Naslov
Isoscalar and Isovector Splitting of Pygmy Dipole Structures

Autori
Paar, Nils ; Niu, Yifei ; Vretenar, Dario ; Meng, Jie

Izvornik
Physical Review Letters (0031-9007) 103 (2009), 3; 032502-1

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
nuclear physics; collective excitations; exotic nuclei

Sažetak
The electric dipole response of 140Ce is investigated using the fully consistent relativistic quasiparticle random phase approximation. By analyzing the isospin structure of the E1 response, it is shown that the low-energy (pygmy) strength separates into two segments with different isospin character. The more pronounced pygmy structure at lower energy is composed of predominantly isoscalar states with surface-peaked transition densities. At somewhat higher energy the calculated E1 strength is primarily of isovector character, as expected for the low-energy tail of the giant dipole resonance. The results are in qualitative agreement with those obtained in recent (gamma, gamma') and (alpha, alpha'gamma) experiments, and provide a simple explanation for the splitting of low-energy E1 strength into two groups of states with different isospin structure and radial dependence of the corresponding transition densities.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

Napomena
Projekt UKF 17/08

POVEZANOST RADA