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title: A BRIGHT, SPATIALLY EXTENDED LENSED GALAXY AT z = 1.7 BEHIND THE CLUSTER RCS2 032727-132623; abstract: We present the discovery of an extremely bright and extended lensed source from the second Red Sequence Cluster Survey (RCS2). RCSGA 032727-132609 is spectroscopically confirmed as a giant arc and counterimage of a background galaxy at z = 1.701, strongly lensed by the foreground galaxy cluster RCS2 032727-132623 at z = 0.564. The giant arc extends over ~38\u0027\u0027 and has an integrated r-band magnitude of 19.1, making it ~20 times larger and ~3.5 times brighter than the prototypical lensed galaxy MS1512-cB58. This is the brightest distant lensed galaxy in the universe known to date. We have collected photometry in nine bands, ranging from u to Ks , which densely sample the rest-frame UV and optical light, including the age-sensitive 4000 A break. A lens model is constructed for the system and results in a robust total magnification of 2.04 ± 0.16 for the counterimage; we estimate an average magnification of 17.2 ± 1.4 for the giant arc based on the relative physical scales of the arc and counterimage on the sky. Fits of single-component spectral energy distribution models to the photometry result in a moderately young age, t = 80 ± 40 Myr, small amounts of dust, E(B – V) ≤ 0.11, and an exponentially declining star formation history with e-folding time τ = 10 – 50 Myr. After correcting for the lensing magnification, we find a stellar mass of M * ~ 1010 M ☉ and a current star formation rate (SFR) ≤77 M ☉ yr–1. Allowing for episodic star formation, an underlying old burst could contain up to twice the mass inferred from single-component modeling. RCSGA 032727-132609 is typical of the known population of star-forming galaxies near this redshift in terms of its age and stellar mass. Its large magnification and spatial extent provide a unique opportunity to study the physical properties of an individual high-redshift star-forming galaxy in great detail, opening up a new window to the process of galaxy evolution between z = 1.7 and our local universe. | 161,700 |
title: Constraints on modified Gauss-Bonnet gravity during big bang nucleosynthesis; abstract: The modified gravity is considered to be one of possible explanations of the accelerated expansions of the present and the early universe. We study effects of the modified gravity on big bang nucleosynthesis (BBN). If effects of the modified gravity are significant during the BBN epoch, they should be observed as changes of primordial light element abundances. We assume a $f(G)$ term with the Gauss-Bonnet term $G$, during the BBN epoch. A power-law relation of $df/dG \\propto t^p$ where $t$ is the cosmic time was assumed for the function $f(G)$ as an example case. We solve time evolutions of physical variables during BBN in the $f(G)$ gravity model numerically, and analyzed calculated results. It is found that a proper solution for the cosmic expansion rate can be lost in some parameter region. In addition, we show that calculated results of primordial light element abundances can be significantly different from observational data. Especially, observational limits on primordial D abundance leads to the strongest constraint on the $f(G)$ gravity. We then derive constraints on parameters of the $f(G)$ gravity taking into account the existence of the solution of expansion rate and final light element abundances. | 161,701 |
title: Generation mechanism of a hierarchy of vortices in a turbulent boundary layer; abstract: To understand the generation mechanism of a hierarchy of multiscale vortices in a high-Reynolds-number turbulent boundary layer, we conduct direct numerical simulations and educe the hierarchy of vortices by applying a coarse-graining method to the simulated turbulent velocity field. When the Reynolds number is high enough for the premultiplied energy spectrum of the streamwise velocity component to show the second peak and for the energy spectrum to obey the power law, small-scale vortices, that is, vortices sufficiently smaller than the height from the wall, in the log layer are generated predominantly by the stretching in strain-rate fields at larger scales rather than by the mean-flow stretching. In such a case, the twice-larger scale contributes most to the stretching of smaller-scale vortices. This generation mechanism of small-scale vortices is similar to the one observed in fully developed turbulence in a periodic cube and consistent with the picture of the energy cascade. On the other hand, large-scale vortices, that is, vortices as large as the height, are stretched and amplified directly by the mean flow. We show quantitative evidence of these scale-dependent generation mechanisms of vortices on the basis of numerical analyses of the scale-dependent enstrophy production rate. We also demonstrate concrete examples of the generation process of the hierarchy of multiscale vortices. | 161,702 |
title: Size-induced metal insulator transition and glassy magnetic behavior in La0.5Sr0.5CoO3 nanoparticles; abstract: Structural, electrical, and magnetic properties of La0.5Sr0.5CoO3 nanoparticles prepared by sol-gel technique are investigated and the results reveal a size-induced metal insulator transition in the electrotransport behavior. The field cooled and zero field cooled magnetizations display a broad paramagnetic to ferromagnetic transition at Tc with a large magnetic irreversibility. Attempts are made to get an idea about the spin states in the nanoparticles. The observed frequency dependent shoulder in the in-phase (χ′) component and the peak in the out of phase (χ″) component of the ac susceptibility in the low temperature region indicate the glassy nature of the samples. | 161,703 |
title: Measurement of Single Event Upsets in the ALICE-TPC Front-End Electronics; abstract: The Time Projection Chamber of the ALICE ex- periment at the CERN Large Hadron Collider features highly integrated on-detector read-out electronics. It is following the general trend of high energy physics experiments by placing the front-end electronics as close to the detector as possible—only some 10 cm away from its active volume. Being located close to the beams and the interaction region, the electronics is subject to a moderate radiation load, which allowed us to use commercial off-the-shelf components. However, they needed to be selected and qualified carefully for radiation hardness and means had to be taken to protect their functionality against soft errors, i. e. single event upsets. Here we report on the first measurements of LHC induced radiation effects on ALICE front-end electronics and on how they attest to expectations. | 161,704 |
title: TWO-DIMENSIONAL NUMERICAL STUDY FOR RAYLEIGH-TAYLOR AND RICHTMYER-MESHKOV INSTABILITIES IN RELATIVISTIC JETS; abstract: We study the stability of a non-rotating single-component jet using two-dimensional special relativistic hydrodynamic simulations. By assuming translational invariance along the jet axis, we exclude the destabilization effect by Kelvin-Helmholtz mode. The nonlinear evolution of the transverse structure of the jet with a normal jet velocity is highlighted. An intriguing finding in our study is that Rayleigh-Taylor and Richtmyer-Meshkov type instabilities can destroy cylindrical jet configuration as a result of spontaneously induced radial oscillating motion. This is powered by in situ energy conversion between the thermal and bulk kinetic energies. The effective inertia ratio of the jet to the surrounding medium η determines a threshold for the onset of instabilities. The condition η \u003c 1 should be satisfied for the transverse structure of the jet being persisted. | 161,705 |
title: String gas cosmology; abstract: A critical review and summary of string gas cosmology is presented. A pedagogical derivation of the effective action starting from string theory, emphasizing the necessary approximations that must be invoked, is included. Working in the effective theory, that at late times it is not possible to stabilize the extra dimensions by a gas of massive string winding modes is demonstrated. Additional string gases are considered that contain so-called enhanced symmetry states. These string gases are very heavy initially, but drive the moduli to locations that minimize the energy and pressure of the gas. Both classical and quantum gas dynamics are considered, where in the former the validity of the theory is questionable and some fine-tuning is required, but in the latter a consistent and promising stabilization mechanism that is valid at late times is found. In addition, string gases provide a framework to explore dark matter, presenting alternatives to the cold dark matter model recently considered by Gubser and Peebles. Also quantum trapping with string gases as a method for including dynamics on the string landscape is discussed. | 161,706 |
title: Vector mesons and an interpretation of Seiberg duality; abstract: We interpret the dynamics of Supersymmetric QCD (SQCD) in terms of ideas familiar from the hadronic world. Some mysterious properties of the supersymmetric theory, such as the emergent magnetic gauge symmetry, are shown to have analogs in QCD. On the other hand, several phenomenological concepts, such as “hidden local symmetry” and “vector meson dominance,” are shown to be rigorously realized in SQCD. These considerations suggest a relation between the flavor symmetry group and the emergent gauge fields in theories with a weakly coupled dual description. | 161,707 |
title: Natural convection flow of Cu–Water nanofluid in horizontal cylindrical annuli with inner triangular cylinder using lattice Boltzmann method; abstract: Abstract In this paper the lattice Boltzmann method is used to investigate the effect of nanoparticles on natural convection heat transfer in two-dimensional horizontal annulus. The study consists of an annular-shape enclosure, which is created between a heated triangular inner cylinder and a circular outer cylinder. The inner and outer surface temperatures were set as hot (Th) and cold temperatures (Tc), respectively and assumed to be isotherms. The effect of nanoparticle volume fraction to the enhancement of heat transfer was examined at different Rayleigh numbers. Furthermore, the effect of vertical, horizontal, and diagonal eccentricities at various locations is examined at Ra = 104. The result is presented in the form of streamlines, isotherms, and local and average Nusselt number. Results show that the Nusselt number and the maximum stream functions increase by augmentation of solid volume fraction. Average Nusselt number increases when the inner cylinder moves downward, but it decreases, when the location of inner cylinder changes horizontally. | 161,708 |
title: The 11-year cycle of solar activity and configurations of the planets; abstract: In this paper a parameter was used, viz., the average difference between the heliocentric longitudes (ADL) of the planets Venus, Earth, and Jupiter. For the minimum ADL (the planets are in conjunction), as well as at the minimum deviation of the planets from a line passing through them and the Sun at the location of the planets on opposite sides from the Sun, an index was composed that uniquely describes the 11-year cycle of solar activity. | 161,709 |
title: LOW-MASS X-RAY BINARIES AND GLOBULAR CLUSTERS IN EARLY-TYPE GALAXIES. II. GLOBULAR CLUSTER CANDIDATES AND THEIR MASS-METALLICITY RELATION; abstract: We present an astrometry and photometry catalogue of globular cluster (GC) candidates detected with the Hubble Space Telescope Wide Field Planetary Camera 2 in a sample of 19 early-type galaxies, appropriate for comparison with the low-mass X-ray binary populations observed with Chandra. In a companion paper, we present the Chandra data and investigate the relation between these populations. We demonstrate that, although there is little evidence of a color-magnitude correlation for the GCs, after estimating mass and metallicity from the photometry under the assumption of a single-age simple stellar population, there is a significant positive correlation between mass and metallicity. We constrained [Z/H] = (-2.1 ± 0.2) + (0.25 ± 0.04)log10M, with a 1σ intrinsic scatter of 0.62 dex in metallicity. If GCs are bimodal in metallicity, this relation is consistent with recent suggestions of a mass-metallicity relation only for metal-poor clusters. Adopting a new technique to fit the GC luminosity function (GCLF) accounting for incompleteness and the Eddington bias, we compute the V-band local GC specific frequency (SN ) and specific luminosity (SL ) of each galaxy. We show that SL is the more robust measure of the richness of a GC population where a significant fraction is undetected due to source detection incompleteness. We find that the absolute magnitude of the GCLF turnover exhibits intrinsic scatter from galaxy to galaxy of ~0.3 mag (1σ), limiting its accuracy as a standard distance measure. | 161,710 |
title: Active tuning of high frequency resonators and filters; abstract: In this paper, we present a new electromechanical approach of active control of high temperature superconducting (HTS) resonator and filter center frequency. The design of the tunable devices incorporates piezoelectric bender or tube actuator, which acts as a varactor of the resonance circuit, with YBCO thin film on LAO substrate. The resonator has an unloaded Q of over 18,000 at 77 K and a center frequency of 362 MHz and a tuning range of over 20% with unloaded Q over 10,000. By applying different voltages to the piezoelectric bender, we have tuned the resonance frequency over 30% with a good linearity and high Q. Based on this structure, a two-pole HTS bandpass filter was designed, fabricated and tested. The filter has a tunable center frequency from 17 to 20 MHz while maintaining a 2.5% 3dB bandwidth, and an insertion loss of less than 0.5 dB at 77 K. | 161,711 |
title: Baryon-pion couplings from large-Nc QCD; abstract: Abstract We derive a set of consistency conditions for the pion-baryon coupling constants in the large- N c limit of QCD. The consitency conditions have a unique solution which are precisely the values for the pion-baryon coupling constants in the Skyrme model. We also prove that non-relativistic SU(2 N f spin-flavor symmetry (where N f is the number of light flavors) is a symmetry of the baryon-pion couplings in the large- N c limit of QCD. The symmetry breaking corrections to the pion-baryon couplings vanish to firts order in 1 N c . Consistency conditions for the other couplings, such as the magnetic moments are also derived. | 161,712 |
title: Phase formation and ferrimagnetism of GdCo9Si4; abstract: The phase relations of the GdCo13−x Six system have been studied by means of scanning microscopy, microprobe analysis and x-ray diffraction. Single-phase samples GdCo9±δSi4∓δ (structure type LaFe9Si4 with space group I 4/mcm) ar ef ormed in a narrow composition range |δ| 0.2, where GdCo9Si4 forms as af ully ordered ternary compound. The magnetic properties of GdCo9Si4 have been investigated by ac susceptibility, magnetization, specific heat and resistivity measurements. These experiments reveal ferrimagnetism below about 47 K, which is analysed in terms of a two-sublattice molecular field model with a local moment Gd subsystem coupling antiparallel to the itinerant ferromagnetic Co 3d sublattice. The 3d–3d exchange of the latter is the driving force for the onset of long range magnetic order. The validity of the twosublattice model is demonstrated by high field measurements, showing that the ferrimagnetic coupling starts to break up at a lower critical field µ0 Hl � 27 T. The magnetic ground state of GdCo9Si4 has been analysed on a microscopic basis via LSDA electronic structure calculations. (Some figures in this article are in colour only in the electronic version) | 161,713 |
title: Measurement of the Zγ→νν‾γ production cross section in pp collisions at s=8 TeV and limits on anomalous ZZγ and Zγγ trilinear gauge boson couplings; abstract: An inclusive measurement of the Zγ → ννγ production cross section in pp collisions at √s = 8 TeV is presented, using data corresponding to an integrated luminosity of 19.6 fb^(−1) collected with the CMS detector at the LHC. This measurement is based on the observation of events with large missing energy and with a single photon with transverse momentum above 145 GeV and absolute pseudorapidity in the range |η|\u003c1.44. The measured Zγ → ννγ production cross section, 52.7±2.1 (stat)±6.4 (syst)±1.4 (lumi) fb, agrees well with the standard model prediction of 50.0_(−2.2)^(+2.4) fb. A study of the photon transverse momentum spectrum yields the most stringent limits to date on the anomalous ZZγ and Zγγ trilinear gauge boson couplings. | 161,714 |
title: Cosmological applications in Kaluza-Klein theory; abstract: The field equations of Kaluza-Klein (KK) theory have been applied in the domain of cosmology. These equations are solved for a flat universe by taking the gravitational and the cosmological constants as a function of time t. We use Taylor\u0027s expansion of cosmological function, $\\Lambda(t)$, up to the first order of the time $t$. The cosmological parameters are calculated and some cosmological problems are discussed. | 161,715 |
title: The pion-nucleon σ term from pionic atoms; abstract: Abstract Earlier work suggested that the in-medium πN threshold isovector amplitude b 1 ( ρ ) gets renormalized in pionic atoms by ∼ 30 % away from its ρ = 0 free-space value, relating such renormalization to the leading low-density decrease of the in-medium quark condensate q ¯ q \u003e and the pion decay constant f π in terms of the pion-nucleon σ term σ π N . Accepting the validity of this approach, we extracted σ π N from a large-scale fit of pionic-atom level shift and width data across the periodic table. Our fitted value σ π N = 57 ± 7 MeV is robust with respect to variation of πN interaction terms other than the isovector s-wave term with which σ π N was associated. Higher order corrections to the leading order in density involve some cancellations, suggesting thereby only a few percent overall systematic uncertainty. The value of σ π N derived here agrees with values obtained in several recent studies based on near-threshold πN phenomenology, but sharply disagrees with values obtained in recent direct lattice QCD calculations. | 161,716 |
title: Asymptotic analysis for the conjugate heat transfer problem in an electro-osmotic flow with temperature-dependent properties in a capillary; abstract: In this work, the conjugate heat transfer process in an electro-osmotic flow of a Newtonian liquid is studied asymptotically. The analysis includes Joule heating effects by taking into account the temperature dependent viscosity and electrical conductivity of the electrolyte solution and assuming finite thermal conductivity of the capillary wall. Due to Joule heating effects, temperature gradients in the liquid make the fluid properties change within the capillary, altering the electric potential and flow fields. The dimensionless temperature profiles in the fluid and the capillary wall are obtained as function of the dimensionless parameters involved in the analysis, and the interactions between the coupled continuity, momentum, thermal energy, and potential electric equations are examined in detail. Results show that the Joule heating induces a pressure gradient along the capillary, which in turn modifies the normal plug-like electroosmotic velocity profiles. In addition, it is pointed out that, depending on the values of the dimensionless parameters, the modified velocity profiles can induce positive or negative pressure gradients at the inlet or outlet of the capillary. | 161,717 |
title: Nanometric Magnetic and Piezo Domain Studies on Multiferroic BTO–CFO Based-Nanostructures; abstract: Multiferroic BTO-CFO was chosen for this study to understand multifunctional properties at the nanometer scale. The bulk pellet and nano-structured thin films of these compounds were synthesized. The films fabricated by pulsed laser deposition (PLD) technique, using the same material as target, were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and atomic force microscopy (AFM). About 100-nm-thick films showed different nanostructures of BTO-CFO which PLD grown at deposited in same conditions on various substrates like silicon, quartz, and strontium titanate (STO). Morphological studies revealed the presence of about ~ 50 nm sized nanostructured pillars. The multiferroic properties in these nanocomposite films were characterized using multimode scanning probe microscopy (SPM). Magnetic force microscopy studies revealed the distribution of magnetic domains with a diameter of \u003c; 50 nm range in BTO matrix while using a silicon substrate. Piezo force microscopy available as a special SPM mode provided the evidence on the presence of piezoelectric domain and their behavior. Spatially, varying piezoelectric response was observed. Among the films with composite architectures, nanostructure BTO-CFO film on STO yielded maximum piezo response. Domain interfaces in both cases involving thin films and pellets are bestowed with special features. | 161,718 |
title: Convective flows of colloidal suspension in an inclined closed cell; abstract: The nonlinear spatiotemporal evolution of convective flows is numerically investigated in the case of colloidal suspension filling an inclined closed cell heated from below. The bifurcation diagram (the dependency of the Nusselt number on the Rayleigh number) is obtained. The characteristics of the wave and steady patterns are investigated depending on heat intensity. The travelling wave changing travel direction and the non-regular oscillatory flow are found to be stable solutions within a certain interval of the Rayleigh number. Temporal Fourier decomposition is used together with other diagnostic tools to analyse the complex bifurcation and spatiotemporal properties caused by the interplay of the gravity-induced gradient of concentration and convective mixing of the fluid. It is shown that a more complex flow structure exists at a lower heating intensity (Rayleigh number). | 161,719 |
title: Nanometre-scale probing of spin waves using single electron spins; abstract: Pushing the frontiers of condensed-matter magnetism requires the development of tools that provide real-space, few-nanometre-scale probing of correlated-electron magnetic excitations under ambient conditions. Here we present a practical approach to meet this challenge, using magnetometry based on single nitrogen-vacancy centres in diamond. We focus on spin-wave excitations in a ferromagnetic microdisc, and demonstrate local, quantitative and phase-sensitive detection of the spin-wave magnetic field at ∼50 nm from the disc. We map the magnetic-field dependence of spin-wave excitations by detecting the associated local reduction in the disc\u0027s longitudinal magnetization. In addition, we characterize the spin-noise spectrum by nitrogen-vacancy spin relaxometry, finding excellent agreement with a general analytical description of the stray fields produced by spin-spin correlations in a 2D magnetic system. These complementary measurement modalities pave the way towards imaging the local excitations of systems such as ferromagnets and antiferromagnets, skyrmions, atomically assembled quantum magnets, and spin ice. | 161,720 |
title: Self-suspended micro-resonators patterned in Z-cut lithium niobate membranes; abstract: We report on self-suspended micro-resonators patterned in Z-cut lithium niobate on insulator substrates. The fabrication technique consists of two single steps, focused ion beam milling for the micro- and nano-structuring and subsequent SiO2 etching for the realization of thin self-suspended membranes. The fabrication process of a free-standing photonic crystal cavity and a suspended micro-disk is described and the linear and nonlinear optical properties of the micro-resonators are investigated at telecommunication wavelengths. The whispering gallery modes of the micro-disk are measured experimentally and compared to an analytical model. The fundamental transverse-electric polarized mode of the photonic crystal cavity is measured and compared to three dimensional finite difference time domain simulations. Second harmonic generation enhancement due to the field confinement in the cavity mode is demonstrated. These results are promising for the use of Z-cut lithium niobate self-suspended membranes as platforms for highly efficient miniaturized photonic devices for telecommunication applications. | 161,721 |
title: Multiple gauge fixing conditions; abstract: We consider how more than one gauge fixing condition can be accommodated within the Feynman path integral both by extending the Faddeev–Popov procedure and the Batalin–Vilkovisky approach. The first-order Einstein–Hilbert action in 1 + 1 dimensions and the massless spin-3/2 action are considered. | 161,722 |
title: A model of the VU (volume-unit) meter, with speech applications; abstract: The Volume-Unit (VU) meter, used in speech research prior to the advent of computers and modern signal processing methods, is described in signal processing terms. There are no known software implementations of this meter, which meet the 1954 ASA standard and provide the instantaneous needle level. Important speech applications will be explored, such as making comparisons of speech levels to earlier classic works, and measuring speech levels using traditional methods on modern computers. It is our intention to make this venerable method of measuring speech levels available once again. The VU meter is simulated and its properties are studied. A 1950s vintage and a recent vintage VU meter are studied by comparing the transient responses to tones and measurement of speech levels. Based on these measurements, a software VU meter (henceforth referred to as VUSOFT) is simulated, and verified. The method for reading the meter is explained, and simulated in software. The VU level for speech is shown to depend on ... | 161,723 |
title: Influence of temperature on period of torsion pendulum with a high-Q fused silica fiber; abstract: Due to the high-Q fused silica fiber\u0027s extreme sensitivity to temperature change, the period estimation of torsion pendulum with high precision depends on the effective correction of the thermoelastic effect. In the measurement of G with the time-of-swing method, we analyze the complex relation between temperature and the pendulum\u0027s period and propose a developed method to find the shear thermoelasticity coefficient as well as isolate the influence of temperature on period alone. The result shows that the shear thermoelasticity coefficient is 101(2) × 10(-6)/°C, the resultant correction to Δ(ω(2)) is 9.16(0.18) ppm, and the relative uncertainty to G is less than 1 ppm. | 161,724 |
title: Giant magnetoresistance in mechanical alloyed La0.7Sr0.06Ca0.24MnO3 perovskite; abstract: Abstract Nanocrystalline ferromagnetic La 0.7 Sr 0.06 Ca 0.24 MnO 3 perovskites have been successfully synthesized by mechanical alloying. The effect of grain size on magnetoresistance (MR) has been investigated. The results show that after milling for 100 h the as-made samples exhibit a complete amorphous phase, which crystallizes into a nanocrystalline perovskite-like compound when annealed above 920 K. With increasing annealing temperatures the grain size and the metal–semiconductor transition temperature increases, and the MR effect at 77 K decreases. The peak temperature T p in MR behavior is found to be less affected by the grain size. All the annealed samples exhibit a larger MR at 77 K rather than around the temperature T p . | 161,725 |
title: The role of particle collisions in pneumatic transport; abstract: We analyse the dilute, steady, fully developed flow of relatively massive particles in a turbulent gas in the context of a vertical pipe. The idea is that the exchange of momentum in collisions between the grains and between the grains and the wall plays a significant role in the balance of forces in the particle phase. Consequently, the particle phase is considered to be a dilute system of colliding grains, in which the velocity fluctuations are produced by collisions rather than by the gas turbulence. The balance equations for rapid granular flow are modified to incorporate the drag force from the gas, and boundary conditions, based on collisional exchanges of momentum and energy at the wall, are employed. The turbulence of the gas is treated using a one-equation closure. A numerical solution of the resulting governing equations provides velocity and turbulent energy profiles in agreement with the measurements of Tsuji et al. (1984). | 161,726 |
title: Heavy Quarks in $e^+ e^-$ Annihilation; abstract: We calculate the effects of the pair production of top quarks and their subsequent weak decays on event topologies and inclusive distributions in e+e− annihilation experiments. The resulting jet distributions are compared with those originating from the lighter quarks (u, d, s, c, b) with higher-order QCD corrections included.\r\n\r\nThe calculation is based on the Kobayashi-Maskawa model for the weak decay of the heavy quarks including non-leptonic and semileptonic decay modes. The final evolution of quarks into hadrons has been taken into account using a quark fragmentation model.\r\n\r\nWe find that the jet measures such as sphericity, thrust and acoplanarity are very sensitive to the onset of a new quark threshold in e+e− experiments. A comparison is made with available data from PETRA in the energy range 13 ⩽ Ecm ⩽ 31.6 GeV in order to test the model below the tt production threshold. | 161,727 |
title: The effect of Mo substitution on the phase formation and magnetic properties of RE2(Fe1−xMox)17 alloys (RE=Nd,Gd); abstract: Abstract The phase formation and magnetic properties of RE2(Fe1−xMox)17 alloys (RE=Nd, Gd; 0.00≤x≤0.10) have been investigated by X-ray diffraction and magnetic measurements. The samples were prepared by arc melting and annealing at 1100°C. The Rietveld method was employed to perform a quantitative determination of phase composition and lattice parameters. Our results suggest that the substitution of Mo in 2:17 is low. In the 0.00≤x≤0.05 composition range, samples are almost single phase with the rhombohedral Th2Zn17-type crystal structure; with the substitution of Fe for Mo a slight lattice expansion is induced. For higher Mo concentrations, this phase co-exists with a certain amount of spurious phases. The saturation magnetization and Curie temperatures do not show remarkable variations when Mo replaces Fe in Nd2(Fe1−xMox)17 samples. In Gd2(Fe1−xMox)17 the increase in the Mo content leads to a decrease in both physical quantities. | 161,728 |
title: The 2MASS Redshift Survey: description and data release; abstract: We present the results of the 2MASS Redshift Survey (2MRS), a ten-year project to map the full three-dimensional distribution of galaxies in the nearby universe. The Two Micron All Sky Survey (2MASS) was completed in 2003 and its final data products, including an extended source catalog (XSC), are available online. The 2MASS XSC contains nearly a million galaxies with K_s ≤ 13.5 mag and is essentially complete and mostly unaffected by interstellar extinction and stellar confusion down to a galactic latitude of |b| = 5° for bright galaxies. Near-infrared wavelengths are sensitive to the old stellar populations that dominate galaxy masses, making 2MASS an excellent starting point to study the distribution of matter in the nearby universe. We selected a sample of 44,599 2MASS galaxies with K_s ≤ 11.75 mag and |b| ≥ 5° (≥8° toward the Galactic bulge) as the input catalog for our survey. We obtained spectroscopic observations for 11,000 galaxies and used previously obtained velocities for the remainder of the sample to generate a redshift catalog that is 97.6% complete to well-defined limits and covers 91% of the sky. This provides an unprecedented census of galaxy (baryonic mass) concentrations within 300 Mpc. Earlier versions of our survey have been used in a number of publications that have studied the bulk motion of the Local Group, mapped the density and peculiar velocity fields out to 50 h^(–1) Mpc, detected galaxy groups, and estimated the values of several cosmological parameters. Additionally, we present morphological types for a nearly complete sub-sample of 20,860 galaxies with K_s ≤ 11.25 mag and |b| ≥ 10°. | 161,729 |
title: An assessment of the pulsar outer gap model – II. Implications for the predicted γ-ray spectra; abstract: One of the most important predictions of any gap model for pulsar magnetospheres is the predicted $\\gamma$-ray spectra. In the outer gap model, the properties of the synchro-curvature radiation are sensitive to many parameters, whose realistic ranges have been studied in detail in an accompanying paper. There we demonstrated that the uncertainty in the radius of curvature, the magnetic field geometry, and the X-ray surface flux may affect by orders of magnitude the predicted flux and spectral peak in the $\\gamma$-ray regime. Here, we present a systematic, numerical study of the impact of the different parameters on the particle dynamics along the gap and calculate the emitted synchro-curvature radiation along the trajectory. By integrating the emitted radiation along the gap and convolving it with a parametrized particle distribution, we discuss how the comparison with the wealth of {\\em Fermi}-LAT data can be used to constrain the applicability of the model. The resulting spectra show very different energy peaks, fluxes and shapes, qualitatively matching the great variety of the observed {\\em Fermi}-LAT pulsars. In particular, if we see a large fraction of photons emitted from the initial part of the trajectory, we show that the spectra will be flatter at the low-energy {\\it Fermi}-LAT regime (100 MeV -- 1 GeV). This provides a solution for such observed flat spectra, while still maintain synchro-curvature radiation as the origin of these photons. | 161,730 |
title: Convection Heat Transfer in Rotating Systems; abstract: Publisher Summary Because the convective heat transfer phenomena in rotating systems are intimately related to the flow characteristics, they too are quite complex and offer challenges to theoreticians as well as experimenters. Heat transfer by convection to or from bodies of revolution spinning about their axes of symmetry in an otherwise undisturbed fluid has been studied analytically and experimentally by numerous authors. This chapter summarizes results of more recent investigations. The flow and heat transfer characteristics of spinning bodies of revolution in a forced flow field are important for projectiles or re-entry missiles with spin as well as for certain other engineering problems. The fluid-mechanical phenomena of enclosed rotating disks and of parallel corotating disks are distinctly different from those of disks rotating in an infinite environment. In general, the results for convection heat transfer of a disk rotating in an infinite environment can, therefore, not be applied to shrouded or corotating disks. When a quiescent horizontal layer of fluid is heated from below, the fluid at the bottom becomes lighter than the fluid at the top and convection currents are set into motion. The chapter deals with convection in fluids that are set in motion principally by rotating bounding surfaces, but that do not have an independent axial flow. It also deals with heat transfer by convection in systems in which the fluids also have an independent axial motion superimposed on the rotating motion. | 161,731 |
title: Evidence of spin-density-wave order inRFeAsO1−xFxfrom measurements of thermoelectric power; abstract: Data on the magnetothermopower and specific heat of three compounds belonging to ``1111\u0027\u0027 oxypnictides family are reported. One specimen $({\\text{SmAsFeO}}_{0.8}{\\text{F}}_{0.2})$ is a superconductor with ${T}_{c}=53\\text{ }\\text{K}$, while two others (SmAsFeO and NdAsFeO) are nonsuperconducting parent compounds. Our results confirm that spin-density-wave (SDW) order is present in SmAsFeO and NdAsFeO. In these two samples a strict connection between the thermoelectric power and electronic specific heat is found in the vicinity of SDW transition, which indicates that the chemical potential of charge carriers strongly depends on temperature in this region. Low-temperature data suggest presence of significant contribution magnon drag to the thermoelectric power. | 161,732 |
title: Development of Double-Sided Full-Passing-Column 3D Sensors at FBK; abstract: We report on the main design and technological characteristics related to the latest 3D sensor process developments at Fondazione Bruno Kessler (FBK, Trento, Italy). With respect to the previous version of this technology, which involved columnar electrodes of both doping types etched from both wafer sides and stopping at a short distance from the opposite surface, passing-through columns are now available. This feature ensures better performance, but also a higher reproducibility, which is of concern in medium volume productions. In particular, this R\u0026D project was aimed at establishing a suitable technology for the production of 3D pixel sensors to be installed into the ATLAS Insertable B-Layer. An additional benefit is the feasibility of slim edges, which consist of a multiple ohmic column termination with an overall size as low as 100 μm. Eight batches with two different wafer layouts have been fabricated using this approach, and including several design options, among them the ATLAS 3D sensor prototypes compatible with the new read-out chip FE-I4. | 161,733 |
title: Integrated electro-optic lens/scanner in a LiTaO3 single crystal.; abstract: We report what we believe to be the first stand-alone integrated\nelectro-optic lens and scanner fabricated on a single crystal of\nZ-cut LiTaO3. The independently controlled\nlens and scanner components consist of lithographically defined\ndomain-inverted regions extending through the thickness of the\ncrystal. A lens power of 0.233 cm-1 kV-1\nand a deflection angle of 12.68 mrad kV-1 were observed at\nthe output of the device. | 161,734 |
title: Three-dimensional hairy black holes in teleparallel gravity; abstract: We consider three-dimensional gravity based on torsion. Specifically, we consider an extension of the so-called Teleparallel Equivalent of General Relativity in the presence of a scalar field with a self-interacting potential, where the scalar field is non-minimally coupled with the torsion scalar. Then, we find asymptotically AdS hairy black hole solutions, which are characterized by a scalar field with a power-law behavior, being regular outside the event horizon and null at spatial infinity and by a self-interacting potential, which tends to an effective cosmological constant at spatial infinity. | 161,735 |
title: Atomic hydrogen produced in M33 photodissociation regions; abstract: We derive total (atomic + molecular) hydrogen densities in giant molecular clouds (GMCs) in the nearby spiral galaxy M33 using a method that views the atomic hydrogen near regions of recent star formation as the product of photodissociation. Far-ultraviolet (FUV) photons emanating from a nearby OB association produce a layer of atomic hydrogen on the surfaces of nearby GMCs. Our approach provides an estimate of the total hydrogen density in these GMCs from observations of the excess FUV emission that reaches the GMC from the OB association and of the excess 21-cm radio H I emission produced after these FUV photons convert H-2 into H I on the GMC surface. The method provides an alternative approach to the use of CO emission as a tracer of H-2 in GMCs and is especially sensitive to a range of densities well below the critical density for CO(1-0) emission. We describe our \u0027PDR method\u0027 in more detail and apply it using GALEX FUV and Very Large Array 21-cm radio data to obtain volume densities in a selection of GMCs in the nearby spiral galaxy M33. We have also examined the sensitivity of the method to the linear resolution of the observations used; the results obtained at 20 pc are similar to those for the larger set of data at 80-pc resolution. The cloud densities we derive range from 1 to 500 cm(-3), with no clear dependence on the galactocentric radius; these results are generally similar to those obtained earlier in the cases of M81, M83 and M101 using the same method. | 161,736 |
title: Measurements of the Diffuse Ultraviolet Background and the Terrestrial Airglow with the Space Telescope Imaging Spectrograph; abstract: Far-UV observations in and near the Hubble Deep Fields demonstrate that the Space Telescope Imaging Spectrograph (STIS) may obtain unique and precise measurements of the diffuse far-ultraviolet background. Although STIS is not the ideal instrument for such measurements, high-resolution images allow Galactic and extragalactic objects to be masked to very faint magnitudes, thus ensuring a measurement of the truly diffuse UV signal. The programs we have analyzed were not designed for this scientific purpose, but they would be sufficient to obtain a very sensitive measurement if it were not for a weak but larger than expected signal from airglow in the STIS 1450?1900 ? bandpass. Our analysis shows that STIS far-UV crystal quartz observations taken near the limb during orbital day can detect a faint airglow signal, most likely from N I ?1493, that is comparable to the dark rate and inseparable from the far-UV background. Discarding all but the night data from these data sets yields the diffuse far-ultraviolet background measurement 501 ? 103 photons cm-2 s-1 sr-1 ?-1, along a line of sight with very low Galactic neutral hydrogen column (NH I = 1.5 ? 1020 cm-2) and extinction [E(B-V) = 0.01 mag]. This result is in good agreement with earlier measurements of the far-UV background and should not include any significant contribution from airglow. We present our findings as a warning to other groups who may use the STIS far-UV camera to observe faint extended targets and to demonstrate how this measurement may be properly obtained with STIS. | 161,737 |
title: Dielectric behavior of PbZr0.52Ti0.48O3 thin films: Intrinsic and extrinsic dielectric responses; abstract: The dc electric-field (E) dependence of the dielectric constant (e) in PbZr0.52Ti0.48O3 (PZT) thin films has been studied at cryogenic temperatures in the dc electric-field range of 0–820kV∕cm. Significant suppression of e is observed by an application of E up to 400kV∕cm. The relation of e versus E can be well described by the “multi-polarization mechanism” model, i.e., e(E)=e(0)∕[1+αe(0)3E2]1∕3+(Pjxj∕e0)[cosh(Exj)]−2. By this equation, the field dependence of the extrinsic dielectric response can be subtracted from the whole dielectric response. The results indicate that the analysis of the relation of e versus E could be a way to separate the intrinsic and extrinsic contributions in PZT. | 161,738 |
title: Longitudinal scaling property of the charge balance function in Au plus Au collisions at root s(NN)=200 GeV; abstract: We present measurements of the charge balance function, from the charged particles, for diverse pseudorapidity and transverse momentum ranges in Au + Au collisions at root S(NN) = 200 GeV using the STAR detector at RHIC. We observe that the balance function is boost-invariant within the pseudorapidity coverage vertical bar-1.3, 1.3 vertical bar. The balance function properly scaled by the width of the observed pseudorapidity window does not depend on the position or size of the pseudorapidity window. This scaling property also holds for particles in different transverse momentum ranges. In addition, we find that the width of the balance function decreases monotonically with increasing transverse momentum for all centrality classes. (c) 2010 Elsevier B.V. All rights reserved. | 161,739 |
title: Scalar potentials and accidental symmetries in supersymmetric U(1)' models; abstract: Abstract We address two closely related problems associated with the singlet scalars\u0027 potential that are often present in supersymmetric U ( 1 ) ′ models, especially those which maintain the gauge unification of the MSSM in a simple way. The first is the possibility of an accidental global symmetry which results in a light Goldstone boson. The second is the problem of generating a vacuum expectation value for more than one field without reintroducing the μ problem. We give sufficient conditions for addressing both issues and provide a concrete example to generate them. | 161,740 |
title: Influence of a continuous quenching procedure on the initial stages of spinodal decomposition; abstract: Instead of the standard assumption in the theory of phase separation where an instantaneous quench from an initial equilibrium state to the final state in the two-phase region is assumed, we consider the more realistic situation that the change of the external control parameter (e.g. temperature) can only be performed with finite rates. During the initial stages of spinodal decomposition the system then has some “memory” of the states intermediate between the initial and the final one. This influence of the finite quench rate in continuous quenching procedures is studied within the linearized theory of spinodal decomposition, with the Langer-Baron-Miller decoupling, and with Monte Carlo simulations. Both the case of thermally activated mobilities (applicable to solid metallic alloys) and the case of nearly temperature-independent mobilities (applicable to fluid polymer mixtures) are treated, and possible experimental applications are discussed. We find drastic deviations from the standard instantaneous quench situations in all cases of experimental interest. | 161,741 |
title: LHC and B physics probes of neutrinoless double beta decay in supersymmetry without R-parity; abstract: In the event of an observation of neutrinoless double beta decay, a relevant question would be: what lepton number violating physics is responsible for the decay? The exchange of Majorana neutrinos and/or supersymmetric particles may contribute. We point out that measurements of supersymmetric signals at the LHC, including single slepton production, could be used to help bound some supersymmetric processes contributing to neutrinoless double beta decay. LHC information about the supersymmetric spectrum could be combined with Bd-Bd bar mixing data in order to bound a competing neutrinoless double beta decay process involving sbottom exchange. | 161,742 |
title: Fluid/gravity correspondence and the CFM black brane solutions; abstract: We consider the lower bound for the shear viscosity-to-entropy density ratio, obtained from the fluid/gravity correspondence, in order to constrain the post-Newtonian parameter of brane-world metrics. In particular, we analyse the Casadio–Fabbri–Mazzacurati (CFM) effective solutions for the gravity side of the correspondence and argue that including higher-order terms in the hydrodynamic expansion can lead to a full agreement with the experimental bounds, for the Eddington–Robertson–Schiff post-Newtonian parameter in the CFM metrics. This lends further support to the physical relevance of the viscosity-to-entropy ratio lower bound and fluid/gravity correspondence. Hence we show that CFM black branes are, effectively, Schwarzschild black branes. | 161,743 |
title: Local models of astrophysical discs; abstract: Local models of gaseous accretion discs have been successfully employed for decades to describe an assortment of small-scale phenomena, from instabilities and turbulence, to dust dynamics and planet formation. For the most part, they have been derived in a physically motivated but essentially ad hoc fashion, with some of the mathematical assumptions never made explicit nor checked for consistency. This approach is susceptible to error, and it is easy to derive local models that support spurious instabilities or fail to conserve key quantities. In this paper we present rigorous derivations, based on an asympototic ordering, and formulate a hierarchy of local models (incompressible, Boussinesq, and compressible), making clear which is best suited for a particular flow or phenomenon while spelling out explicitly the assumptions and approximations of each. We also discuss the merits of the anelastic approximation, emphasising that anelastic systems struggle to conserve energy unless strong restrictions are imposed on the flow. The problems encountered by the anelastic approximation are exacerbated by the disk\u0027s differential rotation, but also attend non-rotating systems such as stellar interiors. We conclude with a defence of local models and their continued utility in astrophysical research. | 161,744 |
title: Partition selection in multiscale turbulence modeling; abstract: The variational multiscale (VMS) method for large-eddy simulation (LES) is a promising new approach that employs variational projection to achieve a priori scale separation in lieu of traditional spatial filtering. However, depending on the numerical method used, VMS may not be convenient in all spatial directions. We apply the VMS methodology to a numerical method that does not support explicit scale separation in the wall-normal direction for turbulent channel flow. Similar to the common LES practice of filtering only in the planes, variational projection is performed only in the planes and this strategy is found to be as successful as the full VMS method. However, in all VMS approaches, the partition between the large and small scales and the overall resolution are crucial parameters for obtaining quality solutions. By applying scale separation in just one of the coordinate directions, we have developed a consistent method for partition and resolution selection in channel flow that is related to the ph... | 161,745 |
title: Non-Abelian BFFT embedding, Schrödinger quantization and the field–antifield anomaly of the O(N) nonlinear sigma model; abstract: We have embedded the O(N) nonlinear sigma model in a non-Abelian gauge theory. After that as a first class-system, it was quantized using two different approaches: the functional Schrodinger method and the nonlocal field–antifield procedure. First, the quantization was performed with the functional Schrodinger method, for N = 2, obtaining the wave functionals for the ground and excited states. Second, using the well-known BV formalism, we have computed the one-loop anomaly. This result shows that the classical gauge symmetries, which appear due to the conversion via BFFT method, are broken at the quantum level. | 161,746 |
title: Adaptive, Readily Morphing, Optimized Radiation Shielding for Transit Habitats: Flyby Mars Mission; abstract: Optimization techniques are used to determine the total mass required for additional passive radiation shielding during a space mission to reduce radiation exposures from galactic cosmic rays to NA... | 161,747 |
title: Wall shear stress fluctuations: Mixed scaling and their effects on velocity fluctuations in a turbulent boundary layer; abstract: The present work investigates numerically the statistics of the wall shear stress fluctuations in a turbulent boundary layer (TBL) and their relation to the velocity fluctuations outside of the near-wall region. The flow data are obtained from a Direct Numerical Simulation (DNS) of a zero pressure-gradient TBL using the high-order flow solver Incompact3D [S. Laizet and E. Lamballais, “High-order compact schemes for incompressible flows: A simple and efficient method with quasi-spectral accuracy,” J. Comput. Phys. 228(16), 5989 (2009)]. The maximum Reynolds number of the simulation is Re\u0026#x1d703;≈2000, based on the free-stream velocity and the momentum thickness of the boundary layer. The simulation data suggest that the root-mean-squared fluctuations of the streamwise and spanwise wall shear-stress components τx and τz follow a logarithmic dependence on the Reynolds number, consistent with the empirical correlation of Orlu and Schlatter [R. Orlu and P. Schlatter, “On the fluctuating wall-shear stress in zero pres... | 161,748 |
title: An anti-ferroelectric gated Landau transistor to achieve sub-60 mV/dec switching at low voltage and high speed; abstract: Landau field effect transistors promise to lower the power-dissipation of integrated circuits (ICs) by reducing the subthreshold swing (S) below the Boltzmann limit of 60 mV/dec. The key idea is to replace the classical gate insulator with dielectrics that exhibit negative capacitance (NC) associated with double-well energy landscape, for example, ferroelectrics (FE), air-gap capacitors, or a combination thereof. Indeed, S is dramatically reduced, constrained only by the limits of hysteresis-free operation. Unfortunately, the following limitations apply (i) the need for capacitance matching constrains steep S only to the small subthreshold region for FE based negative capacitance field effect transistor (NCFET) and requires an insulator too thick for sub-20 nm scaling; (ii) the kinetics of mechanical switching for airgap based NCFET obviate high-speed operation; and (iii) the lattice mismatch between the substrate and the dielectric makes defect-free integration difficult. In this article, we demonstrate ... | 161,749 |
title: Kinematics of Outer Halo Globular Clusters in M31; abstract: We present the first kinematic analysis of the far outer halo globular cluster (GC) population in the Local Group galaxy M31. Our sample contains 53 objects with projected radii of ~20-130?kpc, 44 of which have no previous spectroscopic information. GCs with projected radii 30?kpc are found to exhibit net rotation around the minor axis of M31, in the same sense as the inner GCs, albeit with a smaller amplitude of 79 ? 19?km?s?1. The rotation-corrected velocity dispersion of the full halo GC sample is 106 ? 12?km?s?1, which we observe to decrease with increasing projected radius. We find compelling evidence for kinematic coherence among GCs that project on top of halo substructure, including a clear signature of infall for GCs lying along the northwest stream. Using the tracer mass estimator, we estimate the dynamical mass of M31 within 200?kpc to be M M31 = (1.2-1.5) ? 0.2 ? 1012 M ?. This value is highly dependent on the chosen model and assumptions within. | 161,750 |
title: Discovery and cross-section measurement of 58 new fission products in projectile-fission of 750 · A MeV 238U; abstract: Abstract The projectile fission of uranium at relativistic energy impinging on a Be target was investigated with the fragment separator, FRS, in order to produce and identify new isotopes and to measure their production yields. Fifty eight new fragments have been observed with a neutron excess of (N - Z)/Z reaching 0.8 and cross sections as small as 0.3 nb. | 161,751 |
title: Dynamical D-Terms in Supergravity; abstract: Abstract Most phenomenological models of supersymmetry breaking rely on nonzero F-terms rather than nonzero D-terms. An important reason why D-terms are often neglected is that it turns out to be very challenging to realize D-terms at energies parametrically smaller than the Planck scale in supergravity. As we demonstrate in this paper, all conventional difficulties may, however, be overcome if the generation of the D-term is based on strong dynamics. To illustrate our idea, we focus on a certain class of vector-like SUSY breaking models that enjoy a minimal particle content and which may be easily embedded into more complete scenarios. We are then able to show that, upon gauging a global flavor symmetry, an appropriate choice of Yukawa couplings readily allows to dynamically generate a D-term at an almost arbitrary energy scale. This includes in particular the natural and consistent realization of D-terms around, above and below the scale of grand unification in supergravity, without the need for fine-tuning of any model parameters. Our construction might therefore bear the potential to open up a new direction for model building in supersymmetry and early universe cosmology. | 161,752 |
title: Field dependent susceptibility of the 2D ferromagnet (CH3NH3)2CuCl4 in the paramagnetic phase; abstract: Abstract The temperature dependence of the ac susceptibility (χ) at constant applied magnetic field was investigated in the paramagnetic region of the quasi-2D ferromagnet (CH3NH3)2CuCl4. Above the Curie temperature (TC=8.85 K) a maximum in the χ(T,H) curves was observed at Tm(H). The temperature at the maximum increases with increasing applied field. This anomaly is related to short range fluctuations close the order transition. The behavior of Tm(H) is governed by the gap exponent of the scaling function (Δ=γ+β). We found Δ=2.2±0.1 in very good agreement with the previously known values of γ and β. | 161,753 |
title: Regular and black-hole solutions of the Einstein–Yang–Mills–Higgs equations; the case of nonminimal coupling; abstract: Abstract Regular and black-hole solutions of the spontaneously broken Einstein–Yang–Mills–Higgs theory with nonminimal coupling to gravity are shown to exist. The main characteristics of the solutions are presented and differences with respect to the minimally coupled case are studied. Since negative energy densities are found to be possible, traversable wormhole solutions might exist. We prove that they are absent. | 161,754 |
title: Influence of structural disorder on magnetic and transport properties of (La0.7Sr0.3)0.5(Pr0.65Ca0.35)0.5MnO3 films; abstract: Magnetic and transport properties of (La0.7Sr0.3)0.5(Pr0.65Ca0.35)0.5MnO3 films prepared by a “co-deposition” utilizing the laser-ablation technique are investigated in a wide temperature range. The film deposited at 300 °C has a nanocrystalline disordered structure and exhibits a paramagnetic temperature dependence of the magnetization with a narrow peak (ΔT≃10 K) at TG≃45 K, which can be interpreted as a paramagnetic→superparamagnetic transition. A short-term annealing of the as-deposited film at 750 °C leads to the formation of a high-textured polycrystalline microstructure and to the appearance of ferromagnetic (FM) and metal–insulator (MI) transitions at TC≃240 K and TP≃140 K, respectively. The observed discrepancy between TP and TC values can be ascribed to a percolating nature of the MI transition, with an exponent of 5.3 for the percolating conductivity. The film deposited at Tsub≃740 °C is composed of lattice-strain-free and the lattice-strained crystallites with different lattice parameters and ... | 161,755 |
title: Extra-relativistic effects and the Chandrasekhar limit; abstract: We endeavor to take into account the extra-relativistic effects in the mass-energy relation due to Einstein. We consider a modified mass-energy relation and consequently find a strict bound on the Chandrasekhar limit for a white dwarf star. We find that the said limit gets modified to a certain extent, and we have been able to find the maximum mass of a stable white dwarf star. | 161,756 |
title: From Ge(Li) detectors to gamma-ray tracking arrays–50 years of gamma spectroscopy with germanium detectors; abstract: Abstract The structure of the atomic nucleus has been studied to a large extent by gamma-ray spectroscopy using germanium (Ge) detectors. Ge detectors were developed in the 1960s and still offer the best compromise between energy resolution and efficiency for high-resolution gamma-ray spectroscopy. In the 1970s and 1980s the main advances were in the purity and volume of the Ge crystals. More recently the development of highly-segmented Ge detectors has significantly increased the performance and power of detection systems. In a segmented Ge detector the crystal is divided into sections by isolating the contacts. This enables the position of interaction to be determined. The accuracy of the position determination can be improved by the analysis of the shape of the charge signals and of the transient signals in adjacent segments. This technique has led to the concept of gamma-ray tracking in a segmented Ge detector whereby the energy, time and position of all interactions are recorded and the full interaction is reconstructed. This enables a spectrometer system with unprecedented efficiency and energy resolution to be realized. In this article, the history of Ge detectors and Ge detector arrays for nuclear spectroscopy will be reviewed. The technology and properties of highly-segmented coaxial Ge detectors as developed for the European γ -ray tracking array AGATA will be highlighted. | 161,757 |
title: The McGill Magnetar Catalog; abstract: We present a catalog of the 26 currently known magnetars and magnetar candidates. We tabulate astrometric and timing data for all catalog sources, as well as their observed radiative properties, particularly the spectral parameters of the quiescent X-ray emission. We show histograms of the spatial and timing properties of the magnetars, comparing them with the known pulsar population, and we investigate and plot possible correlations between their timing, X-ray, and multiwavelength properties. We find the scale height of magnetars to be in the range 20-31 pc, assuming they are exponentially distributed. This range is smaller than that measured for OB stars, providing evidence that magnetars are born from the most massive O stars. From the same fits, we find that the Sun lies ~13-22 pc above the Galactic plane, consistent with previous measurements. We confirm previously identified correlations between quiescent X-ray luminosity L_X and magnetic field B, as well as X-ray spectral power-law index Gamma and B, and show evidence for an excluded region in a plot of L_X vs. Gamma. We also present an updated kT versus characteristic age plot, showing magnetars and high-B radio pulsars are hotter than lower-B neutron stars of similar age. Finally, we observe a striking difference between magnetars detected in the the hard X-ray and radio bands; there is a clear correlation between the hard and soft X-ray flux, whereas the radio-detected magnetars all have low soft X-ray flux suggesting, if anything, that the two bands are anti-correlated. \r\nAn online version of the catalog is located at this http URL | 161,758 |
title: Effect of non-adiabatic thermal profiles on the inferred compositions of Uranus and Neptune; abstract: It has been a common assumption of interior models that the outer planets of our Solar system are convective, and that the internal temperature distributions are therefore adiabatic. This assumption is also often applied to exoplanets. However, if a large portion of the thermal flux can be transferred by conduction, or if convection is inhibited, the thermal profile could be substantially different and would therefore affect the inferred planetary composition. Here we investigate how the assumption of non-adiabatic temperature profiles in Uranus and Neptune affects their internal structures and compositions. We use a set of plausible temperature profiles together with density profiles that match the measured gravitational fields to derive the planets’ compositions. We find that the inferred compositions of both Uranus and Neptune are quite sensitive to the assumed thermal profile in the outer layers, but relatively insensitive to the thermal profile in the central, high-pressure region. The overall value of the heavy element mass fraction, Z, for these planets is between 0.8 and 0.9. Finally, we suggest that large parts of Uranus’ interior might be conductive, a conclusion that is consistent with Uranus dynamo models and a hot central inner region. | 161,759 |
title: DINEUTRON CORRELATION IN THE GROUND STATE AND E1 EXCITATIONS OF BORROMEAN NUCLEI; abstract: Using a three-body model with density-dependent contact interaction, we discuss the role of dineutron correlation in the ground state properties as well as in the dipole excitation of typical weakly-bound Borromean nuclei, 11Li and 6He. We show that, while both the nuclei manifest themselves similar strong dineutron correlations to each other in the ground state, the energy distributions for the two emitted neutrons from the dipole excitation are considerably different. We also discuss briefly the diproton correlation in a proton-rich Borromean nucleus, 17Ne. | 161,760 |
title: Constraining inflation with future galaxy redshift surveys; abstract: With future galaxy surveys, a huge number of Fourier modes of the distribution of the large scale structures in the Universe will become available. These modes are complementary to those of the CMB and can be used to set constraints on models of the early universe, such as inflation. Using a MCMC analysis, we compare the power of the CMB with that of the combination of CMB and galaxy survey data, to constrain the power spectrum of primordial fluctuations generated during inflation. We base our analysis on the Planck satellite and a spectroscopic redshift survey with configuration parameters close to those of the Euclid mission as examples. We first consider models of slow-roll inflation, and show that the inclusion of large scale structure data improves the constraints by nearly halving the error bars on the scalar spectral index and its running. If we attempt to reconstruct the inflationary single-field potential, a similar conclusion can be reached on the parameters characterizing the potential. We then study models with features in the power spectrum. In particular, we consider ringing features produced by a break in the potential and oscillations such as in axion monodromy. Adding large scale structures improves the constraints on features by more than a factor of two. In axion monodromy we show that there are oscillations with small amplitude and frequency in momentum space that are undetected by CMB alone but can be measured by including galaxy surveys in the analysis. | 161,761 |
title: Valence Imbalance of Manganese Ions between Surface and Bulk Enhanced by Fermi-Surface Structure in Layered Manganites; abstract: To investigate valence imbalance phenomena between the surface and bulk in layered manganites, we analyze an eg-orbital degenerate double-exchange model with surfaces for two types of t2g spin structures. We reconfirm that the surface-induced Friedel oscillations occur in the charged structure and that the number of Mn4+ ions on the surface is larger than that in the bulk. This tendency is found to be more significant, when the eg-electron system has Fermi-surface structures with better nesting properties. The behavior of the Friedel oscillations depends on the nesting properties of the Fermi-surface curves along the direction of the oscillations, and not on the dimension of the system itself. We believe that these results will be useful for the development of high-efficiency cathodes in Li-ion batteries and catalysts. | 161,762 |
title: High mass photon pairs in ℓ+ℓ−γγ events at LEP; abstract: Abstract From the analysis of the reactions e + e − → l + l − ( nγ ) ( l = e , μ , τ ) we observe four events, one e + e − γγ and three μ + μ − γγ , with the invariant mass of the photon pairs close to 60 GeV. These events were selected from a data sample collected in the L3 detector corresponding to 950 000 produced Z 0 \u0027s. More data are necessary to ascertain the origin of these events. | 161,763 |
title: Equation of state of hot and dense QCD: resummed perturbation theory confronts lattice data; abstract: We perform a detailed analysis of the predictions of resummed perturbation theory for the pressure and the second-, fourth-, and sixth-order diagonal quark number susceptibilities in a hot and dense quark-gluon plasma. First, we present an exact one-loop calculation of the equation of state within hard-thermal-loop perturbation theory (HTLpt) and compare it to a previous one-loop HTLpt calculation that employed an expansion in the ratios of thermal masses and the temperature. We nd that this expansion converges reasonably fast. We then perform a resummation of the existing four-loop weak coupling expression for the pressure, motivated by dimensional reduction. Finally, we compare the exact one-loop HTLpt and resummed dimensional reduction results with state-of-the-art lattice calculations and a recent mass-expanded three-loop HTLpt calculation. | 161,764 |
title: The eccentric massive binary V380 Cyg: revised orbital elements and interpretation of the intrinsic variability of the primary component; abstract: We present a detailed analysis and interpretation of the hig h-mass binary V380 Cyg, based on high-precision space photometry gathered with the Kepler space mission as well as highresolution ground-based spectroscopy obtained with thehermes spectrograph attached to the 1.2m Mercator telescope. We derive a precise orbital solution and the full physical properties of the system, including dynamical component mass estimates of 11.43±0.19 and 7.00±0.14 M⊙ for the primary and secondary, respectively. Our frequency analysis reveals the rotation frequency of the primary in both the photometric and spectroscopic data and additional low-amplitude stochastic variability at low freq uency in the space photometry with characteristics that are compatible with recent theoretic al predictions for gravity-mode oscillations excited either by the convective core or by sub-s urface convective layers. Doppler Imaging analysis of the Silicon lines of the primary suggests the presence of two high-contrast stellar surface abundance spots which are located either at the same latitude or longitude. Comparison of the observed properties of the binary with present-day single-star evolutionary models shows that the latter are inadequate and lack a serious amount of near-core mixing. | 161,765 |
title: Phase transition in compact stars: nucleation mechanism and $\gamma$-ray bursts revisited; abstract: We have revisited the nucleation process based on the Lifshitz-Kagan theory, which is the underlying mechanism of conversion of a pulsar constituted of hadronic matter to a quark star. We have selected appropriate models that have been tested against experimental and observational constraints to restrict the model arbitrariness present in previous investigations. The phase transition pressures and chemical potentials have been identified and afterwards, the tunneling probabilities and the nucleation time were computed. The critical pressures for which the half life of the metastable hadronic phase is one year were obtained. Even with the restrictions imposed to the selection of models, the results remained model dependent, but we found that the tunneling that makes possible the appearance of stable matter requires an overpressure that is practically independent of the quark matter bag constant. Finally, we have confirmed that the nucleation process can be one of the causes of gamma-ray bursts. | 161,766 |
title: Earth matter effects at very long baselines and the neutrino mass hierarchy; abstract: We study matter effects which arise in the muon neutrino oscillation and survival probabilities relevant to atmospheric neutrino and very long baseline (\u003e4000 Km) beam experiments. The interrelations between the three probabilities P{sub {mu}}{sub e}, P{sub {mu}}{sub {tau}}, and P{sub {mu}}{sub {mu}} are examined. It is shown that large and observable sensitivity to the neutrino mass hierarchy can be present in P{sub {mu}}{sub {mu}} and P{sub {mu}}{sub {tau}}. We emphasize that at baselines \u003e7000 Km, matter effects in P{sub {mu}}{sub {tau}} are important under certain conditions and can be large. The muon survival rates in experiments with very long baselines thus depend on matter effects in both P{sub {mu}}{sub {tau}} and P{sub {mu}}{sub e}. We also indicate where these effects provide sensitivity to {theta}{sub 13} and identify ranges of energies and baselines where this sensitivity is maximum. The effect of parameter degeneracies in the three probabilities at these baselines and energies is studied in detail and large parts of the parameter space are identified which are free from these degeneracies. In the second part of the paper, we focus on using the matter effects studied in the first part as a means of determining the mass hierarchy via atmospheric neutrinos.more » Realistic event rate calculations are performed for a charge discriminating 100 kT iron calorimeter which demonstrate the possibility of realizing this very important goal in neutrino physics. It is shown that for atmospheric neutrinos, a careful selection of energy and baseline ranges is necessary in order to obtain a statistically significant signal, and that the effects are largest in bins where matter effects in both P{sub {mu}}{sub e} and P{sub {mu}}{sub {tau}} combine constructively. Under these conditions, up to a 4{sigma} signal for matter effects is possible (for {delta}{sub 31}\u003e0) within a time scale appreciably shorter than the one anticipated for neutrino factories.« less | 161,767 |
title: Meson spectra and m T scaling in p + p , d + Au, and Au + Au collisions at s N N = 200 GeV; abstract: The meson spectra provide insight into the particle production mechanism and interaction in the hadronic and quark gluon plasma (QGP) phases. The detailed study of systematics of meson spectra is important also because it acts as an ingredient for estimating the hadronic decay backgrounds in the photon, single lepton, and dilepton spectra which are the penetrating probes of quark gluon plasma. In this work, we parametrize experimentally measured pion spectra and then obtain the spectra of other light mesons using a property known as ${m}_{T}$ scaling. The ${m}_{T}$ scaled spectra for each meson is compared with experimental data for $p+p$, $d$ + Au, and Au + Au systems at $\\ensuremath{\\surd}{s}_{NN}$ = 200 GeV. The agreement of the ${m}_{T}$ scaled and experimental data shapes are excellent in most cases and their fitted relative normalization gives ratio of meson to pion ${m}_{T}$ spectra. These ratios are useful to obtain the hadronic decay contribution in photonic and leptonic channels but also point to the quantitative changes in the dynamics of the heavy ion collision over $p+p$ collisions. It is shown that, the particles with charm contents behave differently as compared to pions in $d$ + Au systems and particles either with strange or charm contents behave differently from pions in Au + Au systems. For Au + Au system, three centrality classes have been studied which reveal that for the particles, such as kaon and $\\ensuremath{\\varphi}$, peripheral collision data are better reproduced as compared to central collision data and their relative ratios with pions also increase as the collisions become more central. | 161,768 |
title: Size-induced appearance of ferroelectricity in thin antiferroelectric films; abstract: Abstract In the paper we consider size effects on phase transitions and polar properties of thin antiferroelectric films. We extend the phenomenological approach proposed by Kittel for thin films allowing for gradient (correlation) energy and depolarization field energy. Surface piezoelectric effect as well as misfit strain appear due to lattice constants mismatch between the film and its substrate. Direct variational method is used to derive the free energy with renormalized coefficients depending on the film thickness. Obtained free energy expression allows the calculation of phase diagrams and all electro-physical properties by a conventional minimization procedure. Approximate analytical expressions for the paraelectric–antiferroelectric–ferroelectric transition temperature dependences on film thickness, polarization gradient coefficient, and extrapolation lengths were obtained. The thickness dependence of the electric field critical value that causes antiferroelectric–ferroelectric phase transition was calculated. Under favorable conditions the antiferroelectric phase at first transforms into ferroelectric one and then into paraelectric phase with the decrease of the film thickness. Proposed theoretical consideration explains the experimental results obtained in antiferroelectric PbZrO 3 thin films. | 161,769 |
title: Pulsar Acceleration by Asymmetric Emission of Sterile Neutrinos; abstract: A convincing explanation for the observed pulsar large peculiar velocities is still missing. We argue that any viable particle physics solution would most likely involve the resonant production of a noninteracting neutrino νs of mass m ~ 20-50 keV. We propose a model where anisotropic magnetic field configurations strongly bias the resonant spin flavor precession of tau antineutrinos into νs. For internal magnetic fields Bint 1015 G, a τ-νs transition magnetic moment of the order of 10-12 Bohr magnetons is required. The asymmetric emission of νs from the core can produce sizable natal kicks and account for recoil velocities of several hundred kilometers per second. | 161,770 |
title: MASS DEPENDENCE OF p-NUCLEUS TOTAL REACTION CROSS SECTION AND GAMBHIR–PATIL NUCLEON DENSITY DISTRIBUTION; abstract: Total reaction cross sections for 50 and 100 MeV protons have been calculated for several nuclei using Gambhir–Patil semi-phenomenological nucleon density in the Coulomb modified Glauber model. It is shown that the semi-phenomenological nucleon density distribution provides quite satisfactory description of the observed A-dependence of the proton reaction cross sections. | 161,771 |
title: Direct numerical simulation and statistical analysis of stress-driven turbulent Couette flow with a free-slip boundary; abstract: The effects of free-slip boundary on shear turbulence are studied numerically using the direct numerical simulation (DNS) approach. The flow considered in this study is a stress-driven turbulent Co... | 161,772 |
title: Mode competition in modulated Taylor-Couette flow; abstract: The effects of harmonically oscillating the inner cylinder about a zero mean rotation in a Taylor–Couette flow are investigated experimentally and numerically. The resulting time-modulated circular Couette flow possesses a Z2 spatio-temporal symmetry which gives rise to two distinct modulated Taylor vortex flows. These flows are initiated at synchronous bifurcations, have the same spatial symmetries, but are characterized by different spatio-temporal symmetries and axial wavenumber. Mode competition between these two states has been investigated in the region where they bifurcate simultaneously. In the idealized numerical model, the two flows have been found to coexist and be stable in a narrow region of parameter space. However, in the physical experiment, neither state has been observed in the coexistence region. Instead, we observe noise-sustained flows with irregular time-dependent axial wavenumber. Movies are available with the online version of the paper. | 161,773 |
title: Complementary metal-oxide semiconductor-compatible detector materials with enhanced 1550 nm responsivity via Sn-doping of Ge/Si(100); abstract: Previously developed methods used to grow Ge1−ySny alloys on Si are extended to Sn concentrations in the 1019−1020 cm−3 range. These concentrations are shown to be sufficient to engineer large increases in the responsivity of detectors operating at 1550 nm. The dopant levels of Sn are incorporated at temperatures in the 370–390 °C range, yielding atomically smooth layers devoid of threading defects at high growth rates of 15–30 nm/min. These conditions are far more compatible with complementary metal-oxide semiconductor processing than the high growth and processing temperatures required to achieve the same responsivity via tensile strain in pure Ge on Si. A detailed study of a detector based on a Sn-doped Ge layer with 0.25% (1.1 × 1020 cm−3) Sn range demonstrates the responsivity enhancement and shows much better I-V characteristics than previously fabricated detectors based on Ge1−ySny alloys with y = 0.02.Previously developed methods used to grow Ge1−ySny alloys on Si are extended to Sn concentrations in the 1019−1020 cm−3 range. These concentrations are shown to be sufficient to engineer large increases in the responsivity of detectors operating at 1550 nm. The dopant levels of Sn are incorporated at temperatures in the 370–390 °C range, yielding atomically smooth layers devoid of threading defects at high growth rates of 15–30 nm/min. These conditions are far more compatible with complementary metal-oxide semiconductor processing than the high growth and processing temperatures required to achieve the same responsivity via tensile strain in pure Ge on Si. A detailed study of a detector based on a Sn-doped Ge layer with 0.25% (1.1 × 1020 cm−3) Sn range demonstrates the responsivity enhancement and shows much better I-V characteristics than previously fabricated detectors based on Ge1−ySny alloys with y = 0.02. | 161,774 |
title: Current star formation in early-type galaxies and the K+A phenomenon; abstract: We present the results of an effort to identify and study a sample of the likely progenitors of elliptical (E) and lenticular (S0) K+A galaxies. To achieve this, we have searched a sample ∼11 000 nearby (m r \u003c 16) early-type galaxies selected by morphology from the Sloan Digital Sky Survey (SDSS) main spectroscopic sample for actively star-forming E and S0 galaxies. Using emission-line ratios and visual inspection of SDSS g-band images, we have identified 335 galaxies from the SDSS Fourth Data Release (DR4) as actively star-forming E and S0 galaxies. These galaxies make up about 3 per cent of the total early-type sample and less than 1 per cent of all main galaxies with m r \u003c 16. We also identified a sample of ∼400 K+A galaxies from DR4 with m r \u003c 16; more than half of these are E and S0 galaxies. We find that star-forming early-type galaxies and K+A galaxies have similar mass distributions; they are on average less massive than typical early-type galaxies but more massive than the average starforming galaxy. Both of these types of galaxies are found in higher fractions among all galaxies in lower density environments. The fractions of star-forming E and S0 galaxies and E and S0 K+A galaxies depend on environment in nearly the same way. Model spectra fit to the stellar continua of the star-forming E and S0 galaxies showed that their properties are consistent with star formation episodes of � 1 Gyr in duration. The modelling results imply that on average, the star formation episodes will increase the stellar masses by about 4 per cent. The results also imply that only episodes that increase the stellar mass by more than 2‐5 per cent will lead to K+A galaxies as we have defined them and that this is true for roughly 80 per cent of the star-forming E and S0 galaxies in our sample. The estimated typical increase in stellar mass | 161,775 |
title: Further explorations of Skyrme-Hartree-Fock-Bogoliubov mass formulas. XII. Stiffness and stability of neutron-star matter; abstract: We construct three new Hartree-Fock-Bogoliubov (HFB) mass models, labeled HFB-19, HFB20, and HFB-21, with unconventional Skyrme forces containing t4 and t5 terms, i.e., densitydependent generalizations of the usual t1 and t2 terms, respectively. The new forces underlying these models are fitted respectively to three different realistic equations of state of neutron matter for which the density dependence of the symmetry energy ranges from the very soft to the very stiff, reflecting thereby our present lack of complete knowledge of the high-density behavior of nuclear matter. All unphysical instabilities of nuclear matter, including the transition to a polarized state in neutron-star matter, are eliminated with the new forces. At the same time the new models fit essentially all the available mass data with rms deviations of 0.58 MeV and give the same high quality fits to measured charge radii that we obtained in earlier models with conventional Skyrme forces. Being constrained by neutron matter, these new mass models, which all give similar extrapolations out to the neutron drip line, are highly appropriate for studies of the r-process and the outer crust of neutron stars. Moreover, the underlying forces, labeled BSk19, BSk20 and BSk21, respectively, are well adapted to the study of the inner crust and core of neutron stars. The new family of Skyrme forces thus opens the way to a unified description of all regions of neutron stars. | 161,776 |
title: Note on Invariance of One-Dimensional Lattice-Boltzmann Equation; abstract: Invariance of the one-dimensional lattice Boltzmann model is proposed together with its rigorous theoretical background. It is demonstrated that the symmetry inherent in Navier–Stokes equations is not really recovered in the one-dimensional lattice Boltzmann equation (LBE), especially for shock calculation. Symmetry breaking may be the inherent cause for the non-physical oscillations in the vicinity of the shock for LBE calculation. | 161,777 |
title: Dynamical estimate of post main sequence stellar masses in 47 Tucanae; abstract: We use the effects of mass segregation on the radial distribution of different stellar populations in the core of 47 Tucanae to find estimates for the masses of stars at different post main sequence evolutionary stages. We take samples of main sequence (MS) stars from the core of 47 Tucanae, at different magnitudes (i.e. different masses), and use the effects of this dynamical process to develop a relation between the radial distance (RD) at which the cumulative distribution reaches the 20th and 50th percentile, and stellar mass. From these relations we estimate the masses of different post MS populations. We find that mass remains constant for stars going through the evolutionary stages between the upper MS up to the horizontal branch (HB). By comparing RDs of the HB stars with stars of lower masses, we can exclude a mass loss greater than 0.09M during the red giant branch (RGB) stage at nearly the 3{\\sigma} level. The slightly higher mass estimates for the asymptotic giant branch (AGB) are consistent with the AGB having evolved from somewhat more massive stars. The AGB also exhibits evidence of contamination by more massive stars, possibly blue stragglers (BSS), going through the RGB phase. We do not include the BSS in this paper due to the complexity of these objects, instead, the complete analysis of this population is left for a companion paper. The process to estimate the masses described in this paper are exclusive to the core of 47 Tuc. | 161,778 |
title: Discovery of HE 1523–0901, a Strongly r-Process-enhanced Metal-poor Star with Detected Uranium*; abstract: We present age estimates for the newly discovered, very r-process-enhanced metal-poor star HE 1523-0901 ([Fe/H] = -2.95) based on the radioactive decay of Th and U. The bright (V = 11.1) giant was found among a sample of bright metal-poor stars selected from the Hamburg/ESO Survey. From an abundance analysis of a high-resolution (R = 75,000) VLT/UVES spectrum, we find HE 1523-0901 to be strongly overabundant in r-process elements ([r/Fe] = 1.8). The abundances of heavy neutron-capture elements (Z \u003e 56) measured in HE 1523-0901 match the scaled solar r-process pattern extremely well. We detect the strongest optical U line at 3859.57 A. For the first time, we are able to employ several different chronometers, such as the U/Th, U/Ir, Th/Eu, and Th/Os ratios to measure the age of a star. The weighted average age of HE 1523-0901 is 13.2 Gyr. Several sources of uncertainties are assessed in detail. | 161,779 |
title: UBVR POLARIMETRY OF EVOLVED CARBON STARS NEAR THE GALACTIC EQUATOR; abstract: We present polarimetry and photometry in the UBVR bands of nine low Galactic latitude carbon stars (| b II | ≤ 15°) over a period of one year: V384 Per, ST Cam, S Aur, CL Mon, HV Cas, Y Tau, TT Cyg, U Cyg, and V1426 Cyg. We have corrected the observed values for the effects of extinction and polarization by the interstellar medium to obtain the intrinsic polarization and photometry of the stars. All the observed objects present polarization in at least two bands. There is a statistical correlation between the temporal mean polarization p at each filter band and the IR color K – [12] with the redder stars tending to be more polarized. A related trend is found between polarization and mass-loss rate in gas. The degree of polarization increases with the mass-loss rate at around . We found two stars—TT Cyg and ST Cam—that increase polarization with decreasing mass-loss rate below this value. Multiple observations of TT Cyg, U Cyg, and V1426 Cyg during the campaign show no correlation between polarization and luminosity in any of the UBVR bands. Therefore, the distribution of the scatterers shall vary with time in a very irregular way. | 161,780 |
title: Infrared problems in quantum electrodynamics; abstract: We present a self-contained treatment of the infrared problem in Quantum Electrodynamics. Our program includes a derivation and proof of finiteness of modified reduction formulae for scattering in Coulomb potentials and unitary extensions of the relativistic Coulomb amplitudes in the forward direction. The renormalization structure of the theory is discussed in connection with the infrared problem and the renormalization group is reconsidered and shown to be inadequate for the “improvement” of perturbation theoretic results. However, simple forms of the renormalization group equations are easily established, which allow for a simple discussion of the renormalization structure and the extraction of physical quantities out of Green functions normalized at an arbitrary mass μ \u003c m (m is the fermion mass). As an example of such a quantity we consider the construction of a renormalized and infrared finite mass-operator in presence of external fields. Scattering theory in Quantum Electrodynamics is elaborated in the context of the coherent state formulation of the asymptotic condition. Dimensional regularization techniques are systematically used for the reduction of coherent states and the construction of S-matrix elements and the cross-section formulae. The latter are obtained in a relatively simple form, which allows for a direct comparison with the exact cross-section formulae derived in the traditional context. This establishes the equivalence of the two approaches at the cross-section level. Various applications illustrate the techniques presented here and relative topics are discussed. | 161,781 |
title: Neutrino and axion emissivities of neutron stars from nucleon–nucleon scattering data; abstract: Abstract Neutrino and axion production in neutron stars occurs mainly as bremsstrahlung from nucleon–nucleon (NN) scattering. The energy radiated via neutrinos or axions is typically very small compared to other scales in the two-nucleon system. The rate of emission of such “soft” radiation is directly related to the on-shell NN amplitude, and thereby to the NN experimental data. This facilitates the model-independent calculation of the neutrino and axion radiation rates which is presented here. We find that the resultant rates are roughly a factor of four below earlier estimates based on a one-pion-exchange NN amplitude. | 161,782 |
title: An Emergent Change of Phase for Electronics; abstract: Correlated electrons in transition metal oxides can form a variety of electronic phases. The phase change between these various states gives rise to novel device functions, including sensing, signal conversion, and nonvolatile memory, and is now at the frontier of research on \"emergent research device materials.\" Those oxide devices may have an advantage over conventional semiconductor devices for added functionality and future downsizing to the nanoscale. The elucidation of the microscopic physics behind their operation is a key step for further development. | 161,783 |
title: A comprehensive simulation of weak-light phase-locking for space-borne gravitational wave antenna; abstract: A comprehensive simulation was performed to better understand the impacts and effects of the additional technical noises on weak-light phase-locking for LISA. The result showed that the phase of the slave laser tracked well with the received transmitting light under different noise level, and the locking precision was limited by the phase readout noise when the laser frequency noise and clock jitter noise were removed. This result was then confirmed by a benchtop experimental test. The required LISA noise floor was recovered from the simulation which proved the validity of the simulation program. In order to convert the noise function into real time data with random characteristics, an algorism based on Fourier transform was also invented. | 161,784 |
title: Annular flow of viscoelastic fluids: Analytical and numerical solutions; abstract: This work provides analytical and numerical solutions for the linear, quadratic and exponential Phan–Thien–Tanner (PTT) viscoelastic models, for axial and helical annular fully-developed flows under no slip and slip boundary conditions, the latter given by the linear and nonlinear Navier slip laws. The rheology of the three PTT model functions is discussed together with the influence of the slip velocity upon the flow velocity and stress fields. For the linear PTT model, full analytical solutions for the inverse problem (unknown velocity) are devised for the linear Navier slip law and two different slip exponents. For the linear PTT model with other values of the slip exponent and for the quadratic PTT model, the polynomial equation for the radial location (b) of the null shear stress must be solved numerically. For both models, the solution of the direct problem is given by an iterative procedure involving three nonlinear equations, one for b, other for the pressure gradient and another for the torque per unit length. For the exponential PTT model we devise a numerical procedure that can easily compute the numerical solution of the pure axial flow problem. | 161,785 |
title: TASISpec—A highly efficient multi-coincidence spectrometer for nuclear structure investigations of the heaviest nuclei; abstract: TASISpec (TASCA in Small Image mode Spectroscopy) combines composite Ge- and Si-detectors for a new detector setup aimed towards multi-coincidence gamma -ray, X-ray, conversion electron, fission fragment, and a-particle spectroscopy of the heaviest nuclei. It exploits the TASCA separator\u0027s unique small image focal mode, i.e. the fact that evaporation residues produced in fusion-evaporation reactions can be focused into an area of less than 3 cm in diameter. This provides the possibility to pack detectors in very close geometry, resulting in an unprecedented detection efficiency of radioactive decays in prompt and delayed coincidence with implanted nuclei. Crown Copyright (C) 2010 Published by Elsevier B.V. All rights reserved. | 161,786 |
title: NLTE opacity calculations: C-Si and C-Ge mixtures; abstract: Abstract The opacity is an important issue in the knowledge of the radiative properties of ICF and astrophysical plasmas. We present the opacity of dopants (silicon, germanium) embedded in the ablator of some ICF capsules. In recent works, Hill and Rose calculated the opacity of silicon in LTE and non-LTE plasmas, while Minguez and co-workers focused on the opacity of carbon. We have used the Cowan code to calculate the atomic structure of carbon, silicon and germanium in various ionic stages. The cross-sections of atomic processes (collisional excitation, collisional ionization) are obtained by fitting the values given by the code FAC to the Van Regemorter-like formulas of Sampson and Zhang. A corrected Gaunt factor is then obtained. A collisional-radiative code was developed in order to obtain the ionic populations, the level populations and the opacity. Line broadening and line shift are taken into account. The ionization potential depression is included in our calculations. The effect of a radiation field on the opacity is examined. | 161,787 |
title: To the origin of the difference of FSI phases in B→ππ and B→ρρ decays; abstract: Abstract The final state interactions (FSI) model in which soft rescattering of low mass intermediate states dominates is suggested. It explains why the strong interaction phases are large in the B d → π π channel and are considerably smaller in the B d → ρ ρ one. Direct CP asymmetries of B d → π π decays which are determined by FSI phases are considered as well. | 161,788 |
title: Space Telescope and optical reverberation mapping project. V. Optical spectroscopic campaign and emission-line analysis for NGC 5548.; abstract: © 2017. The American Astronomical Society. All rights reserved.We present the results of an optical spectroscopic monitoring program targeting NGC 5548 as part of a larger multiwavelength reverberation mapping campaign. The campaign spanned 6 months and achieved an almost daily cadence with observations from five ground-based telescopes. The Hβ and He ii λ4686 broad emission-line light curves lag that of the 5100 +-optical continuum by 4.17+0.36-0.36 and 0.79+0.35-0.34 days, respectively. The Hβ lag relative to the 1158 ultraviolet continuum light curve measured by the Hubble Space Telescope is ∼50% longer than that measured against the optical continuum, and the lag difference is consistent with the observed lag between the optical and ultraviolet continua. This suggests that the characteristic radius of the broad-line region is ∼50% larger than the value inferred from optical data alone. We also measured velocity-resolved emission-line lags for Hβ and found a complex velocity-lag structure with shorter lags in the line wings, indicative of a broad-line region dominated by Keplerian motion. The responses of both the Hβ and He ii emission lines to the driving continuum changed significantly halfway through the campaign, a phenomenon also observed for C iv, Lyα, He ii(+O iii]), and Si iv(+O iv]) during the same monitoring period. Finally, given the optical luminosity of NGC 5548 during our campaign, the measured Hβ lag is a factor of five shorter than the expected value implied by the R BLR-L AGN relation based on the past behavior of NGC 5548. | 161,789 |
title: Spherical collapse in vacuum f ( R ) gravity; abstract: A constant curvature spherically symmetric vacuum collapse in f(R) gravity is investigated. It is found that even a vacuum collapse may lead to a future curvature singularity which may be covered by a horizon leading to a black hole depending on the initial profile of the geometry. | 161,790 |
title: A piezoelectric pseudo-bimorph actuator; abstract: We report a piezoelectric pseudo-bimorph actuator, which is made of only one single plate with interdigitated electrodes on both sides and polarized alternately in longitudinal direction. Like a bimorph actuator, it can also produce a large bending actuation based on anti-symmetrically longitudinal piezoelectric d33 strain effect under an applied electric field. The presented pseudo-bimorph actuator shows much better temperature stability than conventional piezoelectric bimorph actuators from room temperature to the depolarization temperature of the material due to lacking of interface strain loss. | 161,791 |
title: Photovoltaic effect of lead lanthanum zirconate titanate in a layered film structure design; abstract: This letter reports on the formation of a layered film structure and the highly improved photovoltaic output of the lead lanthanum zirconate titanate (PLZT) employed. The photovoltaic current of the PLZT film per unit width was more than 102 times larger than that of bulk PLZT, while the photovoltaic voltage per unit thickness in the layered film structure was almost the same as that in bulk ceramics. These differences are due to the characteristics of the film structure and configuration of the electrode. A simple model is used for the phenomenological explanation of the improved photovoltaic effect of the PLZT film. | 161,792 |
title: The GeV-scale dark matter with B–L asymmetry; abstract: Abstract One of important properties of dark matter is its stability. The U ( 1 ) B – L gauge symmetry is the most attractive symmetry to guarantee the stability. Though the symmetry is expected to be broken at very high energy scale to account for tiny neutrino masses through the seesaw mechanism, the residual discrete symmetry of U ( 1 ) B – L can stabilize the dark matter naturally. We prove that, when there is new physics connecting B–L charges of dark matter and standard model particles at the scale between the electroweak and the U ( 1 ) B – L breaking, the mass of dark matter is definitely predicted to be ( 5 – 7 ) / Q DM GeV ( Q DM is the B–L charge of dark matter) independent not only of details of the new physics but also of its energy scale. We also show two attractive examples. First one is the scalar dark matter with the B–L charge of one or two third, which turns out to be very consistent with current CoGeNT results. Another one is the fermionic dark matter having the B–L charge of one third, which is also attractive from the viewpoint of model building. | 161,793 |
title: BIMETRIC GRAVITY THEORY, VARYING SPEED OF LIGHT AND THE DIMMING OF SUPERNOVAE; abstract: In the bimetric scalar–tensor gravitational theory there are two frames associated with the two metrics ĝμν and gμν, which are linked by the gradients of a scalar field ϕ. The choice of a comoving frame for the metric ĝμν or gμν has fundamental physical consequences for local observers in either metric spacetimes, while maintaining diffeomorphism invariance. If the metric gμν is chosen to be associated with comoving coordinates, then the speed of light varies in the frame with the metric ĝμν. Observers in this frame see the dimming of supernovae because of the increase of luminosity distance versus red shift, due to an increasing speed of light in the past universe. Moreover, in this frame the scalar field ϕ describes a dark energy component in the Friedmann equation for the cosmic scale without acceleration. If we choose ĝμν to be associated with comoving coordinates, then an observer in the gμν metric frame will observe the universe to be accelerating and the supernovae will appear to be farther away. T... | 161,794 |
title: Regular ferroelectric domain array in lithium niobate crystals for nonlinear optic applications; abstract: Abstract We present our experimental investigations of the domain evolution in lithium niobate. Particular attention is paid to the short-pitch and nanoscale domain patterning. We demonstrate the production of domain patterns with period down to 2.6 μ.m in 0.5-mm-thick LiNbO3wafers by backswitched poling using lithographic stripe electrodes and nanoscale domain patterns consisting of strictly oriented arrays of nanodomains (diameter down to 30 nm, density up to 100 μm−2). | 161,795 |
title: Effects of convex transverse curvature on wall-bounded turbulence. Part 1. The velocity and vorticity; abstract: Convex transverse curvature effects in wall-bounded turbulent flows are significant if the boundary-layer thickness is large compared to the radius of curvature (large γ = δ/ a ). The curvature affects the inner part of the flow if a + , the cylinder radius in wall units, is small. Two direct numerical simulations of a model problem approximating axial flow boundary layers on long cylinders were performed for γ = 5 ( a + ≈ 43) and γ = 11 ( a + ≈ 21). Statistical and structural data were extracted from the computed flow fields. The effects of the transverse curvature were identified by comparing the present results with those of the plane channel simulation of Kim, Moin \u0026 Moser (1987), performed at a similar Reynolds number. As the curvature increases, the skin friction increases, the slope of the logarithmic region decreases and turbulence intensities are reduced. Several turbulence statistics are found to scale with a curvature dependent velocity scale derived from the mean momentum equation. Near the wall, the flow is more anisotropic than in the plane channel with a larger percentage of the turbulent kinetic energy resulting from the streamwise velocity fluctuations. As the curvature increases, regions of strong normal vorticity develop near the wall. | 161,796 |
title: Super hilltop inflation; abstract: In this paper, we consider logarithmic radiative corrections and higher order terms to the supersymmetric hilltop F- and D-term hybrid inflation models. Conventional F- and D-term hybrid inflation only predicts ns0.98. We show that via a positive quadratic and a negative quartic correction the spectral index can be reduced to ns = 0.96 suggested from latest WMAP result and also cosmic string problem appeared in SUSY hybrid inflation can be solved with mild tuning of the parameters if κ0.01 for F-term inflation and g0.05 for D-term inflation. | 161,797 |
title: b→s+γ and b→s+g in N=1 supergravity theories; abstract: Abstract We compite the b→s+γ and b→s+g decay rates in a spontaneous broken N=1 supergravity theory with radiative electroweak breaking. We find that the ARGUS result BR ( B 0 → K 0∗ + γ) −4 implies lower bounds on the masses of the gluinos and the lightest down squark which are in the same region as those provided by the direct (unsuccessful) searches of UA1. An improvement on the existing limit of BR (b→s+γ) by an order magnitude can certainly rule out values of squark and gluino masses which are still allowed by the UA1 bounds. | 161,798 |
title: High‐precision transit observations of the exoplanet WASP‐13b with the RISE instrument; abstract: WASP-13b is a sub-Jupiter mass exoplanet orbiting a G1V type star with a period of 4.35 d. The current uncertainty in its impact parameter (0 \u003c b \u003c 0.46) results in poorly defined stellar and planetary radii. To better constrain the impact parameter, we have obtained high-precision transit observations with the rapid imager to search for exoplanets (RISE) instrument mounted on 2.0-m Liverpool Telescope. We present four new transits which are fitted with a Markov chain Monte Carlo routine to derive accurate system parameters. We found an orbital inclination of 85°.2 ± 0°.3 resulting in stellar and planetary radii of 1.56 ± 0.04 R⊙ and 1.39 ± 0.05RJup, respectively. This suggests that the host star has evolved off the main sequence and is in the hydrogen-shell-burning phase. We also discuss how the limb darkening affects the derived system parameters. With a density of 0.17ρJ, WASP-13b joins the group of low-density planets whose radii are too large to be explained by standard irradiation models. We derive a new ephemeris for the system, T0= 245 5575.5136 ± 0.0016 (HJD) and P= 4.353 011 ± 0.000 013 d. The planet equilibrium temperature (Tequ= 1500 K) and the bright host star (V= 10.4 mag) make it a good candidate for follow-up atmospheric studies. | 161,799 |
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