Structures in the nuclear electric-dipole spectrum
Abstract
I undertake an anatomy of the nuclear electric-dipole spectrum and discuss selected observations. First, using data and calculations on 208Pb as a representative case, I identify five conspicuous structures in the spectra of heavy nuclei: (1) the giant dipole resonance (GDR), (2) the dipole compression mode, (3) the isoscalar low-energy dipole mode (IS-LED),(4) the isoscalar mode in the region of the GDR, and (5) a concentration of "pygmy" dipole strength (PDS) between the latter two. Next, compiling the data from Texas A&M I show that the energy of (4) follows roughly a A^{-1/6} dependence on the mass number. Finally, I summarize recent theoretical studies on the PDS in exotic nuclei, which suggest a strong influence of shell effects and loose binding.
Cite
@article{arxiv.1711.10189,
title = {Structures in the nuclear electric-dipole spectrum},
author = {P. Papakonstantinou},
journal= {arXiv preprint arXiv:1711.10189},
year = {2017}
}
Comments
6 pages, 2 figures, Proc. VIII International Symposium on EXOtic Nuclei (EXON 2016), Kazan, Russia, September 5-10, 2016