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HK: Fachverband Physik der Hadronen und Kerne

HK 10: Struktur und Dynamik von Kernen

HK 10.6: Talk

Monday, March 17, 2014, 18:15–18:30, HZ 4

Are the pygmy resonances important for astrophysics? — •Nadia Tsoneva and Horst Lenske — Institut für Theoretische Physik, Universität Giessen

The precise knowledge of nuclear response functions plays a key role in the determination of n-capture reaction rates of importance for the nucleosynthesis of heavier elements. In this connection information on low-energy excitations located around the neutron threshold is needed. Recently, new low-energy modes called pygmy resonances which reveal new aspects on the isospin dynamics of the nucleus have been observed. Their distinct feature is the close connection to nuclear skin oscillations which become visible in transition densities and currents. A successful description of the pygmy resonances could be achieved in our microscopic theoretical approach [1-6]. The method incorporates the density functional theory and QRPA formalism extended with multiphonon degrees of freedom which are found of crucial importance for the understanding of the fine structure of nuclear electric [1-5] and magnetic excitations at low energies [6]. Corresponding theoretical response functions are implemented in the studies of n-capture reaction rates of astrophysical importance [7]. Supported by BMBF project 06GI9109. [1] N. Tsoneva et al., PLB 586 (2004) 213. [2] N. Tsoneva et al. PRC 77, 024321 (2008). [3] N. Tsoneva et al., PLB 695 (2011) 174180. [4] A. Tonchev et al., PRL 104 (2010) 072501. [5] R. Schwengner et al., PRC 87, 024306 (2013). [6] G. Rusev et al., PRL 110, 022503 (2013). [7] R. Raut et al., PRL 111, 112501 (2013).