MadGraph5_aMC@NLO

contribution of mixing terms in breakdown of single graph contributions

Asked by Steven Jeremies

In the web interface which pops up when starting a cross section calculation one can look into the different contributions of the particular diagrams of the process. What´s about the contribution of the mixing terms? I was wondering because I have the same total cross section calculated myself but the single parts have very different contributions and espacially the mixing term seems to be close to zero when I simply calculate the difference between the total cross section and those of the single diagrams. Do I misinterpret this breakdown of the single diagrams maybe?

Thanks in advance!

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Olivier Mattelaer
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Best Olivier Mattelaer (olivier-mattelaer) said : 		#1

Hi,

Those are NOT the contribution of a given diagram but the contribution of the channel of integration associated to a given diagram. The sum of the channel is always equal to the total cross-section.
You can actually change the definition of the channel of integration via the sde_strategy parameter
(see 2102.00773 <https://arxiv.org/abs/2102.00773>)

Cheers,

Olivier

> On 17 Aug 2021, at 15:40, Steven Jeremies <email address hidden> wrote:
>
> New question #698403 on MadGraph5_aMC@NLO:
> https://answers.launchpad.net/mg5amcnlo/+question/698403
>
> In the web interface which pops up when starting a cross section calculation one can look into the different contributions of the particular diagrams of the process. What´s about the contribution of the mixing terms? I was wondering because I have the same total cross section calculated myself but the single parts have very different contributions and espacially the mixing term seems to be close to zero when I simply calculate the difference between the total cross section and those of the single diagrams. Do I misinterpret this breakdown of the single diagrams maybe?
>
> Thanks in advance!
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

Revision history for this message
Steven Jeremies (minits) said : 		#2

Thanks Olivier Mattelaer, that solved my question.