SirlinSimplify
SirlinSimplify[exp]
simplifies spinor chains that contain Dirac matrices using relations derived by A. Sirlin in Nuclear Physics B192 (1981) 93-99. Contrary to the original paper, the sign of the Levi-Civita tensor is chosen as ε0123=1 which is the standard choice in FeynCalc.
See also
Overview, DiracGamma, Spinor, SpinorChainTrick.
Examples
SpinorUBar[p3, m3] . GA[\[Mu], \[Rho], \[Nu], 7] . SpinorU[p1, m1] SpinorUBar[p4, m4] . GA[\[Mu], \[Tau], \[Nu], 7] . SpinorU[p2, m2]
SirlinSimplify[%]
uˉ(p3,m3).γˉμ.γˉρ.γˉν.γˉ7.u(p1,m1)uˉ(p4,m4).γˉμ.γˉτ.γˉν.γˉ7.u(p2,m2)
4gˉρτ(φ(p3,m3)).γˉliS29.γˉ7.(φ(p1,m1))(φ(p4,m4)).γˉliS29.γˉ7.(φ(p2,m2))