FeynCalc manual (development version)

SID

SID[mu] can be used as input for D-1-dimensional \sigma^{\mu } with D-dimensional Lorentz index \mu and is transformed into PauliSigma[LorentzIndex[mu,D],D-1] by FeynCalcInternal.

See also

Overview, PauliSigma, SI, SIE.

Examples

SID[\[Mu]]

\sigma ^{\mu }

SID[\[Mu], \[Nu]] - SID[\[Nu], \[Mu]]

\sigma ^{\mu }.\sigma ^{\nu }-\sigma ^{\nu }.\sigma ^{\mu }

StandardForm[FCI[SID[\[Mu]]]]

(*PauliSigma[LorentzIndex[\[Mu], D], -1 + D]*)

SID[\[Mu], \[Nu], \[Rho], \[Sigma]]

\sigma ^{\mu }.\sigma ^{\nu }.\sigma ^{\rho }.\sigma ^{\sigma }

SID[\[Mu], \[Nu], \[Rho], \[Sigma]] // StandardForm

(*SID[\[Mu]] . SID[\[Nu]] . SID[\[Rho]] . SID[\[Sigma]]*)

SID[\[Alpha]] . (SISD[p] + m) . SID[\[Beta]]

\sigma ^{\alpha }.(m+\sigma \cdot p).\sigma ^{\beta }