MadGraph5_aMC@NLO

Command "generate_events run_01" interrupted with error: in event generation of p p > l- l+ l- l+ [noborn=QCD]

Asked by user1905

Hi Experts,
I am trying to generate a following process:
generate p p > l- l+ l- l+ [noborn=QCD]

The version of MadGraph is 3.4.2. During generation the following error exists:

INFO: Idle: 0, Running: 14, Completed: 187 [ 12m 23s ]
WARNING: local variable 'error' referenced before assignment
WARNING: local variable 'error' referenced before assignment
WARNING: local variable 'error' referenced before assignment
WARNING: local variable 'error' referenced before assignment
WARNING: local variable 'error' referenced before assignment
WARNING: local variable 'error' referenced before assignment
WARNING: local variable 'error' referenced before assignment
WARNING: local variable 'error' referenced before assignment
WARNING: local variable 'error' referenced before assignment
WARNING: local variable 'error' referenced before assignment
WARNING: local variable 'error' referenced before assignment
WARNING: local variable 'error' referenced before assignment
WARNING: local variable 'error' referenced before assignment
INFO: Idle: 0, Running: 1, Completed: 200 [ 13m 21s ]
WARNING: local variable 'error' referenced before assignment
INFO: Idle: 0, Running: 0, Completed: 201 [ 13m 21s ]
local variable 'error' referenced before assignment
Cluster Error detected. Do you want to clean the queue? ("c"=continue the run anyway) [y, n, c][60s to answer]
>
use y
Command "generate_events run_01" interrupted with error:
UnboundLocalError : local variable 'error' referenced before assignment
Please report this bug on https://bugs.launchpad.net/mg5amcnlo
More information is found in '/home/amir/hep/MG5_aMC_v3_4_2/CP_HZZ/pp_2e2mu_nobornQCD/run_01_tag_1_debug.log'.
Please attach this file to your report.

any commnets and suggestions are highly appreciated.

cheers!!

Question information

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

Hi,

The first question that I would ask is actually about physics.

When you provide that syntax "[noborn=", you force madgraph to assume that the syntax : "p p > l- l+ l- l+" does not have any diagram.
Obviously this is not True in the standard model. So I would need more information about the model/loop filtering that you use that allow you to do that.

If you did not, then your loop computation will not be finite and we did not try to make the code to detect those issues. But this can be a reason of your issue.

Cheers,

Olivier

Revision history for this message
user1905 (userinhep) said : 		#2

Hi Olivier,
The idea behind this event generation was to target the Higgs production via gluon-gluon fusion and further decay of Higgs to 4 lepton. If the way i have followed is incorrect, can you kindly suggest the syntax to accurately target those production channel. I have been able to do produce higgs and its decay using folling syntax:

generate g g > h [noborn=QCD]

and decay the higgs using madspin with flag set spinmode=none.

Thanks!!

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

If you are interested in the ONSHELL higgs contribution to 4 lepton, then indeed
generate g g > h [noborn=QCD]
and then let the Higgs decay into 4 leptons via the syntax
decay h > l+ l+ l- l-
within madspin can make sense.

Cheers,

Olivier

Revision history for this message
user1905 (userinhep) said : 		#4

Thanks Olivier Mattelaer, that solved my question.