MadGraph5_aMC@NLO

poles do not cancel

Asked by Kirill Skovpen

Hello,

I have the following problem while trying to generate the process tZq (Z->ll) + j:

import model loop_sm-no_b_mass
define p = g u c d s u~ c~ d~ s~
define j = g u c d s u~ c~ d~ s~
define l+ = e+ mu+
define l- = e- mu-
define vl = ve vm vt
define vl~ = ve~ vm~ vt~
define p g u c s d b u~ c~ s~ d~ b~
define j = g u c s d b u~ c~ s~ d~ b~
define l+ e+ mu+ ta+
define l- e- mu- ta-
define vl ve vm vt
define vl~ ve~ vm~ vt~
generate p p > t l- l+ j j / h [QCD]

The crash info is appended below:

INFO: Compiling directories...
INFO: Compiling on 24 cores
INFO: Compiling P0_ug_tamtaptdbx_no_h...
INFO: Compiling P0_gb_tamtaptscx_no_h...
INFO: Compiling P0_bg_tamtaptscx_no_h...
INFO: Compiling P0_gb_emeptscx_no_h...
INFO: Compiling P0_ub_emeptdg_no_h...
INFO: Compiling P0_gu_tamtaptdbx_no_h...
INFO: Compiling P0_gsx_emeptcxbx_no_h...
INFO: Compiling P0_ub_tamtaptdg_no_h...
INFO: Compiling P0_bu_tamtaptdg_no_h...
INFO: Compiling P0_udx_emeptbxg_no_h...
INFO: Compiling P0_bu_emeptdg_no_h...
INFO: Compiling P0_gsx_tamtaptcxbx_no_h...
INFO: Compiling P0_gu_emeptdbx_no_h...
INFO: Compiling P0_ug_emeptdbx_no_h...
INFO: Compiling P0_bsx_emeptcxg_no_h...
INFO: Compiling P0_udx_tamtaptbxg_no_h...
INFO: Compiling P0_sxg_tamtaptcxbx_no_h...
INFO: Compiling P0_bg_emeptscx_no_h...
INFO: Compiling P0_sxg_emeptcxbx_no_h...
INFO: Compiling P0_sxc_emeptbxg_no_h...
INFO: Compiling P0_bsx_tamtaptcxg_no_h...
INFO: Compiling P0_sxc_tamtaptbxg_no_h...
INFO: Compiling P0_sxb_emeptcxg_no_h...
INFO: Compiling P0_sxb_tamtaptcxg_no_h...
INFO: P0_ub_emeptdg_no_h done.
INFO: P0_udx_emeptbxg_no_h done.
INFO: P0_bu_emeptdg_no_h done.
INFO: P0_sxb_emeptcxg_no_h done.
INFO: P0_sxc_emeptbxg_no_h done.
INFO: P0_sxg_emeptcxbx_no_h done.
INFO: P0_bg_emeptscx_no_h done.
INFO: P0_gu_emeptdbx_no_h done.
INFO: P0_gb_emeptscx_no_h done.
INFO: P0_ug_emeptdbx_no_h done.
INFO: P0_gsx_emeptcxbx_no_h done.
INFO: P0_bsx_emeptcxg_no_h done.
INFO: P0_udx_tamtaptbxg_no_h done.
INFO: P0_bu_tamtaptdg_no_h done.
INFO: P0_sxb_tamtaptcxg_no_h done.
INFO: P0_bsx_tamtaptcxg_no_h done.
INFO: P0_ug_tamtaptdbx_no_h done.
INFO: P0_gu_tamtaptdbx_no_h done.
INFO: P0_sxc_tamtaptbxg_no_h done.
INFO: P0_bg_tamtaptscx_no_h done.
INFO: P0_gb_tamtaptscx_no_h done.
INFO: P0_gsx_tamtaptcxbx_no_h done.
INFO: P0_ub_tamtaptdg_no_h done.
INFO: P0_sxg_tamtaptcxbx_no_h done.
INFO: Checking test output:
INFO: P0_gu_emeptdbx_no_h
INFO: Result for test_ME:
INFO: Passed.
INFO: Result for test_MC:
INFO: Passed.
INFO: Result for check_poles:
Error detected in "launch --multicore --nb_core=24"
write debug file /grid_mnt/opt__sbg__cms__ui5_data1/kskovpen/ttH/CMSSW_5_3_16_patch1/src/tZqGEN/MG5_aMC_v2_1_2/TZJets_FINALj/run_03_tag_1_debug.log
If you need help with this issue please contact us on https://answers.launchpad.net/madgraph5
aMCatNLOError : Poles do not cancel, run cannot continue
quit
INFO:

I tried to manually run check_poles with playing with settings but all events fail to pass this check.

Could you please let me know if there is something I could try to solve this issue ?

Thanks a lot,

Kirill

Question information

Language:
English Edit question
Status:
Solved
For:
MadGraph5_aMC@NLO Edit question
Assignee:
marco zaro Edit question
Solved by:
marco zaro
Solved:
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Last reply:
Revision history for this message
Olivier Mattelaer (olivier-mattelaer) said : 		#1

Hi Kiril,

This process should not be possible to do in 5 flavor since you should have a t t~ contribution for the real in that scheme.
Could you try in 4 flavor?

Cheers,

Olivier

Revision history for this message
Kirill Skovpen (kirill-skovpen) said : 		#2

Hi Olivier,

Thanks a lot for your reply. I tried to run the computation in 4FS but I am running into the same issue with 'poles do not cancel'. Is there something else I could try ?

Thanks,

Kirill

Revision history for this message
Best marco zaro (marco-zaro) said : 		#3

Hi,
the poles miscancelation that you notice is due to the fact that virtual diagrams with a w boson in the loop are not included in the current version.
such diagrams are zero when no jets are added, but with the 2 extra jets they are there.
for the moment the only solution is to disable the pole check and to neglect these diagram (such classes are typically small, because of color suppression).

#IRPoleCheckThreshold and #PrecisionVirtualAtRunTime
to -1d0

See also https://answers.launchpad.net/mg5amcnlo/+question/251302

Cheers,

Marco

Revision history for this message
Kirill Skovpen (kirill-skovpen) said : 		#4

Thanks marco zaro, that solved my question.