•ππππγγ

llt = (WriteString["stdout", "."] ; UNMSplit[#, x, DropOrder -> 4, DiagonalToU -> True]) & /@ Expand[Lagrangian[ChPTPhoton2[2]]] ;

...

lltt = ArgumentsSupply[llt, x, RenormalizationState[0], ExpansionOrder -> 4, DropOrder -> 4, DiagonalToU -> True] ;

ArgumentsSupply :: argxpr : Warning : The argument x is already in the expression.

lll = DiscardTerms[lltt, Retain -> {Particle[Pion , RenormalizationState[0]] -> 4, Particle[Photon , RenormalizationState[0]] -> 2}, Method -> Expand] ;

llle = ExpandU[lll, CommutatorReduce -> True] // Simplify ;

$IsoIndicesCounter = 0 ;

llll = IsoIndicesSupply[llle] // Simplify ;

fields = {QuantumField[Particle[Pion, RenormalizationState[0]], SUNIndex[I1]][p1], QuantumField[Particle[Pion, RenormalizationState[0]], SUNIndex[I2]][p2], QuantumField[Particle[Pion, RenormalizationState[0]], SUNIndex[I3]][p3], QuantumField[Particle[Pion, RenormalizationState[0]], SUNIndex[I4]][p4], QuantumField[Particle[Photon, RenormalizationState[0]], LorentzIndex[μ5]][p5], QuantumField[Particle[Photon, RenormalizationState[0]], LorentzIndex[μ6]][p6]}

{π^( )^I _ 1, π^( )^I _ 2, π^( )^I _ 3, π^( )^I _ 4, γ^( ) _ μ _ 5, γ^( ) _ μ _ 6}

melsimplified = FeynRule[llll, fields] // SUNReduce[#, FullReduce -> True] & // Simplify

1/(24 (f _ π^(ó  ))^2) (i (e^( ))^2 g^(μ _ 5 μ _ 6) (22 δ _ (3 I _ 1)^(2) δ _ (3 I _ 4)^(2) δ _ (I _ 2 I _ 3)^(2) - 54 δ _ (I _ 1 I _ 4)^(2) δ _ (I _ 2 I _ 3)^(2) - 64 δ _ (I _ 1 I _ 3)^(2) δ _ (I _ 2 I _ 4)^(2) + δ _ (3 I _ 3)^(2) (42 δ _ (3 I _ 4)^(2) δ _ (I _ 1 I _ 2)^(2) + 22 δ _ (3 I _ 2)^(2) δ _ (I _ 1 I _ 4)^(2) + 32 δ _ (3 I _ 1)^(2) δ _ (I _ 2 I _ 4)^(2)) - 74 δ _ (I _ 1 I _ 2)^(2) δ _ (I _ 3 I _ 4)^(2) + δ _ (3 I _ 2)^(2) (32 δ _ (3 I _ 4)^(2) δ _ (I _ 1 I _ 3)^(2) + 42 δ _ (3 I _ 1)^(2) δ _ (I _ 3 I _ 4)^(2)) + 5 f _ (3 I _ 1 I _ 4)^(2) f _ (3 I _ 2 I _ 3)^(2) + 5 f _ (3 I _ 1 I _ 3)^(2) f _ (3 I _ 2 I _ 4)^(2) + 5 f _ (3 I _ 1 I _ 2)^(2) f _ (3 I _ 3 I _ 4)^(2)))

Converted by Mathematica  (July 10, 2003)