Twist2GluonOperator[{p, mu, a}, {nu, b}] or Twist2GluonOperator[p, {mu, a}, {nu, b}] or Twist2GluonOperator[p, mu,a, nu,b] yields the 2-gluon operator (p is ingoing momentum corresponding to Lorentz index mu).
Twist2GluonOperator[{p,mu,a}, {q,nu,b}, {k,la,c}] or Twist2GluonOperator[ p,mu,a , q,nu,b , k,la,c] gives the 3-gluon operator.
Twist2GluonOperator[{p,mu,a}, {q,nu,b}, {k,la,c}, {s,si,d}] or Twist2GluonOperator[p,mu,a , q,nu,b , k,la,c , s,si,d] yields the 4-Gluon operator.
The dimension is determined by the option Dimension. The setting of the option Polarization (unpolarized: 0; polarized: 1) determines whether the unpolarized or polarized Feynman rule is returned.
With the setting Explicit set to False the color-structure and the (1+(-1)^OPEm) (for polarized: (1-(-1)^OPEm)) is extracted and the color indices are omitted in the arguments of Twist2GluonOperator.
Overview, Twist2QuarkOperator.
The setting All for Explicit performs the sums.
Twist2GluonOperator[{p, \[Mu], a}, {q, \[Nu], b}, {r, \[Rho], c}, Polarization -> 1, Explicit -> All]\left(1-(-1)^m\right) g_s f^{abc} \left(O_{\nu \, \rho \, \mu }^{\text{G3}}(q,r,p)\right)