2,718 research outputs found

    Heavy mesons in the Quark Model

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    Since the discovery of the J/ψJ/\psi, the quark model was very successful in describing the spectrum and properties of heavy mesons including only qqˉq\bar q components. However since 2003, with the discovery of the X(3872)X(3872), many states that can not be accommodated on the naive quark model have been discovered, and they made unavoidable to include higher Fock components on the heavy meson states. We will give an overview of the success of the quark model for heavy mesons and point some of the states that are likely to be more complicated structures such as meson-meson molecules.Comment: Contribution to the Proceedings of the 15th International Workshop on Meson Physics - MESON201

    A very broad X(4260) and the resonance parameters of the 3D vector charmonium state

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    We argue that the X(4260) enhancement contains a wealth of information on vector c-cbar spectroscopy. We discuss the shape of the X(4260) observed in the OZI-forbidden process "electron-positron into J/psi and a pair of charged pions", in particular at and near vector charmonium resonances as well as open-charm threshold enhancements. The resulting very broad X(4260) structure does not seem to classify itself as a vector charmonium resonance, but its detailed shape allows to identify new vector c-cbar states. Here, we estimate the resonance parameters of the psi(3D) state.Comment: 4 pages, 5 figures; version 2: 2 figures replace

    Puzzles in quarkonium hadronic transitions with two pion emission

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    The anomalously large rates of some hadronic transitions from quarkonium are studied using QCD multipole expansion (QCDME) in the framework of a constituent quark model which has been successful in describing hadronic phenomenology. The hybrid intermediate states needed in the QCDME method are calculated in a natural extension of our constituent quark model based on the Quark Confining String (QCS) scheme. Some of the anomalies are explained due to the presence of an hybrid state with a mass near the mass of the decaying resonance whereas other are justified by the presence of molecular components in the wave function. Some unexpected results are pointed out.Comment: Conference proceedings of the XI Quark Confinement and the Hadron Spectrum (CONFINEMENT XI). Saint Petersburg (Russia) from 8 to 12 September 201

    Recomendações técnicas para o cultivo de melancia (Citrullus lanatus [Thumb.] Matsumura & Nakai) no Amapá.

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    Introdução; Botanica; Cultivares; Clima e época de plantio; Solo; Adubação; Preparo da terra; Preparo de mudas; Transplante; Crescimento e desenvolvimento; Tratos culturais; Doenças; Rotação de culturas; Colheita; Armazenamento; Mercado; Coeficientes técnicos; Bibliografia consultada.bitstream/item/97840/1/CPAF-AP-1999-Recomendacoes-melancia.pd

    Physics of outgassing

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    The X(3872) and other possible XYZXYZ molecular states

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    We perform a coupled channel calculation of the DDDD^* and ccˉc\bar c sectors in the framework of a constituent quark model. The interaction for the DDDD^* states is obtained using the Resonant Group Method (RGM) and the underlying quark interaction model. The coupling with the two quark system is performed using the 3P0^3 P_0 model. The X(3872) is found as a molecular state with a sizable ccˉc\bar c component. A comparison with Belle and BaBar data has been done, finding a good agreement. Other possible molecular molecular states are discussed.Comment: 5 pages, 5 figures, Proceedings to the Hadron 2009 - XIII International Conference on Hadron Spectroscopy, Florida State University (USA

    A 300 GHz "Always-in-Focus" Focusing System for Target Detection

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    A focusing system for a 300 GHz radar with 5 m target distance and 10 mm diameter spot size resolution is proposed. The focusing system is based on a Gaussian telescope scheme and its main parameters have been de¬signed using Gaussian beam quasi-optical propagation theory with an in-house developed MATLAB® based analysis tool. Then, this approach has been applied to a real focusing system based on two elliptical mirrors in order to reduce the distortion and cross-polar level and a plane mirror to provide scanning capabilities. The over¬all system has been simulated with a full-wave electromag¬netic simulator and its behavior is presented. With this approach, the focusing system always works "in-focus" since the only mirror that is rotated when scanning is the output plane mirror, so the beam is almost not distorted. The design process, although based in the well-known Gaussian beam quasi-optical propagation theory, provides a fast and accurate method and minimizes the overall size of the mirrors. As a consequence, the size of the focusing system is also reduced
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