Johan Thorén
Decomposing colour structures into multiplet bases


In this thesis a method for decomposing QCD colour structures into multiplet bases is described. The method is applicable for any number of gluons and quarks. To achieve the decomposition requires the knowledge of group theoretical weights, so- called Wigner 3j and 6j coefficients. The number of required coefficients have been calculated for up to 12 external gluons, and been shown to scale well in the number of external partons. How to calculate the coefficients have been shown and for 6 external gluons they have been calculated. Furthermore the colour structures of Ng − 1 basis vectors radiating a gluon have been decomposed into the Ng basis vectors. The viability of this has been examined for up to 10 external gluons by counting how many Ng basis vectors are projected on by the colour structures.

LU TP 14-22