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Changes between Version 2 and Version 3 of Models/HiggsEffective

v2	v3
30	30	== The non-propagating auxiliary particle T ==
31	31
32		To describe the four-gluon-Higgs coupling a vertex with 5 external lines is needed. This can~~not be done with !MadGraph. However, there is a way to circumvent this~~ problem by introducing non-propagating auxiliary particles. It is possible to rewrite the four-gluon interactions as two three-point interactions connected by the new auxiliary tensor particle (called tn internally, and shows as T in the MG diagrams, the PDG code is 99). The troublesome five-point interaction (between the four gluons and the Higgs) reduces then to three three-point interactions.
	32	To describe the four-gluon-Higgs coupling a vertex with 5 external lines is needed. This can be done with !MadGraph5 (But not with !MadGraph4). However, there is a way to circumvent the !Madgraph4 problem by introducing non-propagating auxiliary particles. It is possible to rewrite the four-gluon interactions as two three-point interactions connected by the new auxiliary tensor particle (called tn internally, and shows as T in the MG diagrams, the PDG code is 99). The troublesome five-point interaction (between the four gluons and the Higgs) reduces then to three three-point interactions.
33	33
34	34	Notice that the color part of the four-gluon vertex is exactly like the sum of the s-, t-, and u-channel exchange diagram, where the exchanged particle is in the adjoint representation of color, i.e. an octet.