例文
- The branching fractions above are the PDG central values, and their uncertainties are not quoted.
- The neutral pion has also been observed to decay into positronium with a branching fraction of the order of 10 & minus; 9.
- Also observed, for charged pions only, is the very rare " pion beta decay " ( with branching fraction of about 10 " 8 ) into a neutral pion, an electron and an electron antineutrino ( or for positive pions, a neutral pion, a positron, and electron neutrino ).
