In-medium Effects in the Eta-Photoproduction through the S11S_{11} Resonance with the Relativistic Approach

In-medium effects in photon excitation of the S$_{11}$ resonance from nucleon and its decay to $\eta$-meson using the RMF approach is studied. We examine the in-medium effects by varing the Dirac fields of the nucleon and the S$_{11}$ resonance separately. We obtained a conclusion that the Dirac fields of the nucleon, which reduces the nucleon effective mass, enlarge the width of S$_{11}$ resonance, and small Dirac-fields of the resonance shifts the peak position, and these combined effects can explain the in-medium properties observed in the experimental data for $^{12}$C($\gamma$,$\eta$) reaction.Comment: 10 pages and 3 figure

Hyperon-Quark Mixed Phase in Compact Stars

We investigate the properties of the hadron-quark mixed phase in compact stars using a Brueckner-Hartree-Fock framework for hadronic matter and the MIT bag model for quark matter. We find that the equation of state of the mixed phase is similar to that given by the Maxwell construction. The composition of the mixed phase, however, is very different from that of the Maxwell construction; in particular, hyperons are completely suppressed.Comment: oral presentation at INPC 2007, Toky

Relativistic Effects in the Transverse Flow in the Molecular Dynamics Framework

In order to investigate relativistic effects we compare the transverse flow calculated by using the four versions of the QMD approaches with that of the full covariant RQMD approach. From the comparison we conclude that the simplified RQMD (RQMD/S), which uses the common time coordinate to all particles, can be used instead of RQMD up to 6 GeV/u.Comment: 6pages, Latex is used, 1 Postscript figures are available by request from [email protected]

Coulomb screening effect on the nuclear-pasta structure

Using the density functional theory (DFT) with the relativistic mean field (RMF) model, we study the non-uniform state of nuclear matter, ``nuclear pasta''. We self-consistently include the Coulomb interaction together with other interactions. It is found that the Coulomb screening effect is significant for each pasta structure but not for the bulk equation of state (EOS) of the nuclear pasta phase