36,184 research outputs found

    Higgs radiation off quarks in supersymmetric theories at e^+e^- colliders

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    Yukawa couplings between Higgs bosons and quarks in supersymmetric theories can be measured in the processes e^+e^- -> Q Qbar + Higgs. We have determined the cross sections of these processes in the minimal supersymmetric model including the complete set of next-to-leading order QCD corrections for all channels.Comment: 12 pages, latex, 3 figure

    Towards Semantic Fast-Forward and Stabilized Egocentric Videos

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    The emergence of low-cost personal mobiles devices and wearable cameras and the increasing storage capacity of video-sharing websites have pushed forward a growing interest towards first-person videos. Since most of the recorded videos compose long-running streams with unedited content, they are tedious and unpleasant to watch. The fast-forward state-of-the-art methods are facing challenges of balancing the smoothness of the video and the emphasis in the relevant frames given a speed-up rate. In this work, we present a methodology capable of summarizing and stabilizing egocentric videos by extracting the semantic information from the frames. This paper also describes a dataset collection with several semantically labeled videos and introduces a new smoothness evaluation metric for egocentric videos that is used to test our method.Comment: Accepted for publication and presented in the First International Workshop on Egocentric Perception, Interaction and Computing at European Conference on Computer Vision (EPIC@ECCV) 201

    Multi-wavelength variability properties of Fermi blazar S5 0716+714

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    S5 0716+714 is a typical BL Lacertae object. In this paper we present the analysis and results of long term simultaneous observations in the radio, near-infrared, optical, X-ray and γ\gamma-ray bands, together with our own photometric observations for this source. The light curves show that the variability amplitudes in γ\gamma-ray and optical bands are larger than those in the hard X-ray and radio bands and that the spectral energy distribution (SED) peaks move to shorter wavelengths when the source becomes brighter, which are similar to other blazars, i.e., more variable at wavelengths shorter than the SED peak frequencies. Analysis shows that the characteristic variability timescales in the 14.5 GHz, the optical, the X-ray, and the γ\gamma-ray bands are comparable to each other. The variations of the hard X-ray and 14.5 GHz emissions are correlated with zero-lag, so are the V band and γ\gamma-ray variations, which are consistent with the leptonic models. Coincidences of γ\gamma-ray and optical flares with a dramatic change of the optical polarization are detected. Hadronic models do not have the same nature explanation for these observations as the leptonic models. A strong optical flare correlating a γ\gamma-ray flare whose peak flux is lower than the average flux is detected. Leptonic model can explain this variability phenomenon through simultaneous SED modeling. Different leptonic models are distinguished by average SED modeling. The synchrotron plus synchrotron self-Compton (SSC) model is ruled out due to the extreme input parameters. Scattering of external seed photons, such as the hot dust or broad line region emission, and the SSC process are probably both needed to explain the γ\gamma-ray emission of S5 0716+714.Comment: 43 pages, 13 figures, 3 tables, to be appeared in Ap

    Hole burning in a nanomechanical resonator coupled to a Cooper pair box

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    We propose a scheme to create holes in the statistical distribution of excitations of a nanomechanical resonator. It employs a controllable coupling between this system and a Cooper pair box. The success probability and the fidelity are calculated and compared with those obtained in the atom-field system via distinct schemes. As an application we show how to use the hole-burning scheme to prepare (low excited) Fock states.Comment: 7 pages, 10 figure

    Electronic structure and bonding in unligated and ligated FeII porphyrins

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    The electronic structure and bonding in a series of unligated and ligated FeII porphyrins (FeP) are investigated by density functional theory (DFT). All the unligated four-coordinate iron porphyrins have a 3A2g ground state that arises from the (dxy)2(dz2)2(dπ)2 configuration. The calculations confirm experimental results on Fe tetraphenylporphine but do not support the resonance Raman assignment of Fe octaethylporphine as 3Eg, nor the early assignment of Fe octamethyltetrabenzporphine as 5B2g. For the six-coordinate Fe–P(L)2 (L = HCN, pyridine, CO), the strong-field axial ligands raise the energy of the Fe dz2 orbital, thereby making the iron porphyrin diamagnetic. The calculated redox properties of Fe–P(L)2 are in agreement with experiment. As models for deoxyheme, the energetics of all possible low-lying states of FeP(pyridine) and FeP(2-methylimidazole) have been studied in detail. The groundstate configuration of FeP(2-methylimidazole) was confirmed to be high-spin (dxy)2(dz2)1(dπ)2(dx2−y2)1; FeP (pyridine) is shown to be a poor model for high-spin deoxyheme. © 2002 American Institute of Physics

    Consistent Construction of Perturbation Theory on Noncommutative Spaces

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    We examine the effect of non-local deformations on the applicability of interaction point time ordered perturbation theory (IPTOPT) based on the free Hamiltonian of local theories. The usual argument for the case of quantum field theory (QFT) on a noncommutative (NC) space (based on the fact that the introduction of star products in bilinear terms does not alter the action) is not applicable to IPTOPT due to several discrepancies compared to the naive path integral approach when noncommutativity involves time. These discrepancies are explained in detail. Besides scalar models, gauge fields are also studied. For both cases, we discuss the free Hamiltonian with respect to non-local deformations.Comment: 22 pages; major changes in Section 3; minor changes in the Introduction and Conclusio

    On the Connection Between Momentum Cutoff and Operator Cutoff Regularizations

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    Operator cutoff regularization based on the original Schwinger's proper-time formalism is examined. By constructing a regulating smearing function for the proper-time integration, we show how this regularization scheme simulates the usual momentum cutoff prescription yet preserves gauge symmetry even in the presence of the cutoff scales. Similarity between the operator cutoff regularization and the method of higher (covariant) derivatives is also observed. The invariant nature of the operator cutoff regularization makes it a promising tool for exploring the renormalization group flow of gauge theories in the spirit of Wilson-Kadanoff blocking transformation.Comment: 28 pages in plain TeX, no figures. revised and expande

    Decomposition of stochastic flows with automorphism of subbundles component

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    We show that given a GG-structure PP on a differentiable manifold MM, if the group G(M)G(M) of automorphisms of PP is big enough, then there exists the quotient of an stochastic flows phitphi_t by G(M)G(M), in the sense that ϕt=ξtρt\phi_t = \xi_t \circ \rho_t where ξtG(M)\xi_t \in G(M), the remainder ρt\rho_t has derivative which is vertical but transversal to the fibre of PP. This geometrical context generalizes previous results where MM is a Riemannian manifold and ϕt\phi_t is decomposed with an isometric component, see Liao \cite{Liao1} and Ruffino \cite{Ruffino}, which in our context corresponds to the particular case of an SO(n)-structure on MM.Comment: To appear in Stochastics and Dynamics, 201

    Incorporating Digital Badges and Ontology into Project-Based Learning

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    The rapid development of technology makes learning goals much more complex, diverse, and keeping changing. In reality, each product of design must be 'ultimately particular', which complicates the holistic learning objectives of a technology training class in the school setting, and, in turn, it runs the risk of becoming disconnected in the minds of learners and teachers. In order to address this issue, a solution named DBOPBL (Digital Badges, Ontology & Project Based Learning) is put forward in this paper.published_or_final_versio

    A Note on the Local Cosmological Constant and the Dark Energy Coincidence Problem

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    It has been suggested that the Dark Energy Coincidence Problem could be interpreted as a possible link between the cosmological constant and a massive graviton. We show that by using that link and models for the graviton mass a dark energy density can be obtained that is indeed very close to measurements by WMAP. As a consequence of the models, the cosmological constant was found to depend on the density of matter. A brief outline of the cosmological consequences such as the effect on the black hole solution is given
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