Spinor[p, m, o]
is the head of Dirac spinors. Which of the spinors , , or is understood, depends on the sign of the momentum argument p
and the relative position of Spinor
in the chain.
Spinor[Momentum[p], m]
means if it stands at the beginning of the chain.
Spinor[Momentum[p], m]
means if it stands at the end of the chain.
Spinor[-Momentum[p], m]
means if it stands at the beginning of the chain.
Spinor[-Momentum[p], m]
means if it stands at the end of the chain.
Spinors of fermions of mass are normalized to have and .
The optional argument o
can be used for additional degrees of freedom. If no optional argument o
is supplied, a 1
is substituted in.
Overview, FermionSpinSum, DiracSimplify, SpinorU, SpinorV, SpinorUBar, SpinorVBar, SpinorUBarD, SpinorUD, SpinorVD, SpinorVBarD.
[Momentum[p]] Spinor
[Momentum[p], m] Spinor
FeynCalc uses covariant normalization (as opposed to e.g. the normalization used in Bjorken & Drell).
[Momentum[p], m] . Spinor[Momentum[p], m] // DiracSimplify Spinor
[Spinor[-Momentum[p], m] . GS[p]] DiracSimplify
[Momentum[p]] // StandardForm
Spinor
(*Spinor[Momentum[p], 0, 1]*)
[Spinor[Momentum[p]], D] // StandardForm
ChangeDimension
(*Spinor[Momentum[p, D], 0, 1]*)
[Momentum[p], m] // StandardForm
Spinor
(*Spinor[Momentum[p], m, 1]*)
SmallVariable
s are discarded by Spinor
.
[Momentum[p], SmallVariable[m]] // StandardForm
Spinor
(*Spinor[Momentum[p], 0, 1]*)