47,237 research outputs found

    DsJ+(2632)D_{sJ}^+(2632): An Excellent Candidate of Tetraquarks

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    We analyze various possible interpretations of the narrow state DsJ(2632)D_{sJ}(2632) which lies 100 MeV above threshold. This interesting state decays mainly into DsηD_s \eta instead of D0K+D^0 K^+. If this relative branching ratio is further confirmed by other experimental groups, we point out that the identification of DsJ(2632)D_{sJ}(2632) either as a csˉc\bar s state or more generally as a 3ˉ{\bf {\bar 3}} state in the SU(3)FSU(3)_F representation is probably problematic. Instead, such an anomalous decay pattern strongly indicates DsJ(2632)D_{sJ}(2632) is a four quark state in the SU(3)FSU(3)_F 15{\bf 15} representation with the quark content 122(dsdˉ+sddˉ+suuˉ+usuˉ2sssˉ)cˉ{1\over 2\sqrt{2}} (ds\bar{d}+sd\bar{d}+su\bar{u}+us\bar{u}-2ss\bar{s})\bar{c}. We discuss its partners in the same multiplet, and the similar four-quark states composed of a bottom quark BsJ0(5832)B_{sJ}^0(5832). Experimental searches of other members especially those exotic ones are strongly called for

    A Comprehensive View of the 2006 December 13 CME: From the Sun to Interplanetary Space

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    The biggest halo coronal mass ejection (CME) since the Halloween storm in 2003, which occurred on 2006 December 13, is studied in terms of its solar source and heliospheric consequences. The CME is accompanied by an X3.4 flare, EUV dimmings and coronal waves. It generated significant space weather effects such as an interplanetary shock, radio bursts, major solar energetic particle (SEP) events, and a magnetic cloud (MC) detected by a fleet of spacecraft including STEREO, ACE, Wind and Ulysses. Reconstruction of the MC with the Grad-Shafranov (GS) method yields an axis orientation oblique to the flare ribbons. Observations of the SEP intensities and anisotropies show that the particles can be trapped, deflected and reaccelerated by the large-scale transient structures. The CME-driven shock is observed at both the Earth and Ulysses when they are separated by 74^{\circ} in latitude and 117^{\circ} in longitude, the largest shock extent ever detected. The ejecta seems missed at Ulysses. The shock arrival time at Ulysses is well predicted by an MHD model which can propagate the 1 AU data outward. The CME/shock is tracked remarkably well from the Sun all the way to Ulysses by coronagraph images, type II frequency drift, in situ measurements and the MHD model. These results reveal a technique which combines MHD propagation of the solar wind and type II emissions to predict the shock arrival time at the Earth, a significant advance for space weather forecasting especially when in situ data are available from the Solar Orbiter and Sentinels.Comment: 26 pages, 10 figures. 2008, ApJ, in pres

    Object Contour and Edge Detection with RefineContourNet

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    A ResNet-based multi-path refinement CNN is used for object contour detection. For this task, we prioritise the effective utilization of the high-level abstraction capability of a ResNet, which leads to state-of-the-art results for edge detection. Keeping our focus in mind, we fuse the high, mid and low-level features in that specific order, which differs from many other approaches. It uses the tensor with the highest-levelled features as the starting point to combine it layer-by-layer with features of a lower abstraction level until it reaches the lowest level. We train this network on a modified PASCAL VOC 2012 dataset for object contour detection and evaluate on a refined PASCAL-val dataset reaching an excellent performance and an Optimal Dataset Scale (ODS) of 0.752. Furthermore, by fine-training on the BSDS500 dataset we reach state-of-the-art results for edge-detection with an ODS of 0.824.Comment: Keywords: Object Contour Detection, Edge Detection, Multi-Path Refinement CN

    Breakdown effect of periodic perturbations to the robustness of topological phase\\ in a gyromagnetic photonic crystal

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    In the known field of topological photonics, what remains less so is the breakdown effect of topological phases deteriorated by perturbation. In this paper, we investigate the variance on topological invariants for a periodic Kekul\'e medium perturbed in unit cells, which was a gyromagnetic photonic crystal holding topological phases induced by \emph{synchronized rotation} of unit cells. Two parameters for geometric and material perturbation are respectively benchmarked to characterise the topological degradation. Our calculation demonstrates that such a periodic perturbation easily destructs the topological phase, and thus calls for further checkups on robustness under such unit-cell-perturbation in realization.Comment: 9 pages, 6 figures, 1 table, re-submitted to Phys. Lett.

    Heavy Pentaquarks

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    We construct the spin-flavor wave functions of the possible heavy pentaquarks containing an anti-charm or anti-bottom quark using various clustered quark models. Then we estimate the masses and magnetic moments of the JP=12+J^P={1\over 2}^+ or 32+{3\over 2}^+ heavy pentaquarks. We emphasize the difference in the predictions of these models. Future experimental searches at BESIII, CLEOc, BELLE, and LEP may find these interesting states

    Computing the lower and upper bounds of Laplace eigenvalue problem: by combining conforming and nonconforming finite element methods

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    This article is devoted to computing the lower and upper bounds of the Laplace eigenvalue problem. By using the special nonconforming finite elements, i.e., enriched Crouzeix-Raviart element and extension Q1rotQ_1^{\rm rot}, we get the lower bound of the eigenvalue. Additionally, we also use conforming finite elements to do the postprocessing to get the upper bound of the eigenvalue. The postprocessing method need only to solve the corresponding source problems and a small eigenvalue problem if higher order postprocessing method is implemented. Thus, we can obtain the lower and upper bounds of the eigenvalues simultaneously by solving eigenvalue problem only once. Some numerical results are also presented to validate our theoretical analysis.Comment: 19 pages, 4 figure

    Magnetic resonances of helical textures in 3He-A

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    Pentaquark Magnetic Moments In Different Models

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    We calculate the magnetic moments of the pentaquark states from different models and compare our results with predictions of other groups.Comment: 17 pages, no figur

    Online EV Charge Scheduling Based on Time-of-Use Pricing and Peak Load Minimization: Properties and Efficient Algorithms

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    Electric vehicles (EVs) endow great potentials for future transportation systems, while efficient charge scheduling strategies are crucial for improving profits and mass adoption of EVs. Two critical and open issues concerning EV charging are how to minimize the total charging cost (Objective 1) and how to minimize the peak load (Objective 2). Although extensive efforts have been made to model EV charging problems, little information is available about model properties and efficient algorithms for dynamic charging problems. This paper aims to fill these gaps. For Objective 1, we demonstrate that the greedy-choice property applies, which means that a globally optimal solution can be achieved by making locally optimal greedy choices, whereas it does not apply to Objective 2. We propose a non-myopic charging strategy accounting for future demands to achieve global optimality for Objective 2. The problem is addressed by a heuristic algorithm combining a multi-commodity network flow model with customized bisection search algorithm in a rolling horizon framework. To expedite the solution efficiency, we derive the upper bound and lower bound in the bisection search based on the relationship between charging volume and parking time. We also explore the impact of demand levels and peak arrival ratios on the system performance. Results show that with prediction, the peak load can converge to a globally optimal solution, and that an optimal look-ahead time exists beyond which any prediction is ineffective. The proposed algorithm outperforms the state-of-the-art algorithms, and is robust to the variations of demand and peak arrival ratios

    Large NcN_c Expansion and the Parity Violating π,N,Δ\pi, N, \Delta Couplings

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    In the limit of large NcN_c we first consider the NcN_c ordering of the various parity violating π,N,Δ\pi, N, \Delta couplings. Then we derive the relations among these couplings and consistency relations from the stability of these couplings under the chiral loop corrections with and without the mass splitting between NN and Δ\Delta. Especially we find that hΔ=35hπh_\Delta =-{3\over \sqrt{5}}h_\pi in the large NcN_c limit, which correctly reproduces the relative sign and magnitude of the "DDH" values for these PV couplings
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