SID[mu]
can be used as input for -dimensional with -dimensional Lorentz index and is transformed into PauliSigma[LorentzIndex[mu,D],D-1]
by FeynCalcInternal
.
Overview, PauliSigma, SI, SIE.
[\[Mu]] SID
[\[Mu], \[Nu]] - SID[\[Nu], \[Mu]] SID
StandardForm[FCI[SID[\[Mu]]]]
(*PauliSigma[LorentzIndex[\[Mu], D], -1 + D]*)
[\[Mu], \[Nu], \[Rho], \[Sigma]] SID
[\[Mu], \[Nu], \[Rho], \[Sigma]] // StandardForm
SID
(*SID[\[Mu]] . SID[\[Nu]] . SID[\[Rho]] . SID[\[Sigma]]*)
[\[Alpha]] . (SISD[p] + m) . SID[\[Beta]] SID