119530185
A Unified Description of N-N and Y-N Interactions on Quark Model*
A quark-quark interaction is derived from the Linear expression of Lagrangian which is invariant under the SU(3)(L) x SU(3)(R) infinitesimal transformation, and further used to make a unified study on the N-N and Y-N scattering processes.
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.
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.
115307247
E2/M1 ratio of the Delta gamma N transition within the chiral constituent quark model
118630729
The luminosity function of Swift long gamma-ray bursts
The formation rate of long gamma-ray bursts (GRBs) could follow the cosmic star formation rate (SFR) incorporating with cosmic metallicity evolution. Therefore, the luminosity function (LF) of GRBs can in principle be explored by modeling the redshift-luminosity distributions of Swift observed GRBs. For an assumed LF form as �z(L) / e −L p/L (L=Lp) −� (1 + z) � , we found that (1) the approximate broken-power law distribution of the luminosities of the Swift observed GRBs is probably caused by the luminosity selection of the telescope by reducing the number of the GRBs with low luminosities, (2) the evolution of the LF could approach to be very weak, i.e., � � 0, if the GRB environments are metal-poor as Z < (0:1 0:3)Z� , and (3) the slope of the LF can be derived to be within � � (1:55 1:72) by fitting the redshift distribution of the GRBs and qualitatively explaining the luminosity distribution. Finally, we also suggest an empirical detection efficiency as a function of flux for the Swift Burst Alert Telescope (BAT) in order to model the logN logP distribution of the GRBs.
119302412
HOW CAN NEWLY BORN RAPIDLY ROTATING NEUTRON STARS BECOME MAGNETARS
In a newly born (high-temperature and Keplerian rotating) neutron star, r-mode instability can lead to stellar differential rotation, which winds the seed poloidal magnetic field (∼10{sup 11} G) to generate an ultra-high (∼10{sup 17} G) toroidal field component. Subsequently, by succumbing to the Tayler instability, the toroidal field could be partially transformed into a new poloidal field. Through such dynamo processes, the newly born neutron star with sufficiently rapid rotation could become a magnetar on a timescale of ∼10{sup 2} {sup –} {sup 3} s, with a surface dipolar magnetic field of ∼10{sup 15} G. Accompanying the field amplification, the star could spin down to a period of ∼5 ms through gravitational wave radiation due to the r-mode instability and, in particular, the non-axisymmetric stellar deformation caused by the toroidal field. This scenario provides a possible explanation for why the remnant neutron stars formed in gamma-ray bursts and superluminous supernovae could be millisecond magnetars.
118606996
Modelling the multiwavelength light curves of PSR B1259−63/SS 2883
PSR B1259-63/SS 2883 is a binary system in which a 48-ms pulsar orbits around a Be star in a high eccentric orbit with a long orbital period of about 3.4 yr. Extensive broadband observational data are available for this system from radio band to very high energy (VHE) range. The multi-frequency emission is unpulsed and nonthermal, and is generally thought to be related to the relativistic electrons accelerated from the interaction between the pulsar wind and the stellar wind, where X-ray emission is from the synchrotron process and the VHE emission is from the inverse Compton (IC) scattering process. Here a shocked wind model with variation of the magnetization parameter σ is developed for explaining the observations. By choosing proper parameters, our model could reproduce two-peak profile in X-ray and TeV light curves. The effect of the disk exhibits an emission and an absorption components in the X-ray and TeV bands respectively. We suggest that some GeV flares will be produced by Doppler boosting the synchrotron spectrum. This model can possibly be used and be checked in other similar systems such as LS I+61 o 303 and LS 5039.
52103890
A past capture event at Sagittarius A* inferred from the fluorescent X-ray emission of Sagittarius B clouds
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.
119705192
Preliminary study of the K N interaction in a chiral constituent quark model
A preliminary investigation of $\overline{K}N$ interaction is performed within a chiral constituent quark model by solving the resonating group method (RGM) equation. The model parameters are taken from our previous work, which gave a satisfactory description of the $S$-, $P$-, $D$-, $F$-wave $\mathit{KN}$ scattering phase shifts. The channel-coupling between $\overline{K}N,\ensuremath{\pi}\ensuremath{\Lambda}$ and $\ensuremath{\pi}\ensuremath{\Sigma}$ is considered, and the scattering phase shifts as well as the bound-state problem of $\overline{K}N$ are dynamically studied. The results show that the $S$-wave $\overline{K}N$ interaction in the isospin $I=0$ channel is attractive, and in the extended chiral SU(3) quark model such an attraction can make for a $\overline{K}N$ bound state, which appears as a $\ensuremath{\pi}\ensuremath{\Sigma}$ resonance in the coupled-channel calculation, while the chiral SU(3) quark model cannot accommodate the existence of a $\overline{K}N$ bound state. It seems that the vector meson exchanges are necessary to be introduced in the quark-quark interactions if one tries to explain the $\ensuremath{\Lambda}(1405)$ as a $\overline{K}N$ bound state or a $\ensuremath{\pi}\ensuremath{\Sigma}$-$\overline{K}N$ resonance state.