set parton masses to zero (shower=OFF)

Dear Lorena,
thank you for your feedback.

The mass values assigned to quarks and gluons are the default ones used by the shower
(for example, Herwig6 uses a non zero constituent gluon mass), hence we write these values
in the LH event files in order for the shower to go smooth. These numerical values can be
changed by editing the files MCmasses_XXX.inc (with XXX = the name of the shower).
Since these are include files, you have to edit them and then remove all the object files
before the run.
The operation of setting the MC parton masses to zero is technically fine, however let me
draw your attention on two very important points.
a) The MC@NLO NLO LH files (contrarily to the Madgraph LO ones) are meaningless (i.e.
unphysical) if not showered; in other words you cannot make physical plots out of the
un-showered LH MC@NLO NLO files.
b) If you shower with 0 masses the Monte Carlo could crash (for example this will happen
if you use a null gluon mass in Herwig6).

For the 5F scheme problem: what are the exact operations you did, and what error did you
get?

Cheers.
Paolo

Hi Paolo

Thanks a lot. It worked... i tried this already but forgot to remove the object files (ups), now it works!

For the 5F scheme:
I launch aMC@NLO then i redefine the proton and jets to include also the b quark

>define p = g u c d s u~ c~ d~ s~ b b~
>define j = g u c d s u~ c~ d~ s~ b b~

then I generate the process

>generate p p > Z QED=2 QCD=2 [all=QCD] QCD=6
> output TEST
>launch

(with settings
order=NLO
fixed_order=OFF
shower=OFF
 madspin=OFF)

then an error is produced :

Error detected in "launch auto "write debug file /MG5_aMC_v2_0_1/bin/TESTTEST/run_01_tag_1_debug.log
aMCatNLOError : An error occurred during the collection of results. Please check the .log files inside the directories which failed.

The debug.log file looks like this:

launch auto
Traceback (most recent call last):
File "/home/rothen/Software/aMC@NLO/MG5_aMC_v2_0_1/madgraph/interface/extended_cmd.py", line 841, in onecmd
    return self.onecmd_orig(line, **opt)
File "/home/rothen/Software/aMC@NLO/MG5_aMC_v2_0_1/madgraph/interface/extended_cmd.py", line 834, in onecmd_orig
    return func(arg, **opt)
File "/home/rothen/Software/aMC@NLO/MG5_aMC_v2_0_1/madgraph/interface/amcatnlo_run_interface.py", line 1031, in do_launch
    evt_file = self.run(mode, options)
File "/home/rothen/Software/aMC@NLO/MG5_aMC_v2_0_1/madgraph/interface/amcatnlo_run_interface.py", line 1363, in run
    self.cross_sect_dict = self.read_results(output, mode)
File "/home/rothen/Software/aMC@NLO/MG5_aMC_v2_0_1/madgraph/interface/amcatnlo_run_interface.py", line 1421, in read_results
    'Please check the .log files inside the directories which failed.')
aMCatNLOError: An error occurred during the collection of results.
Please check the .log files inside the directories which failed.
Value of current Options:
              text_editor : None
              web_browser : None
        cluster_temp_path : None
       group_subprocesses : False
                  timeout : 60
            cluster_queue : None
         madanalysis_path : None
                   lhapdf : lhapdf-config
ignore_six_quark_processes : False
                 mg5_path : /home/rothen/Software/aMC@NLO/MG5_aMC_v2_0_1
    loop_optimized_output : True
    cluster_status_update : (600, 30)
               hepmc_path : None
             pythia8_path : None
                hwpp_path : None
   automatic_html_opening : False
       cluster_retry_wait : 300
             stdout_level : 20
          pythia-pgs_path : None
                  td_path : None
             delphes_path : None
              thepeg_path : None
             cluster_type : condor
      exrootanalysis_path : None
         fortran_compiler : None
                      OLP : MadLoop
              auto_update : 7
         cluster_nb_retry : 1
               eps_viewer : None
             syscalc_path : None
                  fastjet : None
                    gauge : unitary
      complex_mass_scheme : False
                  nb_core : 8
                 run_mode : 2

Hi Lorena,
as for the 5F scheme, the problem you're experiencing should
be due to the mismatch between the b mass you assume in the
model you're using (SM with massive b by default), and the
masslessness that you implicitly assume when including the b
in the definition of proton (and jet).
What you have to do if you want a b in the proton is to import
the massless-b SM (by typing "import model sm-no_b_mass") before
generating the process.
The sequence 'import', 'define', 'generate', 'launch' should go
through. Let me know if this solves your issue.
Cheers.
Paolo

> For the 5F scheme:
> I launch aMC@NLO then i redefine the proton and jets to include also the b quark
>
>> define p = g u c d s u~ c~ d~ s~ b b~
>> define j = g u c d s u~ c~ d~ s~ b b~
>
> then I generate the process
>
>> generate p p > Z QED=2 QCD=2 [all=QCD] QCD=6
>> output TEST
>> launch
>
> (with settings
> order=NLO
> fixed_order=OFF
> shower=OFF
> madspin=OFF)
>
> then an error is produced :
>
> Error detected in "launch auto "write debug file /MG5_aMC_v2_0_1/bin/TESTTEST/run_01_tag_1_debug.log
> aMCatNLOError : An error occurred during the collection of results. Please check the .log files inside the directories which failed.
>
> The debug.log file looks like this:
>
> launch auto
> Traceback (most recent call last):
> File "/home/rothen/Software/aMC@NLO/MG5_aMC_v2_0_1/madgraph/interface/extended_cmd.py", line 841, in onecmd
> return self.onecmd_orig(line, **opt)
> File "/home/rothen/Software/aMC@NLO/MG5_aMC_v2_0_1/madgraph/interface/extended_cmd.py", line 834, in onecmd_orig
> return func(arg, **opt)
> File "/home/rothen/Software/aMC@NLO/MG5_aMC_v2_0_1/madgraph/interface/amcatnlo_run_interface.py", line 1031, in do_launch
> evt_file = self.run(mode, options)
> File "/home/rothen/Software/aMC@NLO/MG5_aMC_v2_0_1/madgraph/interface/amcatnlo_run_interface.py", line 1363, in run
> self.cross_sect_dict = self.read_results(output, mode)
> File "/home/rothen/Software/aMC@NLO/MG5_aMC_v2_0_1/madgraph/interface/amcatnlo_run_interface.py", line 1421, in read_results
> 'Please check the .log files inside the directories which failed.')
> aMCatNLOError: An error occurred during the collection of results.
> Please check the .log files inside the directories which failed.
> Value of current Options:
> text_editor : None
> web_browser : None
> cluster_temp_path : None
> group_subprocesses : False
> timeout : 60
> cluster_queue : None
> madanalysis_path : None
> lhapdf : lhapdf-config
> ignore_six_quark_processes : False
> mg5_path : /home/rothen/Software/aMC@NLO/MG5_aMC_v2_0_1
> loop_optimized_output : True
> cluster_status_update : (600, 30)
> hepmc_path : None
> pythia8_path : None
> hwpp_path : None
> automatic_html_opening : False
> cluster_retry_wait : 300
> stdout_level : 20
> pythia-pgs_path : None
> td_path : None
> delphes_path : None
> thepeg_path : None
> cluster_type : condor
> exrootanalysis_path : None
> fortran_compiler : None
> OLP : MadLoop
> auto_update : 7
> cluster_nb_retry : 1
> eps_viewer : None
> syscalc_path : None
> fastjet : None
> gauge : unitary
> complex_mass_scheme : False
> nb_core : 8
> run_mode : 2
>
> --
> You received this question notification because you are a direct
> subscriber of the question.

hi Paolo

Thanks a lot, now everything works!

Thanks
Lorena