2020/09/30 by G. G. Kiss, G. Kiss, T. N. Szegedi +7 · 23 citations
Chemistry · Engineering · Physics and Astronomy · #Astrophysics #Atomic physics #Chemistry #Ejecta #Neutrino #Neutron #Nuclear Physics and Applications #Nuclear physics #Nuclear physics research studies #Nuclear reaction #Nuclear reactor physics and engineering #Nucleosynthesis #Physics #Reaction rate #Supernova #nucl-ex #r-process
paper · pdf · doi:10.3847/1538-4357/abd2bc
published in The Astrophysical Journal 908(2), 202 (IOP Publishing)
openalex created_date 2020/10/01 · openalex publication_date 2021/02/01 · arxiv created 2021/03/02 · arxiv updated 2021/03/03 · openalex updated_date 2026/08/06
Abstract Lighter heavy elements beyond iron and up to around silver can form in neutrino-driven ejecta in core-collapse supernovae and neutron star mergers. Slightly neutron-rich conditions favor a weak r -process that follows a path close to stability. Therefore, the beta decays are slow compared to the expansion timescales, and ( α ,n) reactions become critical to move matter toward heavier nuclei. The rates of these reactions are calculated with the statistical model and their main uncertainty, at energies relevant for the weak r -process, is the α +nucleus optical potential. There are several sets of parameters to calculate the α +nucleus optical potential leading to large deviations for the reaction rates, exceeding even one order of magnitude. Recently the 96 Zr( α ,n) 99 Mo reaction has been identified as a key reaction that impacts the production of elements from Ru to Cd. Here, we present the first cross section measurement of this reaction at energies (6.22 MeV ≤ E c.m. ≤ 12.47 MeV) relevant for the weak r -process. The new data provide a stringent test of various model predictions which is necessary to improve the precision of the weak r -process network calculations. The strongly reduced reaction rate uncertainty leads to very well-constrained nucleosynthesis yields for Z = 44–48 isotopes under different neutrino-driven wind conditions.