-Alfvén waves. It turns out that in propagation transverse to the magnetic field no anomaly effect appears while in parallel to the magnetic field we find sound waves become dispersive due to anomaly.
Quantum anomalous Hall effect in real materials
Zhang, Jiayong; Zhao, Bao; Zhou, Tong; Yang, Zhongqin
2016-11-01
Under a strong magnetic field, the quantum Hall (QH) effect can be observed in two-dimensional electronic gas systems. If the quantized Hall conductivity is acquired in a system without the need of an external magnetic field, then it will give rise to a new quantum state, the quantum anomalous Hall (QAH) state. The QAH state is a novel quantum state that is insulating in the bulk but exhibits unique conducting edge states topologically protected from backscattering and holds great potential for applications in low-power-consumption electronics. The realization of the QAH effect in real materials is of great significance. In this paper, we systematically review the theoretical proposals that have been brought forward to realize the QAH effect in various real material systems or structures, including magnetically doped topological insulators, graphene-based systems, silicene-based systems, two-dimensional organometallic frameworks, quantum wells, and functionalized Sb(111) monolayers, etc. Our paper can help our readers to quickly grasp the recent developments in this field. Project supported by the National Basic Research Program of China (Grant No. 2011CB921803), the National Natural Science Foundation of China (Grant No. 11574051), the Natural Science Foundation of Shanghai, China (Grant No. 14ZR1403400), and Fudan High-end Computing Center, China.
Anomalous flows in a sunspot penumbra
Louis, Rohan E; Mathew, Shibu K; Venkatakrishnan, P
2014-01-01
High-resolution spectropolarimetric observations of active region NOAA 11271 were obtained with the spectro-polarimeter on board Hinode to analyze the properties of an anomalous flow in the photosphere in a sunspot penumbra. We detect a blue-shifted feature that appeared on the limb-side penumbra of a sunspot and that was present intermittently during the next two hours. It exhibited a maximum blue-shift of 1.6 km/s, an area of 5.2 arcsec^2, and an uninterrupted lifetime of 1 hr. The blue-shifted feature, when present, lies parallel to red-shifts. Both blue and red shifts flank a highly inclined/horizontal magnetic structure that is radially oriented in the penumbra. The low-cadence SP maps reveal changes in size, radial position in the penumbra and line-of-sight velocity of the blue-shifted feature, from one scan to the other. There was an increase of nearly 500 G in the field strength and a marginal reduction in the field inclination of about 10 deg with the onset of the blue-shifts. In the chromosphere, in...
Anomalous Light Phenomena vs. Bioelectric Brain Activity
Teodorani, M.; Nobili, G.
We present a research proposal concerning the instrumented investigation of anomalous light phenomena that are apparently correlated with particular mind states, such as prayer, meditation or psi. Previous research by these authors demonstrate that such light phenomena can be monitored and measured quite efficiently in areas of the world where they are reported in a recurrent way. Instruments such as optical equipment for photography and spectroscopy, VLF spectrometers, magnetometers, radar and IR viewers were deployed and used massively in several areas of the world. Results allowed us to develop physical models concerning the structural and time-variable behaviour of light phenomena, and their kinematics. Recent insights and witnesses have suggested to us that a sort of "synchronous connection" seems to exist between plasma-like phenomena and particular mind states of experiencers who seem to trigger a light manifestation which is very similar to the one previously investigated. The main goal of these authors is now aimed at the search for a concrete "entanglement-like effect" between the experiencer's mind and the light phenomena, in such a way that both aspects are intended to be monitored and measured simultaneously using appropriate instrumentation. The goal of this research project is twofold: a) to verify quantitatively the existence of one very particular kind of mind-matter interaction and to study in real time its physical and biophysical manifestations; b) to repeat the same kind of experiment using the same test-subject in different locations and under various conditions of geomagnetic activity.
Anomalous transport from holography. Pt. II
Energy Technology Data Exchange (ETDEWEB)
Bu, Yanyan; Sharon, Amir [Ben-Gurion University of the Negev, Department of Physics, Beersheba (Israel); Lublinsky, Michael [Ben-Gurion University of the Negev, Department of Physics, Beersheba (Israel); University of Connecticut, Physics Department, Storrs, CT (United States)
2017-03-15
This is a second study of chiral anomaly-induced transport within a holographic model consisting of anomalous U(1){sub V} x U(1){sub A} Maxwell theory in Schwarzschild-AdS{sub 5} spacetime. In the first part, chiral magnetic/separation effects (CME/CSE) are considered in the presence of a static spatially inhomogeneous external magnetic field. Gradient corrections to CME/CSE are analytically evaluated up to third order in the derivative expansion. Some of the third order gradient corrections lead to an anomaly-induced negative B{sup 2}-correction to the diffusion constant. We also find modifications to the chiral magnetic wave nonlinear in B. In the second part, we focus on the experimentally interesting case of the axial chemical potential being induced dynamically by a constant magnetic and time-dependent electric fields. Constitutive relations for the vector/axial currents are computed employing two different approximations: (a) derivative expansion (up to third order) but fully nonlinear in the external fields, and (b) weak electric field limit but resuming all orders in the derivative expansion. A non-vanishing nonlinear axial current (CSE) is found in the first case. The dependence on magnetic field and frequency of linear transport coefficient functions is explored in the second. (orig.)
Anomalous transport from holography: Part II
Bu, Yanyan; Sharon, Amir
2016-01-01
This is a second study of chiral anomaly induced transport within a holographic model consisting of anomalous $U(1)_V\\times U(1)_A$ Maxwell theory in Schwarzschild-$AdS_5$ spacetime. In the first part, chiral magnetic/separation effects (CME/CSE) are considered in presence of a static spatially-inhomogeneous external magnetic field. Gradient corrections to CME/CSE are analytically evaluated up to third order in the derivative expansion. Some of the third order gradient corrections lead to an anomaly-induced negative $B^2$-correction to the diffusion constant. We also find non-linear modifications to the chiral magnetic wave (CMW). In the second part, we focus on the experimentally interesting case of the axial chemical potential being induced dynamically by a constant magnetic and time-dependent electric fields. Constitutive relations for the vector/axial currents are computed employing two different approximations: (a) derivative expansion (up to third order) but fully nonlinear in the external fields, and (...
EAWE: Examination of Anomalous World Experience.
Sass, Louis; Pienkos, Elizabeth; Skodlar, Borut; Stanghellini, Giovanni; Fuchs, Thomas; Parnas, Josef; Jones, Nev
2017-01-01
The "EAWE: Examination of Anomalous World Experience" is a detailed semi-structured interview format whose aim is to elicit description and discussion of a person's experience of various aspects of their lived world. The instrument is grounded in the tradition of phenomenological psychopathology and aims to explore, in a qualitatively rich manner, six key dimensions of subjectivity - namely, a person's experience of: (1) Space and objects, (2) Time and events, (3) Other persons, (4) Language (whether spoken or written), (5) Atmosphere (overall sense of reality, familiarity, vitality, meaning, or relevance), and (6) Existential orientation (values, attitudes, and worldviews). The EAWE is based on and primarily directed toward experiences thought to be common in, and sometimes distinctive of, schizophrenia spectrum conditions. It can, however, also be used to investigate anomalies of world experience in other populations. After a theoretical and methodological introduction, the EAWE lists 75 specific items, often with subtypes, in its six domains, together with illustrative quotations from patients. The EAWE appears in a special issue of Psychopathology that also contains an orienting preface (where the difficulty as well as necessity of studying subjective life is acknowledged) and a brief reliability report. Also included are six ancillary or background articles, which survey phenomenologically oriented theory, research, and clinical lore relevant to the six experiential domains. © 2017 S. Karger AG, Basel.
Anomalous Transfer of Syntax between Languages
Vaughan-Evans, Awel; Kuipers, Jan Rouke; Thierry, Guillaume
2014-01-01
Each human language possesses a set of distinctive syntactic rules. Here, we show that balanced Welsh-English bilinguals reading in English unconsciously apply a morphosyntactic rule that only exists in Welsh. The Welsh soft mutation rule determines whether the initial consonant of a noun changes based on the grammatical context (e.g., the feminine noun cath—“cat” mutates into gath in the phrase y gath—“the cat”). Using event-related brain potentials, we establish that English nouns artificially mutated according to the Welsh mutation rule (e.g., “goncert” instead of “concert”) require significantly less processing effort than the same nouns implicitly violating Welsh syntax. Crucially, this effect is found whether or not the mutation affects the same initial consonant in English and Welsh, showing that Welsh syntax is applied to English regardless of phonological overlap between the two languages. Overall, these results demonstrate for the first time that abstract syntactic rules transfer anomalously from one language to the other, even when such rules exist only in one language. PMID:24920636
Heterogeneous anomalous diffusion in view of superstatistics
Energy Technology Data Exchange (ETDEWEB)
Itto, Yuichi
2014-08-22
Highlights: • A theory is developed for a generalized fractional kinetics in view of superstatistics. • The present theory explicitly takes into account the existence of a large time-scale separation in the infection pathway. • The present theory implies a scaling nature of the motion of the virus. - Abstract: It is experimentally known that virus exhibits stochastic motion in cytoplasm of a living cell in the free form as well as the form being contained in the endosome and the exponent of anomalous diffusion of the virus fluctuates depending on localized areas of the cytoplasm. Here, a theory is developed for establishing a generalized fractional kinetics for the infection pathway of the virus in the cytoplasm in view of superstatistics, which offers a general framework for describing nonequilibrium complex systems with two largely separated time scales. In the present theory, the existence of a large time-scale separation in the infection pathway is explicitly taken into account. A comment is also made on scaling nature of the motion of the virus that is suggested by the theory.
Anomalous transport from holography. Part I
Energy Technology Data Exchange (ETDEWEB)
Bu, Yanyan [Department of Physics, Ben-Gurion University of the Negev,Beer-Sheva 84105 (Israel); Lublinsky, Michael [Department of Physics, Ben-Gurion University of the Negev,Beer-Sheva 84105 (Israel); Physics Department, University of Connecticut,2152 Hillside Road, Storrs, CT 06269-3046 (United States); Sharon, Amir [Department of Physics, Ben-Gurion University of the Negev,Beer-Sheva 84105 (Israel)
2016-11-17
We revisit the transport properties induced by the chiral anomaly in a charged plasma holographically dual to anomalous U(1){sub V}×U(1){sub A} Maxwell theory in Schwarzschild-AdS{sub 5}. Off-shell constitutive relations for vector and axial currents are derived using various approximations generalising most of known in the literature anomaly-induced phenomena and revealing some new ones. In a weak external field approximation, the constitutive relations have all-order derivatives resummed into six momenta-dependent transport coefficient functions: the diffusion, the electric/magnetic conductivity, and three anomaly induced functions. The latter generalise the chiral magnetic and chiral separation effects. Nonlinear transport is studied assuming presence of constant background external fields. The chiral magnetic effect, including all order nonlinearity in magnetic field, is proven to be exact when the magnetic field is the only external field that is turned on. Non-linear corrections to the constitutive relations due to electric and axial external fields are computed.
Anomalous diffusion on the Hanoi networks
Boettcher, S.; Gonçalves, B.
2008-11-01
Diffusion is modeled on the recently proposed Hanoi networks by studying the mean-square displacement of random walks with time, langr2rang~t2/dw. It is found that diffusion —the quintessential mode of transport throughout Nature— proceeds faster than ordinary, in one case with an exact, anomalous exponent dw=2- log2(phi)=1.30576... . It is an instance of a physical exponent containing the "golden ratio"\\phi=(1+\\sqrt{5})/2 that is intimately related to Fibonacci sequences and since Euclid's time has been found to be fundamental throughout geometry, architecture, art, and Nature itself. It originates from a singular renormalization group fixed point with a subtle boundary layer, for whose resolution phi is the main protagonist. The origin of this rare singularity is easily understood in terms of the physics of the process. Yet, the connection between network geometry and the emergence of phi in this context remains elusive. These results provide an accurate test of recently proposed universal scaling forms for first passage times.
Brothers, Julie A; Gaynor, J William; Jacobs, Jeffrey P; Caldarone, Christopher; Jegatheeswaran, Anusha; Jacobs, Marshall L
2010-12-01
The anomalous aortic origin of a coronary artery from the wrong sinus of Valsalva with interarterial, intramural, and/or intraconal course is a rare congenital anomaly that is associated with a high risk of sudden death in children. The Congenital Heart Surgeons' Society established the Registry of Anomalous Aortic Origin of the Coronary Artery to help determine the outcome of children and young adults managed with surgical intervention versus observation and to test the hypothesis that subsets of patients with anomalous aortic origin of a coronary artery can be identified in whom the risk of intervention is less than the risk of observation. All institutional members of the Congenital Heart Surgeons' Society were recruited for participation. The registry consists of a retrospective cohort of patients diagnosed between 1 January, 1998 and 20 January, 2009 and a prospective, population-based cohort of patients newly diagnosed from 21 January, 2009 onwards. Baseline demographics, diagnoses, and results of tests will be obtained through a review of the medical records. Annual follow-up data will be collected. Data will be analysed for different factors of risk at diagnosis, different strategies of treatment, and the impact of both on the outcomes of the patients. As of June 2010, 28 institutions had applied for approval from their institutional review board and 16 institutions had received approval from their institutional review board. Seventy-four patients have enrolled to date. We hope to use the established Pediatric Cardiomyopathy Registry as a guide to successful implementation, with a cooperative effort between institutions. The overall purpose of the Registry of Anomalous Aortic Origin of the Coronary Artery is to determine the outcome of surgical intervention versus observation in children and young adults with anomalous aortic origin of a coronary artery, and to describe the natural and "unnatural" history of these patients over the course of their lifetime
Qureshi, N.; Zbiri, M.; Rodríguez-Carvajal, J.; Stunault, A.; Ressouche, E.; Hansen, T. C.; Fernández-Díaz, M. T.; Johnson, M. R.; Fuess, H.; Ehrenberg, H.; Sakurai, Y.; Itou, M.; Gillon, B.; Wolf, Th.; Rodríguez-Velamazan, J. A.; Sánchez-Montero, J.
2009-03-01
We present a combination of ab initio calculations, magnetic Compton scattering, and polarized neutron experiments, which elucidate the density distribution of unpaired electrons in the kagome staircase system Co3V2O8 . Ab initio wave functions were used to calculate the spin densities in real and momentum spaces, which show good agreement with the respective experiments. It has been found that the spin polarized orbitals are equally distributed between the t2g and the eg levels for the spine (s) Co ions while the eg orbitals of the cross-tie (c) Co ions only represent 30% of the atomic spin density. Furthermore, the results reveal that the magnetic moments of the cross-tie Co ions, which are significantly smaller than those of the spine Co ions in the zero-field ferromagnetic structure, do not saturate by applying an external magnetic field of 2 T along the easy axis a . In turn, the increasing bulk magnetization, which can be observed by field dependent macroscopic measurements, originates from induced magnetic moments on the O and V sites. The refined individual magnetic moments are μ(Coc)=1.54(4)μB , μ(Cos)=2.87(3)μB , μ(V)=0.41(4)μB , μ(O1)=0.05(5)μB , μ(O2)=0.35(5)μB , and μ(O3)=0.36(5)μB combining to the same macroscopic magnetization value, which was previously only attributed to the Co ions.
Zabotin, N A; Kovalenko, E S; Frolov, V L; Komrakov, G P; Mityakov, N A; Sergeev, E N
2001-01-01
Multiple scattering from artificial random irregularities HF-induced in the ionosphere F region causes significant attenuation of both ordinary and extraordinary radio waves together with the conventional anomalous absorption of ordinary waves due to their conversion into the plasma waves. To study in detail features of this effect, purposeful measurements of the attenuation of weak probing waves of the extraordinary polarization have been performed at the Sura heating facility. Characteristic scale lengths of the involved irregularities are ~0.1-1 km across the geomagnetic field lines. To determine the spectral characteristics of these irregularities from the extraordinary probing wave attenuation measurements, a simple procedure of the inverse problem solving has been implemented and some conclusions about the artificial irregularity features have been drawn. Theory and details of experiments have been stated earlier. This paper reports results of two experimental campaigns carried out in August 2000 and Ju...
Modelling lightcurves and spectra of transient Anomalous X-ray Pulsars
Zane, S; Turolla, R; Israel, G L; Nobili, L; Stella, L
2011-01-01
We present the first detailed joint modelling of both the timing and spectral properties during the outburst decay of transient anomalous X-ray pulsars. We consider the two sources XTE J1810-197 and CXOU J164710.2-455216, and describe the source decline in the framework of a twisted magnetosphere model, using Monte Carlo simulations of magnetospheric scattering and mimicking localized heat deposition at the NS surface following the activity. Our results support a picture in which a limited portion of the star surface close to one of the magnetic poles is heated at the outburst onset. The subsequent evolution is driven both by the cooling/varying size of the heated cap and by a progressive untwisting of the magnetosphere.
Modelling lightcurves and spectra of transient Anomalous X-ray Pulsars
Zane, S.; Albano, A.; Turolla, R.; Israel, G. L.; Nobili, L.; Stella, L.
2011-09-01
We present the first detailed joint modelling of both the timing and spectral properties during the outburst decay of transient anomalous X-ray pulsars. We consider the two sources XTE J1810-197 and CXOU J164710.2-455216, and describe the source decline in the framework of a twisted magnetosphere model, using Monte Carlo simulations of magnetospheric scattering and mimicking localized heat deposition at the NS surface following the activity. Our results support a picture in which a limited portion of the star surface close to one of the magnetic poles is heated at the outburst onset. The subsequent evolution is driven both by the cooling/varying size of the heated cap and by a progressive untwisting of the magnetosphere.
Interaction of runaway electrons with lower hybrid waves via anomalous Doppler broadening
Martín-Solís, J. R.; Sánchez, R.; Esposito, B.
2002-05-01
Due to the relativistic decrease of the electron cyclotron frequency, a cyclotron resonance may appear between runaway electrons and lower hybrid waves. A single particle description of the runaway dynamics [J. R. Martín-Solís et al., Phys. Plasmas 5, 2370 (1998)] is extended to analyze the effect of the interaction of runaway electrons with lower hybrid waves via anomalous Doppler broadening. The conditions under which the resonant interaction can play a role in limiting the runaway energy are established and it is shown that, under typical lower hybrid current drive operation parameters, an efficient wave-particle coupling may occur. Observations of a fast pitch angle scattering event during the current decay phase of Ohmic discharges in the Toroidal Experiment for Technically Oriented Research (TEXTOR) [R. J. E. Jaspers, Ph.D. thesis, Technical University Eindhoven (1995)] are interpreted in terms of such interaction.
Subwavelength nonlinear phase control and anomalous phase matching in plasmonic metasurfaces
Almeida, Euclides; Shalem, Guy; Prior, Yehiam
2016-01-01
Metasurfaces, and in particular those containing plasmonic-based metallic elements, constitute an attractive set of materials with a potential for replacing standard bulky optical elements. In recent years, increasing attention has been focused on their nonlinear optical properties, particularly in the context of second and third harmonic generation and beam steering by phase gratings. Here, we harness the full phase control enabled by subwavelength plasmonic elements to demonstrate a unique metasurface phase matching that is required for efficient nonlinear processes. We discuss the difference between scattering by a grating and by subwavelength phase-gradient elements. We show that for such interfaces an anomalous phase-matching condition prevails, which is the nonlinear analogue of the generalized Snell's law. The subwavelength phase control of optical nonlinearities paves the way for the design of ultrathin, flat nonlinear optical elements. We demonstrate nonlinear metasurface lenses, which act both as generators and as manipulators of the frequency-converted signal.
The Chelyabinsk Meteorite Hits an Anomalous Zone in the Urals
Kochemasov, G. G.
2013-09-01
The Chelyabinsk meteorite is "strange" because it hits an area in the Urals where anomalous events are observed: shining skies, light balls, UFOs, electrphonic bolids. The area tectonically occurs at the intersection of two fold belts: Urals and Timan.
Theoretical model for a Stark anomalous dispersion optical filter
Yin, B.; Shay, T. M.
1993-01-01
A theoretical model for the first atomic Stark anomalous dispersion optical filter is reported. The results show the filter may serve as a widely tunable narrow bandwidth and high throughput optical filter for freespace laser communications and remote sensing.
Sampling and Characterization of 618-2 Anomalous Material
Energy Technology Data Exchange (ETDEWEB)
A.E. Zacharias
2006-04-27
Excavation of the 618-2 Burial Ground has produced many items of anomalous waste. Prior to temporary packaging and/or storage, these items have been characterized in the field to identify radiological and industrial safety conditions.
In-plane magnetization-induced quantum anomalous Hall effect.
Liu, Xin; Hsu, Hsiu-Chuan; Liu, Chao-Xing
2013-08-23
The quantum Hall effect can only be induced by an out-of-plane magnetic field for two-dimensional electron gases, and similarly, the quantum anomalous Hall effect has also usually been considered for systems with only out-of-plane magnetization. In the present work, we predict that the quantum anomalous Hall effect can be induced by in-plane magnetization that is not accompanied by any out-of-plane magnetic field. Two realistic two-dimensional systems, Bi2Te3 thin film with magnetic doping and HgMnTe quantum wells with shear strains, are presented and the general condition for the in-plane magnetization-induced quantum anomalous Hall effect is discussed based on the symmetry analysis. Nonetheless, an experimental setup is proposed to confirm this effect, the observation of which will pave the way to search for the quantum anomalous Hall effect in a wider range of materials.
The Interacting Boson Model for Anomalous Rotational Bands
Institute of Scientific and Technical Information of China (English)
QIANCheng－De; LIUDang－Bo; 等
2002-01-01
The interacting boson model for anomalous rotational bands is proposed.In the rotational SU(3) limit an asymptotic limit is discussed.Within the framework of the model several analytic relations for energies and electromagnetic transition rates are derived.
Anomalous scaling of a scalar field advected by turbulence
Energy Technology Data Exchange (ETDEWEB)
Kraichnan, R.H. [Robert H. Kraichnan, Inc., Santa Fe, NM (United States)
1995-12-31
Recent work leading to deduction of anomalous scaling exponents for the inertial range of an advected passive field from the equations of motion is reviewed. Implications for other turbulence problems are discussed.
Silveirinha, Mario G
2016-01-01
In time-reversal invariant electronic systems the scattering matrix is anti-symmetric. This property enables an effect, designated here as "scattering anomaly", such that the electron transport does not suffer from back reflections, independent of the specific geometry of the propagation path or the presence of time-reversal invariant defects. In contrast, for a generic time-reversal invariant photonic system the scattering matrix is symmetric and there is no similar anomaly. Here, it is theoretically proven that despite these fundamental differences there is a wide class of photonic platforms - in some cases formed only by time-reversal invariant media - in which the scattering anomaly can occur. It is shown that an optical system invariant under the action of the composition of the time-reversal, parity and duality operators is characterized by an anti-symmetric scattering matrix. Specific examples of photonic platforms wherein the scattering anomaly occurs are given, and it is demonstrated with full wave n...
2002-01-01
The proposal concerns an extension to higher energies of previous experiments which have provided evidence for anomalously short reaction mean free paths among projectile fragments from heavy ion interactions.\\\\ \\\\ It is intended to provide information on the interaction properties of projectile fragments, mainly 3He, P, D, T as well as of scattered 4He nuclei in passive detectors exposed to beams of energies exceeding those available in previous experim factor of about 7. \\\\ \\\\ Interaction mean free paths and event topologies will be measured in a nuclear emulsion stack (LBL) of 7.5~cm~x~5~cm~x~25~cm dimensions. Decay effects will be recorded by comparing the activity of spallation residues in dense and diluted copper target assemblies (Marburg). Target fragmentation will be studied in a stack of silverchloride crystal foils (Frankfurt) of about 7~cm~x~6~cm~x~1~cm dimensions. The \\alpha beam ejected at EJ~62 will be used to provide both exposures at high intensity of 10|1|2 alphas on th and at low intensity ...
Introduction to neutron scattering
Energy Technology Data Exchange (ETDEWEB)
Fischer, W.E. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)
1996-11-01
We give here an introduction to the theoretical principles of neutron scattering. The relationship between scattering- and correlation-functions is particularly emphasized. Within the framework of linear response theory (justified by the weakness of the basic interaction) the relation between fluctuation and dissipation is discussed. This general framework explains the particular power of neutron scattering as an experimental method. (author) 4 figs., 4 refs.
Anomalous magnetic moment of anyons in three dimensional CP$^{N-1}$ model
Hong, D K; Hong, Deog Ki; Kim, Jin Young
1995-01-01
We calculate the anomalous magnetic moment of anyons in three dimensional CP^{N-1} model with a Chern-Simons term in various limits in 1/N expansion. We have found that for anyons of infinite mass the gyromagnetic ratio (g-factor) is 2 up to the next-to-leading order in 1/N. Our result supports a recent claim that the g-factor of nonrelativistic anyons is exactly two. We also found that for -{8\\over\\pi }<\\theta<0, the electromagnetic interation between two identical aynons of large mass are attractive.
Observation of anomalous phonons in orthorhombic rare-earth manganites
Gao, P.; Chen, H. Y.; Tyson, T. A.; Liu, Z. X.; Bai, J. M.; Wang, L. P.; Choi, Y. J.; Cheong, S.-W.
2010-12-01
We observe the appearance of a phonon near the lock-in temperature in orthorhombic REMnO3 (RE denotes rare earth) (RE: Lu and Ho) and anomalous phonon hardening in orthorhombic LuMnO3. The anomalous phonon occurs at the onset of spontaneous polarization. No such changes were found in incommensurate orthorhombic DyMnO3. These observations directly reveal different electric polarization mechanisms in the E-type and incommensurate-type orthorhombic REMnO3.
Searching for the fourth family quarks through anomalous decays
Sahin, M.; Sultansoy, S.; Turkoz, S.
2010-09-01
The flavor democracy hypothesis predicts the existence of the fourth standard model family. Because of the high masses of the fourth family quarks, their anomalous decays could be dominant if certain criteria are met. This will drastically change the search strategy at hadron colliders. We show that the fourth standard model family down quarks with masses up to 400-450 GeV can be observed (or excluded) via anomalous decays by Tevatron.
Strong anomalous diffusion of the phase of a chaotic pendulum
Cagnetta, Francesco; Gonnella, Giuseppe; Mossa, Alessandro; Ruffo, Stefano
2015-07-01
In this letter we consider the phase diffusion of a harmonically driven undamped pendulum and show that it is anomalous in the strong sense. The role played by the fractal properties of the phase space is highlighted, providing an illustration of the link between deterministic chaos and anomalous transport. Finally, we build a stochastic model which reproduces most properties of the original Hamiltonian system by alternating ballistic flights and random diffusion.
Anomalous drift of spiral waves in heterogeneous excitable media
Sridhar, S; Panfilov, Alexander V
2009-01-01
We study the drift of spiral waves in a simple model of heterogeneous excitable medium, having gradients in local excitability or cellular coupling. For the first time, we report the anomalous drift of spiral waves towards regions having higher excitability, in contrast to all earlier observations in reaction-diffusion models of excitable media. Such anomalous drift can promote the onset of complex spatio-temporal patterns, e.g., those responsible for life-threatening arrhythmias in the heart.
Simulation framework for spatio-spectral anomalous change detection
Energy Technology Data Exchange (ETDEWEB)
Theiler, James P [Los Alamos National Laboratory; Harvey, Neal R [Los Alamos National Laboratory; Porter, Reid B [Los Alamos National Laboratory; Wohlberg, Brendt E [Los Alamos National Laboratory
2009-01-01
The authors describe the development of a simulation framework for anomalous change detection that considers both the spatial and spectral aspects of the imagery. A purely spectral framework has previously been introduced, but the extension to spatio-spectral requires attention to a variety of new issues, and requires more careful modeling of the anomalous changes. Using this extended framework, they evaluate the utility of spatial image processing operators to enhance change detection sensitivity in (simulated) remote sensing imagery.
Design of apochromatic telescope without anomalous dispersion glasses
Institute of Scientific and Technical Information of China (English)
Qinghua Yang; Baochang Zhao; Renkui Zhou
2008-01-01
A novel lens 8vstem with correction of secondary spectrum without using anomalous glasses is presented.The lens system comprises four separated lens components,with three of them being subapertures.Two examples of apochromatic telescope are presented,both with the use of typical normal glasses,namely crown K9 and flint F5 glasses,and low-cost slightly anomalous dispersion glasses.Secondary spectrum and other chromatic aberrations of the two design examples are corrected.
Anomalous origin of right coronary artery from pulmonary artery
Directory of Open Access Journals (Sweden)
Rajat Gupta
2012-01-01
Full Text Available Anomalous origin of coronary artery from the pulmonary artery is a rare anomaly that most frequently involves the left coronary artery and very rarely the right coronary artery. These lesions can be missed on echocardiography unless carefully looked for. We describe a case of isolated anomalous origin of right coronary artery from pulmonary artery diagnosed on echocardiography and confirmed by computed tomography (CT angiography.
Analysis on Anomalous Precipitation in Southern China During Winter Monsoons
Institute of Scientific and Technical Information of China (English)
HE Xicheng; DING Yihui; HE Ruyi; HE Jinhai; LI Qiaoping
2007-01-01
The winters of 1997/1998 and 1998/1999, corresponding to El Ni(n)o and La Ni(n)a episodes, respectively,were two typical rain-abundant and -scarce seasons for the southern China. In order to understand the cause of the anomalous precipitation during the two winters, a comparative analysis technique has been employed to investigate the differences in general circulation and moisture transportation between the two seasons.The results show that the abundant rainfall during the winter of 1997/1998 was associated with the ENSO warm episode event, eastward shifted weak westerly trough/ridge, weakened East Asian winter monsoon (EAWM), strengthened subtropical high, and presented two anti-cyclonic circulations over Hokkaido and the Philippine Sea, respectively, as well as one cyclonic circulation over the Yangtze River Basin in the anomalous wind fields of the lower troposphere. During the rain-scarce winter, however, the patterns of equatorial sea surface temperature anomalies and the circulation systems both in upper and lower levels were nearly the opposite of those during the rain-abundant winter. It has also been discovered that the water vapor over southern China during the winters came mainly from the southwesterly flow ahead of troughs in the southern branch of westerlies and the turning flow over the South China Sea-Indo-China Peninsula area; and the moisture transportation channels varied significantly with regard to height. The intensified flow in the southern branch of westerlies and the anti-cyclonic circulation anomaly over the Philippine Sea during the winter of 1997/1998 were favorable for moisture transportation to mainland China, however the two moisture transportation streams were dramatically weakened during the winter of 1998/1999 due to weak westerly flow and the dominance of a cold high system in the lower level over the southeast coast of China. Such a significant inter-annual change of moisture transportation is a key factor resulting in the
Tortuosity and anomalous diffusion in the neuromuscular junction
Lacks, Daniel J.
2008-04-01
The signal transfer from nerve to muscle occurs by diffusion across the neuromuscular junction. The continuum level analysis of diffusion processes is based on the diffusion equation, which in one dimension is ∂c/∂t=D(∂2c/∂x2) , where c is the molecular concentration and D is the diffusivity. However, in confined systems such as the neuromuscular junction, the diffusion equation may not be valid, and even if valid the value of D may be altered by the confinement. In this paper, Monte Carlo simulations are used to probe diffusion at the molecular level in a realistic model of a neuromuscular junction. The results show that diffusion is anomalous (i.e., not described by the diffusion equation) for time scales less than ˜0.01s , which is the time scale relevant for signaling processes in the synapse. At longer time scales, the diffusion is normal (i.e., described by the diffusion equation), but with a value of D that is reduced by a factor of ˜5 times compared to the value for diffusion in open space. As the width of the synaptic cleft decreases, these effects become even more pronounced. The physical basis of these results is described in terms of the structure of the neuromuscular junction.
Characterization of anomalous Zeeman patterns in complex atomic spectra
Pain, Jean-Christophe
2012-01-01
The modeling of complex atomic spectra is a difficult task, due to the huge number of levels and lines involved. In the presence of a magnetic field, the computation becomes even more difficult. The anomalous Zeeman pattern is a superposition of many absorption or emission profiles with different Zeeman relative strengths, shifts, widths, asymmetries and sharpnesses. We propose a statistical approach to study the effect of a magnetic field on the broadening of spectral lines and transition arrays in atomic spectra. In this model, the sigma and pi profiles are described using the moments of the Zeeman components, which depend on quantum numbers and Land\\'{e} factors. A graphical calculation of these moments, together with a statistical modeling of Zeeman profiles as expansions in terms of Hermite polynomials are presented. It is shown that the procedure is more efficient, in terms of convergence and validity range, than the Taylor-series expansion in powers of the magnetic field which was suggested in the past...
On the Limitations of the Anomalous Microwave Emission Emissivity
Directory of Open Access Journals (Sweden)
Christopher T. Tibbs
2012-01-01
Full Text Available Many studies of anomalous microwave emission (AME have computed an AME emissivity to compare the strength of the AME detected in different regions. Such a value is usually defined as the ratio between the intensity of the AME at 1 cm and the thermal dust emission at 100 μm. However, as studies of Galactic dust emission have shown, the intensity of the thermal dust emission at 100 μm is strongly dependent on the dust temperature, which has severe implications for the AME emissivity defined in this way. In this work, we illustrate and quantify this effect and find that the AME emissivity decreases by a factor of 11.1 between dust temperatures of 20 and 30 K. We, therefore, conclude that computing the AME emissivity relative to the 100 μm emission does not allow for accurate comparisons between the AME observed in different environments. With this in mind, we investigate the use of other tracers of the dust emission with which to compute the AME emissivity and we ultimately conclude that, despite the difficulty in deriving its value, the column density of the dust would be the most suitable quantity with which to compute the AME emissivity.
Evolving magnetic equilibria in anomalous turbulent transport simulations
Lee, Jungpyo; Cerfon, Antoine; Highcock, Edmund; Barnes, Michael
2014-10-01
The evolution of poloidal and toroidal magnetic fluxes in a tokamak are determined by Faraday's law in which electric field needs to be consistent with 1-D radial transports of density, temperature, and toroidal angular momentum. Consistency is required because the transport of the thermodynamic variables depends on the 2-D magnetic equilibrium that changes depending on the radial pressure profile. For neoclassical transport, consistency is achieved through a proper treatment of the parallel electric field and Ohm's law [Hinton and Hazeltine (1976), Hirshman and Jardin (1979)]. Recently, consistency for the anomalous turbulent transport has been studied analytically using a Lagrangian formulation of gyrokinetics [Sugama et al. (2014)]. In this poster, we propose a simple numerical model to evolve both the magnetic equilibrium and the radial profile of density, temperature, and toroidal angular frequency due to turbulent transport with a fixed q (safety factor) profile. The constraint of fixed q profile makes the evolution self-consistent only if the transport time scale is much smaller than the resistive current diffusion time scale. In this model, we use the transport code TRINITY coupled with the local gyrokinetic code GS2 and the q-solver version of the Grad-Shafranov code ECOM.
Transient Phenomena in Anomalous X-ray Pulsars
Israel, GianLuca; Burgay, Marta; Rea, Nanda; Possenti, Andrea; Dall'Osso, Simone; Stella, and Luigi
2007-01-01
In 2003 a previously unpulsed Einstein and ROSAT source cataloged as soft and dim (Lx of few 10^33 ergs) thermal emitting object, namely XTE J1810-197, was identified as the first unambiguous transient Anomalous X-ray Pulsar. Two years later this source was also found to be a bright highly polarized transient radio pulsar, a unique property among both AXPs and radio pulsars. In September 2006 the Swift Burst Alert Telescope (BAT) detected an intense burst from the candidate AXP CXOU J164710.2-455216, which entered in an outburst state reaching a peak emission of at least a factor of 300 higher than quiescence. Here, we briefly outline the recent results concerning the outburst phenomena observed in these two AXPs. In particular, XTE J1810-197 has probed to be a unique laboratory to monitor the timing and spectral properties of a cooling/fading AXP, while new important information have been inferred from X-ray and radio band simultaneous observations. CXOU J164710.2-455216 has been monitored in X-rays and radi...
Elastic scattering phenomenology
Energy Technology Data Exchange (ETDEWEB)
Mackintosh, R.S. [The Open University, School of Physical Sciences, Milton Keynes (United Kingdom)
2017-04-15
We argue that, in many situations, fits to elastic scattering data that were historically, and frequently still are, considered ''good'', are not justifiably so describable. Information about the dynamics of nucleon-nucleus and nucleus-nucleus scattering is lost when elastic scattering phenomenology is insufficiently ambitious. It is argued that in many situations, an alternative approach is appropriate for the phenomenology of nuclear elastic scattering of nucleons and other light nuclei. The approach affords an appropriate means of evaluating folding models, one that fully exploits available empirical data. It is particularly applicable for nucleons and other light ions. (orig.)
Structural controls on anomalous transport in fractured porous rock
Edery, Yaniv; Geiger, Sebastian; Berkowitz, Brian
2016-07-01
Anomalous transport is ubiquitous in a wide range of disordered systems, notably in fractured porous formations. We quantitatively identify the structural controls on anomalous tracer transport in a model of a real fractured geological formation that was mapped in an outcrop. The transport, determined by a continuum scale mathematical model, is characterized by breakthrough curves (BTCs) that document anomalous (or "non-Fickian") transport, which is accounted for by a power law distribution of local transition times ψ>(t>) within the framework of a continuous time random walk (CTRW). We show that the determination of ψ>(t>) is related to fractures aligned approximately with the macroscopic direction of flow. We establish the dominant role of fracture alignment and assess the statistics of these fractures by determining a concentration-visitation weighted residence time histogram. We then convert the histogram to a probability density function (pdf) that coincides with the CTRW ψ>(t>) and hence anomalous transport. We show that the permeability of the geological formation hosting the fracture network has a limited effect on the anomalous nature of the transport; rather, it is the fractures transverse to the flow direction that play the major role in forming the long BTC tail associated with anomalous transport. This is a remarkable result, given the complexity of the flow field statistics as captured by concentration transitions.
Observability of stochastic resonance in neutron scattering.
Condat, C A; Lamberti, P W
1999-10-01
The observability of the stochastic resonance phenomenon in a neutron scattering experiment is investigated, considering that the scatterer can hop between two sites. Under stochastic resonance conditions scattered intensity is transferred from the quasielastic region to two inelastic peaks. The magnitude of the signal-to-noise ratio is shown to be similar to that arising in the corresponding power spectrum. Effects of potential asymmetry are discussed in detail. Asymmetry leads to a reduction of the signal-to-noise ratio by a factor of 1-xi(2), where xi is an asymmetry parameter which is zero for symmetric problems and equal to unity in a completely asymmetric case.
Compton scattering in the Endpoint Model
Dagaonkar, Sumeet
2016-01-01
We use the Endpoint model for exclusive hadronic processes to study Compton scattering of the proton. The parameters of the Endpoint model are fixed using the data for $F_1$ and the ratio of Pauli and Dirac form factors ($F_2/F_1$) and then used to get numerical predictions for the differential scattering cross section. We studied the Compton scattering at fixed $\\theta_{CM}$ in the $s \\sim t \\gg \\Lambda_{QCD}$ limit and at fixed $s$ much larger than $t$ limit. We observed that the calculations in the Endpoint Model give a good fit with experimental data in both regions.
Anomalous bending effect in photonic crystal fibers.
Tu, Haohua; Jiang, Zhi; Marks, Daniel L; Boppart, Stephen A
2008-04-14
An unexpected transmission loss up to 50% occurs to intense femtosecond pulses propagating along an endlessly single-mode photonic crystal fiber over a length of 1 m. A specific leaky-fiber mode gains amplification along the fiber at the expense of the fundamental fiber mode through stimulated four-wave mixing and Raman scattering, leading to this transmission loss. Bending near the fiber entrance dissipates the propagating seed of this leaky mode, preventing the leaky mode amplification and therefore enhancing the transmission of these pulses.
Energy Technology Data Exchange (ETDEWEB)
Jardillier, Johann [Lab. de Physique Corpusculaire, Clermont-Ferrand-2 Univ., 63 - Aubiere (France)
1999-09-21
In the quark model, the proton is described as a system of three quarks UUD. However, recent experiments (CERN, SLAC) have shown that the strange quarks may contribute in a significant way to the mass and the spin of the proton. The HAPPEX experiment gives one further knowledge about the question of the role the strange quarks play inside the proton. It measures parity violating asymmetry in the scattering of polarized electrons from a proton because the latter is sensitive to the contribution of the strange quarks to the electromagnetic form factors of the nucleon. The observed asymmetry is in the order of a few ppm (part per million). The main difficulty of the experiment is to identify, to estimate and to minimize, as much as possible, all the systematic effects which could give rise to false asymmetries. This thesis discusses the principle of the HAPPEX experiment, its implementation at the Jefferson Lab (JLab), the processing and the analysis of the data, the systematic errors, and finally presents the result of the first data taking (1999) and its present interpretation. The HAPPEX experiment has measured, at Q{sup 2} = 0.5 (GeV/c){sup 2}, a strange quarks contribution of (1.0 {+-} 2.3)% to the electromagnetic form factors of the nucleon. The statistics and the systematic effects (measure of the electron beam polarization and knowledge of the neutron electric form factor) contribute equally to the error. (author)
Institute of Scientific and Technical Information of China (English)
季向东; 马建平; 袁锋
2007-01-01
We argue a factorization formula for semi-inclusive deep-inelastic scattering with hadrons in the current fragmentation region detected at low transverse momentum. To facilitate the factorization, we introduce the transverse-momentum dependent parton distributions and fragmentation functions with gauge links slightly off the light-cone, and with soft-gluon radiations subtracted. We verify the factorization to one-loop order in perturbative quantum chromodynamics and argue that it is valid to all orders in perturbation theory.%论证了在小横动量区域内半深度非弹性散射量子色动力学因子化公式.为完成因子化,引进了依赖于横动量的部分子分布函数和碎裂函数,并扣除了软胶子辐射.在单圈图的情形下,证明了因子化的成立,同时论证了在微扰论的任意阶该因子化的正确性.
Stover, John C.
1991-12-01
Optical scatter is a bothersome source of optical noise, limits resolution and reduces system throughput. However, it is also an extremely sensitive metrology tool. It is employed in a wide variety of applications in the optics industry (where direct scatter measurement is of concern) and is becoming a popular indirect measurement in other industries where its measurement in some form is an indicator of another component property - like roughness, contamination or position. This paper presents a brief review of the current state of this technology as it emerges from university and government laboratories into more general industry use. The bidirectional scatter distribution function (or BSDF) has become the common format for expressing scatter data and is now used almost universally. Measurements made at dozens of laboratories around the country cover the spectrum from the uv to the mid- IR. Data analysis of optical component scatter has progressed to the point where a variety of analysis tools are becoming available for discriminating between the various sources of scatter. Work has progressed on the analysis of rough surface scatter and the application of these techniques to some challenging problems outside the optical industry. Scatter metrology is acquiring standards and formal test procedures. The available scatter data base is rapidly expanding as the number and sophistication of measurement facilities increases. Scatter from contaminants is continuing to be a major area of work as scatterometers appear in vacuum chambers at various laboratories across the country. Another area of research driven by space applications is understanding the non-topographic sources of mid-IR scatter that are associated with Beryllium and other materials. The current flurry of work in this growing area of metrology can be expected to continue for several more years and to further expand to applications in other industries.
Scatter dose calculation for anti-scatter linear grids in mammography.
Al Kafi, M A; Maalej, N; Naqvi, A A
2009-10-01
Monte Carlo simulations were used to optimize the geometry of a mammography anti-scatter linear grid to achieve minimum scatter-to-primary ratio (SPR) for different X-ray tube voltages. A single optimum design of the grid with 0.9mm septa height, 12microm septa thickness and 100microm interspace thickness was found for breast phantom thicknesses between 30 and 80mm. The optimal grid has 0.153-0.330 scatter-to-primary ratio, a Bucky factor (BF) less than 2.5 and a contrast improvement factor (CIF) of 1.3.
Mahakrishnan, Sathiya; Chakraborty, Subrata; Vijay, Amrendra
2016-09-15
Diffusion, an emergent nonequilibrium transport phenomenon, is a nontrivial manifestation of the correlation between the microscopic dynamics of individual molecules and their statistical behavior observed in experiments. We present a thorough investigation of this viewpoint using the mathematical tools of quantum scattering, within the framework of Boltzmann transport theory. In particular, we ask: (a) How and when does a normal diffusive transport become anomalous? (b) What physical attribute of the system is conceptually useful to faithfully rationalize large variations in the coefficient of normal diffusion, observed particularly within the dynamical environment of biological cells? To characterize the diffusive transport, we introduce, analogous to continuous phase transitions, the curvature of the mean square displacement as an order parameter and use the notion of quantum scattering length, which measures the effective interactions between the diffusing molecules and the surrounding, to define a tuning variable, η. We show that the curvature signature conveniently differentiates the normal diffusion regime from the superdiffusion and subdiffusion regimes and the critical point, η = ηc, unambiguously determines the coefficient of normal diffusion. To solve the Boltzmann equation analytically, we use a quantum mechanical expression for the scattering amplitude in the Boltzmann collision term and obtain a general expression for the effective linear collision operator, useful for a variety of transport studies. We also demonstrate that the scattering length is a useful dynamical characteristic to rationalize experimental observations on diffusive transport in complex systems. We assess the numerical accuracy of the present work with representative experimental results on diffusion processes in biological systems. Furthermore, we advance the idea of temperature-dependent effective voltage (of the order of 1 μV or less in a biological environment, for example
SCATTERING FUNCTION OF POLYMER BLENDS
Institute of Scientific and Technical Information of China (English)
Lin-ping Ke; Mei-li Guo; De-lu Zhao
2004-01-01
For a system of flexible polymer molecules, the concepts of two concentrations, namely the segmental and the molecular concentrations, have been proposed in this paper. The former is equivalent to the volume fraction. The latter can be defined as the number of the gravity centers of macromolecules in a unit volume. The two concentrations should be correlated with each other by the conformational function of the polymer chain and should be discussed in different thermodynamic equations. On the basis of these concepts it has been proved that the Flory-Huggins entropy of mixing should be the result of the mixing "ideal gases of the gravity centers of macromolecules". The general correlation between the free energy of mixing and the scattering function (structural factor) of polymer blends has been studied based on the general fluctuation theory. When the Flory-Huggins free energy of mixing is adopted, the de Gennes scattering function of a polymer blend can be derived.
Inelastic Light Scattering Processes
Fouche, Daniel G.; Chang, Richard K.
1973-01-01
Five different inelastic light scattering processes will be denoted by, ordinary Raman scattering (ORS), resonance Raman scattering (RRS), off-resonance fluorescence (ORF), resonance fluorescence (RF), and broad fluorescence (BF). A distinction between fluorescence (including ORF and RF) and Raman scattering (including ORS and RRS) will be made in terms of the number of intermediate molecular states which contribute significantly to the scattered amplitude, and not in terms of excited state lifetimes or virtual versus real processes. The theory of these processes will be reviewed, including the effects of pressure, laser wavelength, and laser spectral distribution on the scattered intensity. The application of these processes to the remote sensing of atmospheric pollutants will be discussed briefly. It will be pointed out that the poor sensitivity of the ORS technique cannot be increased by going toward resonance without also compromising the advantages it has over the RF technique. Experimental results on inelastic light scattering from I(sub 2) vapor will be presented. As a single longitudinal mode 5145 A argon-ion laser line was tuned away from an I(sub 2) absorption line, the scattering was observed to change from RF to ORF. The basis, of the distinction is the different pressure dependence of the scattered intensity. Nearly three orders of magnitude enhancement of the scattered intensity was measured in going from ORF to RF. Forty-seven overtones were observed and their relative intensities measured. The ORF cross section of I(sub 2) compared to the ORS cross section of N2 was found to be 3 x 10(exp 6), with I(sub 2) at its room temperature vapor pressure.
Energy Technology Data Exchange (ETDEWEB)
Capozza, Luigi
2010-08-19
Within the A4 experiment the contributions of the strange quark to the electromagnetic form factors of the proton are measured. These see-quark effects in low energy observables are very important for the understanding of hadron structure, because they are a direct manifestation of QCD degrees of freedom in the non-perturbative regime. Linear combinations of the strangeness vector form factors of the proton (G{sub E}{sup s} and G{sub M}{sup s}) are accessible experimentally by measuring the parity violating asymmetry in the cross section of the elastic scattering of longitudinal polarised electrons off unpolarised nucleons. Two such measurements were published by the A4 collaboration before this work. Both of them were forward angle measurements at the Q{sup 2} values of 0.23 and 0.10 (GeV/c){sup 2}, respectively. A measurement at backward angle with a beam energy of 315 MeV was performed for separating G{sub E}{sup s} and G{sub M}{sup s} at the higher of these Q{sup 2} values. In the A4 experiment a longitudinally polarised electron beam scatters on a liquid hydrogen target. Single scattered electrons are counted with a Cherenkov calorimeter. The separation of elastic from inelastic events is achieved by means of calorimetric energy measurement. For the backward angle measurement a plastic scintillator was installed as electron tagger for suppressing the {gamma} background coming from the decay of {pi}{sup 0} mesons. In order to make the data analysis possible the energy spectra needed to be studied thoroughly. This was done in this work using detailed simulations of both the scattering processes suffered by beam electrons and of the response of the detectors. A method for handling the remaining background due to {gamma} conversion before the scintillator has been also developed. The simulation results agree with the measured spectra at the 5% level and the strategy for handling the background was shown to be feasible. The asymmetry value obtained by handling the
Resonant cyclotron scattering in magnetars' emission
Rea, Nanda; Turolla, Roberto; Lyutikov, Maxim; Gotz, Diego
2008-01-01
We present a systematic application of a resonant cyclotron scattering (RCS) model to a comprehensive set of magnetars, including canonical and transient anomalous X-ray pulsars, and soft gamma repeaters. In this scenario, non-thermal magnetar spectra in the soft X-rays (i.e. below ~10keV) result from resonant cyclotron scattering of the thermal surface emission by hot magnetospheric plasma. We find that this model can successfully account for the X-ray emission of magnetars, while using the same number of free parameters than the commonly used empirical blackbody plus power-law model. We find that the entire class of sources is characterized by magnetospheric plasma with similar properties, in particular the optical depth is in a quite narrow range (tau_{res} ~1-2). This leads to an estimate of the magnetospheric electron densities at the resonance n_e ~ 1.5x10^{13} tau_{res} cm^{-3}, which is 3 orders of magnitudes greater than n_{GJ}, the Goldreich-Julian electron density for pulsar magnetospheres. The inf...
Streamlined Modeling for Characterizing Spacecraft Anomalous Behavior
Klem, B.; Swann, D.
2011-09-01
Anomalous behavior of on-orbit spacecraft can often be detected using passive, remote sensors which measure electro-optical signatures that vary in time and spectral content. Analysts responsible for assessing spacecraft operational status and detecting detrimental anomalies using non-resolved imaging sensors are often presented with various sensing and identification issues. Modeling and measuring spacecraft self emission and reflected radiant intensity when the radiation patterns exhibit a time varying reflective glint superimposed on an underlying diffuse signal contribute to assessment of spacecraft behavior in two ways: (1) providing information on body component orientation and attitude; and, (2) detecting changes in surface material properties due to the space environment. Simple convex and cube-shaped spacecraft, designed to operate without protruding solar panel appendages, may require an enhanced level of preflight characterization to support interpretation of the various physical effects observed during on-orbit monitoring. This paper describes selected portions of the signature database generated using streamlined signature modeling and simulations of basic geometry shapes apparent to non-imaging sensors. With this database, summarization of key observable features for such shapes as spheres, cylinders, flat plates, cones, and cubes in specific spectral bands that include the visible, mid wave, and long wave infrared provide the analyst with input to the decision process algorithms contained in the overall sensing and identification architectures. The models typically utilize baseline materials such as Kapton, paints, aluminum surface end plates, and radiators, along with solar cell representations covering the cylindrical and side portions of the spacecraft. Multiple space and ground-based sensors are assumed to be located at key locations to describe the comprehensive multi-viewing aspect scenarios that can result in significant specular reflection
Institute of Scientific and Technical Information of China (English)
HOU Zhi-Ling; KONG Ling-Bao; JIN Hai-Bo; CAO Mao-Sheng; LI Xiao; QI Xin
2012-01-01
The electromagnetic parameters (permittivity and permeability) method, retrieved from the reflection and transmission coefficients of a slab, is presented. Improvements over existing methods, including the determination of the permittivity, permeability and impedance of the slab, are expressed as explicit functions of the S parameters for both the time-dependent factors, eiωt and e-iωt (ω is the angular frequency of the incident electromagnetic wave), and the proper selection of the sign of impedance and the real part of the refractive index. Moreover, based on the retrieving method, the calculations of the electromagnetic parameters of the conventional-material teflon slab standard sample through the experimental data of the S parameters are performed, which confirm the validity of the technique for the retrieval of electromagnetic parameters.%The electromagnetic parameters (permittivity and permeability) method,retrieved from the reflection and transmission coefficients of a slab,is presented.Improvements over existing methods,including the determination of the permittivity,permeability and impedance of the slab,are expressed as explicit functions of the S parameters for both the time-dependent factors,eiwt and e-iwt (ω is the angular frequency of the incident electromagnetic wave),and the proper selection of the sign of impedance and the real part of the refractive index.Moreover,based on the retrieving method,the calculations of the electromagnetic parameters of the conventional-material teflon slab standard sample through the experimental data of the S parameters are performed,which confirm the validity of the technique for the retrieval of electromagnetic parameters.
On the anomalous U(1) in free fermionic superstring models
Energy Technology Data Exchange (ETDEWEB)
Cleaver, G.B. [Univ. of Pennsylvania, Philadelphia, PA (United States). Dept. of Physics and Astronomy; Faraggi, A.E. [Florida Univ., Gainesville, FL (United States). Inst. for Fundamental Theory
1997-11-01
The realistic free fermionic models have had an intriguing success in explaining different properties of the observed particle spectrum. In this paper the authors discuss in some detail the anomalous U(1) symmetry which exists in these models. They study the properties of the anomalous U(1) in both the more realistic NAHE-based free fermionic models and those in a general NAHE class. Appearance of an anomalous U(1) in the more realistic NAHE models is shown to be an effect of reduction of world-sheet supersymmetry from (2,2) to (2,0). They show, however, that in more general (2,1) and (2,0) models, all U(1) can remain anomaly-free under certain conditions. Several phenomenological issues related to the anomalous U(1) are discussed. In particular, they note that in some examples the anomalous U(1) arises from the breaking E{sub 6} {yields} SO(10) {times} U(1){sub A}, resulting in U(1){sub A} being family universal.
ANOMALOUS MICROWAVE EMISSION IN H ii REGIONS: IS IT REALLY ANOMALOUS? THE CASE OF RCW 49
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Paladini, Roberta [Infrared Processing Analysis Center, California Institute of Technology, 770 South Wilson Ave., Pasadena, CA 91125 (United States); Ingallinera, Adriano; Agliozzo, Claudia; Umana, Grazia; Trigilio, Corrado [Osservatorio Astrofisico di Catania, Via S. Sofia 78, I-95123 Catania Italy (Italy); Tibbs, Christopher T. [Scientific Support Office, Directorate of Science and Robotic Exploration,European Space Research and Technology Centre (ESA/ESTEC), Keplerlaan 1, 2201 AZ, Noordwijk (Netherlands); Noriega-Crespo, Alberto [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Dickinson, Clive [Jodrell Bank Centre for Astrophysics, Alan Turing Building, School of Physics and Astronomy, The University of Manchester, Oxford Road, Manchester M13 9PL (United Kingdom)
2015-11-01
The detection of an excess of emission at microwave frequencies with respect to the predicted free–free emission has been reported for several Galactic H ii regions. Here, we investigate the case of RCW 49, for which the Cosmic Background Imager tentatively (∼3σ) detected Anomalous Microwave Emission (AME) at 31 GHz on angular scales of 7′. Using the Australia Telescope Compact Array, we carried out a multi-frequency (5, 19, and 34 GHz) continuum study of the region, complemented by observations of the H109α radio recombination line. The analysis shows that: (1) the spatial correlation between the microwave and IR emission persists on angular scales from 3.′4 to 0.″4, although the degree of the correlation slightly decreases at higher frequencies and on smaller angular scales; (2) the spectral indices between 1.4 and 5 GHz are globally in agreement with optically thin free–free emission, however, ∼30% of these are positive and much greater than −0.1, consistent with a stellar wind scenario; and (3) no major evidence for inverted free–free radiation is found, indicating that this is likely not the cause of the Anomalous Emission in RCW 49. Although our results cannot rule out the spinning dust hypothesis to explain the tentative detection of AME in RCW 49, they emphasize the complexity of astronomical sources that are very well known and studied, such as H ii regions, and suggest that, at least in these objects, the reported excess of emission might be ascribed to alternative mechanisms such as stellar winds and shocks.