High-spin intruder states in the fp shell nuclei and isoscalar proton-neutron correlations

We perform a systematic shell-model and mean-field study of fully-aligned, high-spin f_{7/2}^{n} seniority isomers and d_{3/2}^{-1} f_{7/2}^{n+1} intruder states in the A~44 nuclei from the lower-fp shell. The shell-model calculations are performed in the full sdfp configuration space allowing 1p-1h cross-shell excitations. The self-consistent mean-field calculations are based on the Hartree-Fock approach with the Skyrme energy density functional that reproduces empirical Landau parameters. While there is a nice agreement between experimental and theoretical relative energies of fully-aligned states in N>Z nuclei, this is no longer the case for the N=Z systems. The remaining deviation from the data is attributed to the isoscalar proton-neutron correlations. It is also demonstrated that the Coulomb corrections at high spins noticeably depend on the choice of the energy density functional.Comment: 4 pages. submitted to Phys. Rev. Let

Pairing in Nuclei

Simple generic aspects of nuclear pairing in homogeneous medium as well as in finite nuclei are discussed. It is argued that low-energy nuclear structure is not sensitive enough to resolve fine details of nuclear nucleon-nucleon (NN) interaction in general and pairing NN interaction in particular what allows for regularization of the ultraviolet (high-momentum) divergences and a consistent formulation of effective superfluid local theory. Some aspects of (dis)entanglement of pairing with various other effects as well as forefront ideas concerning isoscalar pairing are also briefly discussed.Comment: Invited talk presented at the International Conference on Finite Fermionic Systems, Nilsson Model 50 Years,Lund, Sweden, June 14-18, 2005, 7 LaTeX pages, 4 encapsulated postscript figure

Similarity Analysis of Nonlinear Equations and Bases of Finite Wavelength Solitons

We introduce a generalized similarity analysis which grants a qualitative description of the localised solutions of any nonlinear differential equation. This procedure provides relations between amplitude, width, and velocity of the solutions, and it is shown to be useful in analysing nonlinear structures like solitons, dublets, triplets, compact supported solitons and other patterns. We also introduce kink-antikink compact solutions for a nonlinear-nonlinear dispersion equation, and we construct a basis of finite wavelength functions having self-similar properties.Comment: 18 pages Latex, 6 figures ep

Probing sd-fp cross-shell interactions via terminating configurations in Sc42,43

An experimental study of the lower fp-shell nuclei Sc42,43 was performed via αpn and αp evaporation, respectively, from Ne20 + Si28 and Mg24 + Mg24 fusion-evaporation reactions. The experiments were conducted with the Gammasphere and Microball detector arrays. The level schemes of both nuclei have been extended considerably. Terminating states associated with the f7/2n and d3/2-1f7/2n+1 configurations were identified in each nuclide and incorporated into detailed comparisons with neighboring nuclei and with shell model calculations. The energy differences between the terminating states provide a test of the sd-fp cross-shell interactions in these calculations

Shell model analysis of intruder states and high- K isomers in the fp shell

We perform a systematic shell-model study of collective intruder structures and fully aligned high-spin states in nuclei from the lower-fp shell in the sdfp configuration space. We analyze the intruder structures associated with the 1p-1h cross-shell excitations from the sd shell that have been observed in several nuclei from this region, including 44Ti and 44Sc. We compare the shell-model calculations to the recent mean-field work (H. Zduńczuk, W. Satuła, R.A. Wyss, nucl-th/0408018) and experimental data (M. Lach, J. Styczeń, private communication). The high-spin behavior may be understood in terms of the competing cross-shell proton and neutron excitations. The interplay between proton and neutron intruder states is reflected in the angular-momentum dependence of electromagnetic rates

Antisoliton model for fission modes

Abstract Antisolitons traveling on the surface of a nucleus are shown to generate highly deformed shapes. The dynamics is based on solutions of the non-linear Korteweg-de Vries (KdV) equation. The theory is used to model the onset of nuclear fission. Aspects of the dynamics, its relation to fluid mechanics, and some conceptual problems arising from the application of the theory are also discussed. Fission is a division of a nucleus into two parts. This division occurs as a result of extreme deformation, driven by competition between the Coulomb repulsion of the constitutent protons and mutual attraction of the system's nucleons due to the nucleon-nucleon interaction. The dynamics of fission is often simulated using the concept of a liquid drop model (LDM) which parametermizes the nucleus in terms of its surface expanded in terms of spherical harmonic