Existence of nuclei with unusual neutron excess?

AbstractA realistic model is suggested based on the quasiparticle Lagrange version of the self-consistent Finite Fermi Systems theory supplemented with the microscopically calculated surface parameters of the Landau–Migdal interaction amplitude. The latter are expressed in terms of the off-shell T-matrix of free NN-scattering and show a strong dependence on the chemical potential of a nucleus under consideration in the drip line vicinity. This effect could result in shifting the neutron drip line position to very large values of the neutron excess

The role of the boundary conditions in the Wigner-Seitz approximation applied to the neutron star inner crust

The influence of the boundary conditions used in the Wigner-Seitz approximation applied to the neutron star inner crust is examined. The generalized energy functional method which includes neutron and proton pairing correlations is used. Predictions of two versions of the boundary conditions are compared with each other. The uncertainties in the equilibrium configuration (Z,R_c) of the crust, where Z is the proton charge and R_c the radius of the Wigner-Seitz cell, correspond to variation of Z by 2 -- 6 units and of R_c, by 1 -- 2 fm. The effect of the boundary conditions is enhanced at increasing density. These uncertainties are smaller than the variation of Z and R_c coming from the inclusion of pairing. The value of the pairing gap itself, especially at high density, can depend on the boundary condition used.Comment: LaTeX, 11 pages, 3 figures, to be published in Phys. Lett.

Phonon effects on the double mass differences in magic nuclei.

Theoretical Physic

Solution of the microscopic gap equation for a slab of nuclear matter with the Paris NN-potential

The gap equation in the $^1S_0$-channel is solved for a nuclear slab with the separable form of the Paris potential. The gap equation is considered in the model space in terms of the effective pairing interaction which is found in the complementary subspace. The absolute value of the gap $\Delta$ turned out to be very sensitive to the cutoff $K_{max}$ in the momentum space in the equation for the effective interaction. It is necessary to take $K_{max}=160-180 fm^{-1}$ to guarantee 1% accuracy for $\Delta$. The gap equation itself is solved directly, without any additional approximations. The solution reveals the surface enhancement of the gap $\Delta$ which was earlier found with an approximate consideration. A strong surface-volume interplay was found also implying a kind of the proximity effect. The diagonal matrix elements of $\Delta$ turned out to be rather close to the empirical values for heavy atomic nuclei.Comment: 17 pages, 12 figure

Interaction of the single-particle and collective degrees of freedom in non-magic nuclei: the role of phonon tadpole terms

A method of a consistent consideration of the phonon contributions to mass and gap operators in non-magic nuclei is developed in the so-called g^2 approximation, where g is the low-lying phonon creation amplitude. It includes simultaneous accounting for both the usual non-local terms and the phonon tadpole ones. The relations which allow the tadpoles to be calculated without any new parameters are derived. As an application of the results, the role of the phonon tadpoles in the single-particle strength distribution and in the single-particle energies and gap values has been considered. Relation to the problem of the surface nature of pairing is discussed.Comment: 22 pages, 7 figure

Negative Kaons in Dense Baryonic Matter

Kaon polarization operator in dense baryonic matter of arbitrary isotopic composition is calculated including s- and p-wave kaon-baryon interactions. The regular part of the polarization operator is extracted from the realistic kaon-nucleon interaction based on the chiral and 1/N_c expansion. Contributions of the Lambda(1116), Sigma(1195), Sigma*(1385) resonances are taken explicitly into account in the pole and regular terms with inclusion of mean-field potentials. The baryon-baryon correlations are incorporated and fluctuation contributions are estimated. Results are applied for K- in neutron star matter. Within our model a second-order phase transition to the s-wave K- condensate state occurs at rho_c \gsim 4 \rho_0 once the baryon-baryon correlations are included. We show that the second-order phase transition to the p-wave $K^-$ condensate state may occur at densities $\rho_c \sim 3\div 5 \rho_0$ in dependence on the parameter choice. We demonstrate that a first-order phase transition to a proton-enriched (approximately isospin-symmetric) nucleon matter with a p-wave K- condensate can occur at smaller densities, \rho\lsim 2 \rho_0. The transition is accompanied by the suppression of hyperon concentrations.Comment: 41 pages, 24 figures, revtex4 styl