MadGraph5_aMC@NLO

Failed to disable systematics

Asked by Maksym Ovchynnikov

I am using the HeavyN model, https://feynrules.irmp.ucl.ac.be/wiki/HeavyN, to launch the process

generate p p > n1 e+

add process p p > n1 e-

in order to obtain the .hepmc file with vetoed events instead of weigted events I tried to remove the systematics using the option

False = use_syst

However, when launcing the MadGraph I got an error

Command "launch auto " interrupted with error:
MadGraph5Error : A compilation Error occurs when trying to compile /home/movchynnikov/Downloads/MG5_aMC_v2_6_5/bin/HNL-from-W-NLO/Source.
 The compilation fails with the following output message:
     gfortran -O -fno-automatic -ffixed-line-length-132 -c alfas_functions.f
     gfortran -O -fno-automatic -ffixed-line-length-132 -c -o setrun.o setrun.f
     run_card.inc:151:14:

            USE_SYST = ' False '
                   1
     Error: Symbol ‘use_syst’ at (1) has no IMPLICIT type
     make: *** [makefile:33: setrun.o] Error 1

 Please try to fix this compilations issue and retry.
 Help might be found at https://answers.launchpad.net/mg5amcnlo.
 If you think that this is a bug, you can report this at https://bugs.launchpad.net/mg5amcnlo
Please report this bug on https://bugs.launchpad.net/mg5amcnlo
More information is found in '/home/movchynnikov/Downloads/MG5_aMC_v2_6_5/bin/HNL-from-W-NLO/run_03_tag_1_debug.log'.
Please attach this file to your report.

What can be a reason of this?

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Solved by:
Olivier Mattelaer
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Olivier Mattelaer (olivier-mattelaer) said : 		#1

I believe that you are running a NLO process, while this option only exists for LO ones.
(i.e. that the process that you indicate in your question is not the one you actually use)

If you think that I'm wrong, please attach the debug file
/home/movchynnikov/Downloads/MG5_aMC_v2_6_5/bin/HNL-from-W-NLO/run_03_tag_1_debug.log

Cheers,

Olivier

On 14 Aug 2019, at 13:47, Maksym Ovchynnikov <<email address hidden><mailto:<email address hidden>>> wrote:

False = use_syst

Revision history for this message
Maksym Ovchynnikov (name-xxx) said : 		#2

You are right, thank you. I provided incorrect syntax. The correct is

generate p p > n1 e+ [QCD]
add process p p > n1 e- [QCD]

However, the same option (False = use_syst) worked for the process

generate p p > h [noborn=QCD]
add process p p > h j [noborn=QCD]

What is the difference between these two syntaxes such that the second works fine?

Could you please tell me how to find weight value in the .hepmc file? Is it contained in a string with E?

Revision history for this message
Best Olivier Mattelaer (olivier-mattelaer) said : 		#3

HI,

The second process is a one loop process. Where at the lowest order in pertrubation, the Feynman diagram is a loop.
The [noborn=QCD] is the syntax to generate such type of processes.

Such computation are at LO accuracy (a NLO computation for such processes would need two loop to be included which we can not do). And this is way for such processes, you have the exact same option as for any other LO processes definition.

>
> Could you please tell me how to find weight value in the .hepmc file? Is it contained in a string with E?

That I do not know, my only suggestion is to read the paper describing the hepmc convention.

Cheers,

Olivier

> On 14 Aug 2019, at 14:07, Maksym Ovchynnikov <email address hidden> wrote:
>
> Question #682882 on MadGraph5_aMC@NLO changed:
> https://answers.launchpad.net/mg5amcnlo/+question/682882
>
> Status: Answered => Open
>
> Maksym Ovchynnikov is still having a problem:
> You are right, thank you. I provided incorrect syntax. The correct is
>
> generate p p > n1 e+ [QCD]
> add process p p > n1 e- [QCD]
>
> However, the same option (False = use_syst) worked for the process
>
> generate p p > h [noborn=QCD]
> add process p p > h j [noborn=QCD]
>
> What is the difference between these two syntaxes such that the second
> works fine?
>
>
> Could you please tell me how to find weight value in the .hepmc file? Is it contained in a string with E?
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

Revision history for this message
Maksym Ovchynnikov (name-xxx) said : 		#4

Thanks Olivier Mattelaer, that solved my question.