122517767
Structure of H-dihyperon
The structure of H dihyperon (DH) is investigated by employing the SU (3) chiral quark model. As the structure of DH, two different configurations, six-quark cluster configuration and two-cluster configuration, are considered respectively. The result shows that except the sigma chiral field, the overall effect of the other SU (3) chiral fields is destructive in forming a stable DH and the two-cluster configuration is the preferred structure. The resultant mass of DH in a three-coupled-channel calculation in the SU (3) chiral quark model is ranged from 2225 to 2234 MeV.
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.
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.
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.
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
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.
15555566
X-RAY AND HIGH-ENERGY FLARES FROM LATE INTERNAL SHOCKS OF GAMMA-RAY BURSTS
We study afterglow flares of gamma-ray bursts (GRBs) in the framework of the late internal shock (LIS) model based on a careful description for the dynamics of a pair of shocks generated by a collision between two homogeneous shells. First, by confronting the model with some fundamental observational features of X-ray flares, we find some constraints on the properties of the pre-collision shells that are directly determined by the central engine of GRBs. Second, high-energy emission associated with X-ray flares, which arises from synchrotron self-Compton emission of LISs, is investigated in a wide parameter space. The predicted flux of high-energy flares may reach as high as ~10–8 erg cm–2 s–1, which is likely to be detectable with the Large Area Telescope aboard the Fermi Space Telescope (formerly GLAST).
118420850
The role of r-mode damping in the thermal evolution of neutron stars
The thermal evolution of neutron stars (NSs) is investigated through coupling with the evolution of r-mode instability, which is described by a second-order model. The heating effect due to shear viscous damping of the r modes enables us to understand the high temperature of two young pulsars (PSR B0531+21 and RX J0822-4300) in the framework of the simple neutron-proton-electron (npe) NS model, without superfluidity or exotic particles. Moreover, the light curves predicted by the model within an acceptable parameter regime probably cover all of the young and middle-aged pulsars in the Ig T ∞ s -lg t panel, and the artificially strong p superfluidity invoked in some early works is not needed here. Additionally, by considering the radiative viscous damping of the r modes, a surprising extra cooling effect is found that can even exceed the heating effect at times, although it plays a negligible role in the thermal history.
36377156
BRIGHT "MERGER-NOVA" FROM THE REMNANT OF A NEUTRON STAR BINARY MERGER: A SIGNATURE OF A NEWLY BORN, MASSIVE, MILLISECOND MAGNETAR
A massive millisecond magnetar may survive the merger of a neutron star (NS) binary, which would continuously power the merger ejecta. We develop a generic dynamic model for the merger ejecta with energy injection from the central magnetar. The ejecta emission (the “merger-nova”) powered by the magnetar peaks in the UV band and the peak of the light curve progressively shifts to an earlier epoch with increasing frequency. A magnetar-powered mergernova could have an optical peak brightness comparable to a supernova, which is a few tens or hundreds times brighter than the radioactive-powered merger-novae (the so-called macro-nova or kilo-nova). On the other hand, such a merger-nova would peak earlier and have a significantly shorter duration than that of a supernova. An early collapse of the magnetar could suppress the brightness of the optical emission and shorten its duration. Such millisecond-magnetar-powered merger-novae may be detected from NS-NS merger events without an observed short gamma-ray burst, and could be a bright electromagnetic counterpart for gravitational wave bursts due to NS-NS mergers. If detected, it suggests that the merger leaves behind a massive NS, which has important implications for the equation-of-state of nuclear matter. Subject headings: gamma-ray burst: general — supernovae: general — stars: neutron
56454115
The role of newly born magnetars in gamma-ray burst X-ray afterglow emission: Energy injection and internal emission
Swift observations suggest that the central compact objects of some gamma-ray bursts (GRBs) could be newly born millisecond magnetars. Therefore, considering the spin evolution of the magnetars against r-mode instability, we investigate the role of magnetars in GRB X-ray afterglow emission. Besides modifying the conventional energy injection model, we pay particular attention to the internal X-ray afterglow emission, whose luminosity is assumed to track the magnetic dipole luminosity of the magnetars with a certain fraction. Following a comparison between the model and some selected observational samples, we suggest that some so-called canonical X-ray afterglows including the shallow decay, normal decay, and steeper-than-normal decay phases could be internally produced by the magnetars (possibly through some internal dissipations of the magnetar winds), while the (energized) external shocks are associated with another type of X-ray afterglows. If this is true, then from those internal X-ray afterglows we can further determine the magnetic field strengths and the initial spin periods of the corresponding magnetars.