124346116
The Strong decay of s mesons in the quark pair creation model
123526917
Multi-strange hadronic systems in a chiral SU(3) quark mean field model
We apply the chiral SU(3) quark mean field model to investigate the finite nuclei. We find that the combined confining potential chi(c)(C) is more proper to describe finite nuclei compared with the scalar and scalar-vector potentials. The hypernuclei and multi-strange objects which include A and Xi are discussed in this model. The maximum binding energy for such kind of multi-strange objects is about 16-17 MeV and the corresponding strangeness fraction f(s) is around 1.2-1.3. (C) 2002 Elsevier Science B.V. All rights reserved.
115307247
E2/M1 ratio of the Delta gamma N transition within the chiral constituent quark model
121548156
BARYON–BARYON INTERACTION IN THE EXTENDED CHIRAL SU(3) QUARK MODEL
The hyperon-nucleon scattering processes and some dibaryon states are studied both in the chiral SU(3) quark model and in the extended chiral SU(3) quark model by solving the resonating group method (RGM) equation. We find that the short-range interaction could be described either by the one-gluon exchange or by the vector meson exchange for baryon-baryon system.
120491051
Hyperon-Meson Vertices and Hyperon-Nucleon Interactions on Quark Model
In this paper, we introduce two parts of work: the hyperon-meson vertex structure from the one-gluon-exchange quark-antiquark pair creation model and the hyperon-nucleon interactions on a modified quark potential model. For both parts some significant results have been obtained.
122341351
Color screening effect in the quark potential model
By using the color confinement potential which includes the color screening effect, we studied the baryon spectra and the nucleon-nucleon interaction. The results show that the color screening effect not only improves the baryon spectrum calculation, but also can solve the long-tail problem of the color Van der Waals force. A part of the medium attraction of the nuclear force can be obtained from the color Van der Waals force.
118964566
DETERMINING THE LUMINOSITY FUNCTION OF SWIFT LONG GAMMA-RAY BURSTS WITH PSEUDO-REDSHIFTS
The determination of the luminosity function (LF) of gamma-ray bursts (GRBs) is an important role for the cosmological applications of the GRBs, which, however, is seriously hindered by some selection effects due to redshift measurements. In order to avoid these selection effects, we suggest calculating pseudo-redshifts for Swift GRBs according to the empirical L-Ep relationship. Here, such a L-Ep relationship is determined by reconciling the distributions of pseudo- and real redshifts of redshift-known GRBs. The values of Ep taken from Butler's GRB catalog are estimated with Bayesian statistics rather than observed. Using the GRB sample with pseudo-redshifts of a relatively large number, we fit the redshift-resolved luminosity distributions of the GRBs with a broken-power-law LF. The fitting results suggest that the LF could evolve with redshift by a redshift-dependent break luminosity, e.g., Lb = 1.2 × 1051(1 + z)2 erg s–1. The low- and high-luminosity indices are constrained to 0.8 and 2.0, respectively. It is found that the proportional coefficient between the GRB event rate and the star formation rate should correspondingly decrease with increasing redshifts.
120879129
Effect of a strong magnetic field on the surface electric field of strange stars
We made a detailed study of the properties of the electron layer near the quark surface of strange stars with strong (${\sim}10^{14}{-}10^{17}$ G) magnetic fields. The electrostatic potential and the electric field at the quark surface were calculated as functions of the magnetic field intensity of bare strange stars. Using an ultrastrong ($B\geq 2.5\times10^{16}$ G) magnetic field, we found that the distribution of electrons becomes an exponential function of radial distance, which is quite different in a magnetic field-free case. We also calculated the variation in gap width between the strange core and the normal nuclear crust for strange stars, which is due to magnetic field effect.
119105601
Could strange stars be in the color-flavor-locked phase: Tested by their thermal evolutions
The thermal evolution of strange stars in both normal and color-flavor-locked (CFL) phases are investigated together with the evolutions of the stellar rotation and the r-mode instability. The heating effects due to the deconfinement transition of the stellar crust and the dissipation of the r-modes are considered. As a result, the cooling of the stars in the normal phase is found to be not very different from the standard one. In contrast, for the stars in the CFL phase, a big bump during the first hundred years and a steep decay ($\sim$7% in ten years) at the ages of $\sim10^{4-6}$ yrs are predicted in their thermal evolution curves. These unique features provide an effective observational test for determining whether or not the CFL phase is reached in strange stars. This thermal test method is independent of and complementary to the rotational test method, which is a direct consequence of the r-mode instability.
8862653
Shallow decay phase of GRB X-ray afterglows from relativistic wind bubbles
Aims. The postburst object of a GRB is likely to be a highly magnetized, rapidly rotating compact object (e.g., a millisecond magnetar), which could produce an ultrarelativistic electron-positron-pair wind. The interaction of such a wind with an outwardly expanding fireball ejected during the burst leads to a relativistic wind bubble (RWB). We investigate the properties of RWBs and use this model to explain the shallow decay phase of the early X-ray afterglows observed by Swift. Methods. We numerically calculate the dynamics and radiative properties of RWBs. Results. We find that RWBs can fall into two types: forward-shock-dominated and reverse-shock-dominated bubbles. Their radiation during a period of ~$10^{2}{-}10^{5}$ s is dominated by the shocked medium and the shocked wind, respectively, based on different magnetic energy fractions of the shocked materials. For both types, the resulting light curves always have a shallow decay phase, as discovered by Swift. In addition, we provide an example fit to the X-ray afterglows of GRB 060813 and GRB 060814 and show that they could be produced by forward-shock-dominated and reverse-shock-dominated bubbles, respectively. This implies that, for some early afterglows (e.g., GRB 060814), the long-lasting reverse shock emission is strong enough to explain their shallow decay phase.
73573157
Implications of the cosmic infrared background excess for the cosmic star formation
AbstractBy phenomenologically describing the high-redshift star formation history, i.e., $$\dot \rho _ * \left( z \right) \propto \left[ {{{\left( {1 + z} \right)} \mathord{\left/
 {\vphantom {{\left( {1 + z} \right)} {4.5}}} \right.
 \kern-\nulldelimiterspace} {4.5}}} \right]^{ - \alpha }$$, and semi-analytically calculating the fractions of high-redshift Pop I/II and Pop III stars, we investigate the contributions from both high-redshfit Pop I/II and Pop III stars to the observed near-infrared (3 μm < λ < 5 μm) excess in the cosmic infrared background emission. In order to account for the observational level of the near-infrared excess, the power-law index α of the assumed star formation history is constrained to within the range of 0 ≲ α ≲ 1. Such a constraint is obtained under the condition that the viral temperature of dark matter halos belongs to the range of 500 K ⩽ Tvir ⩽ 104 K.