Lets see the reaction:

e<sup>&minus;</sup> &mu;<sup>&minus;</sup>  &ndash;&gt;   e<sup>&minus;</sup> &pi;<sup>&minus;</sup> &nu;<sub>&mu;</sub>

I suppose, that this reaction occurs as follows

e<sup>&minus;</sup> &mu;<sup>&minus;</sup>  &ndash;&gt;  e<sup>&minus;</sup> &mu;<sup>&minus;</sup> &pi;<sup>+</sup> &pi;<sup>&minus;</sup>  &ndash;&gt;  e<sup>&minus;</sup> &pi;<sup>&minus;</sup> &nu;<sub>&mu;</sub>

Is it possible at energy less than 2*140 MeV?


The same is for the analogous reaction

p<SUP>+</SUP> &mu;<SUP>+</SUP>  &ndash;&gt; p<SUP>+</SUP> &pi;<SUP>+</SUP> &nu;&#771;<SUB>&mu;</SUB>