Assertion: muon's number | /r/HasProperty | sf-functions
Facets:
Source sentences:
text: The following general theorem is formulated: The matrix element for the decay of spin-zero mesons with mass m into two leptons with masses μ1 and μ2 respectively contains only terms proportional to μ1/m and μ2/m, if in the open polygonal arc of lepton lines the number of matrices γμ plus the number of internal lines (SF-functions) is odd.