•Generation of topologies and insertion of fields

Construction of topologies:

mesonstop = CreateTopologies[0, 2 -> 3, Adjacencies -> {3, 4}, ExcludeTopologies -> {SelfEnergies, WFCorrections}, CountertermOrder -> 0] ;

Specification of which coupling vectors are to be used:

$VerticesSpecifications = {{VertexFields -> {Pion[0], Pion[0], Photon[0]}, PhiModel -> ChPTVirtualPhotons2, PerturbationOrder -> {2}, CouplingSign -> 1, XFileName -> Automatic}, {VertexFields -> {Pion[0], Pion[0], Pion[0], Pion[0]}, PhiModel -> ChPTVirtualPhotons2, PerturbationOrder -> {2}, CouplingSign -> 1, XFileName -> Automatic}} ;

Field insertion:

InitializeModel["Automatic", GenericModel -> "Automatic", Reinitialize -> True] ;

mesontreeinsert = InsertFields[mesonstop, {Pion[0, {k1}], Pion[0, {k2}]} -> {Pion[0, {k3}], Pion[0, {k4}], Photon[0]}, Model -> "Automatic", GenericModel -> "Automatic", InsertionLevel -> Classes] ;

Graphical representation of the process:

Paint[mesontreeinsert, PaintLevel -> {Classes}, AutoEdit -> False, SheetHeader -> False, Numbering -> False, ColumnsXRows -> {3, 2}] ;

[Graphics:../HTMLFiles/index_24.gif]

[Graphics:../HTMLFiles/index_25.gif]

[Graphics:../HTMLFiles/index_26.gif]

Converted by Mathematica  (July 10, 2003)