Subthreshold kaon (K0 and K+) production in neutron-rich nuclear reactions to probe the kaon-nucleon interaction in nuclear medium and to extract the isospin dependent part of the nuclear equation of state at high-baryon densities, was investigated within the Lanzhou Quantum Molecular Dynamics (LQMD) model by the Theory Group at Institute of Modern Physics, Chinese Academy of Sciences (IMP-CAS).
It was found that the kaon-nucleon (KN) potential played an important role on kaon emission in phase space, in particular, reducing the kaon yields in the mid-rapidity region and also at low transverse momenta, but enhancing the production at high transverse momenta. The isospin ratio of K0/K+ depended on the kaon potential at high transverse momenta, and a flat spectrum appeared after inclusion of the KN potential. The K0/K+ ratio of neutron-rich heavy system in the domain of subthreshold energies was sensitive to the stiffness of nuclear symmetry energy.
The high-density behavior of nuclear symmetry energy was important in understanding the issues of astrophysics, such as the structure of neutron star, the nucleosynthesis during supernova explosion of massive stars etc.
Kaons (K0 and K+) as a probe of nuclear equation of state were produced during the compression stage in heavy-ion collisions without subsequent reabsorption in nuclear medium. The conclusions in this work are helpful for the forthcoming experiments at Heavy Ion Accelerator Facility (HIAF).
The results have been published inPhysical Review C87 (2013) 064605.
This work was supported by the National Natural Science Foundation of China under Grant Nos 10805061 and 11175218, and the Youth Innovation Promotion Association of CAS.
Fig.1 Total multiplicities of K0 and K+ as a function of incident energy in central 197Au+197Au collisions for the hard and supersoft symmetry energies. (Image by IMP)
Fig. 2 Excitation functions of the K0/K+ ratios for central 197Au+197Au collisions. (Image by IMP)
Introduction
