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HK: Fachverband Hadronen und Kerne

HK 38: Nuclear Astrophysics

HK 38.2: Eingeladener Gruppenbericht

Dienstag, 17. März 2009, 17:00–17:30, H-ZO 60

Nuclear physics aspects of the nucleosynthetic p process: where do we stand ? — •S. V. Harissopulos — TANDEM Lab, Inst. of Nuclear Physics, NCSR Demokritos, Athens, Greece

The study of capture reactions at energies well below the Coulomb barrier is quite challenging both in terms of scientific motivation and experimental approach. These reactions are interesting as they are associated with a long-standing astrophysical problem, i.e. how certain heavy-isotopes (p nuclei) observed, so far, only in the solar system, are formed in the Universe (p process). Moreover, p-nuclei abundances are the signatures of the creation mechanism(s)of our solar system, an issue that still remains open. Existing p-process models are still unable to reproduce the observed p-nuclei solar abundances and certain nuclear physics models describing global parameters entering the calculations are inaccurate and unreliable. It is therefore of paramount importance, on top of any astrophysical model improvements, to check the reliability of nuclear physics predictions related to the understanding of the p-nuclei abundance pattern. For this purpose, a new method (4π γ-summing) was developed by “Demokritos" and Bochum which enabled us to study more than 20 (p,γ) and (α,γ) reactions at energies well-below the Coulomb barrier. The paper presents a review of recent theoretical and experimental developments including first attempts to measure cross sections of capture reactions in inverse kinematics using the JUROGAM array. Finally, the question of whether there is sufficient experimental information to put constraints on the theory and draw final conclusions will be discussed.