MadGraph5_aMC@NLO

NLO QED corrections?

Asked by Thor Taylor

Hi,

I would like to be able to calculate the NLO Electroweak corrections to a SM process. Since I know that QCD corrections are applied by appending [QCD] to the process, i tried appending [QED] instead, and got the following error:

Command "generate p p > l+ l+ vl vl j j QED=6 QCD=0 [QED]" interrupted with error:
InvalidCmd : Perturbation order QED is not among the perturbation orders allowed for by the loop model.

So it appears that I have the correct syntax, but I'm still missing something. I tried manually importing the model loop_sm, because that is the model loaded to do NLO QCD loops, but it didn't help.

What am I doing wrong?

P.S. Is it possible to calculate both the QCD and the QED NLO corrections simultaneously? The syntax " ... [QCD] [QED]" doesn't appear to be recognized.

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Olivier Mattelaer (olivier-mattelaer) said : 		#1

Hi Thor,

We can not compute NLO electroweak correction for the moment.

On the other hand, we are able to compute electroweak loop.
The only model available for electroweak loop is loop_qcd_qed_sm.
example of syntax:
generate u u~ > e+ e- [virt=QED]

P.S. Is it possible to calculate both the QCD and the QED NLO corrections simultaneously? The syntax " ... [QCD] [QED]" doesn't appear to be recognized.

The correct syntax will be [QCD QED].
As above the computation of the loop is ready:
generate u u~ > e+ e- [virt=QED QCD]

Cheers,

Olivier

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