FAD

Description

FAD is the FeynCalc external form of FeynAmpDenominator and denotes an inverse propagator. FAD[q, q-p, ...] is 1/(q^2 (q-p)^2 ...). FAD[{q1,m}, {q1-p,m}, q2, ...] is 1/( (q1^2 - m^2) ( (q1-p)^2 - m^2 ) q2^2 ... ). Translation into FeynCalc internal form is performed by FeynCalcInternal.

See also:  FAD, FCE, FCI, FeynAmpDenominator, FeynAmpDenominatorSimplify, PropagatorDenominator.

Examples

FAD[q, p - q]

FAD[p, {p - q, m}]

FAD[q, p - q] // FCI // FCE // StandardForm

FAD[q, p - q] // FCI // StandardForm

FAD[p] FAD[p - q]  //  FeynAmpDenominatorCombine // 
      StandardForm