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The second‐order effects (SOE) including a pole contribution of the Λ(1405) (Λ*) and range terms on the structure of multi‐antikaonic nuclei are investigated in a relativistic mean‐field theory coupled with the nonlinear effective chiral Lagrangian. It is shown that, due to the attractive interaction from the Λ*‐pole contribution, the K− mesons and the protons are more attracted each other than the case without the SOE. On the other hand, the density distribution for neutron is pushed outward due to the repulsive effect from the range terms. The SOE on the formation of the bound state of K− mesons are also discussed associated with modification of relevant kaonic modes in a dense medium.

Recently, the central source of Cassiopeia A (Cas A) has been observed, which indicates that the star has large mass and high effective temperature. We suspect that the compact object cools by the standard neutrino emission. We assume that the compact object contains quark matter with colour superconductivity and calculate cooling curves. Considering the Quark‐Hadron Mixed Phase, we obtain cooling curves which are found to be consistent with the observations.

The structure of multi‐antikaonic nuclei (MKN) is investigated in a relativistic mean‐field theory coupled with the nonlinear K− field by the use of effective chiral Lagrangian. The effects of the Λ(1405) range terms on the structure of the MKN are taken into account. It is shown that baryon number density exceeds three times the normal saturation density in the central region of the MKN that a neutron skin structure becomes remarkable as the number of the embedded K− mesons increases. The similarity difference between the MKN kaon condensation in neutron stars are discussed.

We study the hadron‐quark phase transition with finite size effects at a finite temperature. For the hadron phase, we adopt a realistic equation of state with the Brueckner‐Hartree‐Fock theory including hyperons. Properties of the mixed phase are clarified by considering the finite size effects under the Gibbs conditions. We find that the equation of state gets closer to that given by the Maxwell construction. We also find that the equation of state becomes softer than that at a zero temperature for some density region. Moreover, the number of hyperons is suppressed by the presence of quarks. These are characteristic features of the hadron‐quark mixed phase, and should be important for many astrophysical phenomena such as mergers of binary neutron stars.

The effects of the K−K interactions on properties of the multi‐antikaonic nuclei (MKN), in which several K− mesons are embedded to form deeply bound states, are investigated based on chiral symmetry combined with the relativistic mean‐field theory. The K−K interactions originate from two contributions: One is the contact interaction between antikaons inherent in chiral symmetry, and the other is the one generated through coupling between the K− and meson mean fields. It is shown that the former leads to saturation of not only nuclear density profiles but also the strength of the K− field at the center of the MKN and that both parts of the K−K repulsive interactions have a large contribution to the ground state energy of the K− mesons and binding energy of the MKN as the number of the embedded K− mesons increases.

We investigate the properties of nuclear matter at the first-order phase transitions (FOPT) such as liquid-gas phase transition, kaon condensation, and hadron-quark phase transition. As a general feature of the FOPT of matter consisting of many species of charged particles, there appears a mixed phases with regular structures called "pasta" due to the balance of the Coulomb repulsion and the surface tension between two phases. The equation of state (EOS) of mixed phase is different from those obtained by a bulk application of Gibbs conditions or by the Maxwell construction due to the effects of the non-uniform structure. We show that the charge screening and strong surface tension make the EOS close to that of the Maxwell construction., Proceedings for the 6th Japan-Italy symposium on Heavy Ion Physics, Tokai, Japan, 11-15th Nov. 2008. to appear on AIP Conference Proceedings

There are many common features in nuclear data for energy applications and nuclear cosmology/astrophysics, especially the neutron‐capture nucleosynthesis. Therefore it is a natural consequence to think that many of the tools that we have developed for the conventional nuclear‐data applications can be applied for a development of a database for nuclear cosmology/astrophysics. However, there are also many features that are uncommon to these fields, so new development is necessary when we think about a database for nuclear cosmology and astrophysics. Such new development will then give us a new horizon for the conventional nuclear data activities as well. In this paper we will show the present status of our activities in this direction, putting emphasis on data relevant to neutron capture nucleosynthesis, namely s‐ and r‐processes.

We investigate the formation and the decay of heavy systems which are above the fission barrier. By using a microscopic simulation of constraint molecular dynamics (CoMD) on Au+Au collision, we observe composite states stay for very long time before decaying by fission.

The 112Sn+58Ni and 124Sn+64Ni systems at 35 MeV/nucleon have studied by means of the recently proposed Constrained Molecular Dynamics model (CoMD). Different aspects concerning the central and mid‐peripheral collisions are put in evidence. In particular asymmetry distributions of the produced cluster are discussed.