Pygmy Dipole Strength in Exotic Nuclei and the Equation of State

A. Klimkiewicz*, N. Paar, P. Adrich, M. Fallot, T. Le Bleis, D. Rossi, K. Boretzky, T. Aumann, H. Alvarez-Pol, F. Aksouh, J. Benlliure, T. Berg, M. Boehmer, E. Casarejos, M. Chartier, A. Chatillon, D. Cortina-Gil, U. Datta Pramanik, Th W. Elze, H. EmlingO. Ershova, B. Femando-Dominguez, H. Geissel, M. Gorska, M. Heil, M. Hellström, H. Johansson, K. L. Jones, A. Junghans, O. Kiselev, J. V. Kratz, R. Kulessa, N. Kurz, M. Labiche, R. Lemmon, Y. Litvinov, K. Mahata, P. Maierbeck, T. Nilsson, C. Nociforo, R. Palit, S. Paschalis, R. Plag, R. Reifarth, H. Simon, K. Sümmerer, G. Surówka, D. Vretenar, A. Wagner, W. Waluś, H. Weick, M. Winkler

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contribution


A concentration of dipole strengtli at energies below the giant dipole resonance was observed in neutron-rich nuclei around 132Sn in an experiment using the FRS-LAND setup. This socalled "pygmy" dipole strength can be related to the parameters of the symmetry energy and to the neutron skin thickness on the grounds of a relativistic quasiparticle random-phase approximation. Using this ansatz and the experimental findings for 130"Sn and 132Sn, we derive a value of the symmetry energy pressure ofp̄o = 2.2 ±0.5 MeV/fm3. Neutron skin thicknesses of Rn-Rp = 0.23 ± 0.03 fm and 0.24 ± 0.03 fm for 130"Sn and 132Sn, respectively, have been determined. Preliminary results on 68Ni from a similar experiment using an improved setup indicate an enhanced cross section at low energies, while the results for 58Ni are in accordance with results from photoabsorption measurements.

Original languageEnglish
Title of host publicationAIP Conference Proceedings
Number of pages4
Publication statusPublished - 2009
EventInternational Conference on Nuclear Structure and Dynamics '09 - Dubrovnik, Croatia
Duration: 4 May 20098 May 2009


ConferenceInternational Conference on Nuclear Structure and Dynamics '09


  • ,Sn
  • ,Ni
  • Electromagnetic excitation
  • Giant Dipole Resonance
  • Neutron Skin
  • Pygmy Dipole Resonance
  • Symmetry Energy

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