55,921 research outputs found

    A Novel Genetic Algorithm using Helper Objectives for the 0-1 Knapsack Problem

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    The 0-1 knapsack problem is a well-known combinatorial optimisation problem. Approximation algorithms have been designed for solving it and they return provably good solutions within polynomial time. On the other hand, genetic algorithms are well suited for solving the knapsack problem and they find reasonably good solutions quickly. A naturally arising question is whether genetic algorithms are able to find solutions as good as approximation algorithms do. This paper presents a novel multi-objective optimisation genetic algorithm for solving the 0-1 knapsack problem. Experiment results show that the new algorithm outperforms its rivals, the greedy algorithm, mixed strategy genetic algorithm, and greedy algorithm + mixed strategy genetic algorithm

    Isospin effect on baryon and charge fluctuations from the pNJL model

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    We have studied the possible isospin corrections on the skewness and kurtosis of net-baryon and net-charge fluctuations in the isospin asymmetric matter formed in Au+Au collisions at RHIC-BES energies, based on a 3-flavor polyakov-looped Nambu-Jona-Lasinio model. With typical scalar-isovector and vector-isovector couplings leading to the splitting of uu and dd quark chiral phase transition boundaries and critical points, we have observed dramatic isospin effects on the susceptibilities, especially those of net-charge fluctuations. Reliable experimental measurements at even lower collision energies are encouraged to confirm the observed isospin effects.Comment: 6 pages, 3 figure

    The observed charmed hadron Λc(2940)+\Lambda_c(2940)^+ and the DND^*N interaction

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    In this work, we systematically study the interaction of DD^* and nucleon, which is stimulated by the observation of Λc(2940)+\Lambda_c(2940)^+ close to the threshold of DpD^*p. Our numerical result obtained by the dynamical investigation indicates the existence of the DND^*N systems with JP=1/2±,3/2±J^P=1/2^\pm,\,3/2^\pm, which not only provides valuable information to understand the underlying structure of Λc(2940)+\Lambda_c(2940)^+ but also improves our knowledge of the interaction of DD^* and nucleon. Additionally, the bottom partners of the DND^*N systems are predicted, which might be as one of the tasks in LHCb experiment.Comment: 8 pages, 6 Figures. Accepted for publication in Phys. Rev.

    Nucleon Resonances Near 2 GeV

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    The nucleon resonances near 2 GeV are investigated through the Σ\Sigma(1385) and Λ(1520)\Lambda(1520) photoproductions within a Regge-plus-resonance approach based on the new experimental data released by the CLAS Collaboration. The Δ(2000)\Delta(2000) and the N(2120)N(2120) are found essential to reproduce the experimental data and should be assigned as second [Δ5/2+][\Delta 5/2^+] and third [N3/2][N3/2^-] in the constituent quark model, respectively. A calculation of the binding energy and decay pattern supports that the N(1875)N(1875), which is listed in the PDG as the third N3/2N3/2^- nucleon resonance instead of the N(2120)N(2120), is from the Σ(1385)K\Sigma(1385)K interaction rather than a three quark state.Comment: Talk given at the 10th International Workshop on the Physics of Excited Nucleons (NSTAR2015), Osaka, May 201
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