FeynCalc manual (development version)

SISD

SISD[p] can be used as input for D-1-dimensional \sigma^{\mu } p_{\mu } with D-dimensional Lorentz vector p and is transformed into PauliSigma[Momentum[p,D],D-1] by FeynCalcInternal.

See also

Overview, PauliSigma, SIS.

Examples

SISD[p]

\sigma \cdot p

SISD[p] // FCI // StandardForm

(*PauliSigma[Momentum[p, D], -1 + D]*)

SISD[p, q, r, s]

(\sigma \cdot p).(\sigma \cdot q).(\sigma \cdot r).(\sigma \cdot s)

SISD[p, q, r, s] // StandardForm

(*SISD[p] . SISD[q] . SISD[r] . SISD[s]*)

SISD[q] . (SISD[p] + m) . SISD[q]

(\sigma \cdot q).(m+\sigma \cdot p).(\sigma \cdot q)