The isovector dipole strength in nuclei with extreme neutron excess

Daniel Pena Arteaga (1) , E. Khan (1) , Peter Ring (2)

1 IPNO - Institut de Physique Nucléaire d'Orsay
2 Physik Department [Garching]

The E1 strength is systematically analyzed in very neutron-rich Sn nuclei, beyond $^{132}$Sn until $^{166}$Sn, within the Relativistic Quasiparticle Random Phase Approximation. The great neutron excess favors the appearance of a deformed ground state for $^{142−162}$Sn. The evolution of the low-lying strength in deformed nuclei is determined by the interplay of two factors, isospin asymmetry and deformation: while greater neutron excess increases the total low-lying strength, deformation hinders and spreads it. Very neutron rich deformed nuclei may not be as good candidates as stable spherical nuclei like $^{132}$Sn for the experimental study of low-lying E1 strength.

Mots clés: QRPA; RMF; pygmy; GDR; deformed

Domaines: Physique Nucléaire Théorique [nucl-th]

Daniel Pena Arteaga, E. Khan, Peter Ring. The isovector dipole strength in nuclei with extreme neutron excess. 2008. ⟨hal-00345965⟩