SubProcesses doesn't have available phase-space

Asked by Reza Goldouzian on 2021-06-08

Dear Experts,

I am using the following UFO model which violate baryon and lepton numbers with MG5_aMC_v2_6_5.
https://feynrules.irmp.ucl.ac.be/wiki/TopBNV

for generating event I use the following commands

import model bnv-ufo
generate p p > t~ ta+

and when I launch I receive the following error

Command "launch" interrupted with error:
ALOHAERROR : Unable to deal with 4(or more) point interactions
 in presence of majorana particle/flow violation
Please report this bug on https://bugs.launchpad.net/mg5amcnlo
More information is found in 'MG5_debug'.
Please attach this file to your report.

If I comment the following lines in the MG5_aMC_v2_6_5/aloha/create_aloha.py file, everything works.

# if not data == target:
# text = """Unable to deal with 4(or more) point interactions
#in presence of majorana particle/flow violation"""
# raise ALOHAERROR, text

my first question is whether commenting these lines are OK? does it have any negative effect?

My second question is regarding the error I see by adding one jet to the process. If I run

import model bnv-ufo
generate p p > t~ ta+ j

I see the following error

INFO: Update the dependent parameter of the param_card.dat
Generating 10000 events with run name run_01
survey run_01
INFO: compile directory
compile Source Directory
Using random number seed offset = 21
INFO: Running Survey
Creating Jobs
Working on SubProcesses
INFO: P1_gu_txtapdx
INFO: P1_gd_txtapux
INFO: P1_ud_txtapg
 P1_gd_txtapux SubProcesses doesn't have available phase-space.
            Please check mass spectrum.
INFO: Idle: 1, Running: 1, Completed: 2 [ current time: 18h18 ]
INFO: Idle: 0, Running: 2, Completed: 2 [ current time: 18h18 ]
INFO: Idle: 0, Running: 0, Completed: 4 [ 1.3s ]
INFO: End survey
refine 10000
Creating Jobs
INFO: Refine results to 10000
INFO: Generating 10000.0 unweigthed events.
Error when reading /Users/rezagol/calc/MG5_aMC_v2_6_5/PROC_bnv-ufo_2/SubProcesses/P1_gu_txtapdx/G1/results.dat
Command "generate_events run_01" interrupted with error:
IOError : [Errno 2] No such file or directory: '/Users/rezagol/calc/MG5_aMC_v2_6_5/PROC_bnv-ufo_2/SubProcesses/P1_gu_txtapdx/G1/results.dat'
Please report this bug on https://bugs.launchpad.net/mg5amcnlo
More information is found in '/Users/rezagol/calc/MG5_aMC_v2_6_5/PROC_bnv-ufo_2/run_01_tag_1_debug.log'.
Please attach this file to your report.

I read this thread
https://answers.launchpad.net/mg5amcnlo/+question/664726
but it seems everything is updated in MG5_aMC_v2_6_5. I also checked with MG5_aMC_v3_1_0 but I see the same error.
I checked process by process, it seems MG has problem with processes that are initiated by gluon-quark interactions.

Please let me know if any information is needed from my side.

Thanks a lot,
Reza

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Revision history for this message
Olivier Mattelaer (olivier-mattelaer) said :
#1

Hi,

> my first question is whether commenting these lines are OK? does it have any negative effect?

You likely have wrong negative sign in the computation of your four fermion amplitude.
So I would not trust the matrix-element returned for such computation.

Then your second question is likely meaningless (and potentially a consequence of the above issue).

So my advise is to use a fake particle to split the four-fermion operator into two three point interaction and then your compuatation should go trough.

Cheers,

Olivier

> On 8 Jun 2021, at 18:25, Reza Goldouzian <email address hidden> wrote:
>
> New question #697450 on MadGraph5_aMC@NLO:
> https://answers.launchpad.net/mg5amcnlo/+question/697450
>
> Dear Experts,
>
> I am using the following UFO model which violate baryon and lepton numbers with MG5_aMC_v2_6_5.
> https://feynrules.irmp.ucl.ac.be/wiki/TopBNV
>
> for generating event I use the following commands
>
> import model bnv-ufo
> generate p p > t~ ta+
>
> and when I launch I receive the following error
>
> Command "launch" interrupted with error:
> ALOHAERROR : Unable to deal with 4(or more) point interactions
> in presence of majorana particle/flow violation
> Please report this bug on https://bugs.launchpad.net/mg5amcnlo
> More information is found in 'MG5_debug'.
> Please attach this file to your report.
>
> If I comment the following lines in the MG5_aMC_v2_6_5/aloha/create_aloha.py file, everything works.
>
> # if not data == target:
> # text = """Unable to deal with 4(or more) point interactions
> #in presence of majorana particle/flow violation"""
> # raise ALOHAERROR, text
>
> my first question is whether commenting these lines are OK? does it have any negative effect?
>
> My second question is regarding the error I see by adding one jet to the process. If I run
>
> import model bnv-ufo
> generate p p > t~ ta+ j
>
> I see the following error
>
> INFO: Update the dependent parameter of the param_card.dat
> Generating 10000 events with run name run_01
> survey run_01
> INFO: compile directory
> compile Source Directory
> Using random number seed offset = 21
> INFO: Running Survey
> Creating Jobs
> Working on SubProcesses
> INFO: P1_gu_txtapdx
> INFO: P1_gd_txtapux
> INFO: P1_ud_txtapg
> P1_gd_txtapux SubProcesses doesn't have available phase-space.
> Please check mass spectrum.
> INFO: Idle: 1, Running: 1, Completed: 2 [ current time: 18h18 ]
> INFO: Idle: 0, Running: 2, Completed: 2 [ current time: 18h18 ]
> INFO: Idle: 0, Running: 0, Completed: 4 [ 1.3s ]
> INFO: End survey
> refine 10000
> Creating Jobs
> INFO: Refine results to 10000
> INFO: Generating 10000.0 unweigthed events.
> Error when reading /Users/rezagol/calc/MG5_aMC_v2_6_5/PROC_bnv-ufo_2/SubProcesses/P1_gu_txtapdx/G1/results.dat
> Command "generate_events run_01" interrupted with error:
> IOError : [Errno 2] No such file or directory: '/Users/rezagol/calc/MG5_aMC_v2_6_5/PROC_bnv-ufo_2/SubProcesses/P1_gu_txtapdx/G1/results.dat'
> Please report this bug on https://bugs.launchpad.net/mg5amcnlo
> More information is found in '/Users/rezagol/calc/MG5_aMC_v2_6_5/PROC_bnv-ufo_2/run_01_tag_1_debug.log'.
> Please attach this file to your report.
>
> I read this thread
> https://answers.launchpad.net/mg5amcnlo/+question/664726
> but it seems everything is updated in MG5_aMC_v2_6_5. I also checked with MG5_aMC_v3_1_0 but I see the same error.
> I checked process by process, it seems MG has problem with processes that are initiated by gluon-quark interactions.
>
> Please let me know if any information is needed from my side.
>
> Thanks a lot,
> Reza
>
>
>
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

Revision history for this message
Reza Goldouzian (rgoldouz) said :
#2

Thanks Olivier for your prompt reply.

Would you please point me to a document or explain how to split the four-fermion operator into two three point interaction?
Can I use the same UFO? or I need a new one with new particles/interactions?

Thanks a lot,
Reza

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

Hi,

> Would you please point me to a document or explain how to split the four-fermion operator into two three point interaction?

I do not know if such document exists. Yes you need to generate a new UFO model.
So since you use FeynRules for doing that, I would suggest to check their documentation if they have made a note about that.

Cheers,

Olivier

> On 8 Jun 2021, at 19:20, Reza Goldouzian <email address hidden> wrote:
>
> Question #697450 on MadGraph5_aMC@NLO changed:
> https://answers.launchpad.net/mg5amcnlo/+question/697450
>
> Reza Goldouzian posted a new comment:
> Thanks Olivier for your prompt reply.
>
> Would you please point me to a document or explain how to split the four-fermion operator into two three point interaction?
> Can I use the same UFO? or I need a new one with new particles/interactions?
>
> Thanks a lot,
> Reza
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

Revision history for this message
Reza Goldouzian (rgoldouz) said :
#4

Dear Olivier, All,

Just to inform you,
Gauthier kindly updated the TOP BNV UFO to solve this issue.

https://feynrules.irmp.ucl.ac.be/wiki/TopBNV

Thanks,
Reza

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