Matter-enhanced antineutrino flavor transformation and supernova nucleosynthesis.

Matter-enhanced antineutrino flavor transformation between {bar {nu}}{sub {ital e}} and {bar {nu}}{sub {mu}({tau})} can occur in supernovas if the vacuum masses for these species satisfy {ital m}{sub @g}{bar n}{sub {ital e}}{gt}{ital m}{sub @g}{bar n}{sub {mu}({tau})}. For {delta}{ital m}{sup 2}{gt}1 eV{sup 2}, such flavor transformation can affect the electron fraction {ital Y}{sub {ital e}} in the neutrino-heated supernova ejecta. We point out that such flavor transformations will not drive {ital Y}{sub {ital e}}{gt}0.5 at the {ital r}-process nucleosynthesis epoch in the best available supernova model for such nucleosynthesis. Consequently, there is no obvious conflict between the matter-enhanced antineutrino flavor transformation {bar {nu}}{sub {ital e}{parallel}}{bar {nu}}{sub {mu}({tau})} and {ital r}-process nucleosynthesis in the neutrino-heated supernova ejecta.