Article ID Journal Published Year Pages File Type
1854529 Progress in Particle and Nuclear Physics 2011 5 Pages PDF
Abstract

A search of the pygmy resonance in 68Ni was made using the virtual photon technique. The experiment was carried out using the radioactive beam 68Ni at 600 A MeV, produced with fragmentation of 86Kr at 900 A MeV on a 9Be target. The 68Ni beam was separated by a fragment separator, and the γγ-rays produced at the interaction with the Au target were detected with the RISING and FRS set-up at the GSI laboratory in Germany, also including the HECTOR array. The measured γγ-ray spectra show a peak centered at approximately 11 MeV, whose intensity can be explained in term of an enhanced strength of the dipole response function (pygmy resonance). A pygmy structure of this type was also predicted by different models for this unstable neutron-rich nucleus. Correlations between the behavior of the nuclear symmetry energy, the neutron skins, and the percentage of energy-weighted sum rule (EWSR) exhausted by the pygmy dipole resonance (PDR) are investigated by using different random phase approximation (RPA) models.

Related Topics
Physical Sciences and Engineering Physics and Astronomy Nuclear and High Energy Physics
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