Abstract

The behavior of pions is studied in systems where their normal leptonic decay is forbidden. When thermal fluctuations are present, a low decay rate results, and as a consequence of lepton recombination, the number of pions remains almost unaltered. Compact star conditions are favorable for the formation of such intermediate state of charged pions: near condensation and almost stable, leading to a continuum source of antineutrinos. In particular, protoneutron stars could be a scenario where this state of matter is relevant.