Gamma-Proton NLO calculation without gamma pdf

Asked by BruceLee on 2018-07-16

Dear MadGraph Group:
     I'm BruceLee. I'm trying to calculate gamma-proton collide @NLO without no gamma pdf. I succeeded to do it at leading order.
Now for the next-to-leading order in QCD,
MG5_aMC>generate a p > z j [QCD]
I changed the collider type and energy in run_card.dat as followed :
#***********************************************************************
# Collider type and energy *
#***********************************************************************
  0 = lpp1 ! beam 1 type (0 = no PDF)
  1 = lpp2 ! beam 2 type (0 = no PDF)
  6500.0 = ebeam1 ! beam 1 energy in GeV
  6500.0 = ebeam2 ! beam 2 energy in GeV
#***********************************************************************
Then I got the followed warning and error :
WARNING: No integration channels found for contribution P0_au_zu
WARNING: No integration channels found for contribution P0_ad_zd
WARNING: No integration channels found for contribution P0_aux_zux
WARNING: No integration channels found for contribution P0_adx_zdx
INFO: Setting up grids
INFO: Idle: 0, Running: 0, Completed: 0 [ current time: 19h29 ]
INFO: Computing upper envelope
INFO: Idle: 0, Running: 0, Completed: 0 [ current time: 19h29 ]
Command "launch auto " interrupted with error:
IndexError : list index out of range
Please report this bug on https://bugs.launchpad.net/mg5amcnlo
More information is found in '/home/brucelee/work/rp/question/apzj-qcd/run_01_tag_1_debug.log'.
Please attach this file to your report.
INFO:
quit
INFO:

The important information in run_01_tag_1_debug.log :
launch auto
Traceback (most recent call last):
  File "/home/brucelee/software/MG5_aMC_v2_6_3_2/madgraph/interface/extended_cmd.py", line 1501, in onecmd
    return self.onecmd_orig(line, **opt)
  File "/home/brucelee/software/MG5_aMC_v2_6_3_2/madgraph/interface/extended_cmd.py", line 1450, in onecmd_orig
    return func(arg, **opt)
  File "/home/brucelee/software/MG5_aMC_v2_6_3_2/madgraph/interface/amcatnlo_run_interface.py", line 1664, in do_launch
    evt_file = self.run(mode, options)
  File "/home/brucelee/software/MG5_aMC_v2_6_3_2/madgraph/interface/amcatnlo_run_interface.py", line 1898, in run
    jobs_to_collect,mint_step,mode,mode_dict[mode],fixed_order=False)
  File "/home/brucelee/software/MG5_aMC_v2_6_3_2/madgraph/interface/amcatnlo_run_interface.py", line 2128, in collect_the_results
    jobs_to_run_new=self.update_jobs_to_run(req_acc,integration_step,jobs_to_run,fixed_order)
  File "/home/brucelee/software/MG5_aMC_v2_6_3_2/madgraph/interface/amcatnlo_run_interface.py", line 2506, in update_jobs_to_run
    jobs[i]['nevents'] += 1
IndexError: list index out of range

Question information

Language:
English Edit question
Status:
Solved
For:
MadGraph5_aMC@NLO Edit question
Assignee:
Rikkert Frederix Edit question
Solved by:
Olivier Mattelaer
Solved:
2018-07-17
Last query:
2018-07-17
Last reply:
2018-07-17

This kind of computation is not possible at NLO so far.

Cheers,

Olivier

> On 16 Jul 2018, at 13:52, BruceLee <email address hidden> wrote:
>
> New question #670900 on MadGraph5_aMC@NLO:
> https://answers.launchpad.net/mg5amcnlo/+question/670900
>
> Dear MadGraph Group:
> I'm BruceLee. I'm trying to calculate gamma-proton collide @NLO without no gamma pdf. I succeeded to do it at leading order.
> Now for the next-to-leading order in QCD,
> MG5_aMC>generate a p > z j [QCD]
> I changed the collider type and energy in run_card.dat as followed :
> #***********************************************************************
> # Collider type and energy *
> #***********************************************************************
> 0 = lpp1 ! beam 1 type (0 = no PDF)
> 1 = lpp2 ! beam 2 type (0 = no PDF)
> 6500.0 = ebeam1 ! beam 1 energy in GeV
> 6500.0 = ebeam2 ! beam 2 energy in GeV
> #***********************************************************************
> Then I got the followed warning and error :
> WARNING: No integration channels found for contribution P0_au_zu
> WARNING: No integration channels found for contribution P0_ad_zd
> WARNING: No integration channels found for contribution P0_aux_zux
> WARNING: No integration channels found for contribution P0_adx_zdx
> INFO: Setting up grids
> INFO: Idle: 0, Running: 0, Completed: 0 [ current time: 19h29 ]
> INFO: Computing upper envelope
> INFO: Idle: 0, Running: 0, Completed: 0 [ current time: 19h29 ]
> Command "launch auto " interrupted with error:
> IndexError : list index out of range
> Please report this bug on https://bugs.launchpad.net/mg5amcnlo
> More information is found in '/home/brucelee/work/rp/question/apzj-qcd/run_01_tag_1_debug.log'.
> Please attach this file to your report.
> INFO:
> quit
> INFO:
>
>
> The important information in run_01_tag_1_debug.log :
> launch auto
> Traceback (most recent call last):
> File "/home/brucelee/software/MG5_aMC_v2_6_3_2/madgraph/interface/extended_cmd.py", line 1501, in onecmd
> return self.onecmd_orig(line, **opt)
> File "/home/brucelee/software/MG5_aMC_v2_6_3_2/madgraph/interface/extended_cmd.py", line 1450, in onecmd_orig
> return func(arg, **opt)
> File "/home/brucelee/software/MG5_aMC_v2_6_3_2/madgraph/interface/amcatnlo_run_interface.py", line 1664, in do_launch
> evt_file = self.run(mode, options)
> File "/home/brucelee/software/MG5_aMC_v2_6_3_2/madgraph/interface/amcatnlo_run_interface.py", line 1898, in run
> jobs_to_collect,mint_step,mode,mode_dict[mode],fixed_order=False)
> File "/home/brucelee/software/MG5_aMC_v2_6_3_2/madgraph/interface/amcatnlo_run_interface.py", line 2128, in collect_the_results
> jobs_to_run_new=self.update_jobs_to_run(req_acc,integration_step,jobs_to_run,fixed_order)
> File "/home/brucelee/software/MG5_aMC_v2_6_3_2/madgraph/interface/amcatnlo_run_interface.py", line 2506, in update_jobs_to_run
> jobs[i]['nevents'] += 1
> IndexError: list index out of range
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

BruceLee (brucelee403) said : #2

Dear Olivier:
Thanks so much for your quick answer.
Another question , if I want to calculate the gamma-proton collision @NLO with a gamma pdf, which can be described by Equivalent Photon Approximation(EPA). That's to say ,I want repalace the gamma pdf with a new analytic expression.How can I do this calculation with MadGraph5?

Rikkert Frederix (frederix) said : #3

Dear BruceLee,

The PDFs are calculated in the pdg2pdf() function in Source/PDF/pdg2pdf*.f. (Depending on which version of LHAPDF you are using -- if any -- only one of the pdg2pdf*.f files is compiled and included in the PDF library). Hence, that should be the place to include it.

However, at NLO you have to be very careful with computing NLO corrections to such a process. In particular, the "initial-state" photon could be coming from a quark -> quark+photon branching. Hence, you have to include also the quark initiated contributions, since formally one cannot distinguish these processes. In other words, you have to include the photon in both the 'p' and 'j' and generate
p p > z j [QCD]
See also appendix D of 1804.10017

Best regards,
Rikkert

BruceLee (brucelee403) said : #4

Thanks Olivier Mattelaer, that solved my question.

BruceLee (brucelee403) said : #5

Dear Rikkert
Thanks so much for your answer and advice.
Best wishes,
Bruce