We present a generalization of the infinitesimal gauge transformation for nonabelian fields on the stack of branes up to the third order in $\Phi$. We test the gauge invariance of the action up to the fifth order in $\Phi$ for $D$-instantons. This substantiates the Myers formula for the Chern-Simons term in action, which describes interaction with the RR fields of $N$ coincident $\Dp$ branes.
Categories: hep-th