ccbar photoproduction in (UPC )PbPb collision

Hi,

I have been trying to generate ccbar through Pb-Pb UPC collision., and I'm working with the latest MadGraph version (3-4-2).
The card below runs without any major error, although I have a couple of warnings, like:

"update the strong coupling value (alpha_s) to the value from the pdf selected: 0.13"
"lpp1 '2' not compatible with pdlabel1 'nn23lo1'. Change pdlabel1 to none"
( if I add update ionpdf option, it doesn't run)

My question is, I'm not sure if I'm setting the ccbar photoproduction correctly. To me, setting lpp1 2 is not making any difference to the momentum distribution of the output particles. what am I missing? Is there any other configuration I should take into account? (I followed the discussion on top photoproduction in pPb, as well)

I also have concerns about units.. sorry if it's stupid but I was not sure if the madGraph energy units are in GeV, and if so, I suppose, the integrated Pythia8 takes care of the conversion in case of showering.. (as far as I understood the Pythia E unit is MeV).

Another question that I have that is more on the Pythia side is if I want to feed the MG output to a standalone Pythia8, how should I take care of the unit conversion not to make a mess?

thanks,
Zahra
//----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

#-----Model

import model sm
set group_subprocesses False
generate a a > c c~
#generate a a > ta+ ta-
#output photo_PbPb_gammagamma_tautau
output test_ccbar
set automatic_html_opening False

#----- Launch
launch
shower=Pythia8
done

#------ RUN

set nevents 4000
set PbPb
set lpp1 2
set fixed_scale 1500
set ebeam1 208*2560
set ebeam2 208*2560

the output unto the shower point (for some reason it shows that the showing is off in the beginning but it does it anyway):

************************************************************
* *
* W E L C O M E to *
* M A D G R A P H 5 _ a M C @ N L O *
* *
* *
* * * *
* * * * * *
* * * * * 5 * * * * *
* * * * * *
* * * *
* *
* VERSION 3.4.2 2023-01-20 *
* *
* The MadGraph5_aMC@NLO Development Team - Find us at *
* https://server06.fynu.ucl.ac.be/projects/madgraph *
* and *
* http://amcatnlo.web.cern.ch/amcatnlo/ *
* *
* Type 'help' for in-line help. *
* Type 'tutorial' to learn how MG5 works *
* Type 'tutorial aMCatNLO' to learn how aMC@NLO works *
* Type 'tutorial MadLoop' to learn how MadLoop works *
* *
************************************************************
load MG5 configuration from input/mg5_configuration.txt
fastjet-config does not seem to correspond to a valid fastjet-config executable (v3+). We will use fjcore instead.
 Please set the 'fastjet'variable to the full (absolute) /PATH/TO/fastjet-config (including fastjet-config).
 MG5_aMC> set fastjet /PATH/TO/fastjet-config

set lhapdf to lhapdf-config
None does not seem to correspond to a valid lhapdf-config executable.
Please set the 'lhapdf' variable to the (absolute) /PATH/TO/lhapdf-config (including lhapdf-config).
Note that you can still compile and run aMC@NLO with the built-in PDFs
 MG5_aMC> set lhapdf /PATH/TO/lhapdf-config

Using default eps viewer "evince". Set another one in ./input/mg5_configuration.txt
Using default web browser "firefox". Set another one in ./input/mg5_configuration.txt
import /afs/cern.ch/work/z/zghorban/MadGraph/Madgraph/MG5_aMC_v3_4_2/example.dat
The import format was not given, so we guess it as command
import model sm
INFO: Restrict model sm with file models/sm/restrict_default.dat .
INFO: Run "set stdout_level DEBUG" before import for more information.
INFO: Change particles name to pass to MG5 convention
Defined multiparticle p = g u c d s u~ c~ d~ s~
Defined multiparticle j = g u c d s u~ c~ d~ s~
Defined multiparticle l+ = e+ mu+
Defined multiparticle l- = e- mu-
Defined multiparticle vl = ve vm vt
Defined multiparticle vl~ = ve~ vm~ vt~
Defined multiparticle all = g u c d s u~ c~ d~ s~ a ve vm vt e- mu- ve~ vm~ vt~ e+ mu+ t b t~ b~ z w+ h w- ta- ta+
set group_subprocesses False
Set group_subprocesses to False
Note that you need to regenerate all processes
generate a a > c c~
INFO: Checking for minimal orders which gives processes.
INFO: Please specify coupling orders to bypass this step.
INFO: Trying process: a a > c c~ WEIGHTED<=4 @1
INFO: Process has 2 diagrams
1 processes with 2 diagrams generated in 0.004 s
Total: 1 processes with 2 diagrams
output test_ccbar_noPhoto
INFO: directory /afs/cern.ch/work/z/zghorban/MadGraph/Madgraph/MG5_aMC_v3_4_2/test_ccbar_noPhoto already exists.
If you continue this directory will be deleted and replaced.
Do you want to continue? [y, n]
found line : set automatic_html_opening False
This answer is not valid for current question. Keep it for next question and use here default: y
INFO: initialize a new directory: test_ccbar_noPhoto
INFO: remove old information in test_ccbar_noPhoto
INFO: Generating Helas calls for process: a a > c c~ WEIGHTED<=4 @1
INFO: Processing color information for process: a a > c c~ @1
INFO: Creating files in directory P1_aa_ccx
INFO: Generating Feynman diagrams for Process: a a > c c~ WEIGHTED<=4 @1
Generated helas calls for 1 subprocesses (2 diagrams) in 0.004 s
Wrote files for 8 helas calls in 0.270 s
ALOHA: aloha starts to compute helicity amplitudes
ALOHA: aloha creates 1 routines in 0.380 s
The option group_subprocesses is modified [Auto] but will not be written in the configuration files.
If you want to make this value the default for future session, you can run 'save options --all'
save configuration file to /afs/cern.ch/work/z/zghorban/MadGraph/Madgraph/MG5_aMC_v3_4_2/test_ccbar_noPhoto/Cards/me5_configuration.txt
INFO: Use Fortran compiler gfortran
INFO: Use c++ compiler g++
INFO: Generate jpeg diagrams
INFO: Generate web pages
Output to directory /afs/cern.ch/work/z/zghorban/MadGraph/Madgraph/MG5_aMC_v3_4_2/test_ccbar_noPhoto done.
Type "launch" to generate events from this process, or see
/afs/cern.ch/work/z/zghorban/MadGraph/Madgraph/MG5_aMC_v3_4_2/test_ccbar_noPhoto/README
Run "open index.html" to see more information about this process.
set automatic_html_opening False
This option will be the default in any output that you are going to create in this session.
In order to keep this changes permanent please run 'save options'
launch
************************************************************
* *
* W E L C O M E to *
* M A D G R A P H 5 _ a M C @ N L O *
* M A D E V E N T *
* *
* * * *
* * * * * *
* * * * * 5 * * * * *
* * * * * *
* * * *
* *
* VERSION 3.4.2 2023-01-20 *
* *
* The MadGraph5_aMC@NLO Development Team - Find us at *
* https://server06.fynu.ucl.ac.be/projects/madgraph *
* *
* Type 'help' for in-line help. *
* *
************************************************************
INFO: load configuration from /afs/cern.ch/work/z/zghorban/MadGraph/Madgraph/MG5_aMC_v3_4_2/test_ccbar_noPhoto/Cards/me5_configuration.txt
INFO: load configuration from /afs/cern.ch/work/z/zghorban/MadGraph/Madgraph/MG5_aMC_v3_4_2/input/mg5_configuration.txt
INFO: load configuration from /afs/cern.ch/work/z/zghorban/MadGraph/Madgraph/MG5_aMC_v3_4_2/test_ccbar_noPhoto/Cards/me5_configuration.txt
generate_events run_01
The following switches determine which programs are run:
/=================== Description ===================|============= values ==============|======== other options ========\
| 1. Choose the shower/hadronization program | shower = OFF | Pythia8 |
| 2. Choose the detector simulation program | detector = Not Avail. | Please install module |
| 3. Choose an analysis package (plot/convert) | analysis = Not Avail. | Please install module |
| 4. Decay onshell particles | madspin = OFF | ON|onshell|full |
| 5. Add weights to events for new hypp. | reweight = OFF | ON |
\=======================================================================================================================/
Either type the switch number (1 to 5) to change its setting,
Set any switch explicitly (e.g. type 'shower=Pythia8' at the prompt)
Type 'help' for the list of all valid option
Type '0', 'auto', 'done' or just press enter when you are done.
set nevents 4000
INFO: modify parameter nevents of the run_card.dat to 4000
set PbPb
INFO: modify parameter lpp1 of the run_card.dat to 1
INFO: modify parameter lpp2 of the run_card.dat to 1
INFO: modify parameter nb_proton1 of the run_card.dat to 82
INFO: modify parameter nb_neutron1 of the run_card.dat to 126
INFO: modify parameter mass_ion1 of the run_card.dat to 195.0820996698
INFO: modify parameter nb_proton2 of the run_card.dat to 82
INFO: modify parameter nb_neutron2 of the run_card.dat to 126
INFO: modify parameter mass_ion2 of the run_card.dat to 195.0820996698
set lpp1 2
INFO: modify parameter lpp1 of the run_card.dat to 2
set fixed_scale 1500
INFO: modify parameter fixed_fac_scale of the run_card.dat to True
INFO: modify parameter fixed_ren_scale of the run_card.dat to True
INFO: modify parameter scale of the run_card.dat to 1500.0
INFO: modify parameter dsqrt_q2fact1 of the run_card.dat to 1500.0
INFO: modify parameter dsqrt_q2fact2 of the run_card.dat to 1500.0
set ebeam1 208*2560
INFO: modify parameter ebeam1 of the run_card.dat to 532480.0
set ebeam2 208*2560
INFO: modify parameter ebeam2 of the run_card.dat to 532480.0
Do you want to edit a card (press enter to bypass editing)?
/------------------------------------------------------------\
| 1. param : param_card.dat |
| 2. run : run_card.dat |
| 3. pythia8 : pythia8_card.dat |
\------------------------------------------------------------/
 you can also
   - enter the path to a valid card or banner.
   - use the 'set' command to modify a parameter directly.
     The set option works only for param_card and run_card.
     Type 'help set' for more information on this command.
   - call an external program (ASperGE/MadWidth/...).
     Type 'help' for the list of available command
 [0, done, 1, param, 2, run, 3, pythia8, enter path]
The answer to the previous question is not set in your input file
Use 0 value
INFO: Update the dependent parameter of the param_card.dat
WARNING: update the strong coupling value (alpha_s) to the value from the pdf selected: 0.13
lpp1 '2' not compatible with pdlabel1 'nn23lo1'. Change pdlabel1 to none
fixed factorization scale is used for beam1. You can prevent this by setting fixed_fac_scale1 to False
Generating 4000 events with run name run_01
survey run_01
lpp1 '2' not compatible with pdlabel1 'nn23lo1'. Change pdlabel1 to none
fixed factorization scale is used for beam1. You can prevent this by setting fixed_fac_scale1 to False
INFO: compile directory
fixed factorization scale is used for beam1. You can prevent this by setting fixed_fac_scale1 to False
compile Source Directory
Using random number seed offset = 21
INFO: Running Survey
Creating Jobs
Working on SubProcesses
INFO: P1_aa_ccx
INFO: Idle: 1, Running: 0, Completed: 0 [ current time: 14h56 ]
INFO: Idle: 0, Running: 0, Completed: 1 [ 0.82s ]
INFO: Idle: 0, Running: 0, Completed: 1 [ 0.82s ]
INFO: End survey
refine 4000
Creating Jobs
INFO: Refine results to 4000
INFO: Generating 4000.0 unweighted events.
sum of cpu time of last step: 0 second
INFO: Effective Luminosity 0.6876002750401101 pb^-1
INFO: need to improve 2 channels
- Current estimate of cross-section: 6980.799999999999 +- 50.58454186804502
    P1_aa_ccx
INFO: Idle: 1, Running: 5, Completed: 0 [ current time: 14h56 ]
INFO: Idle: 0, Running: 0, Completed: 6 [ 0.9s ]
INFO: Combining runs
sum of cpu time of last step: 5 seconds
INFO: finish refine
refine 4000 --treshold=0.9
No need for second refine due to stability of cross-section
INFO: Combining Events
lpp1 '2' not compatible with pdlabel1 'nn23lo1'. Change pdlabel1 to none
fixed factorization scale is used for beam1. You can prevent this by setting fixed_fac_scale1 to False
  === Results Summary for run: run_01 tag: tag_1 ===

     Cross-section : 6977 +- 22.48 pb
     Nb of events : 4000

INFO: Running Systematics computation
lpp1 '2' not compatible with pdlabel1 'nn23lo1'. Change pdlabel1 to none
fixed factorization scale is used for beam1. You can prevent this by setting fixed_fac_scale1 to False
INFO: # Events generated with PDF: NNPDF23_lo_as_0130_qed (247000)
INFO: # Will Compute 145 weights per event.
INFO: # Currently at event 0 [elapsed time: 0.021 s]
INFO: # Currently at event 2500 [elapsed time: 7.1 s]
INFO: #***************************************************************************
#
# original cross-section: 6976.800000000481
# scale variation: + 9% -8.91%
# central scheme variation: + 0% -50.2%
# PDF variation: +51.1% -51.1%
#
# dynamical scheme # 1 : 4073.66 +14.9% -14.8% # \sum ET
# dynamical scheme # 2 : 4073.66 +14.9% -14.8% # \sum\sqrt{m^2+pt^2}
# dynamical scheme # 3 : 3470.98 +17.4% -17.3% # 0.5 \sum\sqrt{m^2+pt^2}
# dynamical scheme # 4 : 4293.86 +14.1% -14.1% # \sqrt{\hat s}
#***************************************************************************

INFO: End of systematics computation
store_events
INFO: Storing parton level results
INFO: End Parton
reweight -from_cards
decay_events -from_cards
INFO: Running Pythia8 [arXiv:1410.3012]
Splitting .lhe event file for PY8 parallelization...
Submitting Pythia8 jobs...
Pythia8 shower jobs: 1 Idle, 9 Running, 0 Done [5 seconds]