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An inelastic proton scattering experiment was performed with the combined setup SONIC@HORUS at a beam energy of 15 MeV in Cologne. First results for the deduced branching ratios as well as the E1 strength distribution obtained with the 124Sn(p,pγ) reaction are presented. Additionally, a qualitative comparison to excitations in experiments with different probes like (α,αγ) and (&#947,γ) will be discussed. [ABSTRACT FROM AUTHOR]

The microscopic structure of the low-energy electric dipole response, commonly denoted as pygmy dipole resonance (PDR), was studied for 120Sn in a 119Sn(d,pγ)120Sn experiment. Unprecedented access to the single-particle structure of excited 1- states below and around the neutron-separation threshold was obtained by comparing experimental data to predictions from a novel theoretical approach. The novel approach combines detailed structure input from energy-density functional plus quasiparticle-phonon model theory with reaction theory to obtain a consistent description of both the structure and reaction aspects of the process. The presented results show that the understanding of one-particle-one-hole structures of the 1- states in the PDR region is crucial to reliably predict properties of the PDR and its contribution to nucleosynthesis processes. [ABSTRACT FROM AUTHOR]

Background: In the A ≈ 50 mass region M 1 spin-flip transitions are prominent around 9 MeV. An accumulation of 1 - states between 5 and 8 MeV generating additional E 1 strength, also denoted as pygmy dipole resonance, has been established in many nuclei with neutron excess within the last decade. Purpose: The γ -decay behavior of J = 1 states has been investigated in an NRF experiment. M 1 excitations have been compared to shell model calculations. Methods: J = 1 states were excited by quasi-monoenergetic, linearly polarized γ -ray beams generated by laser-Compton backscattering at the HI γ S facility, Durham, NC, USA. Depopulating γ rays were detected with the multidetector array γ 3. Results: For eleven beam-energy settings the γ -decay behavior of dipole states was analyzed by a state-to-state analysis and average γ -decay branching ratios have been investigated. 34 parity quantum numbers were assigned to J = 1 states. Conclusions: Six 1 - states and two 1 + states have been investigated in NRF experiments for the first time. The M 1 strength distribution is in good agreement with shell-model calculations. [ABSTRACT FROM AUTHOR]