CFAD[{{q1 +..., p1 . q2 +...,} {m^2, s}, n}, ...]
denotes a Cartesian propagator given by \frac{1}{[(q_1+\ldots)^2 + p_1 \cdot q_2 ... + m^2 +
s i \eta]^n}, where q_1^2 and
p_1 \cdot q_2 are Cartesian scalar
products in D-1 dimensions.
For brevity one can also use shorter forms such as
CFAD[{q1+ ..., m^2}, ...],
CFAD[{q1+ ..., m^2 , n}, ...],
CFAD[{q1+ ..., {m^2, -1}}, ...], CFAD[q1,...]
etc.
If s is not explicitly specified, its value is
determined by the option EtaSign, which has the default
value -1.
If n is not explicitly specified, then the default value
1 is assumed. Translation into FeynCalcI internal form is
performed by FeynCalcInternal, where a CFAD is
encoded using the special head
CartesianPropagatorDenominator.
Overview, FAD, SFAD, GFAD, FeynAmpDenominator.
CFAD[{{p, 0}, m^2}]\frac{1}{(p^2+m^2-i \eta )}
FeynAmpDenominatorExplicit[%]\frac{1}{m^2+p^2}
CFAD[{{p, 0}, {m^2, 1}}]\frac{1}{(p^2+m^2+i \eta )}
FeynAmpDenominatorExplicit[%]\frac{1}{m^2+p^2}
CFAD[{{p, 0}, -m^2}]\frac{1}{(p^2-m^2-i \eta )}
FeynAmpDenominatorExplicit[%]\frac{1}{p^2-m^2}
CFAD[{{0, p . q}, m^2}]\frac{1}{(p\cdot q+m^2-i \eta )}
FeynAmpDenominatorExplicit[%]\frac{1}{m^2+p\cdot q}
CFAD[{{0, p . q}}]\frac{1}{(p\cdot q-i \eta )}
FeynAmpDenominatorExplicit[%]\frac{1}{p\cdot q}