Search results for "nuclear giant resonances"

Nuclear symmetry energy and neutron skins derived from pygmy dipole resonances

2007

By exploiting Coulomb dissociation of high-energy radioactive beams of the neutron-rich nuclei $^{129\ensuremath{-}132}\mathrm{Sn}$ and $^{133,134}\mathrm{Sb}$, their dipole-strength distributions have been measured. A sizable fraction of ``pygmy'' dipole strength, energetically located below the giant dipole resonance, is observed in all of these nuclei. A comparison with available pygmy resonance data in stable nuclei ($^{208}\mathrm{Pb}$ and $N=82$ isotones) indicates a trend of strength increasing with the proton-to-neutron asymmetry. On theoretical grounds, employing the RQRPA approach, a one-to-one correlation is found between the pygmy strength and parameters describing the density d…