Giant quadrupole resonances in 208Pb, the nuclear symmetry energy, and the neutron skin thickness

Roca-Maza, X. and Brenna, M. and Agrawal, B. K. and Bortignon, P. F. and Colo, G. and Cao, Li-Gang and Paar, Nils and Vretenar, Dario (2013) Giant quadrupole resonances in 208Pb, the nuclear symmetry energy, and the neutron skin thickness. Physical Review C, 87 (3). pp. 34301-9. ISSN 0556-2813

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Abstract

Recent improvements in the experimental determination of properties of the isovector giant quadrupole resonance (IVGQR), as demonstrated in the A=208 mass region, may be instrumental for characterizing the isovector channel of the effective nuclear interaction. We analyze properties of the IVGQR in 208Pb, using both macroscopic and microscopic approaches. The microscopic method is based on families of nonrelativistic and covariant energy density functionals (EDF), characterized by a systematic variation of isoscalar and isovector properties of the corresponding nuclear matter equations of state. The macroscopic approach yields an explicit dependence of the nuclear symmetry energy at some subsaturation density, for instance S(ρ=0.1 fm−3), or the neutron skin thickness Δrnp of a heavy nucleus, on the excitation energies of isoscalar and isovector GQRs. Using available data it is found that S(ρ=0.1 fm−3)=23.3±0.6 MeV. Results obtained with the microscopic framework confirm the correlation of the Δrnp to the isoscalar and isovector GQR energies, as predicted by the macroscopic model. By exploiting this correlation together with the experimental values for the isoscalar and isovector GQR energies, we estimate Δrnp=0.14±0.03 fm for 208Pb, and the slope parameter of the symmetry energy: L=37±18 MeV.

Item Type: Article
Keywords: giant quadrupole resonance, symmetry energy, neutron skin, nuclear energy density functional, quasiparticle random phase approximation
Date: March 2013
Subjects: NATURAL SCIENCES > Physics > Nuclear Physics
Additional Information: Copyright (2013) by the American Physical Society.
Divisions: Faculty of Science > Department of Physics
Project code: 119-1191005-1010
Publisher: American Physical Society
Depositing User: Gordana Stubičan Ladešić
Date Deposited: 09 Jun 2014 10:47
Last Modified: 23 Feb 2016 15:27
URI: http://digre.pmf.unizg.hr/id/eprint/2215

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