Münster 2011 – wissenschaftliches Programm
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HK: Fachverband Physik der Hadronen und Kerne
HK 9: Struktur und Dynamik von Kernen II
HK 9.4: Vortrag
Montag, 21. März 2011, 17:30–17:45, O-1
Quadrupole and other multipole excitations in skin nuclei. — •Nadia Tsoneva and Horst Lenske — Institut für Theoretische Physik, Universität Giessen
Quadrupole excitations are investigated theoretically in Sn nuclei at energies up to 35 MeV. A method incorporating the density functional theory (DFT) and quasiparticle-phonon model (QPM) is applied [1]. A question of a special interest is to what extent the presence of a neutron or proton skin will affect low-energy 2+ states located above the 21+ state and below the neutron threshold, particularly exploring their connection to the thickness of the neutron or proton skin, respectively. By analyzing of the structure and transition densities of the quadrupole states, a new quadrupole mode at excitation energies E*≈ 2-4 MeV is identified and related to pygmy quadrupole resonance (PQR)[2].
Furthermore, the unique character of the PQR states is confirmed in QPM calculations of M1 and E2 transitions indicating that these states are different from the known scissors mode [3] which are typically located in similar energy domain.
Investigations of electric and magnetic dipole strength distributions in skin nuclei at different mass regions are discussed and compared to experimental data [4] . The results reveal interesting aspects of the nuclear isospin dynamics. Supported by BMBF project 06GI9109.
[1] N. Tsoneva, H. Lenske, Phys. Rev. C 77, 024321 (2008).
[2] N. Tsoneva and H. Lenske, PLB, in press, doi:10.1016/j.phys.letb.2010.11.002.
[3] N. Pietralla, et al., Prog. Part. Nucl. Phys. 60 (2008) 225.
[4] A. Tonchev et al., Phys. Rev. Lett. 104 (2010) 072501.