MadGraph5_aMC@NLO

non QCD emission of Gluon

Asked by Taegyu Lee

Hello,

I am aware of the discussion about non-QCD emission of Gluons for some EFT models.
( https://answers.launchpad.net/mg5amcnlo/+question/690133 )
This discussion seems to be around 4 years old and I was wondering if there was any understanding about this.

Would it be fine to believe the result at cross section level as discussed in the old question? Or would it still have some issues even at cross section level??

Thank you very much!

The error message I am referring to is
CRITICAL: Model with non QCD emission of gluon (found 72 of those).
  This type of model is not fully supported within MG5aMC.
  Restriction on LO dynamical scale and MLM matching/merging can occur for some processes.
  Use such features with care.

Best,
Taegyu

Question information

Language:
English Edit question
Status:
Solved
For:
MadGraph5_aMC@NLO Edit question
Assignee:
No assignee Edit question
Solved by:
Olivier Mattelaer
Solved:
Last query:
Last reply:
Revision history for this message
Best Olivier Mattelaer (olivier-mattelaer) said : 		#1

Hi,

Cross-section should be fine, yes.
But note that our default dynamical scale is deactivated in this case (and therefore you are using another one).
Also any cross-section using ickkw=1 should be wrong (and should normally crashed if attempt).
Obviously all cross-section which are never physical (like all the one that need to have a veto implemented at parton-shower) will still be non physical and for those you can not use the ickkw=1 mode/MLM mode.

So this is what was discussed in the previous thread and this is still valid.

Additionally, some work has been done recently about the possibility to do reweighting with such operator and no surprise they were some issue (related to the color).

Cheers,

Olivier

Revision history for this message
Taegyu Lee (taegyulee) said : 		#2

Hello,

I see, thank you very much!

Best,
Taegyu

Revision history for this message
Taegyu Lee (taegyulee) said : 		#3

Thanks Olivier Mattelaer, that solved my question.