MadGraph5_aMC@NLO

Zero cross section, when recreating SM in EWdim6

Asked by Emil Gorm Nielsen

Hi,

I am trying to figure out why my cross sections for EWdim6 are much lower (Order 1/100) than for the standard model, so I tried to recreate the standard model in the EWdim6 model by setting all coefficients to zero.
So I run

import model EWdim6
generate p p > w+ z
output BSMtest
launch
           set nevents 1000
           set CWWWL2 0
           set CWL2 0
           set CBL2 0
           set CPWWWL2 0
           set CPWL2 0

and it returns an error that the cross section gives 0. I assumed that this would just return the standard model cross section?

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MadGraph5_aMC@NLO Edit question
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Solved by:
Olivier Mattelaer
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Best Olivier Mattelaer (olivier-mattelaer) said : 		#1

If you want to have the SM contribution, looks like that you have to specify yourself the coupling order.
The default algorithm to fix the coupling order does not do what you expect him to do in this case.
So you have to do

import model EWdim6
generate p p > w+ z NP=0
output BSMtest
launch

If you want both the SM and the NP contribution, you have to do:

import model EWdim6
generate p p > w+ z NP<=2
output BSMtest
launch

Cheers,

Olivier

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Emil Gorm Nielsen (gorm123) said : 		#2

Thanks Olivier Mattelaer, that solved my question.