Evolution of the N=28 shell closure: a test bench for nuclear forces

Abstract

The evolution of the N=28 shell closure is investigated far from stability. Using the latest results obtained from various experimental techniques, we discuss the main properties of the N=28 isotones, as well as those of the N=27 and N=29 isotones. Experimental results are confronted to various theoretical predictions. These studies pinpoint the effects of several terms of the nucleon-nucleon interaction, such as the central, the spin-orbit, the tensor and the three-body force components, to account for the modification of the N=28 shell gap and spin-orbit splittings. Analogies between the evolution of the N=28 shell closure and other magic numbers originating from the spin-orbit interaction are proposed (N=14,50, 82 and 90). More generally, questions related to the evolution of nuclear forces towards the drip-line, in bubble nuclei, and for nuclei involved in the r-process nucleosynthesis are proposed and discussed.

40 pages,15 figures, Procceedings Nobel Symposium 2012, accepted for publication in Physica Scripta

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Cited by in corpus (30)

• Evolution of shell structure in exotic nuclei
• Precision Atomic Physics Techniques for Nuclear Physics with Radioactive Beams
• Probing the N = 32 shell closure below the magic proton number Z = 20: Mass measurements of the exotic isotopes 52,53K
• A proton density bubble in the doubly magic ${}^{34}$Si nucleus
• Experimental study of the two-body spin-orbit force
• Shell structure of potassium isotopes deduced from their magnetic moments
• Tensor-force effects on single-particle levels and proton bubble structure around the $Z$ or $N=20$ magic number
• Mass Measurements Demonstrate a Strong N =28 Shell Gap in Argon
• Spectroscopy of ${}^{26}$F to probe proton-neutron forces close to the drip line
• Is the structure of 42Si understood?
• Modification of magicity towards the dripline and its impact on electron-capture rates for stellar core-collapse
• Summit of the N=40 Island of Inversion: precision mass measurements and ab initio calculations of neutron-rich chromium isotopes
• Spectroscopy of 46Ar by the (t,p) two-neutron transfer reaction
• Level Structures of ${}^{56,58}$Ca Cast Doubt on a doubly magic ${}^{60}$Ca
• Normal and intruder configurations in ${}^{34}$Si populated in the ${\beta }^{-}$ decay of ${}^{34}$Mg and ${}^{34}$Al
• Spin-orbit coupling and the up-down differential transverse flow in intermediate-energy heavy-ion collisions
• Elastic and quasi-elastic electron scattering on the N = 14, 20, and 28 isotonic chains
• Dynamical effects of spin-dependent interactions in low- and intermediate-energy heavy-ion reactions
• Microscopic study of the Shell Structure evolution in isotopes of light to middle mass range Nuclides
• Shell structure of ${}^{43}$S and collapse of the $N=28$ shell closure
• Neutron Shell Closure at N=32 and N=40 in Ar and Ca Isotopes
• Shell Evolutions and Nuclear Forces
• Shell structure from nuclear observables
• What can we learn from transfer and how is best to do it?
• Effect of the spin-orbit interaction on flows in heavy-ion collisions at intermediate energies
• High-spin structures of ${}^{86,87,88,89}$Y: a shell model interpretation
• Probing properties of nuclear spin-orbit interaction with nucleon spin polarization in intermediate-energy heavy-ion collisions
• Decay spectroscopy of ${}^{50}$Sc and ${}^{50m}$Sc to ${}^{50}$Ti
• News on the nuclear structure of neutron-rich nuclei at and beyond N=28
• Nuclear Structure Studies of Neutron-Rich Nuclei : Astrophysical Implications