pole cancellation

Asked by Sihyun Jeon

Hello,

I have an issue when running MGv299 with the command [1].
I've added "/ n1 n2 n3" as there was an issue with MCatNLO pole checks for processes that involves LNV (p p > tap tam tap vm). This diagrams won't really have any effect in the final results as the masses are set to ridiculously large values (set mn1, ...) and the couplings are turned off (set ven1, ...) so I wonder why this gets problematic.
But anyhow, because I saw LNV subprocesses giving errors, I added "/ n1 n2 n3" to remove such diagrams but I still get an error-like message in the end.

INFO: (Running in /data9/Users/shjeon/THESIS_PROJECTS/PHENOMENOLOGY/TYPEI_SEESAW_MODEL/TTBAR_CHANNEL/MG5_aMC_v2_9_9/lllv_amcatnlo_13tev/MCatNLO/RUN_PYTHIA8_1)
INFO: Idle: 1, Running: 0, Completed: 0 [ current time: 16h06 ]
/data9/Users/shjeon/THESIS_PROJECTS/PHENOMENOLOGY/TYPEI_SEESAW_MODEL/TTBAR_CHANNEL/MG5_aMC_v2_9_9/lllv_amcatnlo_13tev/MCatNLO/RUN_PYTHIA8_1/shower.sh: line 44: 70675 Segmentation fault (core dumped) ./Pythia8.exe Pythia8.cmd > mcatnlo_run.log 2>&1
INFO: Idle: 0, Running: 0, Completed: 1 [ 15.9s ]
INFO: Idle: 0, Running: 0, Completed: 0 [ current time: 16h06 ]
INFO: The file /data9/Users/shjeon/THESIS_PROJECTS/PHENOMENOLOGY/TYPEI_SEESAW_MODEL/TTBAR_CHANNEL/MG5_aMC_v2_9_9/lllv_amcatnlo_13tev/Events/run_01/events_PYTHIA8_0.hepmc.gz has been generated.
It contains showered and hadronized events in the HEPMC format obtained showering the parton-level event file /data9/Users/shjeon/THESIS_PROJECTS/PHENOMENOLOGY/TYPEI_SEESAW_MODEL/TTBAR_CHANNEL/MG5_aMC_v2_9_9/lllv_amcatnlo_13tev/Events/run_01/events.lhe.gz with PYTHIA8
INFO: Run complete

I do have the hepmc file but in the middle I don't know why it gives me segmentation fault so I am not 100% sure about the validity of the hepmc file I get in the end. The logs also don't look so wrong (just pythia giving a long list of particles without any 'error' or 'warning' signs).

Thanks,
Sihyun.

[1] import model SM_HeavyN_Gen3Mass_NLO
define vdecay = ve vm ve~ vm~ vt vt~
define ldecay = e+ mu+ e- mu- ta+ ta-
generate p p > ldecay ldecay ldecay vdecay / n1 n2 n3 [QCD]
output lllv_amcatnlo_13tev -nojpeg
launch
shower = PYTHIA8
set nevents 2000
set no_parton_cut
set pdlabel lhapdf
set lhaid 260400
set lpp1 1
set lpp2 1
set ebeam1 6500
set ebeam2 6500
set mll_sf 10
set dynamical_scale_choice -1
set reweight_scale True
set reweight_pdf False
set store_rwgt_info True
set mn1 999999
set mn2 999999
set mn3 999999
set wn1 100
set wn2 100
set wn3 100
set ven1 0.
set ven2 0.
set ven3 0.
set vmun1 0.
set vmun2 0.
set vmun3 0.
set vtan1 0.
set vtan2 0.
set vtan3 0.

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Revision history for this message
Sihyun Jeon (shjeon) said :
#1

define vdecay = ve vm ve~ vm~ vt vt~
define ldecay = e+ mu+ e- mu- ta+ ta-
generate p p > ldecay ldecay ldecay vdecay [QCD]
output lllv_amcatnlo_13tev -nojpeg
launch
shower = PYTHIA8
set nevents 2000
set no_parton_cut
set pdlabel lhapdf
set lhaid 260400
set lpp1 1
set lpp2 1
set ebeam1 6500
set ebeam2 6500
set mll_sf 10
set dynamical_scale_choice -1
set reweight_scale True
set reweight_pdf False
set store_rwgt_info True

Hmm this also gives segmentation error (purely madgraph internal sm model file)

Revision history for this message
Olivier Mattelaer (olivier-mattelaer) said :
#2

That's a segfault in Pythia8
So I will not be able to comment on that . Can you contact PY8 author?

Cheers,

olivier

Revision history for this message
Sihyun Jeon (shjeon) said :
#3

https://gitlab.com/Pythia8/releases/-/issues/155

 I reported here.
I'll let you know if the fix has been done in case you are interested

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