Accueil du site > Publications récentes > Systematic study of giant quadrupole resonances with the subtracted second random-phase approximation : Beyond-mean-field centroids and fragmentation
O. Vasseur, D. Gambacurta, and M. Grasso
Abstract :
A systematic analysis of giant quadrupole resonances is performed
for several nuclei, from 30Si
to 208Pb,
within the subtracted second random-phase-approximation (SSRPA)
model in the framework of the energy-density-functional theory.
Centroid energies and widths of the isoscalar giant quadrupole
resonances are compared with the corresponding
random-phase-approximation (RPA) values. We find lower SSRPA
centroid energies compared to the RPA values leading, in general,
to a better agreement with the experimental data. As far as the
widths are concerned, we observe for both SSRPA and RPA cases a
global attenuation of the single-particle Landau damping going
from lighter to heavier nuclei, and we obtain, systematically,
larger widths in the SSRPA model compared to the RPA case. For
some selected nuclei for which high-resolution (p,p′)
experimental data are available, namely 40Ca,
90Zr,
120Sn,
and 208Pb,
the theoretical strength distributions are directly compared with
the experimental spectra. We observe a significant improvement,
with respect to RPA results, in the description of the spreading
widths and of the fragmentation of the obtained spectra, due to
the coupling between one-particle–one-hole and
two-particle–two-hole configurations.
Voir en ligne : Phys. Rev. C 98, 044313 (2018)
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