Hi Will,
the change was actually introduce by an update in FeynArts from March 2019
https://github.com/FeynCalc/feynarts-mirror/commit/73094019d93c8a11cf8eee7189e5514a8e9154d6#diff-cc9305310a3b0771b5c2045c39d7cc73R491
so that since then FeynArts joins propagators raised to integers
together, according to
PropagatorDenominator[p_, m_, d___]^n_. ^:=
PropagatorDenominator[p, m, d + n]
Nevertheless, I've just added a new option FeynAmpDenominatorCombine to
FCFAConvert, that should be able to emulate the old behavior. When set
to False, FCFAConvert will return the relevant propagators as e.g.
FAD[p1+p2] ^2 instead of FAD[p1+p4,p1+p4].
I'm not sure that it will give you exactly the same results as before
the change
in FA, but perhaps it still helps to preserve your workflow.
Otherwise, applying FeynAmpDenominatorSplit directly might also be an
option.
Cheers,
Vladyslav
Am 20.06.19 um 18:52 schrieb Will:
> Hi Vladyslav,
>
> I am generating a two-loop amplitude with FeynArts/FeynCalc with the
> development version and I noticed that there are things generated as
>
> IntNEW = FAD[p[1] + p[4], p[1] + p[4]]*FAD[q[1], p[1] + p[4] +
> q[1]]*FAD[q[2], -p[1] - p[4] + q[2]]
>
> and before one uses to have
>
> IntOLD = FAD[p[1] + p[4]]^2 * FAD[q[1], p[1] + p[4] + q[1],q[2],
> -p[1] - p[4] + q[2]]
>
> Is there are way to pass from IntOLD to IntNEW?
>
> Many thanks for your support, Will
>
This archive was generated by hypermail 2b29 : 09/04/20-12:55:05 AM Z CEST