%0 Journal Article
%T Fragmentation of spin-dipole strength in $^{90}$Zr and $^{208}$Pb
%A T. Marketin
%A E. Litvinova
%A D. Vretenar
%A P. Ring
%J Physics
%D 2012
%I arXiv
%R 10.1016/j.physletb.2011.11.050
%X An extension of time-dependent covariant density functional theory that includes particle-vibration coupling is applied to the charge-exchange channel. Spin-dipole excitation spectra are calculated an compared to available data for $^{90}$Zr and $^{208}$Pb. A significant fragmentation is found for all three angular-momentum components of the spin-dipole strength as a result of particle-vibration coupling, as well as a shift of a portion of the strength to higher energy. A high-energy tail is formed in the strength distribution that linearly decreases with energy. Using a model-independent sum rule,the corresponding neutron skin thickness is estimated and shown to be consistent with values obtained at the mean-field level.
%U http://arxiv.org/abs/1204.6260v2