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Register a new userMany-body perturbation calculation of spherical nuclei with a separable monopole interaction: I. Finite nuclei
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We present calculations of ground state properties of spherical, doubly closed-shell nuclei from $^{16}$O to $^{208}$Pb employing the techniques of many-body perturbation theory using a separable density dependent monopole interaction. The model gives results in Hartree-Fock order which are of similar quality to other effective density-dependent interactions. In addition, second and third order perturbation corrections to the binding energy are calculated and are found to contribute small, but non-negligible corrections beyond the mean-field result. The perturbation series converges quickly, suggesting that this method may be used to calculate fully correlated wavefunctions with only second or third order perturbation theory. We discuss the quality of the results and suggest possible methods of improvement.
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Single-particle energies of the $Lambda_c$ chamed baryon are obtained in several nuclei from the relevant self-energy constructed within the framework of a perturbative many-body approach. Results are presented for a charmed baryon-nucleon ($Y_cN$) potential based on a SU(4) extension of the meson-exchange hyperon-nucleon potential $tilde A$ of the J{u}lich group. Three different models (A, B and C) of this interaction, that differ only on the values of the couplings of the scalar $sigma$ meson with the charmed baryons, are considered. Phase shifts, scattering lengths and effective ranges are computed for the three models and compared with those predicted by the $Y_cN$ interaction derived in Eur. Phys. A {bf 54}, 199 (2018) from the extrapolation to the physical pion mass of recent results of the HAL QCD Collaboration. Qualitative agreement is found for two of the models (B and C) considered. Our results for $Lambda_c$-nuclei are compatible with those obtained by other authors based on different models and methods. We find a small spin-orbit splitting of the $p-, d-$ and $f-$wave states as in the case of single $Lambda$-hypernuclei. The level spacing of $Lambda_c$ single-particle energies is found to be smaller than that of the corresponding one for hypernuclei. The role of the Coulomb potential and the effect of the coupling of the $Lambda_cN$ and $Sigma_cN$ channels on the single-particle properties of $Lambda_c-$nuclei are also analyzed. Our results show that, despite the Coulomb repulsion between the $Lambda_c$ and the protons, even the less attractive one of our $Y_cN$ models (model C) is able to bind the $Lambda_c$ in all the nuclei considered. The effect of the $Lambda_cN-Sigma_cN$ coupling is found to be almost negligible due to the large mass difference of the $Lambda_c$ and $Sigma_c$ baryons.
We calculate the scattering lenths A(K-,3He) and A(K-,4He) using the multiple scattering approach and different parameters sets for the elementary a(Kbar,N). Within the zero-range approximation, we find for both systems loosely bound states with binding energies in the range 2-7 MeV and widths 11-18 MeV. It is demonstrated that the existence of deeply bound K-,4He states, which have been predicted in literature, can be tested by measuring the reaction dd -> 4He K-K+ at COSY.
We perform a systematic study of the impact of the J^2 tensor term in the Skyrme energy functional on properties of spherical nuclei. In the Skyrme energy functional, the tensor terms originate both from zero-range central and tensor forces. We build a set of 36 parameterizations, which covers a wide range of the parameter space of the isoscalar and isovector tensor term coupling constants, with a fit protocol very similar to that of the successful SLy parameterizations. We analyze the impact of the tensor terms on a large variety of observables in spherical mean-field calculations, such as the spin-orbit splittings and single-particle spectra of doubly-magic nuclei, the evolution of spin-orbit splittings along chains of semi-magic nuclei, mass residuals of spherical nuclei, and known anomalies of charge radii. Our main conclusion is that the currently used central and spin-orbit parts of the Skyrme energy density functional are not flexible enough to allow for the presence of large tensor terms.
A many-body calculation of $^{11}$Li is presented where the only input is the well-tested, finite-range {it D1S} effective interaction of {it Gogny}. Pairing correlations are included in a constrained Hartree-Fock-Bogolyubov calculation, while long-range collective correlations are introduced using a GCM derived calculation. Correlations are found to play an important role in describing $^{11}$Li. A substantive underlying $^9$Li core of $^{11}$Li is found, which has a different density profile than a free $^9$Li nucleus. This may have significant implications in the use of a three-body framework in studies of $^{11}$Li.
After some short introductory remarks on particular issues on the vector mesons in nuclei, in this paper we present a short review of recent developments concerning the interaction of vector mesons with baryons and with nuclei from a modern perspective using the local hidden gauge formalism for the interaction of vector mesons. We present results for the vector baryon interaction and in particular for the resonances which appear as composite states, dynamically generated from the interaction of vector mesons with baryons, taking also the mixing of these states with pseudoscalars and baryons into account. We then venture into the charm sector, reporting on hidden charm baryon states around 4400 MeV, generated from the interaction of vector mesons and baryons with charm, which have a strong repercussion on the properties of the $J/Psi N$ interaction. We also address the interaction of $K^*$ with nuclei and make suggestions to measure the predicted huge width in the medium by means of the transparency ratio. The formalism is extended to study the phenomenon of $J/psi$ suppression in nuclei via $J/psi$ photoproduction reactions.
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