Investigation of the Pygmy Dipole Resonance in photon scattering experiments

Abstract

The Pygmy Dipole Resonance (PDR) is the dominating electric dipole excitation below and around the particle separation threshold and exhausts only a few percent of the energy-weighted sum rule. Nevertheless, it may have some impact on reaction rates in nucleosynthesis processes. Therefore, investigations to get more insights in this excitation mode are crucial. A common approach to study the PDR of atomic nuclei is the Nuclear Resonance Fluorescence method (NRF) which bases on real-photon scattering. Absolute cross sections, spin and parity quantum numbers are determined in a model-independent way if suited experimental setups are used. In general, there are two complementary NRF experiments which are presented in this paper.