1,924 research outputs found

    Quark Models of Baryon Masses and Decays

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    The description of baryon resonance masses and decays in the constituent quark model is outlined, with emphasis on the potential-model approach combined with the 3P0 pair-creation model of strong decays. This approach allows the estimation of branching fractions for baryon states missing in pion nucleon elastic scattering analyses but expected to be present in electromagnetic production. Prospects for the discovery of hybrid baryons are discussed. A subjective list of the most important corrections required to this approach is presented.Comment: 10 pages, 5 figures. Invited contribution to the COSY Workshop on Baryon Excitations, Juelich, 2-3 May 200

    Structure of baryons in a relativistic quark model

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    Baryonic excitation spectra, electroweak and strong decay properties are discussed within a relativistically covariant constituent quark model based on the instantaneous approximation to the three-body Bethe-Salpeter equation.Comment: 7 pages, 2 figures, Contribution to the Proceedings of the 17th International IUPAP Conference on Few-Body Problems in Physics, Durham, North Carolina, USA, 5-10 June 200

    Evidence for the fourth P11 resonance predicted by the constituent quark model

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    It is pointed out that the third of five low-lying P11 states predicted by a constituent quark model can be identified with the third of four states in a solution from a three-channel analysis by the Zagreb group. This is one of the so-called ``missing'' resonances, predicted at 1880 MeV. The fit of the Zagreb group to the pi N -> eta N data is the crucial element in finding this fourth resonance in the P11 partial wave.Comment: 8 pages, revtex; expanded acknowledgement

    Interpretation of the Theta+ as an isotensor pentaquark with weakly decaying partners

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    The Theta+(1540), recently observed at LEPS, DIANA and CLAS, is hypothesized to be an isotensor resonance. This implies the existence of a multiplet where the Theta++, Theta+ and Theta0 have isospin-violating strong decays, and the Theta+++ and Theta- have weak decays and so are long-lived. Production mechanisms for these states are discussed. The J^P assignment of the Theta is most likely 1/2^- or 3/2^-.Comment: references added, section on pentaquark model revised, 11 pages, LaTeX, accepted for publication in Physics Letters

    ESTABLISHING PRIORITIES AMONG MULTIPLE MANAGEMENT GOALS

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    Institutional and Behavioral Economics,

    K*{\Lambda}(1116) photoproduction and nucleon resonances

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    In this presentation, we report our recent studies on the KΛ(1116)K^*\Lambda(1116) photoproduction off the proton target, using the tree-level Born approximation, via the effective Lagrangian approach. In addition, we include the nine (three- or four-star confirmed) nucleon resonances below the threshold sth2008\sqrt{s}_\mathrm{th}\approx2008 MeV, to interpret the discrepancy between the experiment and previous theoretical studies, in the vicinity of the threshold region. From the numerical studies, we observe that the S11(1535)S_{11}(1535) and S11(1650)S_{11}(1650) play an important role for the cross-section enhancement near the sth\sqrt{s}_\mathrm{th}. It also turns out that, in order to reproduce the data, we have the vector coupling constants gKS11(1535)Λ=(7.09.0)g_{K^*S_{11}(1535)\Lambda}=(7.0\sim9.0) and gKS11(1650)Λ=(5.06.0)g_{K^*S_{11}(1650)\Lambda}=(5.0\sim6.0).Comment: 2 pages, 2 figures, talk given at International Conference on the structure of baryons, BARYONS'10, Dec. 7-11, 2010, Osaka, Japa

    Travels with a Flipcam: bringing the community to people with dementia in a day care setting through visual technology.

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    This paper discusses the exploratory process of making a short digital film with two women with early-onset dementia in a day care setting. The film was produced as part of a larger participatory video (PV) pilot project within the day centre. My main subject here is the adaptations to the standard PV process which I made in order for the two women, Pam and Carol*, to be able to take active part. These adjustments took account of their individual abilities related to cognition, physical mobility and social confidence. I discuss the development of an asynchronous approach, which involved my going out into the local community to capture images of Leeds City Market using a mini-camcorder (Flipcam) and the subsequent addition, at the day centre, of voice-over commentary by the two women in response to the visual images they saw on screen. Extracts from their film narrative presented here suggest that participation in the film-making process helped to reconstruct their sense of cultural identity and social engagement. The resulting short film is now being disseminated to Dementia Studies degree students by way of their social networking site
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