41,616 research outputs found

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

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    In this presentation, we report our recent studies on the Kβˆ—Ξ›(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 sthβ‰ˆ2008\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 gKβˆ—S11(1535)Ξ›=(7.0∼9.0)g_{K^*S_{11}(1535)\Lambda}=(7.0\sim9.0) and gKβˆ—S11(1650)Ξ›=(5.0∼6.0)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

    Influence of external disturbances and compressibility on free turbulent mixing

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    It is shown that disturbances in external flow can significantly affect, by as much as an order of magnitude, the turbulent mixing rate in free shear layers and that the length scale of the external flow disturbances is as important as the amplitude. The difference between the effect of wide-band and narrow-band disturbances is stressed. The model for pressure fluctuation term in the kinetic energy equation is included in a two-equation model. The reduced spreading rate in high Mach number, high Reynolds number, adiabatic, free turbulent shear layers is predicted

    An extension of tribimaximal lepton mixing

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    Harrison, Perkins and Scott have proposed simple charged lepton and neutrino mass matrices that lead to the tribimaximal mixing UTBMU_{\rm TBM}. We consider in this work an extension of the mass matrices so that the leptonic mixing matrix becomes UPMNS=VLℓ†UTBMWU_{\rm PMNS}=V_L^{\ell\dagger}U_{\rm TBM}W, where VLβ„“V_L^\ell is a unitary matrix needed to diagonalize the charged lepton mass matrix and WW measures the deviation of the neutrino mixing matrix from the bimaximal form. Hence, corrections to UTBMU_{\rm TBM} arise from both charged lepton and neutrino sectors. Following our previous work to assume a Qin-Ma-like parametrization VQMV_{\rm QM} for the charged lepton mixing matrix VLβ„“V_L^\ell in which the {\it CP}-odd phase is approximately maximal, we study the phenomenological implications in two different scenarios: VLβ„“=VQM†V_L^\ell=V_{\rm QM}^\dagger and VLβ„“=VQMV_L^\ell=V_{\rm QM}. We find that the latter is more preferable, though both scenarios are consistent with the data within 3Οƒ3\sigma ranges. The predicted reactor neutrino mixing angle ΞΈ13\theta_{13} in both scenarios is consistent with the recent T2K and MINOS data. The leptonic {\it CP} violation characterized by the Jarlskog invariant JCPJ_{\rm CP} is generally of order 10βˆ’210^{-2}.Comment: 20 pages and 8 figures, Accepted in Phys.Review
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