The intermediate mass dileptons from the quark phase,secondary hadronic processes and background sources have been studied based on a relativistic hydrodynamic model.Due to the effect of the phase boundary on the evol...The intermediate mass dileptons from the quark phase,secondary hadronic processes and background sources have been studied based on a relativistic hydrodynamic model.Due to the effect of the phase boundary on the evolution of the system the contribution from the quark phase is much more important than that from secondary processes and is even comparable with that from background sources.This leads to a spectrum without the obvious humps of the hadronic phase contribution and the yield increasing with the incident energy of colliding nuclei.It is shown that the enhancement of dileptons is a signature for the formation of the quark--gluon plasma.展开更多
Total reaction cross sections σR for some proton-rich isotones (N = 10) near ^(23)Al on a carbon target have been measured at intermediate energies in the experiment performed at the Radioactive Ion Beam Line of the ...Total reaction cross sections σR for some proton-rich isotones (N = 10) near ^(23)Al on a carbon target have been measured at intermediate energies in the experiment performed at the Radioactive Ion Beam Line of the Heavy Ion Research Facility in Lanzhou. The Z-dependence of σR shows a remarkable enhancement for ^(23)Al relative to its neighbours. The difference factor d has been deduced from the measured σR by using the Glauber or Boltzmann-Uehling-Uhlenbeck models. From the above analysis, a possible one-proton halo structure is suggested for ^(23)Al.展开更多
Under thermodynamic equilibrium, the initial values of the quark-gluon system from relativistic nucleus-nucleus collisions are obtained. From these initial values we have studied the dilepton production on the basis o...Under thermodynamic equilibrium, the initial values of the quark-gluon system from relativistic nucleus-nucleus collisions are obtained. From these initial values we have studied the dilepton production on the basis of the relativistic hydrodynamic model, and found that with increasing incident energy a characteristic plateau indicating the formation of the quark-gluon plasma appears in the total yield.展开更多
From the full stopping scenario,a relativistic hydrodynamic model describing the evolution of the baryon-rich quark-gluon matter fire-cylinder has been established.Based on it,the rapidity Distribution of dileptons wi...From the full stopping scenario,a relativistic hydrodynamic model describing the evolution of the baryon-rich quark-gluon matter fire-cylinder has been established.Based on it,the rapidity Distribution of dileptons with intermediate invariant masses has been studied.It is found that the quark phase gives the dominant contribution to the dilepton spectrum due to the influence of the phase boundary on the evolution of the system,especially the dilepton yield is strongly suppressed with the increasing rapidity.展开更多
The gap equation for the fermion in the gauged Nambu-Jona-Lasinio(NJL)model is derived in nuclear medium with flavors Nf=2.Based on the gap equation,the fermion mass in nuclear medium is obtained and used to determine...The gap equation for the fermion in the gauged Nambu-Jona-Lasinio(NJL)model is derived in nuclear medium with flavors Nf=2.Based on the gap equation,the fermion mass in nuclear medium is obtained and used to determine the properties of the scalar and pseudoscalar mesons.In contrast to the NJL model,the gluonic part has the one-fourth contribution to the fermion mass.The critical density with the chiral symmetry restored is about 6ρ0.展开更多
A relativistic density-dependent Hartree approach in the chiral-symmetry-breaking field model has been developed for nuclear matter.The coupling constants of the relativistic Hartree-Lagrangian are made density depend...A relativistic density-dependent Hartree approach in the chiral-symmetry-breaking field model has been developed for nuclear matter.The coupling constants of the relativistic Hartree-Lagrangian are made density dependence and obtained from the relativistic Brueckner-Bethe-Goldstone results of nuclear matter.The calculated saturation nuclear density,binding-energy and compressibility for nuclear matter are close to the empirical ones.展开更多
基金Supported in part by the 95'Key Project Funds of the Chinese Academy of Sciences under Grant No.KJ 951-A1-410the National Natural Science Foundation of China under Grant Nos.10075051,59831020 and 19975053.
文摘The intermediate mass dileptons from the quark phase,secondary hadronic processes and background sources have been studied based on a relativistic hydrodynamic model.Due to the effect of the phase boundary on the evolution of the system the contribution from the quark phase is much more important than that from secondary processes and is even comparable with that from background sources.This leads to a spectrum without the obvious humps of the hadronic phase contribution and the yield increasing with the incident energy of colliding nuclei.It is shown that the enhancement of dileptons is a signature for the formation of the quark--gluon plasma.
基金Supported by the Major State Basic Research Development Program under contract No.G200077400。
文摘Total reaction cross sections σR for some proton-rich isotones (N = 10) near ^(23)Al on a carbon target have been measured at intermediate energies in the experiment performed at the Radioactive Ion Beam Line of the Heavy Ion Research Facility in Lanzhou. The Z-dependence of σR shows a remarkable enhancement for ^(23)Al relative to its neighbours. The difference factor d has been deduced from the measured σR by using the Glauber or Boltzmann-Uehling-Uhlenbeck models. From the above analysis, a possible one-proton halo structure is suggested for ^(23)Al.
基金95'Key Funds of the Chinese Academy of Sciences(KJ951-A1-410)the National Natural Science Foundation of China under Grant No.19475060.
文摘Under thermodynamic equilibrium, the initial values of the quark-gluon system from relativistic nucleus-nucleus collisions are obtained. From these initial values we have studied the dilepton production on the basis of the relativistic hydrodynamic model, and found that with increasing incident energy a characteristic plateau indicating the formation of the quark-gluon plasma appears in the total yield.
基金Supported by the 95'Key Project Funds of the Chinese Academy of Sciences under Grant No.KJ 951-A1-410.
文摘From the full stopping scenario,a relativistic hydrodynamic model describing the evolution of the baryon-rich quark-gluon matter fire-cylinder has been established.Based on it,the rapidity Distribution of dileptons with intermediate invariant masses has been studied.It is found that the quark phase gives the dominant contribution to the dilepton spectrum due to the influence of the phase boundary on the evolution of the system,especially the dilepton yield is strongly suppressed with the increasing rapidity.
文摘The gap equation for the fermion in the gauged Nambu-Jona-Lasinio(NJL)model is derived in nuclear medium with flavors Nf=2.Based on the gap equation,the fermion mass in nuclear medium is obtained and used to determine the properties of the scalar and pseudoscalar mesons.In contrast to the NJL model,the gluonic part has the one-fourth contribution to the fermion mass.The critical density with the chiral symmetry restored is about 6ρ0.
基金Supported in part by the National Natural Science Foundation of Chinaby the Grant LWTZ of Chinese Academy of Sciences。
文摘A relativistic density-dependent Hartree approach in the chiral-symmetry-breaking field model has been developed for nuclear matter.The coupling constants of the relativistic Hartree-Lagrangian are made density dependence and obtained from the relativistic Brueckner-Bethe-Goldstone results of nuclear matter.The calculated saturation nuclear density,binding-energy and compressibility for nuclear matter are close to the empirical ones.
