2,549 research outputs found

    Contextual-based Image Inpainting: Infer, Match, and Translate

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    We study the task of image inpainting, which is to fill in the missing region of an incomplete image with plausible contents. To this end, we propose a learning-based approach to generate visually coherent completion given a high-resolution image with missing components. In order to overcome the difficulty to directly learn the distribution of high-dimensional image data, we divide the task into inference and translation as two separate steps and model each step with a deep neural network. We also use simple heuristics to guide the propagation of local textures from the boundary to the hole. We show that, by using such techniques, inpainting reduces to the problem of learning two image-feature translation functions in much smaller space and hence easier to train. We evaluate our method on several public datasets and show that we generate results of better visual quality than previous state-of-the-art methods.Comment: ECCV 2018 camera read

    Analyzing eta' photoproduction data on the proton at energies of 1.5--2.3 GeV

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    The recent high-precision data for the reaction γppη\gamma p\to p\eta' at photon energies in the range 1.5--2.3 GeV obtained by the CLAS collaboration at the Jefferson Laboratory have been analyzed within an extended version of the photoproduction model developed previously by the authors based on a relativistic meson-exchange model of hadronic interactions [Phys. Rev. C \textbf{69}, 065212 (2004)]. The η\eta' photoproduction can be described quite well over the entire energy range of available data by considering S11S_{11}, P11P_{11}, P13P_{13}, and D13D_{13} resonances, in addition to the tt-channel mesonic currents. The observed angular distribution is due to the interference between the tt-channel and the nucleon ss- and uu-channel resonance contributions. The j=3/2j=3/2 resonances are required to reproduce some of the details of the measured angular distribution. For the resonances considered, our analysis yields mass values compatible with those advocated by the Particle Data Group. We emphasize, however, that cross-section data alone are unable to pin down the resonance parameters and it is shown that the beam and/or target asymmetries impose more stringent constraints on these parameter values. It is found that the nucleonic current is relatively small and that the NNηNN\eta^\prime coupling constant is not expected to be much larger than 2.Comment: Revised version based on revised (finalized) CLAS data (14 pages, 10 figures, RevTeX4

    N-Body Nuclear Forces at Short Distances in Holographic QCD

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    We provide a calculation of N-body (N>2) nucleon interactions at short distances in holographic QCD. In the Sakai-Sugimoto model of large N_c massless QCD, N baryons are described by N Yang-Mills instantons in 5 spacetime dimensions. We compute a classical short distance interaction hamiltonian for N 'tHooft instantons. This corresponds to N baryons sharing identical classical spins and isospins. We find that genuine N-body nuclear forces turn out to vanish for N>2, at the leading order. This suggests that classical N-body forces are always suppressed compared with 2-body forces.Comment: 4 page

    Comment on "Valence QCD: Connecting QCD to the Quark Model"

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    I criticize certain conclusions about the physics of hadrons drawn from a "valence QCD" approximation to QCD.Comment: 12 pages, 8 figures; some minor improvements made to the tex

    Possible Molecular Structure of the Newly Observed Y(4260)

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    We suggest that the newly observed resonance Y(4260) is a χcρ0\chi_{c}-\rho^0 molecule, which is an isovector. In this picture, we can easily interpret why Y(4260)π+πJ/ψY(4260)\to \pi^+\pi^-J/\psi has a larger rate than Y(4260)DDˉY(4260)\to D\bar D which has not been observed, and we also predict existence of the other two components of the isotriplet and another two possible partner states which may be observed in the future experiments. A direct consequence of this structure is that for this molecular structure Y(4260)π+πJ/ψY(4260)\to \pi^+\pi^-J/\psi mode is more favorable than Y(4260)KKˉJ/ψY(4260)\to K\bar KJ/\psi which may have a larger fraction if other proposed structures prevail.Comment: 5 pages, 2 figures. Some descriptions changed, more references added and typos corrected. Published version in PR

    Temperature- and Magnetic-Field-Dependent Optical Properties of Heavy Quasiparticles in YbIr2Si2

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    We report the temperature- and magnetic-field-dependent optical conductivity spectra of the heavy electron metal YbIr2_2Si2_2. Upon cooling below the Kondo temperature (TKT_{\rm K}), we observed a typical charge dynamics that is expected for a formation of a coherent heavy quasiparticle state. We obtained a good fitting of the Drude weight of the heavy quasiparticles by applying a modified Drude formula with a photon energy dependence of the quasiparticle scattering rate that shows a similar power-law behavior as the temperature dependence of the electrical resistivity. By applying a magnetic field of 6T below TKT_{\rm K}, we found a weakening of the effective dynamical mass enhancement by about 12% in agreement with the expected decrease of the 4f4f-conduction electron hybridization on magnetic field.Comment: 5 pages, 4 figures. to be published in Journal of the Physical Society of Japan Vol. 79 (2010) No. 1

    Far-infrared optical conductivity of CeCu2Si2

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    Journal ref.: J. Phys.: Condens. Matter 25, 065602 (2013): We investigated the optical reflectivity of the heavy-fermion metal CeCu2Si2 in the energy range 3 meV - 30 eV for temperatures between 4K - 300K. The results for the charge dynamics indicate a behavior that is expected for the formation of a coherent heavy quasiparticle state: Upon cooling the spectra of the optical conductivity indicate a narrowing of the coherent response. Below temperatures of 30 K a considerable suppression of conductivity evolves below a peak structure at 13 meV. We assign this gap-like feature to strong electron correlations due to the 4f-conduction electron hybridization.Comment: 7 pages, 3 figure

    Stochastic Process Associated with Traveling Wave Solutions of the Sine-Gordon Equation

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    Stochastic processes associated with traveling wave solutions of the sine-Gordon equation are presented. The structure of the forward Kolmogorov equation as a conservation law is essential in the construction and so is the traveling wave structure. The derived stochastic processes are analyzed numerically. An interpretation of the behaviors of the stochastic processes is given in terms of the equation of motion.Comment: 12 pages, 9 figures; corrected typo

    Production of f0(1710)f_0(1710), f0(1500)f_0(1500), and f0(1370)f_0(1370) in J/ψJ/\psi hadronic decays

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    A coherent study of the production of f0if_0^i (i=1i=1, 2, 3 corresponding to f0(1710)f_0(1710), f0(1500)f_0(1500), and f0(1370)f_0(1370)) in J/ψVf0VPPJ/\psi\to V f_0 \to V PP is reported based on a previously proposed glueball and QQˉQ\bar{Q} nonet mixing scheme, and a factorization for the decay of J/ψVf0iJ/\psi\to V f_0^i, where VV denotes the isoscalar vector mesons ϕ\phi and ω\omega, and PP denotes pseudoscalar mesons. The results show that the J/ψJ/\psi decays are very sensitive to the structure of those scalar mesons, and suggest a glueball in the 1.51.71.5-1.7 GeV region, in line with Lattice QCD. The presence of significant glueball mixings in the scalar wavefunctions produces peculiar patterns in the branching ratios for J/ψVf0iVPPJ/\psi\to V f_0^i\to VPP, which are in good agreement with the recently published experimental data from the BES collaboration.Comment: Version accepted by PRD; Numerical results in Tab IV and VI changed due to correction of an error in quoting an experimental datum; Conclusion is not change

    A new look at scalar mesons

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    Light scalar mesons are found to fit rather well a diquark-antidiquark description. The resulting nonet obeys mass formulae which respect, to a good extent, the OZI rule. OZI allowed strong decays are reasonably reproduced by a single amplitude describing the switch of a qbar-q pair, which transforms the state into two colourless pseudoscalar mesons. Predicted heavy states with one or more quarks replaced by charm or beauty are briefly described; they should give rise to narrow states with exotic quantum numbers.Comment: 4 pages, 1 figure, misprints corrected, references added, accepted for publication in Phys. Rev. Let
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