MadGraph5_aMC@NLO

Using specific coupling orders

Asked by Jay Vora

Dear Olivier,

I am executing the following generation command using the LO LQ model from here [1]:

p p > top tau j nu QCD=2 QED=2 NP=2

By default, madgraph treats the coupling orders as less than or equal to the number specified. Instead is it possible to somehow specify the exact coupling order to generate? I would like to generate something like this:

p p > top tau j nu QCD<=2 QED<=2 NP==2

Best,
Jay Vora

[1] https://lqnlo.hepforge.org/

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Olivier Mattelaer (olivier-mattelaer) said : 		#1

Yes the "==" is the sign for exactly equal (but note that some of syntax might not be supported --like decay chain--)

Cheers,

Olivier

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Jay Vora (jvora123) said : 		#2

Thanks Olivier Mattelaer, that solved my question.

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Jay Vora (jvora123) said : 		#3

Hi Olivier,

Just a quick follow-up on this... If I want to include diagrams with NP=2 and NP=4, the syntax (NP>0) should take care of both cases right?

When I generate this, I see a tiny XSec change compared to the NP=2 case. This is expected due to small contributions by NP=4 case. However, I do not see the NP=4 diagrams in the list of generated diagrams.

Is there some way to verify I'm generating what I think I'm generating? Your help is greatly appreciated.

Thanks,
Jay

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Olivier Mattelaer (olivier-mattelaer) said : 		#4

If you do not see the diagrams, then it means that it means that you do not include the contribution that you think about.
For NP, many UFO model forbid MG5aMC to include multiple insertion of NP (like all EFT model) this might be the case for your model as well.

Cheers,

Olivier

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Jay Vora (jvora123) said : 		#5

Thanks a lot for all the clarifications, Olivier. Your help is very much appreciated.