3,366 research outputs found

    Parity-violating πNN\pi NN coupling constant from the flavor-conserving effective weak chiral Lagrangian

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    We investigate the parity-violating pion-nucleon-nucleon coupling constant hπNN1h^1_{\pi NN}, based on the chiral quark-soliton model. We employ an effective weak Hamiltonian that takes into account the next-to-leading order corrections from QCD to the weak interactions at the quark level. Using the gradient expansion, we derive the leading-order effective weak chiral Lagrangian with the low-energy constants determined. The effective weak chiral Lagrangian is incorporated in the chiral quark-soliton model to calculate the parity-violating πNN\pi NN constant hπNN1h^1_{\pi NN}. We obtain a value of about 10710^{-7} at the leading order. The corrections from the next-to-leading order reduce the leading order result by about 20~\%.Comment: 12 page

    Optimal design of quadratic electromagnetic exciter

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    The vibration acceleration of collecting plates, which is the core indicator of rapping performance in an electrostatic precipitator’s vibration rapping process, is determined by magnetic force of a quadratic electromagnetic exciter. The larger exciter provides the larger magnetic force, but the installation space for the exciter is limited. Accordingly, this paper presents the optimal design of quadratic electromagnetic exciter to maximize the magnetic force with constraint that the size of exciter is constant. A design optimization problem was formulated in order to find the quadratic electromagnetic exciter shape parameters that maximized the magnetic force. The magnetic force of the quadratic electromagnetic exciter was evaluated using the commercial electromagnetic analysis software “MAXWELL”. For efficient design, we employed metamodel-based design optimization using design of experiments (DOE), metamodels, and an optimization algorithm equipped in PIAnO (Process Integration, Automation and Optimization), a commercial PIDO (Process Integration and Design Optimization) tool. Using the proposed design approach, the optimal magnetic force was increased by 1.68 % compared to the initial one. This result demonstrates the effectiveness of the established analysis and design procedure for the quadratic electromagnetic exciter

    Earnings Management Of Mergers And Acquisitions Of Target Candidates And Deal Withdrawn

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    In this paper, we investigate the tendencies of target candidate companies to manage earnings, which affects financial reporting quality, in order to increase transaction value, and the withdrawal of deals as a result of low financial reporting quality in M&A in a sample of 316 mergers and acquisitions in South Korea between 2002 and 2011. Using the accruals quality measure developed by Dechow and Dichev (2002) as a proxy for financial reporting quality, we find the following. First, the financial reporting quality of target candidate firms is lower than that of non-target candidate firms because target candidate firms engage in earnings management prior to M&A. Second, low-quality financial reporting of target firms is positively related to the likelihood of deal withdrawal as a result of poor financial reporting quality

    Effective field theory of the deuteron with dibaryon field

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    Pionless effective field theory with dibaryon fields is reexamined for observables involving the deuteron. The electromagnetic form factors of the deuteron and the total cross sections of radiative neutron capture on the proton, npdγnp \to d\gamma, are calculated. The low energy constants of vector(photon)-dibaryon-dibaryon vertices in the effective lagrangian are fixed primarily by the one-body vector(photon)-nucleon-nucleon interactions. This scheme for fixing the values of the low energy constants satisfactorily reproduces the results of the effective range theory. We also show that, by including higher order corrections, one can obtain results that are close to those of Argonne v18 potential model.Comment: 25 pages and 11 figures; 16 references added, Figure 6 and 7 replotted, text revised a lot. To be published in Phys. Rev.