$LoadPhi = True;
$LoadFeynArts = True;

Needs["HighEnergyPhysics`FeynCalc`"];

FeynCalc 4.1.1    For help, type ?FeynCalc,  use the built-in help system  or visit www.feyncalc.org

Loading PHI

Loading FeynArts

Cosmetics

Format[EL, TraditionalForm] = 
        StyleForm["e", FontSlant -> Italic];

Format[GStrong, TraditionalForm] = 
        StyleForm["g", FontSlant -> Italic];

MU /: MakeBoxes[MU, TraditionalForm] := 
        SubscriptBox["m", 
          MakeBoxes[
            StyleForm["u", FontSlant -> Plain]]];

MC /: MakeBoxes[MC, TraditionalForm] := 
        SubscriptBox["m", 
          MakeBoxes[
            StyleForm["c", FontSlant -> Plain]]];

MH /: MakeBoxes[MH, TraditionalForm] := 
        SubscriptBox["m", 
          MakeBoxes[
            StyleForm["H", FontSlant -> Plain]]];

MW /: MakeBoxes[MW, TraditionalForm] := 
        SubscriptBox["m", 
          MakeBoxes[
            StyleForm["W", FontSlant -> Plain]]];

MZ /: MakeBoxes[MZ, TraditionalForm] := 
        SubscriptBox["m", 
          MakeBoxes[
            StyleForm["Z", FontSlant -> Plain]]];

SW /: MakeBoxes[SW, TraditionalForm] := 
        SubscriptBox["S", 
          MakeBoxes[
            StyleForm["W", FontSlant -> Plain]]];

tt = CreateTopologies[0, 2 -> 2];

aa = 
        InsertFields[
          tt, {F[3, {1}], -F[3, {1}]} -> {F[
                3, {2}], -F[3, {2}]}, InsertionLevel -> Classes, 
          Model -> "SMQCD", 
          GenericModel -> "Lorentz"];

aa // Paint;

ampFA = CreateFeynAmp[aa];

$FADelta = IndexDelta;

ampFC = ampFA // FAToFC[#, FADeltas -> True] &;

ampFC[[5]]

ampFC[[5]] // Contract // DoSumOver // DotSimplify // 
      Simplify

amp = (FermionSpinSum[# (ComplexConjugate[#] /. {Colour -> Colour1, Gluon -> Gluon1}) /. 
                              SpaceTimeDimensions -> Sequence[] // 
                            Expand] /. 
                        DiracTrace -> (Tr[#, SUNTrace -> False, 
                                DiracTraceEvaluate -> True, 
                                SUNNToCACF -> False] &) // 
                      DiracSimplify // Contract // DoSumOver // 
                SUNReduce[#, SUNN -> 3] & // Simplify) & /@ 
        ampFC