112,790 research outputs found

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

The structure of the molecule-like state of $NK\pi$ with spin-parity
$J^{\pi}={3/2}^-$ and isospin I=1 is studied within the chiral SU(3) quark
model. First we calculate the $NK$, $N\pi$, and $K\pi$ 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 $(NK\pi)_{J^{\pi}={3/2}^-,I=1}$, and the effect of the mixing to
the configuration $(\Delta K)_{J^{\pi}={3/2}^-,I=1}$ is also considered. The
calculated energy is very close to the threshold of the $NK\pi$ 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

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
$\gamma$-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

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

The chiral SU(3) quark model is extended to include an antiquark in order to
study the kaon-nucleon system. The model input parameters $b_u$, $m_u$, $m_s$
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
$\sigma$ is chosen to be 675 MeV and the mixing of $\sigma_0$ and $\sigma_8$ is
considered. Using this model the kaon-nucleon $S$ and $P$ 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 $S_{01}$, $S_{11}$, $P_{01}$,
$P_{03}$, and $P_{11}$ partial waves are in good agreement with the
experimental data while the phase shifts of $P_{13}$ 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

### Baryon-meson interactions in chiral quark model

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

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

The isospin I=0 and I=1 kaon-nucleon $S$, $P$, $D$, $F$ 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
$\Delta K$ states with L=0, I=1 and I=2 are investigated. We find that the
interaction between $\Delta$ and $K$ in the case of L=0, I=1 is attractive,
which is not like the situation of the $NK$ system, where the $S$-wave
interactions between $N$ and $K$ 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 $NN$ and $YN$ scattering calculations, the $\Delta K$
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

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