Nucleosynthesis in Supernovae

Core collapse supernovae are dominated by energy transport from neutrinos. Therefore, some supernova properties could depend on symmetries and features of the standard model weak interactions. The cross section for neutrino capture is larger than that for antineutrino capture by one term of order the neutrino energy over the nucleon mass. This reduces the ratio of neutrons to protons in the $\nu$-driven wind above a protoneutron star by approximately $20\%$ and may significantly hinder $r$-process nucleosynthesis.