•Calculation of the amplitude

amplFC = CreateFCAmp[mesontreeinsert, AmplitudeLevel -> Classes] // Simplify // MomentumCombine // Contract // Simplify // MomentumCombine

{i e^( ) ( p _ 3 - p _ 4 ) · µ ( p _ 1 ) f _ (3 i _ 1 i _ 2)^(2)}

zpion = CheckF[dum, "ChPT2P20o2.Fac"] /. ChPT2 -> ChPTPhoton2

((384 π^2 L _ 4^( ) + 192 π^2 L _ 5^( ) - 32 π^2 λ - log((m _ π^(ó  ))^2/μ^2)) (m _ π^(ó  ))^2)/(24 π^2 (f _ π^(ó  ))^2) + 1

ampl2mult = (2 - zpion) * amplFC[[1]] /. D -> Sequence[] // Simplify

i e^( ) ( p _ 3 - p _ 4 ) · µ ( p _ 1 ) (1 - ((384 π^2 L _ 4^( ) + 192 π^2 L _ 5^( ) - 32 π^2 λ - log((m _ π^(ó  ))^2/μ^2)) (m _ π^(ó  ))^2)/(24 π^2 (f _ π^(ó  ))^2)) f _ (3 i _ 1 i _ 2)^(2)

Converted by Mathematica  (July 10, 2003)