Description:
<jats:p>The lighter heavy elements of the first r-process peak, between strontium and silver, can be synthesized in the moderately neutron-rich neutrino–driven ejecta of either core–collapse supernovae or neutron star mergers via the weak r–process. This nucleosynthesis scenario exhibits uncertainties from the absence of experimental data from (<jats:italic>α</jats:italic>, <jats:italic>xn</jats:italic>) reactions on neutron–rich nuclei, which are currently based on statistical model estimates. We have performed a new impact study to identify the most important (<jats:italic>α</jats:italic>, <jats:italic>xn</jats:italic>) reactions that can affect the production of the lighter heavy elements under different astrophysical conditions using new, constrained (<jats:italic>α</jats:italic>, <jats:italic>xn</jats:italic>) reaction rates based on the Atomki-V2 <jats:italic>α</jats:italic>OMP. Our results show how when reducing the nuclear physics uncertainties, we can use abundance ratios to constrain the astrophysical conditions/environment. This can be achieved in the near future, when the key (<jats:italic>α</jats:italic>, <jats:italic>xn</jats:italic>) reaction rates will be measured experimentally in radioactive beam facilities.</jats:p>