Pair[x, y]
is the head of a special pairing used in the internal representation: x
and y
may have heads LorentzIndex
or Momentum
.
If both x
and y
have head LorentzIndex
, the metric tensor (e.g. ) is understood.
If x
and y
have head Momentum
, a scalar product (e.g. ) is meant.
If one of x
and y
has head LorentzIndex
and the other Momentum
, a Lorentz vector (e.g. ) is implied.
Overview, FV, FVD, MT, MTD, ScalarProduct, SP, SPD.
This represents a -dimensional metric tensor
[LorentzIndex[\[Alpha]], LorentzIndex[\[Beta]]] Pair
This is a D-dimensional metric tensor
[LorentzIndex[\[Alpha], D], LorentzIndex[\[Beta], D]] Pair
If the Lorentz indices live in different dimensions, this gets resolved according to the t’Hooft-Veltman-Breitenlohner-Maison prescription
[LorentzIndex[\[Alpha], n - 4], LorentzIndex[\[Beta]]] Pair
A -dimensional Lorentz vector
[LorentzIndex[\[Alpha]], Momentum[p]] Pair
A -dimensional Lorentz vector
[LorentzIndex[\[Alpha], D], Momentum[p, D]] Pair
-dimensional scalar products of Lorentz vectors
[Momentum[q], Momentum[p]] Pair
[Momentum[p], Momentum[p]] Pair
[Momentum[p - q], Momentum[p]] Pair
[Momentum[p], Momentum[p]]^2 Pair
[Momentum[p], Momentum[p]]^3 Pair
[Pair[Momentum[p - q], Momentum[p]]] ExpandScalarProduct
[Momentum[-q], Momentum[p]] + Pair[Momentum[q], Momentum[p]] Pair