Tomonori Tanigawa

Possibility of \Lambda\Lambda pairing and its dependence on background density in relativistic Hartree-Bogoliubov model

We calculate a \Lambda\Lambda pairing gap in binary mixed matter of nucleons and \Lambda hyperons within the relativistic Hartree-Bogoliubov model. Lambda hyperons to be paired up are immersed in background nucleons in a normal state. The gap is calculated with a one-boson-exchange interaction obtained from a relativistic Lagrangian. It is found that at background density \rho_{N}=2.5\rho_{0} the \Lambda\Lambda pairing gap is very small, and that denser background makes it rapidly suppressed. This result suggests a mechanism, specific to mixed matter dealt with relativistic models, of its dependence on the nucleon density. An effect of weaker \Lambda\Lambda attraction on the gap is also examined in connection with revised information of the \Lambda\Lambda interaction.

Phenomenological construction of a relativistic nucleon–nucleon interaction for the superfluid gap equation in finite density systems

Abstract We construct phenomenologically a relativistic particle–particle channel interaction which suits the gap equation for nuclear matter. This is done by introducing a density-independent momentum-cutoff parameter to the relativistic mean field (Hartree and Hartree–Fock) models so as to reproduce the pairing properties obtained by the Bonn-B potential and not to change the saturation property. The interaction so obtained can be used for the relativistic Hartree–Bogoliubov calculation, but some reservation is necessary for the relativistic Hartree–Fock–Bogoliubov calculation.

Constructing Effective Pair Wave Function from Relativistic Mean Field Theory with a Cutoff

We propose a simple method to reproduce the ^1S_0 pairing properties of nuclear matter, which are obtained using a sophisticated model, by introducing a density-independent cutoff into the relativistic mean field model. This can be applied successfully to the physically relevant density range.