How to set decay width of particle in mg5 script

Asked by satendra kumar on 2018-01-16

Dear All,

Please let me know how to set decay width of particle in mg5 script. For example decay width of the Higgs, I set it as "set wh auto", but it is not working. The whole script is as follows:

import model SM_TauTau_v1_UFO
add model taudecay_UFO
define p = g u c d s u~ c~ d~ s~
define j = g u c d s u~ c~ d~ s~
define p = g u d s c u~ d~ s~ c~
define PP = u d u~ d~
define j = u d u~ d~
define JJ = u d u~ d~
define l+ = e+ mu+
define l- = e- mu-
define vl = ve vm vt
define vl~ = ve~ vm~ vt~
generate p e- > e- j h $$ a, (h > ta+ ta-)
output Pe2tautau_ZFusion_PYTHIA_Zetatt_p25
launch
#launch -i
#multi_run 2
shower=PYTHIA8
done
set zetatt 0.25
#set smkey 0
set wh auto
set nevents 100000
set lpp1 1
set lpp2 0
set ebeam1 7000
set ebeam2 60
set cut_decays T
set ptj 10.0
set ptb 10.0
set etaj 5.0
set etab 5.0
set etal 5.0
done

Question information

Language:
English Edit question
Status:
Solved
For:
MadGraph5_aMC@NLO Edit question
Assignee:
No assignee Edit question
Solved by:
Olivier Mattelaer
Solved:
2018-01-17
Last query:
2018-01-17
Last reply:
2018-01-17

Hi,

The "set wh auto" is actually dependent on the model since each model builder can decide to name the width of the Higgs by another variable. The method which is model independent is:
set decay 25 auto
(since 25 is the official pdg number for the Higgs)

Cheers,

Olivier

"set decay 25 auto" is not working. It made changes in param card as follows:

###################################
## INFORMATION FOR DECAY
###################################
DECAY 6 1.508336e+00 # wt
DECAY 15 2.265000e-12 # wta
DECAY 23 2.495200e+00 # wz
DECAY 24 2.085000e+00 # ww
DECAY 25 Auto # wh
DECAY 1 0.000000e+00 # d : 0.0
DECAY 2 0.000000e+00 # u : 0.0
DECAY 3 0.000000e+00 # s : 0.0
DECAY 4 0.000000e+00 # c : 0.0
DECAY 5 0.000000e+00 # b : 0.0
DECAY 11 0.000000e+00 # e- : 0.0
DECAY 12 0.000000e+00 # ve : 0.0
DECAY 13 0.000000e+00 # mu- : 0.0
DECAY 14 0.000000e+00 # vm : 0.0
DECAY 16 0.000000e+00 # vt : 0.0
DECAY 21 0.000000e+00 # g : 0.0
DECAY 22 0.000000e+00 # a : 0.0
DECAY 111 0.000000e+00 # pi0 : 0.0
DECAY 211 0.000000e+00 # pi+ : 0.0
###################################

Hi,

Yes that I was expecting, this will trigger the code to automatically compute that width.

Cheers,

Olivier

Unfortunately it does not work, It stopped by showing the following text in ME5_debug file

#************************************************************
#* MadGraph5_aMC@NLO/MadEvent *
#* *
#* * * *
#* * * * * *
#* * * * * 5 * * * * *
#* * * * * *
#* * * *
#* *
#* *
#* VERSION 2.6.0 2017-08-16 *
#* *
#* The MadGraph5_aMC@NLO Development Team - Find us at *
#* https://server06.fynu.ucl.ac.be/projects/madgraph *
#* *
#************************************************************
#* *
#* Command File for MadEvent *
#* *
#* run as ./bin/madevent.py filename *
#* *
#************************************************************
generate_events run_01
Traceback (most recent call last):
  File "/opt/baradwaj_grp_sw/satendrak/ROOT/softwares/MG5_aMC_v2_6_0/madgraph/interface/extended_cmd.py", line 1438, in onecmd
    return self.onecmd_orig(line, **opt)
  File "/opt/baradwaj_grp_sw/satendrak/ROOT/softwares/MG5_aMC_v2_6_0/madgraph/interface/extended_cmd.py", line 1392, in onecmd_orig
    return func(arg, **opt)
  File "/opt/baradwaj_grp_sw/satendrak/ROOT/softwares/MG5_aMC_v2_6_0/madgraph/interface/madevent_interface.py", line 2122, in do_generate_events
    postcmd=False)
  File "/opt/baradwaj_grp_sw/satendrak/ROOT/softwares/MG5_aMC_v2_6_0/madgraph/interface/extended_cmd.py", line 1465, in exec_cmd
    stop = Cmd.onecmd_orig(current_interface, line, **opt)
  File "/opt/baradwaj_grp_sw/satendrak/ROOT/softwares/MG5_aMC_v2_6_0/madgraph/interface/extended_cmd.py", line 1392, in onecmd_orig
    return func(arg, **opt)
  File "/opt/baradwaj_grp_sw/satendrak/ROOT/softwares/MG5_aMC_v2_6_0/madgraph/interface/madevent_interface.py", line 2915, in do_survey
    self.configure_directory()
  File "/opt/baradwaj_grp_sw/satendrak/ROOT/softwares/MG5_aMC_v2_6_0/madgraph/interface/madevent_interface.py", line 5280, in configure_directory
    self.do_treatcards('')
  File "/opt/baradwaj_grp_sw/satendrak/ROOT/softwares/MG5_aMC_v2_6_0/madgraph/interface/madevent_interface.py", line 2646, in do_treatcards
    self.check_param_card(pjoin(self.me_dir, 'Cards','param_card.dat'))
  File "/opt/baradwaj_grp_sw/satendrak/ROOT/softwares/MG5_aMC_v2_6_0/madgraph/interface/common_run_interface.py", line 3147, in check_param_card
    self.do_compute_widths('%s %s' % (' '.join(pdg), path))
  File "/opt/baradwaj_grp_sw/satendrak/ROOT/softwares/MG5_aMC_v2_6_0/madgraph/interface/common_run_interface.py", line 2127, in do_compute_widths
    opts = self.check_compute_widths(args)
  File "/opt/baradwaj_grp_sw/satendrak/ROOT/softwares/MG5_aMC_v2_6_0/madgraph/interface/common_run_interface.py", line 235, in check_compute_widths
    restrict=True, complex_mass_scheme=force_CMS)
  File "/opt/baradwaj_grp_sw/satendrak/ROOT/softwares/MG5_aMC_v2_6_0/models/import_ufo.py", line 96, in import_model
    model_path = find_ufo_path(model_name)
  File "/opt/baradwaj_grp_sw/satendrak/ROOT/softwares/MG5_aMC_v2_6_0/models/import_ufo.py", line 85, in find_ufo_path
    raise UFOImportError("Path %s is not a valid pathname" % model_name)
UFOImportError: Path /opt/baradwaj_grp_sw/satendrak/ROOT/softwares/MG5_aMC_v2_\ is not a valid pathname
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