Kohsuke Tsubakihara

Tables of hyperonic matter equation of state for core-collapse supernovae*

We present sets of equation of state (EOS) of nuclear matter including hyperons using an SUf(3) extended relativistic mean field (RMF) model with a wide coverage of density, temperature and charge fraction for numerical simulations of core-collapse supernovae. Coupling constants of ? and ? hyperons with the ? meson are determined to fit the hyperon potential depths in nuclear matter, U?(?0) +30 MeV and U?(?0) ?15 MeV, which are suggested from recent analyses of hyperon production reactions. At low densities, the EOS of uniform matter is connected with the EOS by Shen et al, in which the formation of finite nuclei is included in the Thomas?Fermi approximation. In the present EOS, the maximum mass of neutron stars decreases from 2.17 M? (Ne?) to 1.63 M? (NYe?) when hyperons are included. In a spherical, adiabatic collapse of a 15 M? star by the hydrodynamics without neutrino transfer, hyperon effects are found to be small, since the temperature and density do not reach the region of hyperon mixture, where the hyperon fraction is above 1 % (T > 40 MeV or ?B > 0.4 fm?3).

Analysis of (π K+) and (K-, K+) hypernuclear production spectra in distorted-wave impulse approximation

Abstract.We study the hyperon-nucleus potential with distorted-wave impulse wave approximation (DWIA) using the Greens function method. In order to include the nucleon and hyperon potential effects in Fermi averaging, we introduce the local optimal momentum approximation of target nucleons. We can describe the quasi-free Λ , Σ and Ξ production spectra in a better way than in the standard Fermi-averaged t -matrix treatments.

Possibility of s-wave pion condensates in neutron stars revisited

We examine possibilities of pion condensation with zero momentum (s-wave condensation) in neutron stars by using the pion-nucleus optical potential U and the relativistic mean field (RMF) models. We use low-density phenomenological optical potentials parametrized to fit deeply bound pionic atoms or pion-nucleus elastic scatterings. The proton fraction (Y{sub p}) and electron chemical potential ({mu}{sub e}) in neutron star matter are evaluated in RMF models. We find that the s-wave pion condensation hardly takes place in neutron stars and especially has no chance if hyperons appear in neutron star matter and/or the b{sub 1} parameter in U has density dependence.

A Chiral Symmetric Relativistic Mean Field Model with a Logarithmic sigma Potential

We develop a chiral symmetric relativistic mean field model with a logarithmic sigma potential derived in the strong coupling limit of lattice QCD. We find that both nuclear matter and finite nuclei are accurately described by the present model. The normal vacuum is found to be globally stable at zero and finite baryon densities, and an equation of state with moderate stiffness (K � 280 MeV) is obtained. The binding energies and charge radii of Z closed even-even nuclei are accurately predicted over a wide mass range from C to Pb isotopes, except for underestimates of the binding energies for several jj closed nuclei.

Lambda hypernuclei and neutron star matter in a chiral SU(3) relativistic mean field model with a logarithmic potential

We develop a chiral SU(

Three-body couplings in RMF and its effects on hyperonic star equation of state☆

3

Strong Coupling Limit/Region of Lattice QCD

) symmetric relativistic mean field model with a logarithmic potential of scalar condensates. Experimental and empirical data of symmetric nuclear matter saturation properties, bulk properties of normal nuclei, and separation energies of single- and double-

Hypernuclei and nuclear matter in a chiral SU(3) RMF model

\ensuremath{\Lambda}

Nuclear matter and finite nuclei in an effective chiral model

hypernuclei are well explained. The nuclear matter equation of state (EOS) is found to be softened by

Hypernuclei and dense matter in RMF model with chiral SU(3) potential

\ensuremath{\sigma}\ensuremath{\zeta}