112,131 research outputs found

    N K Pi molecular state with I=1 and J(Pi)=3/2-

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    The structure of the molecule-like state of NKπNK\pi with spin-parity Jπ=3/2J^{\pi}={3/2}^- and isospin I=1 is studied within the chiral SU(3) quark model. First we calculate the NKNK, NπN\pi, and KπK\pi phase shifts in the framework of the resonating group method (RGM), and a qualitative agreement with the experimental data is obtained. Then we perform a rough estimation for the energy of (NKπ)Jπ=3/2,I=1(NK\pi)_{J^{\pi}={3/2}^-,I=1}, and the effect of the mixing to the configuration (ΔK)Jπ=3/2,I=1(\Delta K)_{J^{\pi}={3/2}^-,I=1} is also considered. The calculated energy is very close to the threshold of the NKπNK\pi system. A detailed investigation is worth doing in the further study.Comment: 11 pages, 3 figures; accepted for publication in Phys. Rev.

    A new three-parameter correlation for gamma-ray bursts with a plateau phase in the afterglow

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    Gamma ray bursts (GRBs) have great advantages for their huge burst energies, luminosities and high redshifts in probing the Universe. A few interesting luminosity correlations of GRBs have been used to test cosmology models. Especially, for a subsample of long GRBs with known redshifts and a plateau phase in the afterglow, a correlation between the end time of the plateau phase (in the GRB rest frame) and the corresponding X-ray luminosity has been found. In this paper, we re-analyze the subsample and found that a significantly tighter correlation exists when we add a third parameter, i.e. the isotropic γ\gamma-ray energy release, into the consideration. Additionally, both long and intermediate duration GRBs are consistent with the same three-parameter correlation equation. It is argued that the new three-parameter correlation is consistent with the hypothesis that the subsample of GRBs with a plateau phase in the afterglow be associated with the birth of rapidly rotating magnetars, and that the plateau be due to the continuous energy-injection from the magnetar. It is suggested that the newly born millisecond magnetars associated with GRBs might provide a good standard candle in the Universe.Comment: 11 pages, 3 figures, 1 table; A&A, in pres

    Baryon-meson interactions in chiral quark model

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    Using the resonating group method (RGM), we dynamically study the baryon-meson interactions in chiral quark model. Some interesting results are obtained: (1) The Sigma K state has an attractive interaction, which consequently results in a Sigma K quasibound state. When the channel coupling of Sigma K and Lambda K is considered, a sharp resonance appears between the thresholds of these two channels. (2) The interaction of Delta K state with isospin I=1 is attractive, which can make for a Delta K quasibound state. (3) When the coupling to the Lambda K* channel is considered, the N phi is found to be a quasibound state in the extended chiral SU(3) quark model with several MeV binding energy. (4) The calculated S-, P-, D-, and F-wave KN phase shifts achieve a considerable improvement in not only the signs but also the magnitudes in comparison with other's previous quark model study.Comment: 5 pages, 2 figures. Talk given at 3rd Asia Pacific Conference on Few-Body Problems in Physics (APFB05), Korat, Nakhon Ratchasima, Thailand, 26-30 Jul 200

    Resonating group method study of kaon-nucleon elastic scattering in the chiral SU(3) quark model

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    The chiral SU(3) quark model is extended to include an antiquark in order to study the kaon-nucleon system. The model input parameters bub_u, mum_u, msm_s are taken to be the same as in our previous work which focused on the nucleon-nucleon and nucleon-hyperon interactions. The mass of the scalar meson σ\sigma is chosen to be 675 MeV and the mixing of σ0\sigma_0 and σ8\sigma_8 is considered. Using this model the kaon-nucleon SS and PP partial waves phase shifts of isospin I=0 and I=1 have been studied by solving a resonating group method (RGM) equation. The numerical results of S01S_{01}, S11S_{11}, P01P_{01}, P03P_{03}, and P11P_{11} partial waves are in good agreement with the experimental data while the phase shifts of P13P_{13} partial wave are a little bit too repulsive when the laboratory momentum of the kaon meson is greater than 500 MeV in this present calculation.Comment: 17 pages, 6 figures. Final version for publicatio

    N K and Delta K states in the chiral SU(3) quark model

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    The isospin I=0 and I=1 kaon-nucleon SS, PP, DD, FF wave phase shifts are studied in the chiral SU(3) quark model by solving the resonating group method (RGM) equation. The calculated phase shifts for different partial waves are in agreement with the experimental data. Furthermore, the structures of the ΔK\Delta K states with L=0, I=1 and I=2 are investigated. We find that the interaction between Δ\Delta and KK in the case of L=0, I=1 is attractive, which is not like the situation of the NKNK system, where the SS-wave interactions between NN and KK for both I=0 and I=1 are repulsive. Our numerical results also show that when the model parameters are taken to be the same as in our previous NNNN and YNYN scattering calculations, the ΔK\Delta K state with L=0 and I=1 is a weakly bound state with about 2 MeV binding energy, while the one with I=2 is unbound in the present one-channel calculation.Comment: 14 pages, 6 figures. PRC70,064004(2004