FeynAmpDenominatorSimplify

Description

FeynAmpDenominatorSimplify[exp] tries to simplify each PropagatorDenominator in a canonical way. FeynAmpDenominatorSimplify[exp, q1] simplifies all FeynAmpDenominator's in exp in a canonical way, including some translation of momenta. FeynAmpDenominatorSimplify[exp, q1, q2] additionally removes integrals with no mass scale.

FDS can be used as an alias.

FDS

See also:  OneLoopSimplify.

Examples

The cornerstone of dimensional regularization is that ∫(d^n) 
            k f(k)/(k^(2  m)) =  0 .

FeynAmpDenominatorSimplify[f[k] FAD[k, k], k]

This brings 1/((((k - (Subscript[p, 1])))^2) (((k - (Subscript[p, 2])))^2)) into a standard form.

FeynAmpDenominatorSimplify[FAD[k - (Subscript[p, 1]), k - (Subscript[p, 2])], k]

t = 
      FeynAmpDenominatorSimplify[FAD[k - (Subscript[p, 1]), k - (Subscript[p, 2])] SPD[k, k], 
        k]

r = SPC[t, k, FDS -> True]

OneLoopSimplify[r, k]

FDS[FAD[k - p1, k - p2] SPD[k, OPEDelta]^2, k]

Clear[t, r]