We suggest the use of open bosonic string theory to compute multigluon scattering in QCD, since gauge invariance ,cyclic symmetry etc. are manifest in this approach. The method is illustrated by the computation of five gluon scattering.
Kosower, David; Lee, Bum-Hoon; and Nair, V. Parameswaran, "Multi Gluon Scattering: A String Based Calculation" (1988). CUNY Academic Works.