Gießen 2024 – scientific programme
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HK: Fachverband Physik der Hadronen und Kerne
HK 49: Nuclear Astrophysics IV
HK 49.1: Group Report
Wednesday, March 13, 2024, 17:30–18:00, HBR 14: HS 4
First study of the 139Ba(n,γ)140Ba reaction to constrain the conditions for the astrophysical i process — •Dennis Muecher1, Artemis Spyrou2, Pavel Denissenkov3, Falk Hervig3, Magne Guttormsen4, Ann-Ceceilie Larsen4, and Mathis Wiedeking5 — 1Institut für Kernphysik, Universität zu Köln — 2FRIB, Michigan State University, USA — 3Department of Physics and Astronomy, University of Victoria, Canada — 4Department of Physics, University of Oslo, Norway — 5SSC Laboratory, iThemba LABS, South Africa
The intermediate "i" process was proposed as a plausible scenario to explain some of the unusual abundance patterns observed in metal-poor stars (Denissenkov et al, ApJ Letters 2017). The most important nuclear physics properties entering i-process calculations are the neutron-capture cross sections and they are almost exclusively not known experimentally. In this talk we demonstrate results (Spyrou et al., under review at PRL, 2023) from an experiment using RIBs from CARIBU, Argonne National Laboratory, allowing to experimentally constraint the 139Ba(n,γ)140Ba reaction rate using the newly developed "Shape" method (Muecher et al., PRC 107, L011602, 2023). Our results remove the dominant source of uncertainty for the production of lanthanum, a key indicator of i-process conditions. Our results show that the observed elemental abundances in metal-poor stars are consistent with an i-process scenario at neutron densities of 1013 n/cm3.
Keywords: nucleosynthesis; i process; neutron capture rates; Oslo method