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title: High-order regularization in lattice-Boltzmann equations; abstract: A lattice-Boltzmann equation (LBE) is the discrete counterpart of a continuous kinetic model. It can be derived using a Hermite polynomial expansion for the velocity distribution function. Since LBEs are characterized by discrete, finite representations of the microscopic velocity space, the expansion must be truncated and the appropriate order of truncation depends on the hydrodynamic problem under investigation. Here we consider a particular truncation where the non-equilibrium distribution is expanded on a par with the equilibrium distribution, except that the diffusive parts of high-order non-equilibrium moments are filtered, i.e., only the corresponding advective parts are retained after a given rank. The decomposition of moments into diffusive and advective parts is based directly on analytical relations between Hermite polynomial tensors. The resulting, refined regularization procedure leads to recurrence relations where high-order non-equilibrium moments are expressed in terms of low-order ones. T... | 161,500 |
title: Optical limits of the Glauber approximation for nucleus-nucleus collisions☆; abstract: Abstract We derived a modification of an expression obtained previously for nucleus-nucleus scattering using the Glauber approximation, which considers certain collision processes originally assumed negligible. Our results cast doubt on the validity of previous applications of the optical limit of the Glauber approximation to collisions between finite nuclei. | 161,501 |
title: Double Pass Linear Accelerator - Reflexotron; abstract: Measurements of energy spectra and percentage beam transmissions are given for an S-band linear accelerator through which the electron beam passes twice, in opposite directions. Results are presented for two magnet reflecting systems which have energy acceptance windows, ?E/E, of 2% and 16% where E is the output beam energy after the first pass through the accelerator. For a first pass beam energy of 8 MeV the second pass energy could be varied from 3 MeV to 16 MeV by changing the separation between the accelerator and the magnet system. The corresponding full-width half-maximum energy spreads were 1.6 MeV and 0.7 MeV respectively. The system transmission was 35% first pass (unbunched injected beam) and ~ 100% second pass. | 161,502 |
title: The cold dark matter model with cosmological constant and the flatness constraint; abstract: The Hubble parameter, a function of the cosmological redshift, is derived from the Friedmann-Robertson-Walker equation. The three physical parameters H0, Ω0m and ΩΛ are determined fitting the Hubble parameter to the data from measurements of redshift and luminosity distances of type-Ia supernovae. The best fit is not consistent with the flatness constraint (k = 0). On the other hand, the flatness constraint is imposed on the Hubble parameter and the physical parameters used are the published values of the standard model of cosmology. The result is shown to be inconsistent with the data from type-Ia supernovae. | 161,503 |
title: Emissions from high-density potassium atoms excited by either nanosecond or femtosecond laser pulses; abstract: A study of the emissions, for high atomic density potassium, under nanosecond (ns) or femtosecond (fs) two-photon excitation is presented. It is shown that the parametric emissions (connected to the |6S1/2〉↔|5P3/2〉↔|4S1/2〉 transitions) strongly depend on the excitation intensity and they have a nonlinear and a linear response region, in both kinds of excitation. In the ns excitation, the calculated results of a four-level atomic configuration agree well with the experimental ones, in the case of the path-1 parametric emissions (|6S1/2〉↔|5P3/2〉↔|4S1/2〉) for certain excitation and atomic density parameters. Also, the fields of the atomic path-2 (|6S1/2〉↔|4P3/2〉↔|4S1/2〉) are numerically shown to be amplified spontaneous emission (ASE) or cascade ASE without population inversion, due to the population transfer to the |6S1/2〉 level initially and its subsequent collapse to the lower levels. In the fs excitation, only parametric emissions are observed from both atomic paths and there are not yet numerical calculations available to compare with. However, there is strong similarity of the experimental ns and fs results for the path-1 parametric emissions. | 161,504 |
title: AstroSat view of MAXI J1535−571: broad-band spectro-temporal features; abstract: We present the results of Target of Opportunity (ToO) observations made with AstroSat of the newly discovered black hole binary MAXI J1535-571. We detect prominent C-type quasi-periodic oscillation ... | 161,505 |
title: Element-resolved thermodynamics of magnetocaloric LaFe(13-x)Si(x).; abstract: By combination of two independent approaches, nuclear resonant inelastic x-ray scattering and first-principles calculations in the framework of density functional theory, we demonstrate significant changes in the element-resolved vibrational density of states across the first-order transition from the ferromagnetic low temperature to the paramagnetic high temperature phase of LaFe13-xSix. These changes originate from the itinerant electron metamagnetism associated with Fe and lead to a pronounced magneto-elastic softening despite the large volume decrease at the transition. As a result, the increase in lattice entropy associated with the Fe subsystem is significant and contributes cooperatively with the magnetic and electronic entropy changes to the excellent magneto- and barocaloric properties. | 161,506 |
title: Improved limits on scattering of weakly interacting massive particles from reanalysis of 2013 LUX data; abstract: We present constraints on weakly interacting massive particles (WIMP)-nucleus scattering from the 2013 data of the Large Underground Xenon dark matter experiment, including 1.4×10^{4} kg day of search exposure. This new analysis incorporates several advances: single-photon calibration at the scintillation wavelength, improved event-reconstruction algorithms, a revised background model including events originating on the detector walls in an enlarged fiducial volume, and new calibrations from decays of an injected tritium β source and from kinematically constrained nuclear recoils down to 1.1 keV. Sensitivity, especially to low-mass WIMPs, is enhanced compared to our previous results which modeled the signal only above a 3 keV minimum energy. Under standard dark matter halo assumptions and in the mass range above 4 GeV c^{-2}, these new results give the most stringent direct limits on the spin-independent WIMP-nucleon cross section. The 90% C.L. upper limit has a minimum of 0.6 zb at 33 GeV c^{-2} WIMP mass. | 161,507 |
title: ΛCDM-based Models for the Milky Way and M31. I. Dynamical Models; abstract: We apply standard disk formation theory with adiabatic contraction within cuspy halo models predicted by the standard cold dark matter (?CDM) cosmology. The resulting models are confronted with the broad range of observational data available for the Milky Way and M31 galaxies. We find that there is a narrow range of parameters that can satisfy the observational constraints, but within this range, the models score remarkably well. Our favored models have virial masses of 1012 and 1.6 ? 1012 M? for the Galaxy and for M31, respectively, average spin parameters ? ? 0.03-0.05, and concentrations Cvir = 10-17, typical for halos of this mass in the standard ?CDM cosmology. The models require neither dark matter modifications nor flat cores to fit the observational data. We explore two types of models, with and without the exchange of angular momentum between the dark matter and the baryons. The models without exchange give reasonable rotation curves, fulfill constraints in the solar neighborhood, and satisfy constraints at larger radii, but they may be problematic for fast rotating central bars. We explore models in which the baryons experience additional contraction due to loss of angular momentum to the surrounding dark matter. These models produce similar global properties, but the dark matter is only a 25% of the total mass in the central 3 kpc region, allowing a fast rotating bar to persist. According to preliminary calculations, our model galaxies probably have sufficient baryonic mass in the central ~3.5 kpc to reproduce recent observational values of the optical depth to microlensing events toward the Galactic center. Our dynamical models unequivocally require that about 50% of all the gas inside the virial radius must not be in the disk or in the bulge, a result that is obtained naturally in standard semianalytic models. Assuming that the Milky Way is typical, we investigate whether the range of virial masses allowed by our dynamical models is compatible with constraints from the galaxy luminosity function. We find that if the Milky Way has a luminosity MK = -24.0, then these constraints are satisfied, but if it is more luminous (as expected if it lies on the Tully-Fisher relation), then the predicted space density is larger than the observed space density of galaxies of the corresponding luminosity by a factor of 1.5-2. We conclude that observed rotation curves and dynamical properties of normal spiral galaxies appear to be consistent with standard ?CDM. | 161,508 |
title: A Warp in the Large Magellanic Cloud Disk; abstract: We present a study of the shape of the Large Magellanic Cloud (LMC) disk. We use the brightnesses of core helium burning red clump stars identified in V-I, I color-magnitude diagrams of 50 randomly selected LMC fields observed with the Cerro Tololo Inter-American Observatory 0.9 m telescope to measure relative distances to the fields. Random photometric errors and errors in the calibration are controlled to 1%. Following correction for reddening measured through the color of the red clump, we solve for the inclination and position angle of the line of nodes of the tilted plane of the LMC, finding i = 358 ± 24 and θ = 145° ± 4°. Our solution requires that we exclude 15 fields in the southwest of the LMC that have red clump magnitudes ~0.1 mag brighter than the fitted plane. On the basis of these fields, we argue that the LMC disk is warped and twisted, containing features that extend up to 2.5 kpc out of the plane. We argue that alternative ways of producing red clump stars brighter than expected, such as variations in age and metallicity of the stars, are unlikely to explain our observations. | 161,509 |
title: Electrohydrodynamics in leaky dielectric fluids using lattice Boltzmann method; abstract: Abstract The application of an electric field on a multi-component leaky dielectric fluid system leads to an electric stress at the fluid–fluid interface. To capture the effect of these electric stresses, we report a new method to couple the electrostatics and hydrodynamics of leaky dielectric fluids within the framework of the lattice Boltzmann method. The developed methodology relies on obtaining time invariant solution to the equation governing the divergence of current density in the flow domain using a time marching lattice Boltzmann equation or through a finite-difference formulation. The coupling between the low spurious velocity hydrodynamics model and the leaky dielectric counterpart is also illustrated through the use of three case studies involving interaction of single or multiple droplets suspended in an outer fluid under the action of an external electric field. The results obtained from the developed methodology are shown to be in excellent agreement with earlier published analytical and numerical results. Further, the numerical experiments demonstrate that the developed methodology is applicable for both steady- and time-dependent flows. | 161,510 |
title: Excitation of high-spin unnatural parity states in 208Pb from the (p, p′) reaction at 135 MeV; abstract: Abstract Differential cross sections for the excitation of states at 6.42, 6.73 and 7.04 MeV in 208 Pb by 135 MeV protons are reported. Both the excitation energies and the backward peaked angular distributions observed in this experiment and in a recent (e, e′) experiment strongly suggest that these states are predominantly one-particle-one-hole excitations with J π = 12 − , 14 − and 12 − , respectively. The present (p, p′) data are interpreted using a distorted wave impluse approximation and the effect of configuration mixing between the two 12 − states is investigated. | 161,511 |
title: Optical-model analysis of exotic atom data: (II). Antiprotonic and sigma atoms; abstract: Abstract Data for antiprotonic and sigma atoms are fitted using a simple optical model with a potential proportional to the nuclear density. The potential strength can be related to the free hadron-nucleon scattering length using a model due to Deloff. A good overall representation of the data is also obtained with a black-sphere model. | 161,512 |
title: Elastic scattering and charge exchange reaction with light neutron rich exotic beams; abstract: Abstract The elastic scattering of 6 He, 10,11 Be secondary beams on a (CH 2 ) 3 target and the charge exchange reaction p( 6 He, 6 Li)n have been measured. A microscopic optical potential was used to reproduce the proton-nucleus elastic scattering data. No clear signature of a halo structure was found in the present data for the elastic scattering and charge exchange reaction, due to the lack of large angle measurement. | 161,513 |
title: Cosmological bounds on the field content of asymptotically safe gravity-matter models; abstract: Abstract We use the non-Gaussian fixed points (NGFPs) appearing in the renormalization group flow of gravity and gravity–matter systems to construct models of NGFP-driven inflation via a renormalization group improvement scheme. The cosmological predictions of these models depend sensitively on the characteristic properties of the NGFPs, including their position and stability coefficients, which in turn are determined by the field content of the underlying matter sector. We demonstrate that the NGFPs appearing in gravity–matter systems where the matter content is close to the one of the standard model of particle physics are the ones compatible with cosmological data. Somewhat counterintuitively, the negative fixed point value of the dimensionless cosmological constant is essential for these findings. | 161,514 |
title: Muon Physics: A Pillar of the Standard Model; abstract: Since its discovery in the 1930s, the muon has played an important role in our quest to understand the sub-atomic theory of matter. The muon was the first second-generation standard-model particle to be discovered, and its decay has provided information on the ( Vector – Axial Vector ) structure of the weak interaction, the strength of the weak interaction, G F , and the conservation of lepton number (flavor) in muon decay. The muon\u0027s anomalous magnetic moment has played an important role in restricting theories of physics beyond the standard standard model, where at present there is a 3.4σ difference between the experiment and standard-model theory. Its capture on the atomic nucleus has provided valuable information on the modification of the weak current by the strong interaction which is complementary to that obtained from nuclear β decay. | 161,515 |
title: Effect of the magnetic field at the inner core boundary on the flow in the Earth's core; abstract: Abstract In the problem of Geodynamo, boundary conditions for the `inviscid\u0027 problem were obtained on the basis of solutions in the boundary layers. Using these boundary conditions, the hydrodynamic part of the problem in the axisymmetric case was solved analytically. On this basis, a computer code has been created free of the need to resolve boundary layers that sharply increases the rate of computational process. Computer simulations with this code confirmed the conclusion of Hollerbach [Hollerbach, R., 1994. Magnetohydrodynamic Ekman and Stewartson layers in a rotating spherical shell. Proc. R. Soc. London, Ser. A, 444 (1994) pp. 333–346.] (obtained by a different approach) that sufficiently strong magnetic fields suppress the discontinuity on the Stewartson cylinder circumscribing the inner core of the Earth and parallel to the axis of the rotation. The boundary conditions for magnetic field show that a concentrated generation of the toroidal field can occur in the boundary layer. Such a concentrated generation seems to take place in the Glatzmaier and Roberts numerical solution [Glatzmaier G.A., Roberts, P.H., 1995. A three-dimension convective dynamo solution with rotating and finitely conducting inner core and mantle. Phys. Earth Planet. Inter. 91 (1995) pp. 63–76.]. | 161,516 |
title: Phase states for a three-level atom interacting with quantum fields; abstract: We introduce phase operators associated with the algebra su(3), which is the appropriate tool to describe three-level systems. The rather unusual properties of this phase are caused by the small dimension of the system and are explored in detail. When a three-level atom interacts with a quantum field in a cavity, a polynomial deformation of this algebra emerges in a natural way. We also introduce a polar decomposition of the atom-field relative amplitudes that leads to a Hermitian relative-phase operator, whose eigenstates correctly describe the corresponding phase properties. We claim that this is the natural variable to deal with quantum interference effects in atom-field interactions. We find the probability distribution for this variable and study its time evolution in some special cases. | 161,517 |
title: The calculation of thermophysical properties of nickel plasma; abstract: The thermophysical properties of Nickel plasma have been calculated for the temperatures 10–60 kK and densities less than 1 g/cm3. These properties are the pressure, internal energy, heat capacity, and the electronic transport coefficients (electrical conductivity, thermal conductivity, and thermal power). The thermodynamic values have been calculated by means of the chemical model, which also allows one to obtain the ionic composition of considered plasma. The composition has been used to calculate the electronic transport coefficients within the relaxation time approximation. The results of the present investigation have been compared with the calculations of other researchers and available data of measurements. | 161,518 |
title: A POSSIBLE MAGNETAR NATURE FOR IGR J16358 4726; abstract: We present detailed spectral and timing analysis of the hard X-ray transient IGR J16358-4726 using multisatellite archival observations. A study of the source flux time history over 6 yr suggests that lower luminosity transient outbursts can be occurring in intervals of at most 1 yr. Joint spectral fits of the higher luminosity outburst using simultaneous Chandra ACIS and INTEGRAL ISGRI data reveal a spectrum well described by an absorbed power-law model with a high-energy cutoff plus an Fe line. We detected the 1.6 hr pulsations initially reported using Chandra ACIS also in the INTEGRAL ISGRI light curve and in subsequent XMM-Newton observations. Using the INTEGRAL data, we identified a spin-up of 94 s ( = 1.6 × 10-4), which strongly points to a neutron star nature for IGR J16358-4726. Assuming that the spin-up is due to disk accretion, we estimate that the source magnetic field ranges between 1013 and 1015 G, depending on its distance, possibly supporting a magnetar nature for IGR J16358-4726. | 161,519 |
title: Theoretical study on phase coexistence in ferroelectric solid solutions near the tricritical point; abstract: Phase coexistence in ferroelectric solid solutions near the tricritical point has been theoretically analyzed by using the Landau-Devonshire theory. Results revealed that different phases having similar potential wells could coexist in a narrow composition range near the tricritical point in the classical Pb(Zr1−xTix)O3 system. The potential barrier between potential wells increases with the decrease of temperature. Coexisting phases or different domains of the same phase can produce adaptive strains to maintain atomic coherency at the interfaces or domain walls. Such compatibility strains have influence on the energy potential as well as the stability of relative phases, leading to the appearance of energetically unfavorable monoclinic phases. Those competing and coexisting phases also construct an easy phase transition path with small energy barrier in between, so that very small stimuli can produce large response in compositions near the morphotropic phase boundary, especially near the tricritical point. | 161,520 |
title: Numerical investigation of a single-mode chemically reacting Richtmyer-Meshkov instability; abstract: We report on high-resolution, numerical simulations of a single-mode, chemically reacting, Richtmyer-Meshkov (RM) instability, at different interface thicknesses. The gases on either side of the diffuse interface were Hydrogen (H\\(_2)\\) and Oxygen (O\\(_2)\\), with a pre-shock Atwood number \\((A_t\\equiv \\frac{\\rho _{h}-\\rho _{l}}{\\rho _{h}+\\rho _{l} })\\) of \\(\\sim \\) 0.5. An incident shock with a Mach number of 1.2 is allowed to traverse from the light (H\\(_2)\\) to the heavy (O\\(_2)\\) medium in the 2D numerical shock tube. The simulations were performed using the astrophysical FLASH code developed at the University of Chicago, with extensive modifications implemented by the authors to describe detailed H\\(_2\\)–O\\(_2\\) chemistry, temperature-dependent specific heats, and multi-species equation of state. The interface thickness was systematically varied in the simulations to study the effect of the total mass of fuel burnt and heat added on the hydrodynamic instability growth rates. In the absence of an incident shock, burning results in the formation of so-called combustion waves, which spontaneously trigger RM and Rayleigh-Taylor like instability growth of the interface. We are able to obtain the resulting growth rates of an imposed sinusoidal perturbation, and compare them with the predictions of an impulsive model, with simple modifications to account for the finite thickness of the interface, density changes due to heat addition, and compression of the material line due to the combustion wave. When additionally an incident shock is present, we observe complex interactions between the shock and the aforementioned combustion waves, resulting in significant non-planar distortions of each. When the unstable interface is subjected to a reshock, significant mixing enhancement is observed, accompanied by a dramatic increase in combustion product formation, and combustion efficiency. | 161,521 |
title: Multiplicity of steady solutions in a two-sided lid-driven cavity with different aspect ratios; abstract: This study presents a continuation method to calculate flow bifurcation in a two-sided lid-driven cavity with different aspect ratios for anti-parallel motion. In anti-parallel motion, the top and bottom walls of the cavity move in opposite directions simultaneously, while the two walls both moving to the right give parallel motion at the same speed. Comprehensive bifurcation diagrams of the cavity flows with different aspect ratios of the cavities are derived via Keller’s continuation method, and linear- stability analysis is used to identify the nature of the various flow solutions. The Reynolds number (1 ≤ Re ≤ 1,200) is used as the continuation parameter to trace the solution curves. In anti-parallel motion, the evolution of the bifurcation diagrams in cases with different aspect ratios (1 ≤ AR ≤ 2.5) is illustrated. Two stable symmetric flows and one stable asymmetric flow are identified, and the existent regions of the stable flows in the aspect ratios and Reynolds numbers are distinguished. The newly found asymmetric flow state can be obtained at a high aspect ratio and a low Reynolds number. | 161,522 |
title: Doppler tomography of the black hole binary A0620-00 and the origin of chromospheric emission in quiescent X-ray binaries; abstract: Doppler tomography of emission line profiles in low mass X-ray binaries allows us to disentangle the different emission sites and study the structure and variability of accretion disks. We present UVES high-resolution spectroscopic observations of the black hole binary A0620-00 at quiescence.These spectroscopic data constrain the orbital parameters Porb=0.32301405(1) d and K2=437.1+-2.0 km/s. These values, together with the mass ratio q=M2/M1=0.062+-0.010, imply a minimum mass for the compact object of M1(sin i)^3=3.15+-0.10 Msun, consistent with previous works.The H$\\alpha$ emission from the accretion disk is much weaker than in previous studies, possibly due to a decrease in disk activity. Doppler imaging of the H$\\alpha$ line shows for the first time a narrow component coming from the secondary star, with an observed equivalent width of 1.4+-0.3 Angstroms, perhaps associated to chromospheric activity. Subtracting a K-type template star and correcting for the veiling of the accretion disk yields to an equivalent width of 2.8+-0.3 Angstroms. A bright hot-spot is also detected at the position where the gas stream trajectory intercepts with the accretion disk. The H$\\alpha$ flux associated to the secondary star is too large to be powered by X-ray irradiation. It is comparable to those observed in RS CVn binaries with similar orbital periods and, therefore, is probably triggered by the rapid stellar rotation. | 161,523 |
title: On measuring CP violation in neutral B-meson decays at the Γ (4S) resonance; abstract: Abstract Within the standard model we carry out an analysis of CP -violating observables in neutral B -meson decays at the Γ (4S) resonance. Both time-dependent and time-integrated CP asymmetries are calculated, without special approximations, to meet various possible measurements at symmetric and asymmetric e + e − B factories. We show two ways to distinguish between direct and indirect CP -violating effects in the CP -eigenstate channels such as B d 0 B d 0 → π + π − and π 0 K S . Reliable knowledge of the Cabibbo-Kobayashi-Maskawa phase and angles can in principle be extracted from measurements of some non- CP -eigenstate channels, e.g. B d 0 B d 0 → D ± π ∓ and (−) D (∗)0 K S , even in the presence of significant final-state interactions. | 161,524 |
title: The shape and surface variation of 2 Pallas from the Hubble Space Telescope.; abstract: We obtained Hubble Space Telescope images of 2 Pallas in September 2007 that reveal distinct color and albedo variations across the surface of this large asteroid. Pallas\u0027s shape is an ellipsoid with radii of 291 (+/-9), 278 (+/-9), and 250 (+/-9) kilometers, implying a density of 2400 (+/-250) kilograms per cubic meter-a value consistent with a body that formed from water-rich material. Our observations are consistent with the presence of an impact feature, 240 (+/-25) kilometers in diameter, within Pallas\u0027s ultraviolet-dark terrain. Our observations imply that Pallas is an intact protoplanet that has undergone impact excavation and probable internal alteration. | 161,525 |
title: Alignment of the CMS silicon tracker during commissioning with cosmic rays; abstract: This is the Pre-print version of the Article. The official published version of the Paper can be accessed from the link below - Copyright @ 2010 IOP | 161,526 |
title: An advanced pulse stretcher for the acquisition of the "Fast" component of BaF/sub 2/ detectors signals; abstract: A fast gateless pulse stretcher has been developed for an easy acquisition of pulse-shape information of BaF/sub 2/ scintillator signals. Commonly, this information is obtained by the use of two QDCs with different integration windows. This technique becomes complex and rather inconvenient when signals need to be delayed. The developed circuit uses a fast-stretcher technique to generate pulse-shape information, which requires no delay lines or gate signals. The outputs consist of two Gaussian signals whose amplitudes are proportional to the height of the BaF/sub 2/ fast component and to the total energy deposited into the scintillator. These outputs are easily acquired with a standard peak ADC with no gate-timing problems. An excellent Fast-Slow separation has been obtained even with small input signals of only few millivolts. This technology is general purpose and can be used with any other scintillator whose light emission is characterized by two components with different lifetimes. | 161,527 |
title: Renormalization scheme and gauge (in)dependence of the generalized Crewther relation: what are the real grounds of the $\beta$-factorization property?; abstract: The scheme and gauge dependence of the factorization property of the RG $\\beta$-function in the $SU(N_c)$ QCD generalized Crewther relation (GCR), which connects the non-singlet contributions to the Adler and Bjorken polarized sum rule functions, is investigated at the $\\mathcal{O}(a^4_s)$ level. In the gauge-invariant $\\rm{\\overline{MS}}$-scheme this property holds at least at this order. To study whether this property is true in all gauge-invariant schemes, we consider the $\\rm{MS}$-like schemes in QCD and the QED-limit of the GCR in the $\\rm{\\overline{MS}}$-scheme and in the $\\rm{MOM}$ and the $\\rm{OS}$ schemes. In these schemes we confirm the existence of the $\\beta$-function factorization in the QCD and QED variants of the GCR. The problem of the possible $\\beta$-factorization in the gauge-dependent renormalization schemes in QCD is studied. We consider the gauge non-invariant $\\rm{mMOM}$ and $\\rm{MOMgggg}$-schemes and demonstrate that in the $\\rm{mMOM}$ scheme at the $\\mathcal{O}(a^3_s)$ level the $\\beta$-factorization is valid for three values of the gauge parameter $\\xi$ only, namely for $\\xi=-3, -1$ and $\\xi=0$. In the $\\mathcal{O}(a^4_s)$ order of PT it remains valid only for case of the Landau gauge $\\xi=0$. \r\nThe consideration of these two schemes for the QCD GCR allows us to conclude that the factorization of RG $\\beta$-function will always be implemented in any $\\rm{MOM}$-like schemes with linear covariant gauge at $\\xi=0$ and $\\xi=-3$ at the $\\mathcal{O}(a^3_s)$ level. It is demonstrated that if factorization property for the $\\rm{MS}$-like schemes is true in all orders of PT, as theoretically indicated, then the factorization will also occur in the arbitrary $\\rm{MOM}$-like scheme in the Landau gauge in all orders of PT as well. | 161,528 |
title: Improved limit on quantum-spacetime modifications of Lorentz symmetry from observations of gamma-ray blazars; abstract: In the quantum-gravity literature there has been interest in the possibility that quantum properties of spacetime might affect the energy/momentum dispersion relation. The most used test theory for data analysis is based on a modification of the laws of propagation proposed in astro-ph/9712103 [Nature and the present best limit on the quantum-gravity scale was obtained in gr-qc/9810044 [Phys.Rev.Lett.83,2108]. I derive an improved limit using recent experimental information on absorption by the infrared diffuse extragalactic background of $\\gamma$-rays emitted by blazars. Foreseeable more accurate determinations of the absorption levels could achieve Planck-scale sensitivity. As a corollary I also show that, contrary to the recent claim of astro-ph/0208507v3, the test theory here considered does not allow decays of photons into electron-positron pairs, and I expose the limitations of phenomenological proposals, such as the one reported in astro-ph/0212190, in which one attempts to infer limits on the kinematic theory here considered through the ad hoc introduction of a dynamical framework. | 161,529 |
title: Discovery of CO absorption at z=0.05 in G0248+430; abstract: Absorption lines in front of distant quasars are quite rare in the millimeter domain. They can however bring a very useful and complementary information to emission lines. \r\nWe report here the detection with NOEMA of CO(1-0) and CN(1-0) lines in absorption, and confirmation of CO emission in the quasar/galaxy pair Q0248+430/G0248+430. The system G0248+430 corresponds to two merging galaxies (a Seyfert and a LINER) at z=0.0519 with a tidal tail just on the line of sight to the background quasar Q0248+430 at z = 1.313. \r\nOptical (CaII, NaI), HI-21cm and OH-1667 MHz absorption lines associated with the tidal tail of the foreground system have previously been detected toward the quasar, while four CO lines at different rotation J levels have been detected in emission from the foreground galaxies. \r\nNew HI 21-cm line observations with the upgraded GMRT array are presented. \r\nWe discuss the molecular content of the merging galaxies, and the physical conditions in the absorbing interstellar medium of the tidal tail. | 161,530 |
title: Silicon Photomultipliers as a Readout System for a Scintillator-Lead Shashlik Calorimeter; abstract: Silicon photomultipliers are silicon devices that in recent times have been proposed as candidates for the replacement of photomultiplier tubes in many experimental situations. In this article we describe the performance of SiPMs as a readout system of a shashlik calorimeter composed of 41 8×8 cm2, 3.27-mm-thick tiles of scintillator and 40 8×8 cm2, 3.27-mm-thick tiles of lead, for a total of ~24 radiation lengths; the light is collected by 64 0.8-mm wave-length-shifter (WLS) fibers grouped in bundles of four for, a total of 16 channels. The SiPMs are manufactured by FBK-irst and have a sensitive area of 1 mm2. The calorimeter has been tested at CERN using both a low (PS T10 beamline) and high (SPS H4 beamline) energy beam during the summer 2009 data taking. | 161,531 |
title: The Invariant Theory of Isotropic Turbulence in Magneto-Hydrodynamics; abstract: In this paper the invariant theory of isotropic turbulence in magneto-hydrodynamics is developed on the basis of the equations of motion recently derived by Batchelor to describe the hydrodynamics of an incompressible fluid which is also a good electrical conductor. The theory allows for the interaction between the electromagnetic field and the turbulent motion when there is no externally imposed electric or magnetic field. Various double and triple correlation tensors involving the components of the velocity and the magnetic field intensity are defined, and three equations governing the scalars defining these tensors are derived; these latter equations admit integrals of Loitsiansky\u0027s type. The equations governing the dissipation of energy by viscosity and conductivity are also derived; they exhibit the manner in which energy is exchanged between the velocity and the magnetic fields. Finally, the equations appropriate for the case, when an external agency supplies kinetic energy to the system at a constant rate and a stationary condition prevails, are obtained; they suggest that the energy in the magnetic field is contained, principally, in the eddies with large wave numbers. | 161,532 |
title: Enhanced multiferroic properties of single-phase BiFeO3 bulk ceramics by Ho doping; abstract: Dense single-phase BiFeO3 and Bi0.9Ho0.1FeO3 ceramics were prepared by the solid-state reaction method. With Ho doping, the remnant polarization of BiFeO3 was enhanced and the switching characteristics improved at low electric fields. Ho doping increased the breakdown voltage with a reduction of the leakage current while mitigating the remnant polarization at high electric fields. These results can explain conflicting findings regarding the effects of rare-earth doping on remnant polarization. Bi0.9Ho0.1FeO3 exhibited peculiar double hysteresis looplike magnetization-magnetic field curves with a much enhanced remnant magnetization. These improved properties obtained by Ho doping demonstrate the possibility of enhancing the multiferroic applicability of BiFeO3. | 161,533 |
title: Perception of musical and lexical tones by Taiwanese-speaking musicians; abstract: This study explored the relationship between music and speech by examining absolute pitch and lexical tone perception. Taiwanese-speaking musicians were asked to identify musical tones without a reference pitch and multispeaker Taiwanese level tones without acoustic cues typically present for speaker normalization. The results showed that a high percentage of the participants (65% with an exact match required and 81% with one-semitone errors allowed) possessed absolute pitch, as measured by the musical tone identification task. A negative correlation was found between occurrence of absolute pitch and age of onset of musical training, suggesting that the acquisition of absolute pitch resembles the acquisition of speech. The participants were able to identify multispeaker Taiwanese level tones with above-chance accuracy, even though the acoustic cues typically present for speaker normalization were not available in the stimuli. No correlations were found between the performance in musical tone identification and the performance in Taiwanese tone identification. Potential reasons for the lack of association between the two tasks are discussed. | 161,534 |
title: Ultraviolet, X-Ray, and Optical Radiation from the Geminga Pulsar*; abstract: We observed the � -ray pulsar Geminga with the FUV-MAMA and NUV-MAMA detectors of the Space Telescope Imaging Spectrometer to measure Geminga’s spectrum and pulsations in the ultraviolet. The slope of the far-ultraviolet (FUV) spectrum is close to that of a Rayleigh-Jeans spectrum, suggesting that the FUV radiation is dominated by thermal emissionfromthe neutron star(NS) surface.ThemeasuredFUVflux,FFUV ¼ (3:7 � 0:2) ; 10 � 15 ergscm � 2 s � 1 inthe1155–17028band,correspondstoabrightnesstemperatureTRJ � (0:3–0:4)(d200/R13) 2 MK,dependingon the interstellarextinction(d ¼ 200d200 pcandR ¼ 13R13 kmarethedistanceandtheNSradius,respectively).Thesoft thermal component of Geminga’s X-ray spectrum measured with the XMM-Newton observatory corresponds to a temperature Ts ¼ 0:49 � 0:01 MK and radius Rs ¼ (12:9 � 1:0)d200 km. Contrary to other NSs detected in the UV-optical,forwhich theextrapolation ofthe X-ray thermalcomponentinto theopticalunderpredicts the observed flux of thermal radiation, the FUV spectrum of Geminga lies slightly below the extrapolation of the soft thermal component,which might beassociatedwith Geminga’s very low temperature.Surprisingly, thethermalFUVradiation is strongly pulsed, showing a narrow dip at a phase close to that of a broader minimum of the soft X-ray light curve. The strong pulsations might be attributed to partial occultations of the thermal UV radiation by regions of the magnetosphere filled with electron/positron plasma. In contrast to the FUV spectrum, the near-infrared (NIR) through near-ultraviolet (NUV) spectrum of Geminga is clearly nonthermal. It can be described by a power-law model, F� / � � � þ1 , with a photon index � ¼ 1:43 � 0:15, close to the slope � ¼ 1:56 � 0:24 of the hard X-ray (E \u003e 2:5 keV) magnetospheric component. The extrapolation of the X-ray magnetospheric spectrum into the optical is marginally consistent with (or perhaps lies slightly above) the observed NIR-optical-NUV spectrum. The NUV pulsations, however, do not show a clear correlation with the hard X-ray pulsations. Subject headingg pulsars: individual (Geminga) — stars: neutron — ultraviolet: stars | 161,535 |
title: On the microscopic foundation of dissipative particle dynamics; abstract: Mesoscopic-particle-based fluid models, such as dissipative particle dynamics, are usually assumed to be coarse-grained representations of an underlying microscopic fluid. A fundamental question is whether there exists a map from microscopic particles in these systems to the corresponding coarse-grained particles, such that the coarse-grained system has the same bulk and transport properties as the underlying system. In this letter, we investigate the coarse-graining of microscopic fluids using a Voronoi-type projection that has been suggested in several studies. The simulations show that the projection fails in defining coarse-grained particles that have a physically meaningful connection to the microscopic fluid. In particular, the Voronoi projection produces identical coarse-grained equilibrium properties when applied to systems with different microscopic interactions and different bulk properties. © EPLA, 2009 | 161,536 |
title: A Broadband Current Preamplifier Configuration for Obtaining Htgh Resolutton Energy and Time Information from Nuclear Radiation Detectors; abstract: A broadband current preamplifier was developed to complement nuclear spectroscopy systems requiring linear gating. The preamplifier stage configuration consists of an FET input, a broadband interstage current gain section, and a high-impedance feedback network. The preamplifier produces a noise line width comparable to charge-sensitive designs having similar parameters. Because of large bandwidths and low-noise performance, the preamplifier, connected directly to a fast leading-edge discriminator, generates very accurate timing data. A preamplifier consisting of three gain stages was built and subsequently tested with Ge(Li) detectors. This preamplifier had a current gain of 10,000, a rise time of 8 nsec with a 10 pF detector capacitance, and a 0-pF noise line width, using an RC-RC ungated filter, of 1.4 keV (fwhm Ge). With the preamplifier operating from a 10 cc Ge(Li) coaxial detector, timing experiments utilizing the 60Co gamma cascade indicated resolutions as low as 1.15 nsec fwhm. | 161,537 |
title: Vibrational excitation of polar molecules by electron impact. II. Direct and resonant excitation in H2O; abstract: For pt.I see ibid., vol.9, no.14, p.2521 (1976). Differential scattering experiments with the crossed-beam method have been performed to study vibrational excitation of H2O by electron impact for collision energies from threshold to 10 eV. Differential and integral cross sections for the excitation of the (100, 001) and 010 modes are given in absolute units. Two distinct resonance regions are observed which are superimposed on a background of direct excitation: strong and sharp threshold resonances and a broad resonance region centred around 6-8 eV. The broad enhancement of the cross sections around 6 eV is attributed to a very short-lived 2A1 state of H2O-. The threshold resonances are interpreted as quasi-bound states in the dipole field of H2O. They are expected to be of general importance in electron-polar-molecule interactions. | 161,538 |
title: Review of Conformally Flat Approximation for Binary Neutron Star Initial Conditions; abstract: The spatially conformally flat approximation (CFA) is a viable method to deduce initial conditions for the subsequent evolution of binary neutron stars employing the full Einstein equations. Here we review the status of the original formulation of the CFA for the general relativistic hydrodynamic initial conditions of binary neutron stars. We illustrate the stability of the conformally flat condition on the hydrodynamics by numerically evolving ~100 quasi-circular orbits. We illustrate the use of this approximation for orbiting neutron stars in the quasi-circular orbit approximation to demonstrate the equation of state dependence of these initial conditions and how they might affect the emergent gravitational wave frequency as the stars approach the innermost stable circular orbit. | 161,539 |
title: Cation distribution and magnetic characterization of the multiferroic cobalt manganese Co2MnO4 spinel doped with bismuth; abstract: Abstract The structural and magnetic properties of the cubic spinel oxide Co 2 MnO 4 ( Fd3m space group) doped with different concentrations of bismuth, were investigated by X-ray diffraction and SQUID magnetometry. The Bi 3+ ions entering into the Co III octahedral sites do not alter the effective moment, μ eff ∼8.2 μ B , whereas both the magnetization M 50 kOe at the highest field (50 kOe) and the field-cooled M FC magnetizations increased when increasing the Bi content. The ferrimagnetic character of the parent compound, Co 2 MnO 4 , is maintained for all materials although the antiferromagnetic interactions Co 2+ –Co 2+ are affected, resulting in higher values of the Curie–Weiss temperature. Due to the large ionic radius of Bi, octahedra distortions occur as well as valence fluctuations of the Mn ions, giving rise to Jahn-Teller effects and enhancing the exchange interactions. The off-center Bi 3+ ion is responsible of non-centrosymmetric charge ordering and should lead to multiferroisme conditions for the Bi x Co 2− x MnO 4 material. | 161,540 |
title: Subdwarf B stars from the common envelope ejection channel; abstract: From the canonical binary scenario, the majority of sdBs are produced from low-mass stars with degenerate cores where helium is ignited in a way of flashes. Due to numerical difficulties, the models of produced sdBs are generally constructed from more massive stars with non-degenerate cores, leaving several uncertainties on the exact characteristics of sdB stars. Employing MESA, we systematically studied the characteristics of sdBs produced from the common envelope (CE) ejection channel, and found that the sdB stars produced from the CE ejection channel appear to form two distinct groups on the effective temperature-gravity diagram. One group (the flash-mixing model) almost has no H-rich envelope and crows at the hottest temperature end of the extremely horizontal branch (EHB), while the other group has significant H-rich envelope and spreads over the whole canonical EHB region. The key factor for the dichotomy of the sdB properties is the development of convection during the first helium flash, which is determined by the interior structure of the star after the CE ejection. For a given initial stellar mass and a given core mass at the onset of the CE, if the CE ejection stops early, the star has a relatively massive H-rich envelope, resulting in a canonical sdB generally. The fact of only a few short-orbital-period sdB binaries being in the flash-mixing sdB region and the lack of He-rich sdBs in short-orbital-period binaries indicate that the flash mixing is not very often in the products of the CE ejection. A falling back process after the CE ejection, similar to that happened in nova, is an appropriate way of increasing the envelope mass, then prevents the flash mixing. | 161,541 |
title: Search for short strings in~$e^+e^-$-annihilation; abstract: In this work the behavior of power corrections to Adler finction in operator product expansion (OPE) is studied, in particular the possible contribution of operator of dimension 2. The OPE terms of dimension 4 and 6 are taken into account. Various experimental data on reactions of $e^+e^-$-annihilation to pion channels ($\\pi^+\\pi^-$, $2\\pi^+2\\pi^-$, $\\pi^+\\pi^-2\\pi^0$, $3\\pi^+3\\pi^-$, $2\\pi^+2\\pi^-2\\pi^0$) are used. The high-precision fits of the experimental data are obtained and used. The method based on Borel transform of Adler function is applied. It is shown that the contribution of operator of dimension 2 is negative being compatible to zero at three standard deviations level. The strong (anti)corellation between short string and local gluon condensate is found. | 161,542 |
title: Odd-even staggering of the nuclear binding energy described by covariant density functional theory with calculations for spherical nuclei; abstract: The odd-even staggerings (OESs) on nuclear binding energies are studied systematically within the spherical covariant density functional (CDF) theories, specifically the relativistic Hartree-Fock-Bogoliubov (RHFB) and the relativistic Hartree-Bogoliubov (RHB) theories. When taking the finite-range Gogny force D1S as an effective pairing interaction, both CDF models can provide appropriate descriptions on the OESs of nuclear binding energies for C, O, Ca, Ni, Zr, Sn, Ce, Gd, and Pb isotopes as well as for N = 50 and 82 isotones. While there still exist some systematical discrepancies from the data, i.e., the underestimated OESs in light C and O isotopes and the overestimated ones in heavy regions, respectively, such discrepancies can be eliminated partially by introducing a Z- or N-dependent strength factor into the pairing force Gogny D1S. As an example of application, distinct improvements are achieved with the optimized pairing force in determining the single-particle configurations of Sn-112,Sn-114,Sn-118,Sn-124. | 161,543 |
title: Determination of the spin-spin coupling constant of the HD isotopologue of hydrogen for the estimate of existence of nonelectromagnetic spin-dependent interaction; abstract: A new experimental value Jpd = 43.115(9) Hz of the spin-spin coupling constant in the HD isotopologue of hydrogen has been obtained. It does not coincide with the value Jpd = 43.31(5) Hz found theoretically by Helgaker et al. in the development of new methods of precise quantum-mechanical calculations at t ≈ 300 K. As was shown by Ledbetter et al., the difference between the experimental and theoretical data for the spinspin coupling constant Jpd in HD allows estimating the limits of existence of anomalous spin-dependent potentials between the nucleons on the atomic scale with orders-of-magnitude higher accuracy than other methods. From the earlier data on this difference (ΔJpd ≈ 0.24 Hz), Ledbetter et al. estimated the upper limit for the mass of pseudoscalar (axion-like) bosons as m a ≤ 1000 eV. By analogy with these estimates, the discrepancy ΔJpd ≈ (0.195 ± 0.051) Hz of the new results can be interpreted as the manifestation of the anomalous interaction. This interaction can be attributed to the exchange of axion-like particles with the mass m a ≈ (800 ± 200) eV. | 161,544 |
title: Measurements of W and Z boson production in association with jets in proton-proton collisions with the ATLAS detector; abstract: Abstract The latest measurements of the production of W or Z boson in association with jets by the ATLAS detector are reported. A data-set of proton-proton collisions corresponding to an integrated luminosity of approximately 4.6 fb -1 have been analysed, and new results of W boson + jet production, the ratio of W to Z boson + jet production, W boson + charm, and Z boson + b -jet production are described. Extensive comparisons from the latest theoretical calculations are also included. | 161,545 |
title: General circulation and transport in Saturn’s upper troposphere and stratosphere; abstract: Abstract We present a model for the general circulation and dynamical transport in Saturn’s upper troposphere and stratosphere and derive the effective advective circulation and eddy transport coefficients required for use in two-dimensional (latitude–altitude) photochemistry–transport models. A three-dimensional Outer-Planet General Circulation Model (OPGCM) is used to generate the transport data. We find that the OPGCM adequately captures the global-scale, pole-to pole temperature contrast, but overestimates mid- and high-latitude temperatures in the summer hemisphere by ∼5 K. In addition, the model reproduces the local temperature minimum seen at the equator in Cassini Composite Infrared Spectrometer (CIRS) 0.1-mbar data but not the local maximum in 1-mbar temperatures, suggesting that it is capturing the phase of Saturn’s Semiannual Oscillation associated with a temperature minimum at the equator but not the opposite phase. The meridional circulation at low latitudes is found to be dominated by a seasonally reversing Hadley circulation, characterized by upwelling near the equator, cross-equatorial flow from summer to winter hemisphere, and strong subsidence centered near 25° latitude in the winter hemisphere. The cross-equatorial flow induces an asymmetry in which the equatorial jet is found to be stronger in the winter than in the summer stratosphere. The location of the subsidence near 25°N for L s ∼ 310° coincides with local maxima in acetylene, diacetylene, and methylacetylene mixing ratios measured by Cassini/CIRS (Guerlet, S., Fouchet, T., Bezard, B., Moses, J.I., Fletcher, L.N., Simon-Miller, A.A., Flasar, F.M. [2010]. Icarus 209, 682–695). This result supports the suggestion by Guerlet et al. (2010) that the hydrocarbon abundances are enhanced at this latitude by pronounced downward transport of hydrocarbon-rich air from above. The lateral eddy diffusion coefficient is found to typically be ∼10 5 –10 6 m 2 s −1 at mid-latitudes, implying meridional eddy transport time scales of order 100–1000 years. | 161,546 |
title: Invariants and the pattern of quark masses and mixings; abstract: Abstract We suggest that the study of weak-basis invariants may play an important role in finding the essential features of the pattern of quark masses and mixings. In particular, we show that the most popular ansatze for the quark mass matrices can be translated into invariant conditions on those matrices. One of these invariant conditions is common to all the ansatze that we have analyzed. | 161,547 |
title: Effect of a magnetic field on the track structure of low-energy electrons: a Monte Carlo study; abstract: The increasing use of MRI-guided radiation therapy evokes the necessity to investigate the potential impact of a magnetic field on the biological effectiveness of therapeutic radiation beams. While it is known that a magnetic field, applied during irradiation, can improve the macroscopic absorbed dose distribution of electrons in the tumor region, effects on the microscopic distribution of energy depositions and ionizations have not yet been investigated. An effect on the number of ionizations in a DNA segment, which is related to initial DNA damage in form of complex strand breaks, could be beneficial in radiation therapy. In this work we studied the effects of a magnetic field on the pattern of ionizations at nanometric level by means of Monte Carlo simulations using the Geant4-DNA toolkit. The track structure of low-energy electrons in the presence of a uniform static magnetic field of strength up to 14 T was calculated for a simplified DNA segment model in form of a water cylinder. In the case that no magnetic field is applied, nanodosimetric results obtained with Geant4-DNA were compared with those from the PTB track structure code. The obtained results suggest that any potential enhancement of complexity of DNA strand breaks induced by irradiation in a magnetic field is not related to modifications of the low-energy secondary electrons track structure. | 161,548 |
title: X-ray Spectrum from a Plastic Window Tube; abstract: The X-ray spectrum from a plastic window tube operated at 150 KV and 15 mA has been determined by means of scintillation spectrometry. Corrections for background, block time, energy resolution and escape of Kx X-ray of iodine have been applied to the data. The peak intensity is obtained at 014 A (90 KeV). The characteristic X-rays of the tungsten target were not distinguishable from the bremsstrahlung continuum. | 161,549 |
title: On the Terminal Rotation Rates of Giant Planets; abstract: Within the general framework of core-nucleated accretion theory of giant planet formation, the conglomeration of massive gaseous envelopes is facilitated by a transient period of rapid accumulation of nebular material. While the concurrent buildup of angular momentum is expected to leave newly formed planets spinning at near-breakup velocities, Jupiter and Saturn, as well as super-Jovian long-period extrasolar planets, are observed to rotate well below criticality. In this work, we demonstrate that the large luminosity of a young giant planet simultaneously leads to the generation of a strong planetary magnetic field, as well as thermal ionization of the circumplanetary disk. The ensuing magnetic coupling between the planetary interior and the quasi-Keplerian motion of the disk results in efficient braking of planetary rotation, with hydrodynamic circulation of gas within the Hill sphere playing the key role of expelling spin angular momentum to the circumstellar nebula. Our results place early-stage giant planet and stellar rotation within the same evolutionary framework, and motivate further exploration of magnetohydrodynamic phenomena in the context of the final stages of giant planet formation. | 161,550 |
title: On the Internal Structure and Magnetic Fields of Venus; abstract: First, a sequence of four-zone models for the interior of Venus is constructed under the assumption of hydrostatic equilibrium. While the equation of state for each zone is taken to be the Bullen\u0027s relation with its coefficients consistent with the PREM Earth model (Dziewonski and Anderson, 1981), the position of core-mantle boundary is determined by matching solutions of the Emden\u0027s equation in different regions. The results of hydrostatic models indicate the presence of a reasonably large molten iron core in Venus, broadly similar to the Earth. It is also found that the position of the core-mantle interface is nearly model-independent. Second, we focus on the question why Venus does not possess a significant global magnetic field and on what we can learn from this fact. Solutions of magnetohydrodynamic equations appropriate for the molten core of Venus are discussed. It is argued that, because the Elsasser number Λ measuring the relative importance of Coriolis and Lorentz forces satisfies Λ ≪ 1, equations for the problem of thermal convection in the Venusian fluid core must be nearly uncoupled with the dynamo equation. The existence of a global magnetic field, though small, then suggests that the size of the magnetic Reynolds numberR\n\n m\n must beR\n\n m\n =O(10), sustaining a dynamo action near its marginal state but not an active dynamo in the Venusian molten core. On the basis of asymptotic relations for finite amplitude convection, a useful constraint on important physical parameters for the liquid core of Venus is derived and discussed. | 161,551 |
title: Terzan 5: a pristine fragment of the Bulge; abstract: We have discovered that Terzan 5, a stellar system in the Galactic Bulge, harbors two stellar populations with different iron content (Δ[Fe/H] ~ 0.5 dex) and possibly different ages. Moreover, the observed chemical patterns significantly differ from those observed in any known genuine globular cluster. These evidences demonstrate that, similarly to ω Centauri in the Halo, Terzan 5 is not a globular cluster, but a stellar system that was able to retain the gas ejected by violent supernova explosions. Moreover the striking chemical similarity with the Bulge stars suggests that Terzan 5 could be the relic of one of the massive clumps that contributed (through strong dynamical interactions with other pre-formed and internally-evolved sub-structures) to the formation of the Galactic Bulge. | 161,552 |
title: Effect of electrode configuration on psychophysical forward masking in cochlear implant listeners.; abstract: Bipolar stimulation has been thought to be more beneficial than monopolar stimulation for speech coding in cochlear implants, on the basis of its more restricted current flow. The present study examined whether bipolar stimulation would indeed lead to reduced channel interaction in a behavioral forward masking experiment tested in four Nucleus® 24 users. The masker was fixed on one channel and three masker levels that were balanced for loudness between the configurations were chosen. As expected, masking was maximal when the masker and probe channels were spatially close and decreased as they were separated. However, overall masking patterns did not consistently demonstrate sharper tuning with bipolar stimulation than monopolar. This implies that the spatial extent of a bipolar current field is not consistently narrower than that of an equally loud monopolar stimulus; therefore, it should not be assumed that bipolar stimulation leads to reduced channel interaction. Notably, bipolar masking patterns appeared to display more variations across channels, possibly influenced more by anatomical and neural irregularities near electrode contacts than monopolar masking patterns. The present psychophysical results provide a theoretical basis regarding the widespread use (and success) of monopolar configurations by implant users. | 161,553 |
title: Limit on a P- and T-Violating Electron-Nucleon Interaction; abstract: Experiment searching for atomic electric-dipole moments (EDM) can set limits on various P- and T-violating properties. In this work we describe calculations of sensitivities of caesium and thallium to a possible P- and T-violating scalar-pseudoscalar electron-nucleon interaction. Combination of our Tl result with the most recent experimental limit for the Tl EDM gives CS = (2 ± 7) 10-7, which is the lowest limit so far obtained for this interaction constant. | 161,554 |
title: Cognitive predictors of perceptual adaptation to accented speech.; abstract: The present study investigated the effects of inhibition, vocabulary knowledge, and working memory on perceptual adaptation to accented speech. One hundred young, normal-hearing adults listened to sentences spoken in a constructed, unfamiliar accent presented in speech-shaped background noise. Speech Reception Thresholds (SRTs) corresponding to 50% speech recognition accuracy provided a measurement of adaptation to the accented speech. Stroop, vocabulary knowledge, and working memory tests were performed to measure cognitive ability. Participants adapted to the unfamiliar accent as revealed by a decrease in SRTs over time. Better inhibition (lower Stroop scores) predicted greater and faster adaptation to the unfamiliar accent. Vocabulary knowledge predicted better recognition of the unfamiliar accent, while working memory had a smaller, indirect effect on speech recognition mediated by vocabulary score. Results support a top-down model for successful adaptation to, and recognition of, accented speech; they add to recent theories that allocate a prominent role for executive function to effective speech comprehension in adverse listening conditions. | 161,555 |
title: Effects of noise suppression and envelope dynamic range compression on the intelligibility of vocoded sentences for a tonal language.; abstract: Vocoder simulation studies have suggested that the carrier signal type employed affects the intelligibility of vocoded speech. The present work further assessed how carrier signal type interacts with additional signal processing, namely, single-channel noise suppression and envelope dynamic range compression, in determining the intelligibility of vocoder simulations. In Experiment 1, Mandarin sentences that had been corrupted by speech spectrum-shaped noise (SSN) or two-talker babble (2TB) were processed by one of four single-channel noise-suppression algorithms before undergoing tone-vocoded (TV) or noise-vocoded (NV) processing. In Experiment 2, dynamic ranges of multiband envelope waveforms were compressed by scaling of the mean-removed envelope waveforms with a compression factor before undergoing TV or NV processing. TV Mandarin sentences yielded higher intelligibility scores with normal-hearing (NH) listeners than did noise-vocoded sentences. The intelligibility advantage of noise-suppressed vocoded speech depended on the masker type (SSN vs 2TB). NV speech was more negatively influenced by envelope dynamic range compression than was TV speech. These findings suggest that an interactional effect exists between the carrier signal type employed in the vocoding process and envelope distortion caused by signal processing. | 161,556 |
title: Cosmological dependence of non-resonantly produced sterile neutrinos; abstract: The detection of a sterile neutrino could constitute the first observation of a particle that could have been produced before Big-Bang Nucleosynthesis (BBN), and could provide information about the yet untested pre-BBN era. The cosmological evolution in this era could be drastically different than typically assumed in what constitutes the standard cosmology, as happens in a variety of motivated particle models. In this work we assess the sensitivity to different pre-BBN cosmologies in which entropy is conserved of 0.01 eV to 1 MeV mass sterile neutrinos produced in the early Universe via resonant active-sterile oscillations, which requires a large lepton asymmetry. We identify mass ranges where it is possible to have two populations of the same sterile neutrino, one with a colder and one with a hotter momentum spectra, which is in principle an observable effect. Furthermore, we show the regions in mass and mixing where fully resonant production (i.e. simultaneously coherent and adiabatic) can occur. We find that in several of the cosmologies we consider, including the standard one, for a lepton asymmetry larger than ~10−4 fully resonantly produced sterile neutrinos in the eV-mass range can evade all cosmological constraints. | 161,557 |
title: Demonstration of a high-contrast optical switching in an atomic Delta system; abstract: We present an experimental study of a Δ system in a room temperature, dilute sample of 85Rb atoms. A Δ system in the D2 manifold of 85Rb is formed by connecting the two lower hyperfine energy levels of a Λ system by a microwave drive field at 3.0357 GHz. We show that when the Rabi frequency of a microwave drive field exceeds that of the optical probe field, a three-wave mixing nonlinear interaction is established. This nonlinear interaction changes the enhanced transmission of the optical probe to a deep absorption for a relative phase difference of π between all the three fields. We establish through our experiment and our numerical simulation, the phase-sensitive and nonlinear nature of the Δ system\u0027s response to the applied microwave and optical fields. Using this feature, we demonstrate a high-contrast microwave phase controlled switch for the optical probe field. In comparison with intensity and phase switching demonstrated with all-optical fields so far, our experiment opens up the possibility of obtaining the highest contrast optical switching with room temperature atoms. | 161,558 |
title: Latest news from PS205 High-precision laser spectroscopy of antiprotonic helium atoms; abstract: Abstract We have performed laser spectroscpy of metastable antiprotonic helium atoms (or “atomcules”) ( p He + ) and have observed a density dependence of the resonance vacuum wavelengths for the known transitions (n, l) = (39,35) → (38,34) and (37,34) → (36,33). They showed linear red-shifts of 0.61 ± 0.01 GHz and 0.22 ± 0.02 GHz per 1 g/l, respectively. With the shift parameters above, the transition vacuum wavelengths were extrapolated to zero-density limits, yielding λ0 = 597.2570 ± 0.0003 nm and λ0 = 470.7220 ± 0.0006 nm, respectively. These values were compared with the result of recent theoretical calculations on the energy of the Coulombic three-body system. including relativistic corrections and the Lamb shift. The agreements between our experimental values and the calculations have become as good as 2 × 10−6. This sets a severe constraint on the antiproton charge (−Q p ) and mass (M p ) that |Q p −Q p |/e −7 |M p −M p /M p × 5 × 10 −7 , under a more precisely known constraint on the charge-to-mass ratio. Thus we have opened a new possibility of measuring fundamental constants of the antiproton. | 161,559 |
title: Constraining cluster masses from the stacked phase space distribution at large radii; abstract: Velocity dispersions have been employed as a method to measure masses of clusters. To complement this conventional method, we explore the possibility of constraining cluster masses from the stacked phase space distribution of galaxies at larger radii, where infall velocities are expected to have a sensitivity to cluster masses. First, we construct a two component model of the three-dimensional phase space distribution of haloes surrounding clusters up to 50 $h^{-1}$Mpc from cluster centres based on $N$-body simulations. We find that the three-dimensional phase space distribution shows a clear cluster mass dependence up to the largest scale examined. We then calculate the probability distribution function of pairwise line-of-sight velocities between clusters and haloes by projecting the three-dimensional phase space distribution along the line-of-sight with the effect of the Hubble flow. We find that this projected phase space distribution, which can directly be compared with observations, shows a complex mass dependence due to the interplay between infall velocities and the Hubble flow. Using this model, we estimate the accuracy of dynamical mass measurements from the projected phase space distribution at the transverse distance from cluster centres larger than $2h^{-1}$Mpc. We estimate that, by using $1.5\\times 10^5$ spectroscopic galaxies, we can constrain the mean cluster masses with an accuracy of 14.5\\% if we fully take account of the systematic error coming from the inaccuracy of our model. This can be improved down to 5.7\\% by improving the accuracy of the model. | 161,560 |
title: Post-starburst quasars: bridging the gap between post-starburst galaxies and quasars; abstract: In order to better understand the nature of post-starburst quasars (PSQs) in the context of galaxy evolution, we compare their properties to those of post-starburst galaxies and quasars from appropriately selected samples possessing similar redshift ($z \\sim 0.3$), luminosity ($M_r \\sim -$23), and data quality. We consider morphologies, spectral features, and derived physical properties of the stellar populations and central supermassive black hole. PSQs themselves come in two types: the more luminous AGNs with more luminous post-starburst stellar populations hosted by elliptical galaxies, some which are clearly merger products, and the less luminous systems existing within relatively undisturbed spiral galaxies and possessing signs of a more extended period of star formation. Post-starburst galaxies (PSQs) have elliptical and disturbed/post-merger morphologies similar to those of the more luminous PSQs, display similar spectral properties, but also can have younger stellar populations for a given starburst mass. Quasars at similar redshifts and luminosities around the Seyfert/quasar transition possess similar AGN characteristics, in terms of black hole mass and accretion rate, compared with those of PSQs, but do not appear to be hosted by galaxies with significant post-starburst populations. Recent studies of more luminous quasars find hosts consistent with those of our luminous PSQs, suggesting that these PSQs may be in transition between post-starburst galaxies and a more luminous quasar stage when the post-starburst stellar population remains dominant. The lower luminosity PSQs appear to differ from lower luminosity quasars (Seyfert galaxies) in terms of more significant star formation in their past. | 161,561 |
title: Possible shape coexistence and magnetic dipole transitions in C-17 and Ne-21; abstract: Japanese Ministry of Education, Culture, Sports, Science and Technology [C(2) 18540290, 20540277]; National Science Foundation of China [10605018]; New Century Excellent Talents in University [NCET-07-0730] | 161,562 |
title: Atomic-like spin noise in solid-state demonstrated with manganese in cadmium telluride; abstract: Spin noise spectroscopy is an optical technique which can probe spin resonances non-perturbatively. First applied to atomic vapours, it revealed detailed information about nuclear magnetism and the hyperfine interaction. In solids, this approach has been limited to carriers in semiconductor heterostructures. Here we show that atomic-like spin fluctuations of Mn ions diluted in CdTe (bulk and quantum wells) can be detected through the Kerr rotation associated to excitonic transitions. Zeeman transitions within and between hyperfine multiplets are clearly observed in zero and small magnetic fields and reveal the local symmetry because of crystal field and strain. The linewidths of these resonances are close to the dipolar limit. The sensitivity is high enough to open the way towards the detection of a few spins in systems where the decoherence due to nuclear spins can be suppressed by isotopic enrichment, and towards spin resonance microscopy with important applications in biology and materials science. | 161,563 |
title: Sensitivity of Carbon and Oxygen Yields to the Triple-Alpha Resonance in Massive Stars; abstract: Abstract Motivated by the possible existence of other universes, this paper considers the evolution of massive stars with different values for the fundamental constants. We focus on variations in the triple alpha resonance energy and study its effects on the resulting abundances of 12C, 16O, and larger nuclei. In our universe, the 0 + energy level of carbon supports a resonant nuclear reaction that dominates carbon synthesis in stellar cores and accounts for the observed cosmic abundances. Here we define ΔER to be the change in this resonant energy level, and show how different values affect the cosmic abundances of the intermediate alpha elements. Using the state of the art computational package MESA, we carry out stellar evolution calculations for massive stars in the range M* = 15 − 40 M ⊙ , and for a wide range of resonance energies. We also include both solar and low metallicity initial conditions. For negative ΔER, carbon yields are increased relative to standard stellar models, and such universes remain viable as long as the production of carbon nuclei remains energetically favorable, and stars remain stable, down to Δ E R ≈ − 300 keV. For positive ΔER, carbon yields decrease, but significant abundances can be produced for resonance energy increments up to Δ E R ≈ + 500 keV. Oxygen yields tend to be anti-correlated with those of carbon, and the allowed range in ΔER is somewhat smaller. We also present yields for neon, magnesium, and silicon. With updated stellar evolution models and a more comprehensive survey of parameter space, these results indicate that the range of viable universes is larger than suggested by earlier studies. | 161,564 |
title: Broad states beyond the neutron drip line - Examples of H-5 and (4)n; abstract: Theoretical studies of broad states in the few-body systems beyond the neutron drip line have been performed. We introduce a theoretical model which allows to incorporate the initial structure of colliding nuclei, reaction mechanism, few-body effects and final-state interactions in studies of broad unbound states. The model is directly related to the sudden-removal approximation for high-energy knock-out or break-up reactions. We apply this model to qualitative studies of some general properties of broad few-body states including correlations for emitted fragments. The theoretical ideas are illustrated mainly using the example of 5H. The prospect for observation of broad continuum structures corresponding to the tetraneutron 4n is also discussed. | 161,565 |
title: Candidate Hα emission and absorption line sources in the Galactic Bulge Survey; abstract: We present a catalogue of candidate H{\\alpha} emission and absorption line sources and blue objects in the Galactic Bulge Survey (GBS) region. We use a point source catalogue of the GBS fields (two strips of (l x b) = (6 x 1) degrees centred at b = 1.5 above and below the Galactic centre), covering the magnitude range 16 \u003c r\u0027 \u003c 22.5. We utilize (r\u0027-i\u0027, r\u0027-H{\\alpha}) colour-colour diagrams to select H{\\alpha} emission and absorption line candidates, and also identify blue objects (compared to field stars) using the r\u0027-i\u0027 colour index. We identify 1337 H{\\alpha} emission line candidates and 336 H{\\alpha} absorption line candidates. These catalogues likely contain a plethora of sources, ranging from active (binary) stars, early-type emission line objects, cataclysmic variables (CVs) and low-mass X-ray binaries (LMXBs) to background active galactic nuclei (AGN). The 389 blue objects we identify are likely systems containing a compact object, such as CVs, planetary nebulae and LMXBs. Hot subluminous dwarfs (sdO/B stars) are also expected to be found as blue outliers. Crossmatching our outliers with the GBS X-ray catalogue yields sixteen sources, including seven (magnetic) CVs and one qLMXB candidate among the emission line candidates, and one background AGN for the absorption line candidates. One of the blue outliers is a high state AM CVn system. Spectroscopic observations combined with the multi-wavelength coverage of this area, including X-ray, ultraviolet and (time-resolved) optical and infrared observations, can be used to further constrain the nature of individual sources. | 161,566 |
title: Hard exclusive two photon processes in QCD; abstract: Abstract This is a short review of some hard two-photon processes: (a) γ γ → P ¯ 1 P 2 , P ¯ 1 P 2 = { π + π − , K + K − , K S K S , π o π o , π o η } , (b) γ γ → V 1 V 2 , V 1 V 2 = { ρ o ρ o , ϕ ϕ , ω ϕ , ω ω } , (c) γ γ → baryon–antibaryon , (d) γ ∗ γ → P o , P o = { π o , η , η ′ , η c } . The available experimental data are presented. A number of theoretical approaches to calculation of these processes is described, both those based mainly on QCD and more phenomenological (the handbag model, the diquark model, etc.). Some theoretical questions tightly connected with this subject are discussed, in particular: the applications of various types of QCD sum rules, the endpoint behavior of the leading twist meson wave functions, etc. | 161,567 |
title: Observational constraints on the tilted flat-XCDM and the untilted nonflat XCDM dynamical dark energy inflation parameterizations; abstract: We constrain tilted spatially-flat and untilted nonflat XCDM dynamical dark energy inflation parameterizations using Planck 2015 cosmic microwave background (CMB) anisotropy data and recent baryonic acoustic oscillations distance measurements, Type Ia supernovae data, Hubble parameter observations, and growth rate measurements. Inclusion of the four non-CMB data sets results in a significant strengthening of the evidence for nonflatness in the nonflat XCDM model from 1.1$\\sigma$ for the CMB data alone to 3.4$\\sigma$ for the full data combination. In this untilted nonflat XCDM case the data favor a spatially-closed model in which spatial curvature contributes a little less than a percent of the current cosmological energy budget; they also mildly favor dynamical dark energy over a cosmological constant at 1.2$\\sigma$. These data are also better fit by the flat-XCDM parameterization than by the standard $\\Lambda$CDM model, but only at 0.3$\\sigma$ significance. Current data is unable to rule out dark energy dynamics. The nonflat XCDM parameterization is compatible with the Dark Energy Survey limits on the present value of the rms mass fluctuations amplitude ($\\sigma_8$) as a function of the present value of the nonrelativistic matter density parameter ($\\Omega_m$), however it does not provide as good a fit to the higher multipole CMB temperature anisotropy data as does the standard tilted flat-$\\Lambda$CDM model. A number of measured cosmological parameter values differ significantly when determined using the tilted flat-XCDM and the nonflat XCDM parameterizations, including the baryonic matter density parameter and the reionization optical depth. | 161,568 |
title: An example of the interplay of nonextensivity and dynamics in the description of QCD matter; abstract: Using a simple quasi-particle model of QCD matter, presented some time ago in the literature, in which interactions are modelled by some effective fugacities z, we investigate the interplay between the dynamical content of fugacities z and effects induced by nonextensivity in situations when this model is used in a nonextensive environment characterized by some nonextensive parameter q $\\neq$ 1 (for the usual extensive case q=1). This allows for a better understanding of the role of nonextensivity in the more complicated descriptions of dense hadronic and QCD matter recently presented (in which dynamics is defined by a lagrangian, the form of which is specific to a given model). | 161,569 |
title: Measurement of the quantum states of squeezed light; abstract: A state of a quantum-mechanical system is completely described by a density matrix or a phase-space distribution such as the Wigner function. The complete family of squeezed states of light (states that have less uncertainty in one observable than does the vacuum state) have been generated using an optical parametric amplifier, and their density matrices and Wigner functions have been reconstructed from measurements of the quantum statistics of their electric fields. | 161,570 |
title: A classical Proca particle; abstract: An elementary particle is described as a spherically symmetric solution of the Proca equations and the Einstein general relativity equations. The mass is found to be of the order of the Planck mass. If the motion of its center of mass is determined by the Dirac equations, it has a spin 1/2.This work is parallel to an earlier one involving the Klein- Gordon equation. | 161,571 |
title: Observation of B+→pΛ̄π+π- at Belle; abstract: We study charmless B + meson decays to the pΛπ + π ― final state using a 605 fb ―1 data sample collected at the Υ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e + e ― collider. There are significant signals found with the pΛ mass peaking near threshold. The observed branching fraction for nonresonant B + → pΛπ + π ― is (5.92 +0.88 ―0.84 (stat) ± 0.69(syst)) × 10 ―6 with a significance of 9.1 standard deviations. We also observe the intermediate three-body decay B + → pAp° with a branching fraction of (4.78 +0.67 ―0.64 (stat) ± 0.60(syst)) × 10 ―6 and a significance of 9.5 standard deviations, and find a hint of a B + → pΛf 2 (1270) signal. No other intermediate three-body decay is found in this study. | 161,572 |
title: Multi-block simulations in general relativity: high-order discretizations, numerical stability and applications; abstract: The need to smoothly cover a computational domain of interest generically requires the adoption of several grids. To solve a given problem under this grid structure, one must ensure the suitable transfer of information among the different grids involved. In this work, we discuss a technique that allows one to construct finite-difference schemes of arbitrary high order which are guaranteed to satisfy linear numerical and strict stability. The method relies on the use of difference operators satisfying summation by parts and penalty terms to transfer information between the grids. This allows the derivation of semi-discrete energy estimates for problems admitting such estimates at the continuum. We analyse several aspects of this technique when used in conjunction with high-order schemes and illustrate its use in one-, two- and three-dimensional numerical relativity model problems with non-trivial topologies, including truly spherical black hole excision. | 161,573 |
title: Physics opportunities with supernova neutrinos; abstract: Abstract The high-statistics neutrino signal from the next nearby supernova (SN) would provide a bonanza of astrophysical and particle-physics information. In particular, there are two new developments in this field: (i) The SASI instability can imprint potentially detectable short-time variations on the neutrino signal. (ii) Collective neutrino oscillations strongly modify the previous paradigm of SN neutrino oscillations with potentially detectable consequences. | 161,574 |
title: First-principles study of charged steps on 180° domain walls in ferroelectric PbTiO3; abstract: The atomic-scale mechanism of domain wall motion in ferroelectrics is commonly accepted to be nucleation and the movement of steps on the domain walls. Although very important in understanding the mechanism of domain wall motion and domain switching, the detailed atomic structures of steps have nevertheless been scarcely explored. In this work, the charged steps of these structures on 180° domain walls in PbTiO3 were investigated using first-principles computations. Contrary to the previous understanding that there is a sudden jump at a step from one atomic plane to an adjacent plane, our computation results suggest that it is actually a gradual transition and the actual steps lie at atomic planes with the approximate Miller indices (3 0 1¯). A large polarization rotation was found around the steps, making the polarization distribution Ising–Neel-like. The barriers for the motion of steps along domain walls were found to be much lower than those for which the domain wall is moving as a whole. These findings provide valuable information for further investigations of the domain switching mechanism at the atomic scale.The atomic-scale mechanism of domain wall motion in ferroelectrics is commonly accepted to be nucleation and the movement of steps on the domain walls. Although very important in understanding the mechanism of domain wall motion and domain switching, the detailed atomic structures of steps have nevertheless been scarcely explored. In this work, the charged steps of these structures on 180° domain walls in PbTiO3 were investigated using first-principles computations. Contrary to the previous understanding that there is a sudden jump at a step from one atomic plane to an adjacent plane, our computation results suggest that it is actually a gradual transition and the actual steps lie at atomic planes with the approximate Miller indices (3 0 1¯). A large polarization rotation was found around the steps, making the polarization distribution Ising–Neel-like. The barriers for the motion of steps along domain walls were found to be much lower than those for which the domain wall is moving as a whole. These findi... | 161,575 |
title: Structure and magnetic properties of Er/sub 2/Fe/sub 17/C/sub x/ compounds; abstract: The interstitial carbides of Er/sub 2/Fe/sub 17/C/sub x/ with x=0.0, 0.5, 1.0, 1.5, 2.0, 2.5 and 3.0 have been synthesized by arc melting and by the Gas-Phase Interaction (GPI) method. The unit-cell volume of the compounds is found to increase with increasing carbon concentration. The dependence of Curie temperatures, spin-reorientation temperatures and the magnetic coupling on the carbon content has been investigated. The spin phase diagram of the series is given. \u003e | 161,576 |
title: Effect of orientational restriction on monolayers of hard ellipsoids.; abstract: The effect of out-of-plane orientational freedom on the orientational ordering properties of a monolayer of hard ellipsoids is studied using the Parsons–Lee scaling approach and replica exchange Monte Carlo computer simulation. Prolate and oblate ellipsoids exhibit very different ordering properties, namely, the axes of revolution of prolate particles tend to lean out, while those of oblate ones prefer to lean into the confining plane. The driving mechanism of this is that the particles try to maximize the available free area on the confining surface, which can be achieved by minimizing the cross section areas of the particles with the plane. In the lack of out-of-plane orientational freedom the monolayer of prolate particles is identical to a two-dimensional hard ellipse system, which undergoes an isotropic–nematic ordering transition with increasing density. With gradually switching on the out-of-plane orientational freedom the prolate particles lean out from the confining plane and destabilisation of the in-plane isotropic–nematic phase transition is observed. The system of oblate particles behaves oppositely to that of prolates. It corresponds to a two-dimensional system of hard disks in the lack of out-of-plane freedom, while it behaves similar to that of hard ellipses in the freely rotating case. Solid phases can be realised by lower surface coverage due to the out-of-plane orientation freedom for both oblate and prolate shapes. | 161,577 |
title: Charge form-factor effects in γ−γ production of non-strongly interacting particles in relativistic heavy-ion collisions; abstract: Abstract We study the γ − γ mechanism for relativistic heavy ions where the photon-photon interaction occurs inside one of the nuclei. Strong absorption effects in overlapping collisions are also taken into account. This leads to some dependence of the cross section on the actual charge distribution inside the nucleus. We give model calculations for μ-and τ-lepton pair production and Higgs production at RHIC and LHC (SSC) energies. The importance of the presently considered effect will depend on the strength of the nuclear interactions of the system produced in the γ − γ collision. | 161,578 |
title: The growth of a grid-generated turbulent mixed layer in a two-fluid system; abstract: This paper describes a laboratory experiment designed to compare measurements with published theoretical ideas of the mixed-layer growth of a two-layer system in which the turbulence is induced by an oscillating grid. Experimental results show excellent agreement with an earlier theory by one of us (Long), in which the mixed-layer depth D * measured from a virtual origin is given by $D_{*}\\sim V_0^{-\\frac{7}{11}}K^{\\frac{9}{11}}t^{\\frac{2}{11}}$ , where K is action, t is time and V 0 is a characteristic velocity of the problem. The experiments also verify Long\u0027s theoretical entrainment relation E = α 2 Ri −7/4 , where E is the entrainment coefficient and $Ri = D^3_{*}\\Delta b/K^2$ , and Δ b is the buoyancy difference between the two layers. The interfacial-layer thickness was observed to be proportional to the depth of the mixed layer, as also predicted by Long. After a certain depth, the entrainment law tends to deviate from Long\u0027s theory. The deviation may be due to wall effects. | 161,579 |
title: DNS of turbulent Couette flow with emphasis on the large-scale structure in the core region; abstract: A series of direct numerical simulation (DNSs) of the turbulent plane Couette flow were performed with various box lengths, L x = 24h, 32h, 45h and 64h, where h is the channel height. The Reynolds numbers Re w (= U w h/ν) of 3000 and 8600 were chosen, where U w is the relative wall speed between top and bottom walls and ν is the kinematic viscosity. In the core region, the meandering of the large-scale structure (LSS) has been captured with a long box size (L x ≥ 32h). Correspondingly, the streamwise two-point correlation decreases and becomes negative at half the box length. The effect of the computational box size on the statistics, e.g. turbulence intensities, is also examined. Significant Reynolds-number dependence is observed in the streamwise LSS. For the higher Reynolds number, both the visualized instantaneous flow field and the pre-multiplied energy spectra show that the LSS can be present, with a finite wavelength of 21–32h in the streamwise direction and a spanwise spacing of 2.1–2.5h. The stru... | 161,580 |
title: Thermally activated avalanches: Jamming and the progression of needle domains; abstract: Large-scale computer simulations of a simple model with a square-lattice topology, a small shear deformation (4° shear angle), and open (free) boundary conditions show that domain boundary movements under adiabatic strain deformation lead to Vogel-Fulcher behavior at high temperatures. The activation energy is independent of temperature and details of the twin patterns. Below the Vogel-Fulcher temperature, no thermal activation was found and the time evolution of the domain pattern becomes athermal. The movement of domain boundaries is now dominated by the nucleation and growth of needle domains. Their movement occurs in fast jerks. The probability to observe jerks follows a power-law spectrum with energy exponents close to α≈2. At even lower temperatures, the boundary kinetics becomes erratic even in our large (106atoms) system. The lateral movement of twin walls is found for our thin twin walls (w=3 layers) to operate by kinks which propagate along the twin wall. The needle domains nucleate either from the surface or from other existing twin walls. Intersections of twin walls constitute pinning centers which impede the free movement of the kinks in the walls. These intersection points then act as a pattern of intrinsic, self-induced defects which lead ultimately to the power-law distribution of the crackling noise of the domain walls. | 161,581 |
title: Numerical simulation of drop deformation and breakup in shear flow; abstract: Three-dimensional numerical simulation of the deformation and breakup of an isolated liquid drop suspended in immiscible viscous fluid under shear flow was performed with diffuse interface method. The governing equations of the model were described by Navier– Stokes– Cahn– Hilliard equations. The surface tension was treated as a modified stress. In this paper, a uniform staggered Cartesian grid was used. The transient Navier– Stokes equations were solved by an approximation projection method based on pressure increment formulation, while the Cahn– Hilliard equations were solved by a nonlinear full approximation multigrid method. The numerical results of the drop deformation and breakup were in good agreement with the experimental measurements. Therefore, the present model could be perfectly applied to study the mechanism of drop deformation and breakup. © 2007 Wiley Periodicals, Inc. Heat Trans Asian Res, 36(5): 286– 294, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.20160 | 161,582 |
title: Electroweak and Bottom Quark Contributions to Higgs Boson plus Jet Production; abstract: This paper presents predictions for jet pseudorapidity (�) and transverse momentum (pT) distributions for the production of the Standard Model Higgs boson in association with a high-pT hadronic jet. We discuss the contributions of electroweak loops and of bottom-quark parton processes to the cross section. The latter arise in the five-flavour scheme. Predictions for the Tevatron and the Large Hadron Collider with 10TeV collision energy are presented. For Higgs boson masses of 120GeV, 160GeV and 200GeV, we find the maximal effects of the electroweak contributions to the | 161,583 |
title: Phase diffusion equation for roll patterns of systems lacking reflectional symmetry; abstract: By symmetry arguments we present the phase diffusion equation for the description of spatially modulated roll patterns of isotropic nonequilibrium systems lacking reflectional symmetry such as high Prandtl number Rayleigh-Benard convection in a fluid layer rotating about a vertical axis. | 161,584 |
title: Nambu-Jona-Lasinio-like models and the low-energy effective action of QCD; abstract: Abstract We present a derivation of the low-energy effective action of an extended Nambu-Jona-Lasinio (ENJL) model to O(p4) in the chiral counting. Two alternative scenarios are considered on how the ENJL model could originate as a low-energy approximation to QCD. The low-energy effective lagrangian we derive includes the usual pseudoscalar Goldstone modes, as well as the lower scalar, vector and axial-vector degrees of freedom. By taking appropriate limits, we recover most of the effective low-energy models discussed in the literature; in particular the gauged Yang-Mills vector lagrangian, the Georgi-Manohar constituent quark-meson model, and the QCD effective action approach model. Another property of the ensuing effective lagrangian is that it incorporates most of the short-distance relations which follow from QCD. (We derive these relations in the presence of all possible gluonic interactions to leading order in the 1 N c expansion.) Finally the numerical predictions are compared with the experimental values of the low-energy parameters. | 161,585 |
title: Expanding amplitude-squeezing bandwidth with off-peak dispersive optical feedback; abstract: Weak dispersive optical feedback has been proved both theoretically and experimentally to be able to reduce the intensity noise of semiconductor lasers and allow the generation of amplitude-squeezed states. I propose a novel scheme exploiting the off-peak optical feedback condition that expands the squeezing bandwidth and significantly enhances the repeatability over the most commonly utilized on-peak optical feedback scheme. Using a realistic model, I show that under the zero-frequency-pulling condition the off-peak scheme greatly enhances the squeezing bandwidth. | 161,586 |
title: Improving relativistic modified Newtonian dynamics with Galileon k-mouflage; abstract: We propose a simple field theory reproducing the MOND phenomenology at galaxy scale, while predicting negligible deviations from general relativity at small scales thanks to an extended Vainshtein (\"k-mouflage\") mechanism induced by a covariant Galileon-type Lagrangian. The model passes solar-system tests at the post-Newtonian order, including those of local Lorentz invariance, and its anomalous forces in binary-pulsar systems are orders of magnitude smaller than the tightest experimental constraints. The large-distance behavior is obtained as in Bekenstein\u0027s tensor-vector-scalar (TeVeS) model, but with several simplifications. In particular, no fine-tuned function is needed to interpolate between the MOND and Newtonian regimes, and no dynamics needs to be defined for the vector field because preferred-frame effects are negligible at small distances. The field equations depend on second (and lower) derivatives, and avoid thus the generic instabilities related to higher derivatives. Their perturbative solution around a Schwarzschild background is remarkably simple to derive. We also underline why the proposed model is particularly efficient within the class of covariant Galileons. | 161,587 |
title: Exclusive measurements of mean pion multiplicities in 4He-nucleus reactions from 200 to 800 MeV/nucleon.; abstract: Mean multiplicities of pi+ and pi- in 4He collisions with C, Cu, and Pb at 200, 600, and 800 MeV/u, and with C and Pb at 400 MeV/u have been measured using the large solid angle detector Diogene. The independence of pion multiplicity on projectile incident energy, target mass and proton multiplicity is studied in comparison with intra-nuclear cascade predictions. The discrepancy between experimental results and theory is pointed out and discussed. | 161,588 |
title: Monte Carlo study of low/high spin transitions; abstract: We study the finite temperature property of a model on two dimensional square lattices with two Ising spins at each lattice site by Monte Carlo simulations. When those Ising spins at a lattice site are parallel the site is said to be in the high-spin state (HS), while when they are antiparallel the site is said to be in the low-spin state (LS). Throughout the study, the energy of HS is presumed to be higher than that of LS. Two Ising spins at each site are added to form a total spin, which interacts with its nearest neighbour total spins via spin-spin couplings. The spin-phonon coupling also is introduced via harmonic springs between nearest neighbour sites with spring constants and equilibrium distances depending on the spin states of the sites involved. In this system, we investigate the feature of transitions between LS and HS (to be called low/high spin transition (LHST)) by varying the temperature. As for the ferromagnetic interaction between total spins, the second order phase transition: pure HS→mixed state of HS and LS is possible to occur in a pure spin system, as is expected from mean field calculations. The role of lattice distortions by the change of lattice spacings is shown to be essential for LHST: pure LS→(pure)HS. In the model investigated, there appears an indication of the strong first order phase transition which reveals a conspicuous hysteresis. | 161,589 |
title: DIZET — Electroweak one-loop corrections for e++e-→f++f- around the Z0 peak; abstract: The use of five gauge invariant form factors allows a dense notation of electroweak one-loop effects for the fermion pair production in e+e- annihilation. Based on this notation a program package (DIZET) has been developed to calculate the differential cross section for these processes. It is evaluated as a function of the energy of the process, the production angle, the longitudinal polarization of the beam particles, and the helicities of the final fermions. | 161,590 |
title: Spectral functions of nuclear matter using self-consistent Green’s function approach based on three-body force; abstract: A self-consistent Green’s Function approach is used to study the influence of short-range correlations beyond the mean-field approach of nuclear matter. The ladder equation, including both particle-particle and hole-hole propagation, is solved in nuclear matter for a realistic interaction derived from the CD-Bonn potential. The hole-hole interaction is used to calculate the spectral functions that describe the distribution of holes below Fermi level. The nucleon spectral functions are calculated from the momentum- and energy-dependent self-energy. For comparison, the calculations are investigated by including nuclear three-body force. These spectral functions directly reflect the effects of the nucleon-nucleon correlations and can be explored by the analysis of nucleon knock-out experiments like $ ({\\rm e, e\u0027 p})$\n . | 161,591 |
title: TOP QUARK PHYSICS, AN EXPERIMENTAL PERSPECTIVE; abstract: An experimental review of the current status of the top quark physics program at hadron colliders is presented. Since the discovery of the top quark at the Fermilab Tevatron collider in 1995, its production and the decay have been studied with an extraordinary level of sophistication both at the Tevatron and at the Large Hadron Collider. The top quark is the heaviest known elementary particle, with possible unique connections to the mechanism of electroweak symmetry breaking. | 161,592 |
title: Nucleosynthesis in Stars and the Chemical Enrichment of Galaxies; abstract: After the Big Bang, production of heavy elements in the early Universe takes place starting from the formation of the first stars, their evolution, and explosion. The first supernova explosions have strong dynamical, thermal, and chemical feedback on the formation of subsequent stars and evolution of galaxies. However, the nature of the Universe\u0027s first stars and supernova explosions has not been well clarified. The signature of the nucleosynthesis yields of the first stars can be seen in the elemental abundance patterns observed in extremely metal-poor stars. Interestingly, those patterns show some peculiarities relative to the solar abundance pattern, which should provide important clues to understanding the nature of early generations of stars. We thus review the recent results of the nucleosynthesis yields of mainly massive stars for a wide range of stellar masses, metallicities, and explosion energies. We also provide yields tables and examine how those yields are affected by some hydrodynamical effe... | 161,593 |
title: The phase transitions, magnetocaloric effect, and magnetoresistance in Co doped Ni–Mn–Sb ferromagnetic shape memory alloys; abstract: The phase transitions, magnetocaloric effect, and magnetoresistance in Ni50−xCoxMn39Sb11 (x=0–11) ferromagnetic shape memory alloys were investigated. The temperatures of martensitic transformation and magnetic transition in austenitic phase depend strongly on the Co concentration, while the magnetic transition temperature in martensitic phase shows small dependence on alloy composition. For 7≤x≤9, the martensitic transformation is accompanied by a sudden change in magnetization. Large positive magnetic entropy changes and negative magnetoresistance near room temperature, which originate from the magnetic-field-induced transformation from the weak-magnetic high-resistance martensitic phase to the ferromagnetic low-resistance parent phase, are observed in these alloys. Our results indicate the potential application of Ni50−xCoxMn39Sb11 alloys in magnetic refrigeration and magnetic sensors. | 161,594 |
title: Half-Lives for Alpha Radioactivity of Elements with 104 ≤ Z ≤ 120 within Unified Fission Model; abstract: α decay half-lives are calculated using the Qα values obtained by Semi-empirical Shell Model in the framework of the Unified Fission Model (UFM) with the Coulomb repulsion, nuclear attraction due to proximity potential, and rotational energy due to angular momentum transfer of α particle. In addition, the calculated and experimental half-lives of 425 nuclei are compared to check the validity of the model applied on α decay. The calculated half-lives of α decay are in good agreement with the experimental data. Finally, some useful predications on the α decay half-lives are provided for future experiments. | 161,595 |
title: Error estimates for the Skyrme-Hartree-Fock model; abstract: There are many complementing strategies to estimate the extrapolation errors of a model which was calibrated in least-squares fits. We consider the Skyrme-Hartree-Fock model for nuclear structure and dynamics and exemplify the following five strategies: uncertainties from statistical analysis, covariances between observables, trends of residuals, variation of fit data, dedicated variation of model parameters. This gives useful insight into the impact of the key fit data as they are: binding energies, charge r.m.s. radii, and charge formfactor. Amongst others, we check in particular the predictive value for observables in the stable nucleus $^{208}$Pb, the super-heavy element $^{266}$Hs, $r$-process nuclei, and neutron stars. | 161,596 |
title: Control optimization in experiments for the heat transfer assessment of saturated packed bed regenerators; abstract: Abstract Many studies about heat transfer characterization of single phase fixed bed matrix regenerators are devoted to the finding of experimental correlations. Despite several deep investigations, the emerged correlations are not well established, indeed the high complexity of the processes involved, the shape of the solid-fluid interface, the complexity of the geometry of the solid matrix, make accurate experimental data difficult to obtain. The aim of the present work pursuit a double objective: (i) to develop and propose an inverse method to identify h, the fluid-matrix heat transfer coefficient, by means of transient simulated experiments, and (ii) to investigate the sensitivity of the h reconstruction process to the variation of the control input parameters and material properties, in order to find the optimal value of the experimental control variables that allows the identification of this unknown coefficient to be performed with “minimum variance”. The reconstruction technique is applied to numerical experiments and it is based on the simulated measurements of oscillating temperatures of the fluid at the inlet and outlet of the regenerator. The identification of h is performed by means of an inverse search technique, driven by the difference between simulated measurements and calculated temperature time histories at the regenerator outlet. At first, experiments in different operating conditions are simulated in order to investigate the ability of the algorithm to identify the correct value of h and its uncertainty. Then a parametric study is performed and the optimal control frequency of the known (imposed) oscillating temperature signal at the inlet is found as a function of the mass flow rate, the geometry and other operating and thermophysical characteristics of the system. | 161,597 |
title: Real‐time, high‐resolution optical beam position‐sensing device; abstract: An optical beam position‐sensing device with real‐time and high‐resolution abilities is described using a Pb2CrO5 thin‐film lateral photodetector. A high resolution of less than 5 nm in an effective measuring range of 16 μm is compatible with a real‐time response of up to 10 kHz. Three parallel, planar gold electrodes evaporated on the film surface in a configuration with two narrow electrode gaps are essential for sensing the position of a light beam. Relationships between photocurrent and light beam position are examined under various combinations of the electrode configuration and beamwidths. The displacement deviation at the surface of the shaft of the rotating motor is measured for a demonstration of real‐time and high‐resolution position sensing. | 161,598 |
title: Cosmological Ohm's law and dynamics of non-minimal electromagnetism; abstract: The origin of large-scale magnetic fields in cosmic structures and the intergalactic medium is still poorly understood. We explore the effects of non-minimal couplings of electromagnetism on the cosmological evolution of currents and magnetic fields. In this context, we revisit the mildly non-linear plasma dynamics around recombination that are known to generate weak magnetic fields. We use the covariant approach to obtain a fully general and non-linear evolution equation for the plasma currents and derive a generalised Ohm law valid on large scales as well as in the presence of non-minimal couplings to cosmological (pseudo-)scalar fields. Due to the sizeable conductivity of the plasma and the stringent observational bounds on such couplings, we conclude that modifications of the standard (adiabatic) evolution of magnetic fields are severely limited in these scenarios. Even at scales well beyond a Mpc, any departure from flux freezing behaviour is inhibited. | 161,599 |
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