Name: Vladyslav Shtabovenko (email_not_shown)
Date: 01/26/17-07:27:24 PM Z


It depends on the size of your calculation and your treatment of IR
divergences. In any case PaXEvaluate (e.g. Package-X) can handle IR
divergences regularized dimensionally.

But for "real" big pheno calculations PaXEvaluate will be probably too
slow and will return huge symbolic results.

If you regularize IR divergences with fake masses (which is LoopTools
default), then you could just tell LoopTools to give you the coefficient
of the 1/eps pole (I think it works via SetLambda, but one has to check
it carefully) and construct the full result of the loop integral as

c0/eps + c1

after which you can put D=4-2 eps and use Series to expand around eps=0.

Cheers,
Vladyslav

Am 26.01.2017 um 17:19 schrieb Davide Racco:
> Thanks very much, the point was indeed that I was wrongly imposing Dimension->4 to get a final numerical result.
> I should then use PaXEvaluate[] in the manipulation of the result with Feyncalc, or leave the evaluation to LoopTools with some other command?
>
> Best,
> Davide
>



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