Color screening effect in b anti-b system

title: Color screening effect in the quark potential model
abstract: 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.

title: Hyperon-Meson Vertices and Hyperon-Nucleon Interactions on Quark Model
abstract: 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.

title: Multi-strange hadronic systems in a chiral SU(3) quark mean field model
abstract: 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.

title: E2/M1 ratio of the Delta gamma N transition within the chiral constituent quark model

title: BARYON–BARYON INTERACTION IN THE EXTENDED CHIRAL SU(3) QUARK MODEL
abstract: 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.

title: Cosmic histories of star formation and reionization: an analysis with a power-law approximation
abstract: With a simple power-law approximation of high-redshift (3.5) star formation history, i.e., *(z)[(1+z)/4.5]??, we investigate the reionization of intergalactic medium (IGM) and the consequent Thomson scattering optical depth for cosmic microwave background (CMB) photons. A constraint on the evolution index ? is derived from the CMB optical depth measured by the Wilkinson Microwave Anisotropy Probe (WMAP) experiment, which reads ? ? 2.18 lg ??3.89, where the free parameter ? is the number of the escaped ionizing ultraviolet photons per baryon. At the same time, the redshift zf at which the IGM is fully ionized can also be expressed as a function of ? as well as ?. By further taking into account the implication of the Gunn-Peterson trough observations to quasars for the full reionization redshift, i.e., 6zf7, we obtain 0.3?1.3 and 80?230. For a typical number of ~ 4000 of ionizing photons released per baryon of normal stars, the fraction of these photons escaping from the stars, fesc, can be constrained to within the range of (2.0?5.8)%.

title: Effect of a strong magnetic field on the surface electric field of strange stars
abstract: 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.

title: A past capture event at Sagittarius A* inferred from the fluorescent X-ray emission of Sagittarius B clouds
abstract: The fluorescent X-ray emission from neutral iron in the molecular clouds [Sagittarius (Sgr) B] indicates that the clouds are being irradiated by an external X-ray source. The source is probably associated with the Galactic central black hole (Sgr A*), which triggered a bright outburst 100 yr ago. We suggest that such an outburst could be due to a partial capture of a star by Sgr A*, during which a jet was generated. Using constraints from the observed flux and the time variability (∼10 yr) of the Sgr B fluorescent emission, we find that the shock produced by the interaction of the jet with the dense interstellar medium represents a plausible candidate for the X-ray source emission.

title: Thermal evolution of rotating strange stars in color superconductivity phase

title: The Newly Born Magnetars Powering Gamma-Ray Burst Internal-Plateau Emission: Are There Strange Stars?
abstract: The internal-plateau X-ray emission of gamma-ray bursts (GRBs) indicates that a newly born magnetar could be the central object of some GRBs. The observed luminosity and duration of the plateaus suggest that, for such a magnetar, a rapid spin with a sub- or millisecond period is sometimes able to last thousands of seconds. In this case, the conventional neutron star (NS) model for the magnetar may be challenged, since the rapid spin of nascent NSs would be remarkably decelerated within hundreds of seconds due to r-mode instability. In contrast, the r-modes can be effectively suppressed in nascent strange stars (SSs). In other words, to a certain extent, only SSs can keep nearly constant extremely rapid spin for a long period of time during the early ages of the stars. We thus propose that the sample of the GRB rapidly spinning magnetars can be used to test the SS hypothesis based on the distinct spin limits of NSs and SSs.