(Li 6, d) and (Li 6, t) reactions on Ne 22 and implications for s -process nucleosynthesis

Abstract

We studied α cluster states in Mg26 via the Ne22(Li6,dγ)Mg26 reaction in inverse kinematics at an energy of 7 MeV/nucleon. States between Ex = 4-14 MeV in Mg26 were populated and relative α spectroscopic factors were determined. Some of these states correspond to resonances in the Gamow window of the Ne22(α,n)Mg25 reaction, which is one of the main neutron sources in the astrophysical s-process. Using our new Ne22(α,n)Mg25 and Ne22(α,γ)Mg26 reaction rates, we performed new s-process calculations for massive stars and asymptotic giant branch stars and compared the resulting abundances with the abundances obtained using other Ne22+α rates from the literature. We observe an impact on the s-process abundances up to a factor of three for intermediate-mass AGB stars and up to a factor of ten for massive stars. Additionally, states in Mg25 at Ex < 7.5 MeV are identified via the Ne22(Li6,t)Mg25 reaction for the first time. We present the (Li6, t) spectroscopic factors of these states and note similarities to the (d,p) reaction in terms of reaction selectivity.