Isoscalar dipole coherence at low energies and forbidden E1 strength

  • P. Papakonstantinou
  • V. Yu. Ponomarev
  • R. Roth
  • J. Wambach
Regular Article - Theoretical Physics


In 16O and 40Ca an isoscalar, low-energy dipole transition (IS-LED) exhausting approximately 4% of the isoscalar dipole (ISD) energy-weighted sum rule is experimentally known, but conspicuously absent from recent theoretical investigations of ISD strength. The IS-LED mode coincides with the so-called isospin-forbidden E1 transition. We report that for N = Z nuclei up to 100Sn the fully self-consistent Random-Phase Approximation (RPA) with finite-range forces, phenomenological and realistic, yields a collective IS-LED mode, typically overestimating its excitation energy, but correctly describing its IS strength and electroexcitation form factor. The presence of E1 strength is solely due to the Coulomb interaction between the protons and the resulting isospin-symmetry breaking. The smallness of its value is related to the form of the transition density, due to translational invariance. The calculated values of E1 and ISD strength carried by the IS-LED depend on the effective interaction used. Attention is drawn to the possibility that in N \( \neq\) Z nuclei this distinct mode of IS surface vibration can develop as such or mix strongly with skin modes and thus influence the pygmy dipole strength as well as the ISD strength function. In general, theoretical models currently in use may be unfit to predict its precise position and strength, if at all its existence.


Form Factor Transition Density Symmetry Energy Giant Dipole Resonance Compression Mode 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


  1. 1.
    M. Harakeh, A. van der Woude, Giant Resonances (Oxford Science Publications, 2001) sect. 4.3Google Scholar
  2. 2.
    N. Paar, D. Vretenar, E. Khan, G. Colò, Rep. Prog. Phys. 70, 691 (2007) and references thereinADSCrossRefGoogle Scholar
  3. 3.
    M. Harakeh, A. Dieperink, Phys. Rev. C 23, 2329 (1981)ADSCrossRefGoogle Scholar
  4. 4.
    T. Poelhekken, S. Hesmondhalgh, H. Hofman, A. van der Woude, M. Harakeh, Phys. Lett. B 278, 423 (1992)ADSCrossRefGoogle Scholar
  5. 5.
    T. Hartmann, M. Babilon, S. Kamerdzhiev, E. Litvinova, D. Savran, S. Volz, A. Zilges, Phys. Rev. Lett. 93, 192501 (2004)ADSCrossRefGoogle Scholar
  6. 6.
    H. Röpke, Eur. Phys. J. A 22, 213 (2004)ADSCrossRefGoogle Scholar
  7. 7.
    H. Miska, H. Gräf, A. Richter, D. Schüll, E. Spamer, O. Titze, Phys. Lett. B 59, 441 (1975)ADSCrossRefGoogle Scholar
  8. 8.
    J. Friedrich, N. Voegler, Phys. Lett. B 217, 220 (1989)ADSCrossRefGoogle Scholar
  9. 9.
    H. Gräf, V. Heil, A. Richter, E. Spamer, W. Stock, O. Titze, Phys. Lett. B 72, 179 (1977)ADSCrossRefGoogle Scholar
  10. 10.
    A. Arima, P. Manakos, D. Strottman, Phys. Lett. B 60, 1 (1975)ADSCrossRefGoogle Scholar
  11. 11.
    F. Barker, Phys. Lett. B 64, 251 (1976)ADSCrossRefGoogle Scholar
  12. 12.
    V. Heil, W. Stock, Phys. Lett. B 65, 412 (1976)ADSCrossRefGoogle Scholar
  13. 13.
    B. Castel, Y. Okuhara, H. Sagawa, Phys. Rev. C 42, R1203 (1990)ADSCrossRefGoogle Scholar
  14. 14.
    J. Blaizot, D. Gogny, Nucl. Phys. A 284, 429 (1977)ADSCrossRefGoogle Scholar
  15. 15.
    K. Heyde, The Nuclear Shell Model (Springer-Verlag, 1990)Google Scholar
  16. 16.
    J. Berger, M. Girod, D. Gogny, Comput. Phys. Commun. 63, 365 (1991)ADSzbMATHCrossRefGoogle Scholar
  17. 17.
    A. Günther, R. Roth, H. Hergert, S. Reinhardt, Phys. Rev. C 82, 024319 (2010)ADSCrossRefGoogle Scholar
  18. 18.
    R. Roth, P. Papakonstantinou, N. Paar, H. Hergert, T. Neff, H. Feldmeier, Phys. Rev. C 73, 044312 (2006)ADSCrossRefGoogle Scholar
  19. 19.
    P. Papakonstantinou, R. Roth, Phys. Lett. B 671, 356 (2009)ADSCrossRefGoogle Scholar
  20. 20.
    R. Roth, T. Neff, H. Feldmeier, Prog. Part. Nucl. Phys. 65, 50 (2010)ADSCrossRefGoogle Scholar
  21. 21.
    P. Papakonstantinou, T.S. Kosmas, J. Wambach, A. Faessler, Phys. Rev. C 73, 035502 (2006)ADSCrossRefGoogle Scholar
  22. 22.
    S. Dietrich, B. Berman, At. Data Nucl. Data Tables 38, 199 (1988)ADSCrossRefGoogle Scholar
  23. 23.
    F. Ajzenberg-Selove, Nucl. Phys. A 460, 1 (1986)ADSCrossRefGoogle Scholar
  24. 24.
    J. Cameron, B. Singh, Nucl. Data Sheets 102, 293 (2004)ADSCrossRefGoogle Scholar
  25. 25.
    D. Ravenhall, J. Wambach, Nucl. Phys. A 475, 468 (1987)ADSCrossRefGoogle Scholar
  26. 26.
    T. Kibédi, R. Spear, At. Data Nucl. Data Tables 80, 35 (2002)ADSCrossRefGoogle Scholar
  27. 27.
    G. Cò, V. De Donno, C. Maieron, M. Anguiano, A. Lallena, Phys. Rev. C 80, 014308 (2009)ADSCrossRefGoogle Scholar
  28. 28.
    E. Lanza, F. Catara, D. Gambacurta, M. André, P. Chomaz, Phys. Rev. C 79, 054615 (2009)ADSCrossRefGoogle Scholar
  29. 29.
    P. Papakonstantinou, J. Wambach, E. Mavrommatis, V.Y. Ponomarev, Phys. Lett. B 604, 157 (2004)ADSCrossRefGoogle Scholar
  30. 30.
    J. Kvasil, N. LoIudice, C. Stoyanov, P. Alexa, J. Phys. G 29, 753 (2003)ADSCrossRefGoogle Scholar
  31. 31.
    T. Buti et al., Phys. Rev. C 33, 755 (1986)ADSCrossRefGoogle Scholar
  32. 32.
    G. Colò, M. Nagarajan, P. Van Isacker, A. Vitturi, Phys. Rev. C 52, R1175 (1995)ADSCrossRefGoogle Scholar
  33. 33.
    W. Satuła, J. Dobaczewski, W. Nazarewicz, M. Rafalski, Phys. Rev. Lett. 103, 012502 (2009)ADSCrossRefGoogle Scholar
  34. 34.
    O. Moreno, E. Moya de Guerra, P. Sarriguren, J. Udías, J. Phys. G 37, 064019 (2010)ADSCrossRefGoogle Scholar
  35. 35.
    W. Satuła, J. Dobaczewski, W. Nazarewicz, M. Rafalski, in International Conference on Nuclear Structure, Nuclear Landscape at the Limits, Zakopane, Poland, 2010, arXiv:1010.3099v1
  36. 36.
    H. Gräf, PhD Thesis, Technische Hochschule, Darmstadt (1977)Google Scholar
  37. 37.
    N. Auerbach, Phys. Rev. C 81, 067305 (2010)ADSCrossRefGoogle Scholar
  38. 38.
    G. Tertychny et al., Phys. Lett. B 647, 104 (2007)ADSCrossRefGoogle Scholar
  39. 39.
    M. Waroquier, Hoher Aggregaatsthesis, University of Gent (1982)Google Scholar
  40. 40.
    M. Waroquier, G. Wenes, K. Heyde, Nucl. Phys. A 404, 298 (1983)ADSCrossRefGoogle Scholar
  41. 41.
    R. Furnstahl, Phys. Lett. B 152, 313 (1985)ADSCrossRefGoogle Scholar
  42. 42.
    J. Terasaki, J. Engel, Phys. Rev. C 74, 044301 (2006)ADSCrossRefGoogle Scholar
  43. 43.
    B. Agrawal, S. Shlomo, A. Sanzhur, Phys. Rev. C 67, 034314 (2003)ADSCrossRefGoogle Scholar
  44. 44.
    J. Decharge, L. Sips, Nucl. Phys. A 407, 1 (1983)ADSCrossRefGoogle Scholar
  45. 45.
    S. Bastrukov, I. Molodtsova, D. Podgainy, S. Mişicu, H.-K. Chang, Phys. Lett. B 664, 258 (2008)ADSCrossRefGoogle Scholar
  46. 46.
  47. 47.
    Y.-W. Lui, D. Youngblood, H. Clark, Y. Tokimoto, B. John, Phys. Rev. C 73, 014314 (2006)ADSCrossRefGoogle Scholar
  48. 48.
    N. Paar, D. Vretenar, T. Niksić, P. Ring, Phys. Rev. C 74, 037303 (2006)ADSCrossRefGoogle Scholar
  49. 49.
    D. Vretenar, A. Wandelt, P. Ring, Phys. Lett. B 487, 334 (2000)ADSCrossRefGoogle Scholar
  50. 50.
    G. Colò, N. Van Giai, P. Bortignon, M. Quaglia, Phys. Lett. B 485, 362 (2000)ADSCrossRefGoogle Scholar
  51. 51.
    A. Zilges, S. Volz, M. Babilon, T. Hartmann, P. Mohr, K. Vogt, Phys. Lett. B 542, 43 (2002)ADSCrossRefGoogle Scholar
  52. 52.
    D. Savran et al., Phys. Rev. Lett. 97, 172502 (2006)ADSCrossRefGoogle Scholar
  53. 53.
    J. Endres et al., Phys. Rev. Lett. 105, 212503 (2010)ADSCrossRefGoogle Scholar

Copyright information

© SIF, Springer-Verlag Berlin Heidelberg 2011

Authors and Affiliations

  • P. Papakonstantinou
    • 1
  • V. Yu. Ponomarev
    • 1
  • R. Roth
    • 1
  • J. Wambach
    • 1
  1. 1.Institut für KernphysikTechnische Universität DarmstadtDarmstadtGermany

Personalised recommendations