•Generation of topologies and insertion of fields

Construction of topologies:

mesonstop = CreateTopologies[1, 2 -> 2, ExcludeTopologies -> {SelfEnergies, WFCorrections}, Adjacencies -> {3, 4, 5, 6}, CountertermOrder -> 0] ;

Specification of which topologies and coupling vectors are to be used. This is necessary only because we use vertices from a "foreign" model, ChPT2.

$VerticesSpecifications = {{VertexFields -> {Pion[0], Pion[0], Photon[0]}, PhiModel -> ChPTPhoton2, PerturbationOrder -> {2}, CouplingSign -> 1, XFileName -> Automatic}, {VertexFields -> {Pion[0], Pion[0], Pion[0], Pion[0]}, PhiModel -> ChPT2, PerturbationOrder -> {2}, CouplingSign -> 1, XFileName -> Automatic}, {VertexFields -> {Pion[0], Pion[0], Photon[0], Photon[0]}, PhiModel -> ChPTPhoton2, PerturbationOrder -> {2}, CouplingSign -> 1, XFileName -> Automatic}, {VertexFields -> {Pion[0], Pion[0], Pion[0], Pion[0], Photon[0]}, PhiModel -> ChPTPhoton2, PerturbationOrder -> {2}, CouplingSign -> 1, XFileName -> Automatic}, {VertexFields -> {Pion[0], Pion[0], Pion[0], Pion[0], Pion[0], Pion[0]}, PhiModel -> ChPT2, PerturbationOrder -> {2}, CouplingSign -> 1, XFileName -> Automatic}, {VertexFields -> {Pion[0], Pion[0], Pion[0], Pion[0], Photon[0], Photon[0]}, PhiModel -> ChPTPhoton2, PerturbationOrder -> {2}, CouplingSign -> 1, XFileName -> Automatic}} ;

Field insertion:

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

mesontreeinsert = InsertFields[mesonstop, {Pion[0, {i1}], Photon[0]} -> {Pion[0, {i2}], Photon[0]}, Model -> "Automatic", GenericModel -> "Automatic", InsertionLevel -> Classes] ;

Graphical representation of the process:

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

[Graphics:../HTMLFiles/index_14.gif]

[Graphics:../HTMLFiles/index_15.gif]

Converted by Mathematica  (July 10, 2003)