Isospin Character of the Pygmy Dipole Resonance in 124Sn

J. Endres, E. Litvinova, D. Savran, P.A. Butler, M.N. Harakeh, S. Harissopulos, R.-D. Herzberg, R. Krücken, A. Lagoyannis, N. Pietralla, V.Yu. Ponomarev, Lucia Popescu, P. Ring, M. Scheck, K. Sonnabend, V.I. Stoica, H.J. Wörtche, A. Zilges, Jan Wagemans

Research outputpeer-review


The pygmy dipole resonance has been studied in the proton-magic nucleus 124Sn with the (α, α′γ) coincidence method at Eα=136  MeV. The comparison with results of photon-scattering experiments reveals a splitting into two components with different structure: one group of states which is excited in (α, α′γ) as well as in (γ, γ′) reactions and a group of states at higher energies which is only excited in (γ, γ′) reactions. Calculations with the self-consistent relativistic quasiparticle time-blocking approximation and the quasiparticle phonon model are in qualitative agreement with the experimental results and predict a low-lying isoscalar component dominated by neutron-skin oscillations and a higher-lying more isovector component on the tail of the giant dipole resonance.
Original languageEnglish
Pages (from-to)212503-212503
JournalPhysical review Letters
Issue number21
StatePublished - 19 Nov 2010

Cite this