CVE[p, i]
is a D-4-dimensional Cartesian vector and is transformed into CartesianPair[CartesianMomentum[p,D-4], CartesianIndex[i,D-4]]
by FeynCalcInternal
.
Overview, FVE, Pair, CartesianPair.
[p, i] CVE
\hat{p}^i
[p - q, i] CVE
\left(\hat{p}-\hat{q}\right)^i
[CVE[p, i]] // StandardForm
FCI
(*CartesianPair[CartesianIndex[i, -4 + D], CartesianMomentum[p, -4 + D]]*)
ExpandScalarProduct
is used to expand momenta in CVE
[CVE[p - q, i]] ExpandScalarProduct
\hat{p}^i-\hat{q}^i