Getting more flavour out of one-flavour QCD

Understand

We argue that no notion of flavour is necessary when performing amplitude calculations in perturbative QCD with massless quarks.

• We show this explicitly at tree-level, using a flavour recursion relation to obtain multi-flavoured QCD from one-flavour QCD.
• The method relies on performing a colour decomposition, under which the one-flavour primitive amplitudes have a structure which is restricted by planarity and cyclic ordering.
• An understanding of SU(3)_c group theory relations between QCD primitive amplitudes and their organisation around the concept of a Dyck tree is also necessary.