MadSpin Not Finishing

Asked by Richard Ruiz on 2018-08-24

Hi Folks,

I am trying to generate a large (>1 M) set of NLO+PS events at 100 TeV. However, during the decay stage, MadSpin starts successfully (as expected) but then gets stuck checking for phase space points. I have tried "fiddling" with some of the MadSpin setup inputs and well, still no success.

Let me know what information you need to help pinpoint the issue.

Best,
Richard

The process is the following:
define ell = e+ e- mu+ mu- ta+ ta-
define vv = ve vm vt ve~ vm~ vt~
generate p p > t t~ ell vv / h QCD=2 QED=2 [QCD]

The decay process is:
define ell = e+ e- mu+ mu- ta+ ta-
define vv = ve ve~ vm vm~ vt vt~
define tt = t t~
define bb = b b~
define ww = w+ w-
decay tt > ww bb, ww > ell vv

The run direction is:
launch
order=NLO
shower=PYTHIA8
madspin=ON
set nevents 3000000
set nevt_job 50000
set no_parton_cut
set jetradius 1.0
set jetalgo -1
done

Input masses include:
    5 4.700000e+00 # MB
    6 1.733000e+02 # MT
   15 1.777000e+00 # MTA
   23 9.118760e+01 # MZ
   25 1.257000e+02 # MH

After event generation, which runs pretty smoothly, the decay process compiles, as one expects, and then gets stuck during the "INFO: Decaying the events... " phase. By stuck, I mean that a single "check" process runs for *hours* and *hours*, and does not complete. I do not think this is unique to ttbar lv, but seems to be a more general problem for high-stat, NLO+PS processes at 100 TeV.

Question information

Language:
English Edit question
Status:
Answered
For:
MadGraph5_aMC@NLO Edit question
Assignee:
No assignee Edit question
Last query:
2018-09-06
Last reply:
2018-09-12
Richard Ruiz (rruiz) said : #1

Bump

Hi,

Can you send me your lhe file?

Such that I can see which events is responsible for this inifinite loop (and therefore be able to reproduce the issue)

Cheers,

Olivier

Richard Ruiz (rruiz) said : #3

Sent! Thanks, Olivier!

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