Dynamical scale for EFTs

Asked by Eirini Kasimi on 2020-11-16

Dear experts,

I have four questions for you:

1) I saw the following questions for the dynamical scales on dim-8 EFTs model for ssWW VBS analysis and I am wondering if
I can conclude that the same is true for dim-6 EFTs models. If yes, do I have to use this dynamical scale either for electroweak and QCD VBS processes using the dim-6 model ?

https://answers.launchpad.net/mg5amcnlo/+question/684056

https://answers.launchpad.net/mg5amcnlo/+question/683400

2) Is this true only when I use EFTs models or I have to produce the samples with this dynamical scale when I don't use an EFT model and I use the default SM-nomasses model of madgraph?

3) Also, do I have to use this scale for dim-6 operators when I produce the WZ inclusive process?

4) Finally, if my samples with EFTs have a dynamical scale=3 and the nominal sample(without an EFT model) is produced with dynamical scale=-1, can I compare the EFT and nominal samples in order to extract some limits or the two samples can't be compared?

Thanks in advance,
Eirini Kasimi

Question information

Language:
English Edit question
Status:
Answered
For:
MadGraph5_aMC@NLO Edit question
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Last query:
2020-11-16
Last reply:
2020-11-18

This question was reopened

Hi,

scale choice are arbitrary and you can pick the scale choice that you prefer technically.
They are no issue to use HT/2 (setup#3) for most processes.
The scale "-1" is designed for matched/merged computation.
The scale "-1" is badly motivated for interference computation

Concerning your questions
1) I have not check the other question but yes the dimension of the EFT operator does not play any role in the discussion

2/3) You can always choose the scale that you want those computations will differ within theoretical uncertainty but they will be all valid.

> 4) Finally, if my samples with EFTs have a dynamical scale=3 and the nominal sample(without an EFT model) is produced with dynamical scale=-1, can I compare the EFT and nominal samples in order to extract some limits or the two samples can't be compared?

No issue here. Even if you were using the same scale you would still have to check what happens with the theoretical error. Changing the central value within the theoretical error should not change your conclusion (or you have a problem)

Cheers,

Olivier

> On 16 Nov 2020, at 12:05, Eirini Kasimi <email address hidden> wrote:
>
> New question #694039 on MadGraph5_aMC@NLO:
> https://answers.launchpad.net/mg5amcnlo/+question/694039
>
> Dear experts,
>
> I have four questions for you:
>
> 1) I saw the following questions for the dynamical scales on dim-8 EFTs model for ssWW VBS analysis and I am wondering if
> I can conclude that the same is true for dim-6 EFTs models. If yes, do I have to use this dynamical scale either for electroweak and QCD VBS processes using the dim-6 model ?
>
> https://answers.launchpad.net/mg5amcnlo/+question/684056
>
> https://answers.launchpad.net/mg5amcnlo/+question/683400
>
> 2) Is this true only when I use EFTs models or I have to produce the samples with this dynamical scale when I don't use an EFT model and I use the default SM-nomasses model of madgraph?
>
> 3) Also, do I have to use this scale for dim-6 operators when I produce the WZ inclusive process?
>
> 4) Finally, if my samples with EFTs have a dynamical scale=3 and the nominal sample(without an EFT model) is produced with dynamical scale=-1, can I compare the EFT and nominal samples in order to extract some limits or the two samples can't be compared?
>
> Thanks in advance,
> Eirini Kasimi
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

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