The role of epithermal neutrons in AGB stars: Boron synthesis

We consider the influence of the capture of epithermal neutrons on the nucleosynthesis in asymptotic giant branch stars (the Petrov-Shlyakhter effect). We show that epithermal neutrons can be captured by nitrogen through the hitherto unanalyzed channel ¹⁴N(n, α)¹¹B. Since the proton concentration in the partial mixing zone is low, this process results in an appreciable boron concentration. This boron can be brought to the stellar surface by peculiar processes. We analyze the boron concentration as a function of the assumed parameters for the partial mixing zone.