= Ghost-loop pole of the gluon self-energy
{title2=$\Pi_{\rm gh,UV}^{\mu\nu,ab}=g^2C_A\delta^{ab}(k^2g^{\mu\nu}+2k^\mu k^\nu)/(96\pi^2\epsilon)$}
With insertion convention $i\Pi$, <ghost propagator> $i/p^2$, and oriented ghost-gluon <Feynman rule> $gf^{abc}p^\mu$ with $p$ pointing away along the ghost arrow, the <ghost loop> is $i\Pi_{\rm gh}=-g^2C_A\delta^{ab}\int d^Dl\,(2\pi)^{-D}(l+k)^\mu l^\nu/[l^2(l+k)^2]$. In <dimensional regularization> with $D=4-\epsilon$, a <Feynman parameter> and a shift give the displayed <ultraviolet pole>. Its contraction is $g^2C_A\delta^{ab}k^2k^\nu/(32\pi^2\epsilon)$; it cancels the nontransverse part of the two-three-gluon-vertex contribution. A different insertion or ghost-vertex convention must be translated before comparing signs.
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