MadGraph5_aMC@NLO

Poles do not cancel in QED NLO process

Asked by user1905

Hi,
We are trying to generate the following process,
e- e+ > b u~ e+ ve [QED]

The model used is loop_qcd_qed_sm-ckm.
We set the complex_mass_Scheme True.
The error we are getting is following,

launch auto --parton
Traceback (most recent call last):
  File "/home/amir/hep/MG5_aMC_v3_5_0_alpha/madgraph/interface/extended_cmd.py", line 1544, in onecmd
    return self.onecmd_orig(line, **opt)
  File "/home/amir/hep/MG5_aMC_v3_5_0_alpha/madgraph/interface/extended_cmd.py", line 1493, in onecmd_orig
    return func(arg, **opt)
  File "/home/amir/hep/MG5_aMC_v3_5_0_alpha/madgraph/interface/amcatnlo_run_interface.py", line 1783, in do_launch
    self.compile(mode, options)
  File "/home/amir/hep/MG5_aMC_v3_5_0_alpha/madgraph/interface/amcatnlo_run_interface.py", line 5509, in compile
    self.check_tests(test, this_dir)
  File "/home/amir/hep/MG5_aMC_v3_5_0_alpha/madgraph/interface/amcatnlo_run_interface.py", line 5522, in check_tests
    return self.parse_check_poles_log(pjoin(dir, '%s.log' % test))
  File "/home/amir/hep/MG5_aMC_v3_5_0_alpha/madgraph/interface/amcatnlo_run_interface.py", line 5555, in parse_check_poles_log
    raise aMCatNLOError('Poles do not cancel, run cannot continue')
madgraph.interface.amcatnlo_run_interface.aMCatNLOError: Poles do not cancel, run cannot continue

Any suggestions are appreciated.

Reagrds

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Olivier Mattelaer (olivier-mattelaer) said : 		#1

Did you read the MC@NLO Electroweak paper?
For your process definition, you should get a warning telling you that what you are doing is likely ... wrong and refer you to that paper.

Actually, I do not understand what you try to achieve but for sure it does not make sense at NLO EW and this is why the code tells you that you do not have a correct cancellation between the real contribution and the virtual (i.e. such computation is either +inf or -inf since you do not have an infra-red save process definition.)

Cheers,

Olivier

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

No such warnings are generated.

there was a typo in the process,
the process generated is :
e- e+ > b u~ e+ ve [QED].

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

Then please check arXiv:1804.10017 and in particular the appendix concerning multi-particles.

Cheers,

Olivier

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