26,034 research outputs found

    Strong decays of N(1535)N^{*}(1535) in an extended chiral quark model

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    The strong decays of the N(1535)N^{*}(1535) resonance are investigated in an extended chiral quark model by including the low-lying qqqqqˉqqqq\bar{q} components in addition to the qqqqqq component. The results show that these five-quark components in N(1535)N^{*}(1535) contribute significantly to the N(1535)NπN^{*}(1535)\to N\pi and N(1535)NηN^{*}(1535)\to N\eta decays. The contributions to the NηN\eta decay come from both the lowest energy and the next-to-lowest energy five-quarks components, while the contributions to the NπN\pi decay come from only the latter one. Taking these contributions into account, the description for the strong decays of N(1535)N^{*}(1535) is improved, especially, for the puzzling large ratio of the decays to NηN\eta and NπN\pi.Comment: 6 pages, 1 figur

    Structure And Properties of Nanoparticles Formed under Conditions of Wire Electrical Explosion

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    Structure and properties of nanoparticles formed under conditions of wire electrical explosion were studied. It was shown that the state of WEE power particles can be characterized as a metastable state. It leads to an increased stability of nanopowders at normal temperatures and an increased reactivity during heating, which is revealed in the form of threshold phenomena.Comment: Submitted on behalf of TIMA Editions (http://irevues.inist.fr/tima-editions

    Strangeness spin, magnetic moment and strangeness configurations of the proton

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    The implications of the empirical signatures for the positivity of the strangeness magnetic moment μs\mu_s, and the negativity of the strangeness contribution to the proton spin Δs\Delta_s, on the possible uudssˉuuds\bar s configurations of five quarks in the proton are analyzed. The empirical signs for the values of these two observables can only be obtained in configurations where the uudsuuds system is orbitally excited and the sˉ\bar s quark is in the ground state. The configurations, in which the sˉ\bar s is orbitally excited, which include the conventional K+Λ0K^+\Lambda^0 congfiguration, with the exception of that, in which the uudsuuds component has spin 2, yield negative values for μs\mu_s. Here the strangeness spin Δs\Delta_s, the strangeness magnetic moment μs\mu_s and the axial coupling constant GAsG_A^s are calculated for all possible configurations of the uudssˉuuds\bar s component of the proton. In the configuration with [4]FS[22]F[22]S[4]_{FS}[22]_F[22]_S flavor-spin symmetry, which is likely to have the lowest energy, μs\mu_s is positive and ΔsGAs1/3μs\Delta_s\simeq G_A^s\simeq -1/3\mu_s.Comment: 17 page

    Breaking the News: First Impressions Matter on Online News

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    A growing number of people are changing the way they consume news, replacing the traditional physical newspapers and magazines by their virtual online versions or/and weblogs. The interactivity and immediacy present in online news are changing the way news are being produced and exposed by media corporations. News websites have to create effective strategies to catch people's attention and attract their clicks. In this paper we investigate possible strategies used by online news corporations in the design of their news headlines. We analyze the content of 69,907 headlines produced by four major global media corporations during a minimum of eight consecutive months in 2014. In order to discover strategies that could be used to attract clicks, we extracted features from the text of the news headlines related to the sentiment polarity of the headline. We discovered that the sentiment of the headline is strongly related to the popularity of the news and also with the dynamics of the posted comments on that particular news.Comment: The paper appears in ICWSM 201

    Entangling two distant nanocavities via a waveguide

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    In this paper, we investigate the generation of continuous variable entanglement between two spatially-separate nanocavities mediated by a coupled resonator optical waveguide in photonic crystals. By solving the exact dynamics of the cavity system coupled to the waveguide, the entanglement and purity of the two-mode cavity state are discussed in detail for the initially separated squeezing inputs. It is found that the stable and pure entangled state of the two distant nanocavities can be achieved with the requirement of only a weak cavity-waveguide coupling when the cavities are resonant with the band center of the waveguide. The strong couplings between the cavities and the waveguide lead to the entanglement sudden death and sudden birth. When the frequencies of the cavities lie outside the band of the waveguide, the waveguide-induced cross frequency shift between the cavities can optimize the achievable entanglement. It is also shown that the entanglement can be easily manipulated through the changes of the cavity frequencies within the waveguide band.Comment: 8 pages, 8 figure

    Laser Control of Dissipative Two-Exciton Dynamics in Molecular Aggregates

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    There are two types of two-photon transitions in molecular aggregates, that is, non-local excitations of two monomers and local double excitations to some higher excited intra-monomer electronic state. As a consequence of the inter-monomer Coulomb interaction these different excitation states are coupled to each other. Higher excited intra-monomer states are rather short-lived due to efficient internal conversion of electronic into vibrational energy. Combining both processes leads to the annihilation of an electronic excitation state, which is a major loss channel for establishing high excitation densities in molecular aggregates. Applying theoretical pulse optimization techniques to a Frenkel exciton model it is shown that the dynamics of two-exciton states in linear aggregates (dimer to tetramer) can be influenced by ultrafast shaped laser pulses. In particular, it is studied to what extent the decay of the two-exciton population by inter-band transitions can be transiently suppressed. Intra-band dynamics is described by a dissipative hierarchy equation approach, which takes into account strong exciton-vibrational coupling in the non-Markovian regime.Comment: revised version, fig. 8 ne

    Tau mesonic decays and strong anomaly of PCAC

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    Strong anomaly of the PCAC is found in τωππν\tau\rightarrow\omega \pi\pi\nu and ωρν\omega\rho\nu in the chiral limit. It originates in WZW anomaly. Theoretical result of τωππν\tau\rightarrow\omega\pi\pi\nu agrees with data well and the measurement of τωρν\tau\rightarrow\omega\rho\nu will confirm the strong anomaly of PCAC. The strong anomaly of PCAC is studied.Comment: 27 page
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