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HK: Fachverband Physik der Hadronen und Kerne

HK 50: Kernphysik / Spektroskopie II

HK 50.6: Vortrag

Freitag, 14. März 2008, 15:30–15:45, 2G

Electroexcitation of the first 1/2⁺ state in ⁹Be and ¹¹B* — •Oleksiy Burda¹, Alex Brown², Christian Forssén³, Peter von Neumann-Cosel¹, and Achim Richter¹ — ¹Institut für Kernphysik, Technische Universität Darmstadt, Germany — ²NSCL, Michigan State University, East Lancing, USA — ³Chalmers University of Technology, Göteborg, Sweden

There is renewed interest in very light nuclei due to the progress in ab initio calculations like the no-core shell model (NCSM) applied to their structure. We present high-resolution inelastic electron scattering experiments on ⁹Be and ¹¹B performed at the S-DALINAC. The low-energy level structure of the ⁹Be nucleus has long been a matter of interest, in particular with respect to the strength of three-body α + α + n cluster configurations. The B(E1) strength for the transition to the 1/2⁺ state extracted from the longitudinal form factor is a factor of two smaller than found from real photon scattering experiments indicating a violation of Siegert^′s theorem. In ¹¹B, the longitudinal form factor of the transition to the 1/2⁺ state shows pronounced selectivity of a deep-hole 0s_1/2→1p_3/2 admixture to the dominant 1p_3/2→1s_1/2 configuration.

^*Supported by the DFG through SFB 634.