CGS[p]
is transformed into
DiracGamma[CartesianMomentum[p]]
by
FeynCalcInternal
.
CGS[p,q, ...]
is equivalent to
CGS[p].CGS[q]
.
Overview, GS, DiracGamma.
[p] CGS
\overline{\gamma }\cdot \overline{p}
[p] // FCI // StandardForm
CGS
(*DiracGamma[CartesianMomentum[p]]*)
[p, q, r, s] CGS
\left(\overline{\gamma }\cdot \overline{p}\right).\left(\overline{\gamma }\cdot \overline{q}\right).\left(\overline{\gamma }\cdot \overline{r}\right).\left(\overline{\gamma }\cdot \overline{s}\right)
[p, q, r, s] // StandardForm
CGS
(*CGS[p] . CGS[q] . CGS[r] . CGS[s]*)
[q] . (CGS[p] + m) . CGS[q] CGS
\left(\overline{\gamma }\cdot \overline{q}\right).\left(\overline{\gamma }\cdot \overline{p}+m\right).\left(\overline{\gamma }\cdot \overline{q}\right)