Unable to produce events with initial 2 photons

Hi,

The pythia-pgs version only support pdf compatible with the very old lhapdf4.
This is why it is not possible for py6 to handle the default pdf set of madgraph.
One simple work around is to use another pdf set for the shower but indeed this does not work for photon initiated process.

The solution should be to run pythia8 on those parton events.
This is not possible inside our framework. But you can use as input of pythia8 the events generated at parton level.
The possibility to run pythia8 inside our framework should be possible inside our framework around september.
An alpha version already exists, you are welcome to give it a try if you want to:
https://code.launchpad.net/~maddevelopers/mg5amcnlo/2.3.3_PY8_install_cmd

Cheers,

Olivier

> On Aug 20, 2016, at 20:08, Alexa <email address hidden> wrote:
>
> New question #355057 on MadGraph5_aMC@NLO:
> https://answers.launchpad.net/mg5amcnlo/+question/355057
>
> Hi,
>
> I have an issue for producing events with 2 photons going to anything, like "a a > u u~" for instance. The parton madevent plots are produced (correctly I think). In my "run_card.dat", I have the following:
>
> #*********************************************************************
> # PDF CHOICE: this automatically fixes also alpha_s and its evol. *
> #*********************************************************************
> nn23lo1 = pdlabel ! PDF set
> 230000 = lhaid ! if pdlabel=lhapdf, this is the lhapdf number
>
> But when running pythia, someway it changes the pdf, and in the resulting ".log" file I have this warning:
>
> ==== PYTHIA WILL USE LHAPDF ====
> WRONG LHAPDF set number = 247000 given! STOP EXE!
> WILL USE 10041 INSTEAD
>
> And, finally, in the same file, I have this errors:
>
> _______________________________________________________________________________
> Starting event loop
>
> Advisory warning type 2 given after 0 PYEXEC calls:
> (PYPREP:) unphysical flavour combination
>
> Advisory warning type 2 given after 0 PYEXEC calls:
> (PYPREP:) unphysical flavour combination
>
> Advisory warning type 2 given after 0 PYEXEC calls:
> (PYPREP:) unphysical flavour combination
>
> Advisory warning type 2 given after 0 PYEXEC calls:
> (PYPREP:) unphysical flavour combination
>
> Advisory warning type 2 given after 0 PYEXEC calls:
> (PYPREP:) unphysical flavour combination
>
> Advisory warning type 2 given after 0 PYEXEC calls:
> (PYPREP:) unphysical flavour combination
>
> Advisory warning type 2 given after 0 PYEXEC calls:
> (PYPREP:) unphysical flavour combination
>
> Advisory warning type 2 given after 0 PYEXEC calls:
> (PYPREP:) unphysical flavour combination
>
> Advisory warning type 2 given after 0 PYEXEC calls:
> (PYPREP:) unphysical flavour combination
>
> Advisory warning type 2 given after 0 PYEXEC calls:
> (PYPREP:) unphysical flavour combination
> Error: x value outside physical range; x = Infinity
> Error: x value outside physical range; x = Infinity
>
> Error type 2 has occured after 1 PYEXEC calls:
> (PYSTRF:) failed to reconstruct jet system
>
> Error type 2 has occured after 1 PYEXEC calls:
> (PYSTRF:) failed to reconstruct jet system
>
> Error type 2 has occured after 2 PYEXEC calls:
> (PYSTRF:) failed to reconstruct jet system
>
> Error type 2 has occured after 2 PYEXEC calls:
> (PYSTRF:) failed to reconstruct jet system
>
> Error type 2 has occured after 3 PYEXEC calls:
> (PYSTRF:) failed to reconstruct jet system
>
> Error type 2 has occured after 3 PYEXEC calls:
> (PYSTRF:) failed to reconstruct jet system
>
> Error type 2 has occured after 4 PYEXEC calls:
> (PYSTRF:) failed to reconstruct jet system
>
> Error type 2 has occured after 4 PYEXEC calls:
> (PYSTRF:) failed to reconstruct jet system
>
> Error type 2 has occured after 5 PYEXEC calls:
> (PYSTRF:) failed to reconstruct jet system
>
> Error type 2 has occured after 5 PYEXEC calls:
> (PYSTRF:) failed to reconstruct jet system
> Error: x value outside physical range; x = Infinity
> Error: x value outside physical range; x = Infinity
> Error: x value outside physical range; x = Infinity
> Error: x value outside physical range; x = Infinity
> Error: x value outside physical range; x = Infinity
> Error: x value outside physical range; x = Infinity
> Error: x value outside physical range; x = Infinity
> Error: x value outside physical range; x = Infinity
>
> At the end of the run, I don't get any plot.
>
> I don't know how to force the code to use the correct pdf or what to do to solve this problem. I tried many things but nothing worked.
>
> Thank you for your help,
> Alexandra L.
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

Hi Olivier,

Thank you for your answer. I tried the alpha version and, although I didn't get the same error, now I get this:

-------- End PYTHIA Event Listing -----------------------------------------------------------------------------------------------
 PYTHIA Warning in StringFragmentation::fragmentToJunction: bad convergence junction rest frame

 Pythia::next(): 1000 events have been generated
 PYTHIA Warning in Pythia::check: not quite matched particle energy/momentum/mass
 PYTHIA Error in StringFragmentation::fragment: stuck in joining
 PYTHIA Error in Pythia::next: hadronLevel failed; try again

 Pythia::next(): 2000 events have been generated

 Pythia::next(): 3000 events have been generated
 PYTHIA Error in SpaceShower::pT2nearThreshold: stuck in loop

 Pythia::next(): 4000 events have been generated

 Pythia::next(): 5000 events have been generated
 PYTHIA Warning in SpaceShower::pT2nextQCD: weight above unity

 Pythia::next(): 6000 events have been generated
 PYTHIA Warning in Pythia::check: energy-momentum not quite conserved

 Pythia::next(): 7000 events have been generated
 PYTHIA Warning in SpaceShower::pT2nextQCD: small daughter PDF

 Pythia::next(): 8000 events have been generated

 Pythia::next(): 9000 events have been generated
 PYTHIA Error in StringFragmentation::fragmentToJunction: caught in junction flavour loop

 *------- PYTHIA Event and Cross Section Statistics -------------------------------------------------------------*
 | |
 | Subprocess Code | Number of events | sigma +- delta |
 | | Tried Selected Accepted | (estimated) (mb) |
 | | | |
 |-----------------------------------------------------------------------------------------------------------------|
 | | | |
 | Les Houches User Process(es) 9999 | 10000 10000 10000 | 6.633e-10 0.000e+00 |
 | ... whereof user classification code 1 | 10000 10000 10000 | |
 | | | |
 | sum | 10000 10000 10000 | 6.633e-10 0.000e+00 |
 | |
 *------- End PYTHIA Event and Cross Section Statistics ----------------------------------------------------------*

 *------- PYTHIA Error and Warning Messages Statistics ----------------------------------------------------------*
 | |
 | times message |
 | |
 | 8 Error in Pythia::next: hadronLevel failed; try again |
 | 5 Error in SpaceShower::pT2nearThreshold: stuck in loop |
 | 7 Error in StringFragmentation::fragment: stuck in joining |
 | 1 Error in StringFragmentation::fragmentToJunction: caught in junction flavour loop |
 | 2 Info from SLHAinterface::initSLHA: No MODSEL found, keeping internal SUSY switched off |
 | 2 Info from SLHAinterface::initSLHA: importing MASS entries |
 | 1 Warning in Pythia::check: energy-momentum not quite conserved |
 | 13 Warning in Pythia::check: not quite matched particle energy/momentum/mass |
 | 2 Warning in SLHAinterface::initSLHA: ignoring DECAY tables |
 | 2 Warning in SLHAinterface::initSLHA: ignoring MASS entries |
 | 2 Warning in SLHAinterface::initSLHA: ignoring empty DECAY tables |
 | 2 Warning in SpaceShower::pT2nextQCD: small daughter PDF |
 | 1 Warning in SpaceShower::pT2nextQCD: weight above unity |
 | 32 Warning in StringFragmentation::fragmentToJunction: bad convergence junction rest frame |
 | |
 *------- End PYTHIA Error and Warning Messages Statistics ------------------------------------------------------*

 Contribution of sample 0 to the inclusive cross section : 6.63300000e-10 +- 6.63300000e-12

Inclusive cross section: 6.63300000e-10 +- 6.63300000e-12 mb

Best regards,
Alexandra L.

Hi Alexandra,

I think that this is ok.
I will let one of the pythia8 author to comment on those warning.

Cheers,

Olivier

Hi,

Thank you. Well, I think it is not completely ok because I don't get plots, the file is empty. Please, let me know what the author tells you.

Thank you,
Alexandra L.

Hi,

We do not have automatic plot for py8 for the moment. You can use plotting routine like MadAnalysis5 or Rivet to make the plots.
Actually, work in the automation with MA5 is in progress (partly in that branch actually). But I do not know the exact status.
And do not know if we will release this PY8 interface with or without the automatic plots.

Cheers,

Olivier

> On Aug 21, 2016, at 15:37, Alexa <email address hidden> wrote:
>
> Question #355057 on MadGraph5_aMC@NLO changed:
> https://answers.launchpad.net/mg5amcnlo/+question/355057
>
> Status: Answered => Open
>
> Alexa is still having a problem:
> Hi,
>
> Thank you. Well, I think it is not completely ok because I don't get
> plots, the file is empty. Please, let me know what the author tells
> you.
>
> Thank you,
> Alexandra L.
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

Hi,

I installed MadAnalysis5 and repeated the process generation. When pythia8 finishes I get this:

INFO: Running Pythia8 [arXiv:1410.3012]
Follow Pythia8 shower by running the following command (in a separate terminal):
    tail -f /Users/alexandralohunova/Desktop/md5_pruebas/2.3.3_PY8_install_cmd/2.3.3_PY8_install_cmd/Test__2/Events/run_01/tag_2_pythia8.log
INFO: Pythia8 shower finished after 25m40s.
  === Results Summary for run: run_01 tag: tag_2 ===

     Cross-section : 0.6633 +- 0.00146 pb
     Nb of events : 10000

INFO: storing files of previous run
INFO: Storing Pythia8 files of previous run
Command "generate_events run_01" interrupted with error:
ValueError : list.remove(x): x not in list
Please report this bug on https://bugs.launchpad.net/mg5amcnlo
More information is found in '/Users/alexandralohunova/Desktop/md5_pruebas/2.3.3_PY8_install_cmd/2.3.3_PY8_install_cmd/Test__2/run_01_tag_2_debug.log'.
Please attach this file to your report.
INFO: storing files of previous run

Finally, I don't get any results.

Thank you for your help,
Alexandra L.

Hi Alexa,

As I said, MA5 should be run OUTSIDE our framework.

The interface within our framework is not yet ready (even for alpha tester).
Also the interface to MA5 that you have in this development version is actually outdated compare to the latest nightly build of that feature.
But event the most uptodate interface with MA5 is currently crashing in a quite systematic way and therefore I can not suggest you to try it.

Cheers,

Olivier

> On Aug 21, 2016, at 22:17, Alexa <email address hidden> wrote:
>
> Question #355057 on MadGraph5_aMC@NLO changed:
> https://answers.launchpad.net/mg5amcnlo/+question/355057
>
> Status: Answered => Open
>
> Alexa is still having a problem:
> Hi,
>
> I installed MadAnalysis5 and repeated the process generation. When
> pythia8 finishes I get this:
>
>
> INFO: Running Pythia8 [arXiv:1410.3012]
> Follow Pythia8 shower by running the following command (in a separate terminal):
> tail -f /Users/alexandralohunova/Desktop/md5_pruebas/2.3.3_PY8_install_cmd/2.3.3_PY8_install_cmd/Test__2/Events/run_01/tag_2_pythia8.log
> INFO: Pythia8 shower finished after 25m40s.
> === Results Summary for run: run_01 tag: tag_2 ===
>
> Cross-section : 0.6633 +- 0.00146 pb
> Nb of events : 10000
>
> INFO: storing files of previous run
> INFO: Storing Pythia8 files of previous run
> Command "generate_events run_01" interrupted with error:
> ValueError : list.remove(x): x not in list
> Please report this bug on https://bugs.launchpad.net/mg5amcnlo
> More information is found in '/Users/alexandralohunova/Desktop/md5_pruebas/2.3.3_PY8_install_cmd/2.3.3_PY8_install_cmd/Test__2/run_01_tag_2_debug.log'.
> Please attach this file to your report.
> INFO: storing files of previous run
>
>
> Finally, I don't get any results.
>
> Thank you for your help,
> Alexandra L.
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.