Electric and Magnetic Dipole Resonances in Heavy Nuclei: The Role of Deformation

• Applicant: Professor Dr. Peter von Neumann-Cosel
• Subject Area: Nuclear and Elementary Particle Physics, Quantum Mechanics, Relativity, Fields
• Term: from 2011 to 2016
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 204313289

• Final Report Year: 2015

Final Report Abstract

Complete electric and magnetic dipole strength distributions in a variety of nuclei have been derived from polarized proton scattering at about 300 MeV and forward angles including 0°. Such data allow to extract the electric dipole polarizability of nuclei including the sizable lowenergy part not known previously. The polarizability is closely linked to the development of a neutron skin in nuclei with neutron excess and the poorly known symmetry energy contribution to the equation of state of neutron-rich matter, which governs the properties of neutron stars. The high energy resolution achieved in these measurements provide information on characteristic scales of the giant dipole resonance decay and level densities. In the present project, experiments have been performed to study in particular the influence of deformation of the nuclear ground state on the dipole strength distributions.

Publications

• Complete electric dipole response and the neutron skin in 208Pb, Phys. Rev. Lett. 107, 062502 (2011)
  A. Tamii, I. Poltoratska, P. von Neumann-Cosel, Y. Fujita, T. Adachi, C.A. Bertulani, J. Carter, M. Dozono, H. Fujita, K. Fujita, Y. Fujita, K. Hatanaka, M. Itoh, T. Kawabata, Y. Kalmykov, A.M. Krumbholz, E. Litvinova, H. Matsubara, K. Nakanishi, R. Neveling, H. Okamura, H.J. Ong, B. Özel-Tashenov, V.Yu. Ponomarev, A. Richter, B. Rubio, H. Sakaguchi, Y. Sakemi, Y. Sasamoto, Y. Shimbara, Y. Shimizu, F.D. Smit, T. Suzuki, Y. Tameshige, J. Wambach, M. Yosoi, and J. Zenihiro
  
• Pygmy dipole resonance in 208Pb, Phys. Rev. C 85, 041304(R) (2012)
  I. Poltoratska, P. von Neumann-Cosel, A. Tamii, T. Adachi, C.A. Bertulani, J. Carter, M. Dozono H. Fujita, K. Fujita, Y. Fujita, K. Hatanaka, M. Itoh, T. Kawabata, Y. Kalmykov, A.M. Krumbholz, E. Litvinova, H. Matsubara, K. Nakanishi, R. Neveling, H. Okamura, H.J. Ong, B. Özel-Tashenov, V.Yu. Ponomarev, A. Richter, B. Rubio, H. Sakaguchi, Y. Sakemi, Y. Sasamoto, Y. Shimbara, Y. Shimizu, F.D. Smit, T. Suzuki, Y. Tameshige, J. Wambach, M. Yosoi, and J. Zenihiro
  
• Complete electric dipole strength and neutron skin in 208Pb, Proceedings 14th International Symposium on Capture Gamma-Ray Spectroscopy and Related Topics, Eds. P.E. Garrett and B. Hadinia (World Scientific, Singapore, 2013) 15
  P. von Neumann-Cosel, I. Poltoratska, and A. Tamii
  
• Electric dipole response of 208Pb from proton inelastic scattering: Constraints on neutron skin thickness and symmetry energy, Eur. Phys. J. A 50, 28 (2014)
  A. Tamii, P. von Neumann-Cosel, and I. Poltoratska
  (See online at https://doi.org/10.1140/epja/i2014-14028-7)
• Fine Structure of the Isovector Giant Dipole Resonance in 208Pb: Characteristic Scales and Level Densities, Phys. Rev. C 89, 054322 (2014)
  I. Poltoratska, R. W. Fearick, A.M. Krumbholz, E. Litvinova, H. Matsubara, P. von Neumann- Cosel, V.Yu. Ponomarev, A. Richter, and A. Tamii
  (See online at https://doi.org/10.1103/PhysRevC.89.054322)
• Investigation of low-energy dipole modes in the heavy deformed nucleus 154Sm via inelastic polarized proton scattering at zero degree, EPJ Web of Conferences 66, 02060 (2014)
  A. Krugmann, D. Martin, P. von Neumann-Cosel, N. Pietralla, and A. Tamii
  (See online at https://doi.org/10.1051/epjconf/20146602060)
• Low-energy electric dipole response of 120Sn from polarized proton scattering, Doctoral Thesis D17, Technische Universität Darmstadt (2014)
  A.M. Krumbholz
  
• Off-Yrast low-spin structure of deformed nuclei at mass number A≈150, Doctoral Thesis D17, Technische Universität Darmstadt (2014)
  A. Krugmann
  
• Complete electric dipole response in 120Sn and 208Pb and implications for neutron skin and symmetry energy, EPJ Web of Conferences 93, 01029 (2015)
  P. von Neumann-Cosel
  (See online at https://doi.org/10.1051/epjconf/20159301029)
• Dipole polarizability of 120Sn and nuclear energy density functionals, Phys. Rev. C 92, 031305(R) (2015)
  T. Hashimoto, A.M. Krumbholz, P.-G. Reinhard, A. Tamii, P. von Neumann-Cosel, T. Adachi, N. Aoi, C.A. Bertulani, H. Fujita, Y. Fujita, E. Ganioglu, K. Hatanaka, C. Iwamoto T. Kawabata, N.T. Khai, A. Krugmann, D. Martin, H. Matsubara, K. Miki, R. Neveling, H. Okamura, H.J. Ong, I. Poltoratska, V.Yu. Ponomarev, A.Richter, H. Sakaguchi, Y. Shimbara, Y. Shimizu, J. Simonis, F.D. Smit, G. Susoy, J.H. Thies, T. Suzuki, M. Yosoi, and J. Zenihiro
  (See online at https://doi.org/10.1103/PhysRevC.92.031305)
• Low-energy electric dipole response in 120Sn, Phys. Lett. B 744, 7 (2015)
  A.M. Krumbholz, P. von Neumann-Cosel, T. Hashimoto, A. Tamii, T. Adachi, C.A. Bertulani, H. Fujita, Y. Fujita, E. Ganioglu, K. Hatanaka, C. Iwamoto, T. Kawabata, N.T. Khai, A. Krugmann, D. Martin, H. Matsubara, R. Neveling, H. Okamura, H.J. Ong, I. Poltoratska, V.Yu. Ponomarev, A. Richter, H. Sakaguchi, Y. Shimbara, Y. Shimizu, J. Simonis, F.D. Smit, G. Süsoy, J.H. Thies, T. Suzuki, M. Yosoi, and J. Zenihiro
  (See online at https://doi.org/10.1016/j.physletb.2015.03.023)
• Non-quenched isoscalar spin-M1 excitations in sd-shell nuclei, Phys. Rev. Lett. 115, 102501 (2015)
  H. Matsubara, A. Tamii, H. Nakada, T. Adachi, J. Carter, M. Dozono, H. Fujita, K. Fujita, Y. Fujita, K. Hatanaka, W. Horiuchi, M. Itoh, T. Kawabata, S. Kuroita, Y. Maeda, P. Navratíl, P. von Neumann-Cosel, R. Neveling, H. Okamura, L. Popescu, I. Poltoratska, A. Richter, B. Rubio, H. Sakaguchi, S. Sakaguchi, Y. Sakemi, Y. Sasamoto, Y. Shimbara, Y. Shimizu, F.D. Smit, K. Suda, Y. Tameshige, H. Tokieda, Y. Yamada, M. Yosoi, and J. Zenihiro
  (See online at https://doi.org/10.1103/PhysRevLett.115.102501)